An Alkali-Metal Halide-Bridged Actinide Phosphinidiide Complex

Article Cite This: Inorg. Chem. XXXX, XXX, XXX−XXX

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An Alkali-Metal Halide-Bridged Actinide Phosphinidiide Complex Congcong Zhang,† Guohua Hou,† Guofu Zi,*,† Wanjian Ding,*,† and Marc D. Walter*,‡ †

Department of Chemistry, Beijing Normal University, Beijing 100875, China Institut für Anorganische und Analytische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany

‡

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S Supporting Information *

ABSTRACT: The salt metathesis reaction of the thorium methyl chloride complex [η5-1,3-(Me3C)2C5H3]2Th(Cl)Me (3) with 2,4,6-(Me3C)3C6H2PHK in benzene furnishes an alkali-metal halide-bridged phosphinidiide actinide metallocene, {[η5-1,3-(Me3C)2C5H3]2Th(P-2,4,6-tBu3C6H2)(ClK)}2 (4), whose structure and reactivity was investigated in detail. On the basis of density functional theory (DFT) studies, the 5f orbitals in the model complex [η 5 -1,3-(Me 3 C) 2 C 5 H 3 ] 2 Th(P2,4,6-tBu3C6H2) (4′) contribute significantly to the bonding of the phosphinidene ThP(2,4,6-tBu3C6H2) moiety. Furthermore, compared to the related thorium imido complex, the bonds between the [η5-1,3-(Me3C)3C5H2]2Th2+ and [P2,4,6-tBu3C6H2]2− fragments are more covalent. The reactivity of compound 4 toward alkynes and a variety of heterounsaturated molecules such as nitriles, isonitriles, carbodiimides, imines, isothiocyanates, aldehydes, ketones, thiazoles, quinolines, organic azides, pyridines, and imidazoles, forming metallacycles, phospholes, imidos, metallaheterocycles, sulfidos, oxidos, pinacolates, pseudophosphinimidos, and phosphidos, was comprehensively studied. Moreover, complex 4 reacts with elemental selenium and PhSSPh, yielding selenido and sulfido compounds, respectively. DFT computations were performed to complement these experimental investigations and to provide further insights.

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to those found for group 4 complexes.7 This motivated us to study actinide complexes with terminal metal−ligand multiple bonds and to explore their reactivity.8 In this context, the first base-free terminal thorium phosphinidene metallocene [η51,2,4-(Me3C)3C5H2]2ThP-2,4,6-tBu3C6H2 was accessed.9 This complex exhibits no reactivity toward alkynes, but it readily reacts with a variety of heterounsaturated molecules such as CS2, isothiocyanates, nitriles, isonitriles, and organic azides, forming carbodithioates, imido complexes, metallaaziridines, and azido compounds.9 Encouraged by these initial results, we have recently expanded our investigations from 1,2,4-(Me3C)3C5H2 to the less sterically encumbered 1,3di-tert-butylcyclopentadienyl ligand, 1,3-(Me3C)2C5H3, to probe the consequences of the reduced steric demand on the intrinsic reactivity of actinide phosphinidenes. In this contribution, the preparation, bonding, and structure− reactivity relationship of a new masked actinide phosphinidene metallocene, {[η5-1,3-(Me3C)2C5H3]2Th(P2,4,6-tBu3C6H2)(ClK)}2 (4), is presented. In addition, a comparison to the related imido (ThNR) complexes is included.

INTRODUCTION Metal-element (ME) multiple-bonded compounds, including terminal phosphinidene complexes (MP), have been an active research area for more than 2 decades.1−3 The interest in metal phosphinidenes originates not only from their high reactivity, which gives access to new phosphorus-containing molecules, organometallic derivatives, and new materials, but also from their potential in phosphorus-element bond synthesis and potentially useful catalytic applications.1−3 Overall, these investigations have been mainly focused on the synthesis and reactivity studies of phosphinidene complexes of the d-block transition metals,1−4 whereas the related terminal phosphinidene actinide complexes have been more or less ignored, which, however, leaves plenty of room to discover their intrinsic reactivity.5 An interesting actinide metal to start these investigations is thorium, which possesses a [Rn] 6d27s2 electronic ground state, and therefore reactivity similar to that of early transition metals might be anticipated, for which several complexes with MPR bonds are known.2 Nevertheless, small-molecule activation has been a highly topical area in actinide chemistry,6 and closely related to this is the influence and participation of the 6d and 5f orbitals in these transformations.7 It is apparent from these investigations that variations in the 5f orbital contribution can subtly modulate the bonding and reactivity of organothorium compounds, which also results in distinctively different reactivity compared © XXXX American Chemical Society

Received: November 1, 2018

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DOI: 10.1021/acs.inorgchem.8b03091 Inorg. Chem. XXXX, XXX, XXX−XXX

Article

Inorganic Chemistry

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RESULTS AND DISCUSSION S y n t h e s i s of { [ η 5 - 1 , 3 - ( M e 3 C ) 2 C 5 H 3 ] 2 T h (  P2,4,6-tBu3C6H2)(ClK)}2 (4). The thorium methyl chloride metallocene, [η5-1,3-(Me3C)2C5H3]2Th(Cl)Me (3), is accessible in a yield of 86% from the reaction of [η5-1,3(Me 3 C) 2 C 5 H 3 ] 2 ThCl 2 (1) with 1 equiv of [η 5 -1,3(Me3C)2C5H3]2ThMe2 (2) in benzene (Scheme 1). The

selected bond distances and angles. The Th−Cl distance is 2.809(1) Å, which is elongated compared to those observed for 1 [2.643(1) and 2.622(1) Å].8d The Th−P distance of 2.560(1) Å is short, and the Th−P−C27 angle of 162.6(2)° is nearly linear. Both features are consistent with the description of a ThP double bond.10 The Th−P distance [2.560(1) Å] may also be put in the context of related distances found in [η5-1,2,4-(Me3C)3C5H2]2ThP-2,4,6-tBu3C6H2 [2.536(2) Å ], 9 [( i Pr 3 SiNCH 2 CH 2 ) 3 NT hPH][Na(12-c-4) 2 ] [2.7584(18) Å],5e {[(η5-C5Me5)2Th(P-2,4,6-iPr3C6H2)(PH-2,4,6- i Pr 3 C 6 H 2 )]K} 2 [2.6957(10) Å], 5g and [(η 5 C 5 Me 5 ) 2 Th(P-2,4,6- i Pr 3 C 6 H 2 )(PH-2,4,6- i Pr 3 C 6 H 2 )][K(2,2,2-cryptand)] [2.6024(9) Å].5g The addition of 18-crown6 to a benzene solution of 4 yields a monomeric terminal thorium phosphinidene, [η5-1,3-(Me3C) 2C5H3]2Th(P2,4,6-tBu3C6H2)[ClK(18-c-6)] (5), in 92% yield, but [K(18c-6)Cl] remains coordinated to stabilize the complex (Scheme 1). An ORTEP of 5 is presented in Figure 2, while relevant bond distances and angles are provided in Table 1. The Th−Cl and Th−P distances of 2.740(1) and 2.582(1) Å, respectively, as well as the Th−P−C27 angle of 171.3(1)°, are very similar to that established for 4 (Table 1). Although the base-free terminal thorium phosphinidene, [η5-1,3-(Me3C)2C5H3]2Th P-2,4,6-tBu3C6H2 (4′), cannot be isolated, it might be accessed as a reactive intermediate after KCl dissociation from 4 in the presence of suitable small molecules. Hence, compound 4 may be considered to be a masked synthon for the terminal phosphinidene thorium metallocene 4′. Bonding Studies. Density functional theory (DFT) computations were conducted at the B3PW91 level of theory on the model complex 4′, in which the [2,4,6-(Me3C)3C6H2P] fragment coordinates to the [η5-1,3-(Me3C)2C5H3]2Th moiety with one Th−P σ bond and two Th−P π bonds, as depicted in Figure 3. As inferred from a natural bond orbital (NBO) analysis, a NBO charge of +1.023 is found on the thorium atom, whereas negative charges of −0.247 and −0.294 are located on the two 1,3-(Me3C)2C5H3 ligands, so that a total positive charge of +0.482 results for the [1,3(Me3C)2C5H3]2Th fragment. The phosphidene fragment carries a negative NBO charge of −0.482, which is divided into −0.179 on the phosphorus atom and −0.303 on the 2,4,6(Me3C)3C6H2 group. NBO analysis also reveals that the σ bond is comprised of a phosphorus hybrid orbital (78.9%; 76.5% 3s and 23.5% 3p) and a thorium hybrid orbital (21.1%; 16.1% 5f and 65.3% 6d). A pure 3p phosphorus-based orbital (74.2%) and a thorium hybrid orbital (25.8%; 66.6% 6d and 31.1% 5f) constitute one of the Th−P π bonds (π1), whereas the other Th−P π bond (π2) is formed by a pure 3p phosphorus-based orbital (69.6%) and a thorium hybrid orbital (30.4%; 76.5% 6d and 19.9% 5f). These computations also disclose that the bonding between the metallocene [1,3(Me3C)2C5H3]2Th2+ and [P{2,4,6-(Me3C)3C6H2}]2− moieties is significantly modulated by the thorium 5f and 6d orbitals. This allows for an efficient transfer of the electron density from the π orbitals of the [2,4,6-(Me3C)3C6H2P] fragment to the electron-deficient and Lewis-acidic thorium atom. These computations are in agreement with our previous observations of enhanced covalence in the bonding between the [Cp2Th]2+ and [PR]2− fragments compared to that in the related thorium imido complex.9 This is also reflected in an increase in the Wiberg bond order for the ThP moiety (2.055) relative to that computed for the ThN moiety in [1,2,4(Me3C)3C5H2]2ThN(p-tolyl) (0.92).8e

Scheme 1. Synthesis of Complexes 4 and 5

further treatment of 3 with 1 equiv of 2,4,6-(Me3C)3C6H2PHK in benzene affords the potassium chloride bridged phosphinidiide thorium complex 4 in 78% yield (Scheme 1). Complex 4 readily dissolves in benzene, from which it can be recrystallized. For its characterization, various spectroscopic techniques, elemental analysis, and single-crystal X-ray diffraction were employed. The singlet at 108.8 ppm in the 31P{1H} NMR spectrum of 4 corresponds to the phosphinidiide ligand.5e,g,9 An ORTEP of 4 is depicted in Figure 1, while Table 1 lists

Figure 1. ORTEP of 4 (thermal ellipsoids drawn at the 35% probability level). B


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Inorganic Chemistry Table 1. Selected Bond Distances (Å) and Angles (deg) for Compounds 4−7, 9−16, and 18−25a compound

C(Cp)−Thb

C(Cp)−Thc

Cp(cent)−Thb

4 5 6a 7 9 10 11 12 13 14 15 16 18 19 20 21 22 23 24 25

2.855(5) 2.850(4) 2.843(4) 2.819(3) 2.843(5) 2.860(4) 2.86(3) 2.859(5) 2.844(9) 2.833(5) 2.887(15) 2.860(3) 2.802(3) 2.833(3) 2.830(3) 2.840(4) 2.834(4) 2.813(7) 2.840(13) 2.805(4)

2.788(5)−2.907(5) 2.767(4)−2.903(4) 2.755(4)−2.933(4) 2.744(3)−2.875(3) 2.769(5)−2.922(5) 2.776(4)−2.968(4) 2.71(2)−3.00(2) 2.759(4)−2.985(5) 2.781(10)−2.948(10) 2.771(5)−2.869(5) 2.800(15)−2.958(14) 2.811(3)−2.930(3) 2.737(3)−2.877(3) 2.764(3)−2.915(3) 2.763(3)−2.883(2) 2.791(4)−2.906(4) 2.761(4)−2.897(4) 2.748(7)−2.871(7) 2.782(12)−2.890(13) 2.749(4)−2.872(4)

2.589(5) 2.583(4) 2.575(4) 2.550(3) 2.576(5) 2.593(4) 2.60(2) 2.596(5) 2.576(9) 2.565(5) 2.621(15) 2.593(3) 2.552(3) 2.566(3) 2.562(3) 2.572(4) 2.566(4) 2.541(7) 2.623(13) 2.532(4)

Th−X P1 2.560(1), Cl1 2.809(1) P1 2.582(1), Cl1 2.740(1) P1 2.665(1), C47 2.382(3) C35 2.460(3), C42 2.480(3) N1 2.136(4), Cl1 2.788(1) N1 2.262(4), P1 2.771(1) N1 2.307(19), N2 2.311(17) N1 2.295(3), N2 2.318(4) N1 2.260(8), N2 2.302(8) S1 2.668(1), S1A 2.668(1) O1 2.135(9), O1A 2.195(8) O1 2.175(2), O2 2.164(2) N1 2.351(2), S1 2.715(1) C27 2.455(4), N1 2.436(3) P1 C27 2.431(2), N1 2.454(2) P1 C27 2.434(4), N1 2.480(4) P1 C27 2.441(4), N1 2.439(4) P1 N1 2.247(6), Cl1 2.698(3) Se1 2.827(2), Se2 2.822(2) S1 2.757(1), S2 2.733(1)

2.917(1) 2.975(2) 3.023(2) 2.981(2)

Cp(cent)−Th−Cp(cent)

X−Th−X/Y

123.0(1) 121.5(1) 121.9(1) 130.8(1) 123.4(1) 134.4(1) 119.8(6) 118.6(1) 127.0(3) 128.9(1) 125.1(4) 116.1(1) 119.8(1) 139.0(1) 138.0(7) 124.2(1) 131.4(1) 126.4(2) 130.3(1) 127.6(1)

89.9(1) 99.4(1) 70.8(1) 77.0(1) 94.4(1) 77.2(1) 59.3(6) 59.5(1) 61.7(3) 84.4(1) 73.9(4) 68.3(1) 76.8(1) 32.0(1)d 32.2(7)d 31.6(1)d 31.4(1)d 98.3(2) 83.3(1) 114.2(1)

a

Cp = cyclopentadienyl ring. bAverage value. cRange. dAngle of C27−Th−N1.

and the internal alkyne PhCCMe to produce a mixture of [2 + 2] addition products [η 5 -1,3-(Me 3 C) 2 C 5 H 3 ] 2 Th[P(2,4,6-tBu3C6H2)CMeCPh] (6a) and [η5-1,3(Me3C)2C5H3]2Th[P(2,4,6-tBu3C6H2)CPhCMe] (6b) in 75% yield (Scheme 2). The reactivity difference between Scheme 2. Synthesis of Complexes 6a and 6b

Figure 2. ORTEP of 5 (thermal ellipsoids drawn at the 35% probability level).

[η5-1,2,4-(Me3C)3C5H2]2ThP-2,4,6-tBu3C6H29 and 4 can presumably be traced to the more open coordination sphere between the [η5-1,3-(Me3C)2C5H3]2Th fragment and the incoming alkyne. The presence of the two isomers 6a and 6b in C6D6 solution in a ratio of 4:1 can be confirmed by 1H NMR spectroscopy, but, unfortunately, this mixture cannot be converted to a single isomer upon heating of the reaction mixture to 100 °C. The steric repulsion between the incoming alkyne and the ThP-2,4,6-tBu3C6H2 fragment determines the selectivity of this reaction. Computational studies reveal that the formation of 6a is energetically more favorable [ΔG(298 K) = −12.6 kcal/mol] than that of 6b [ΔG(298 K) = −6.1 kcal/mol] and the formation of 6a also proceeds with a slightly

Figure 3. Plots of the highest occupied molecular orbitals for 4′ (the hydrogen atoms have been omitted for clarity).

Reactivity Studies. The reactivity of 4 toward unsaturated organic substrates was evaluated. For example, in contrast to the thorium phosphinidene [η5-1,2,4-(Me3C)3C5H2]2ThP2,4,6-tBu3C6H2,9 a clean reaction occurs between complex 4 C


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Inorganic Chemistry lower reaction barrier of ΔG⧧(298 K) = 19.5 kcal/mol (Figure 4), which agrees with our experimental findings. The molecular

Scheme 3. Synthesis of Complex 7

Figure 4. Energy profile (kcal/mol) for the reaction of 4′ + PhC CMe (computed at T = 298 K). [Th] = [η5-1,3-(Me3C)2C5H3]2Th. Ar = 2,4,6-tBu3C6H2.

to yield an eight-membered metallaheterocycle, which further converts via [1,5]-Th migration to afford a four-membered metallaheterocycle. Finally, this four-membered intermediate converts via an intramolecular nucleophilic attack to give 7 (Scheme 3). DFT studies suggest that the formation of 8b is energetically more favorable [ΔG(298 K) = −16.3 kcal/mol] than that of 8a [ΔG(298 K) = −11.2 kcal/mol] and the formation of 8b also takes place with the lower barrier ΔG⧧(298 K) = 21.0 kcal/mol; for details, see Figures 6 and S1.

Figure 5. Molecular structure of 6a (thermal ellipsoids drawn at the 35% probability level).

structure of 6a is shown in Figure 5, and selected bond distances and angles can be found in Table 1. The Th−C47 distance is 2.382(3) Å, whereas the Th−P distance is 2.665(1) Å, and the angle of C47−Th−P is 70.8(1)°. Nevertheless, the treatment of 4 with PhCCCCPh does not form a mixture of isomers; instead, a phospholyl complex, [η5-1,3(Me3C)2C5H3]2Th[1-(2,4,6-tBu3C6H2)-2-C6H4-5-PhC4HP] (7), is isolated in 82% yield (Scheme 3). We propose that, in analogy to the reaction of 4 with PhCCMe (Scheme 2), PhCC−CCPh initially reacts with 4 in a [2 + 2] cycloaddition to yield two isomers of four-membered thorium metallaheterocycles 8a or 8b along with KCl loss (Scheme 3). Furthermore, 8a can be converted to 8b via [1,3]-P migration followed by [1,3]-Th migration. In the next step, 8b participates in a C−H bond activation of the phenyl group

Figure 6. Energy profile (kcal/mol) for the reaction of 4′ + Ph2C4 (computed at T = 298 K). [Th] = [η5-1,3-(Me3C)2C5H3]2Th. Ar = 2,4,6-tBu3C6H2.

Moreover, the conversion of 8a to 8b proceeds via two transition states (TS7b′ and TS7c′) with an overall reaction barrier of ΔG⧧(298 K) = 43.1 kcal/mol (Figure S1), which cannot be overcome at ambient temperature. Nevertheless, when 8b is formed, it converts via C−H bond activation of the phenyl group to INT7a, which further converts via [1,3]-Th migration to INT7b. While INT7b is energetically downhill D


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Inorganic Chemistry from 4′ + Ph2C4 with ΔG(298 K) = −18.6 kcal/mol, the final product 7, which is formed by an intramolecular nucleophilic attack, is more stable [ΔG(298 K) = −42.3 kcal/mol] and the activation barrier of ΔG⧧(298 K) = 14.8 kcal/mol can readily be overcome (Figure 6). Figure 7 depicts the ORTEP of 7, and

Figure 7. Molecular structure of 7 (thermal ellipsoids drawn at the 35% probability level).


{(η 5 -C 5 Me 5 ) 2 Th[P(H)Mes][NC( t Bu)P(Mes)]}[K-2,2,2cryptand] [2.106(5) Å],11 which agrees with a ThN double bond.8−10 Nevertheless, contrary to the reactivity of the thorium phosphinidene complexes [η5-1,2,4(Me3C)3C5H2]2ThP-2,4,6-tBu3C6H2 toward organic isonitriles,9 the five-membered thorium metallaheterocycle [η5-1,3(Me 3 C) 2 C 5 H 3 ][η 5 -κP,κN-1-Me 2 C{CH 2 C(NC 6 H 11 )C(NHC6H11)(P-2,4,6-tBu3C6H2)}-3-(Me3C)C5H3]Th (10) is isolated from the reaction of complex 4 with C6H11NC in 82% yield (Scheme 5). We suggest that one molecule of

the interested reader may refer to Table 1 for selected bond distances and angles. The Th−C35 and Th−C42 distances are very similar to 2.460(3) and 2.480(3) Å, respectively, while the angle of C35−Th−C42 is found to be 77.0(1)°. Moreover, complex 4 reacts readily with heterounsaturated organic substrates. For example, analogous to the reactivity of the phosphinidene complexes [η5-1,2,4-(Me3C)3C5H2]2Th P-2,4,6-tBu3C6H2 toward organic nitriles,9 a [2 + 2] cycloaddition reaction of complex 4 with PhCN, followed by rearrangement to form the dimeric imido compound {[η5-1,3(Me3C)2C5H3]2Th[NC(Ph)(P-2,4,6-tBu3C6H2)](ClK)}2 (9) at room temperature in 88% yield with KCl retention (Scheme 4). The molecular structure of 9 is shown in Figure 8, and selected bond distances and angles are provided in Table 1. The Th−Cl distance is 2.788(1) Å and therefore comparable to those found in 4 and 5 (Table 1). The short Th−N distance of 2.136(4) Å is comparable to that found in



C6H11NC initially reacts with 4 via [2 + 1] cycloaddition accompanied by KCl loss to give a three-membered metallaheterocycle, which forms with a second molecule of C6H11NC, a four-membered metallaheterocycle that further converts in a C−H bond activation to finally furnish complex 10 (Scheme 5). The molecular structure of 10 is depicted in Figure 9, whereas selected bond distances and angles are listed in Table 1. The distance of Th−N is 2.262(4) Å, whereas the distance of Th−P is 2.771(1) Å. E


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Inorganic Chemistry


Scheme 7. Synthesis of Complex 13 Figure 9. Molecular structure of 10 (thermal ellipsoids drawn at the 35% probability level).

Moreover, the treatment of 4 with carbodiimides (RN)2C gives four-membered thorium metallaheterocycles [η5-1,3(Me3C)2C5H3]2Th[N(R)C(P-2,4,6-tBu3C6H2)N(R)] [R = C6H11 (11), iPr (12)] in 85% and 78% yields, respectively (Scheme 6). We propose that (RN)2C initially reacts with 4 Scheme 6. Synthesis of Complexes 11 and 12

is reasonable to assume that a four-membered metallaheterocycle is initially formed when one molecule of PhNCHPh reacts with 4 in a [2 + 2] cycloaddition, and in a second step, this metallaheterocycle eliminates PhCHP-2,4,6-tBu3C6H2 to yield the imido intermediate [η5-1,3-(Me3C)2C5H3]2Th NPh. Nevertheless, the imido intermediate can further spontaneously react with a second molecule of PhNCHPh to furnish complex 13 (Scheme 7). To support this mechanistic scenario, DFT computations were performed: As proposed, complex 4′ initially participates in a [2 + 2] cycloaddition with PhNCHPh to give the heterocyclic intermediate INT13a, from which the imido INT13b and PhCHP-2,4,6-tBu3C6H2 emerge. This thermodynamically driven degradation to INT13b from 4′ + PhNCHPh [ΔG(298 K) = −23.7 kcal/mol] proceeds via two transition states (TS13a and TS13b) with a barrier of ΔG⧧(298 K) = 24.2 kcal/mol (Figure 11). Nevertheless, the following reaction of INT13b with another molecule of PhNCHPh to yield 13 is exergonic [ΔG(298 K) = −31.5 kcal/ mol] and proceeds with a low barrier [ΔG⧧(298 K) = 15.0 kcal/mol]. The overall reaction profile is in line with our experimental findings and the fact that complex 13 is formed at room temperature. Figure 12 shows the ORTEP of 13, while relevant bond distances and angles are presented in Table 1. The Th−N distances are 2.260(8) and 2.302(8) Å, and they are in the same range as those in 11 and 12 (Table 1). M o r e o v e r , a d i m e r i c s u lfi do comp l e x { [ η 5 - 1 , 3 (Me3C)2C5H3]2Th}2(μ-S)2 (14) is isolated from the reaction

via a [2 + 2] cycloaddition, which induces KCl loss and yields a four-membered thorium metallaheterocycle that converts to 11 and 12 by [1,3]-Th migration (Scheme 6). Full characterization of complexes 11 and 12 was accomplished by several spectroscopic techniques, elemental analysis, and also singlecrystal X-ray diffraction. The 13C{1H} NMR spectra of 11 and 12 feature a doublet at δ = 178.5 and 152.1 ppm, respectively, corresponding to the carbon atom of the PC moiety. The molecular structure of 11 is shown in Figure 10, whereas the structure of 12 is provided in the Supporting Information. The Th−N distances are 2.311(17) and 2.307(19) Å for 11, which can be compared to those established for 12 [2.295(3) and 2.318(4) Å]. In contrast, the four-membered thorium metallaheterocycle [η 5 -1,3-(Me 3 C) 2 C 5 H 3 ] 2 Th[N(Ph)C(=NPh)N(Ph)] (13) is isolated when complex 4 is exposed to PhNCHPh at ambient temperature in 82% yield. The addition of various quantities of PhNCHPh to the reaction mixture has no effect on the product formation (Scheme 7). It F


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Inorganic Chemistry Scheme 8. Synthesis of Complex 14

Figure 11. Energy profile (kcal/mol) for the reaction of 4′ + PhNCHPh + PhNCHPh (computed at T = 298 K). [Th] = [η5-1,3(Me3C)2C5H3]2Th. Ar = 2,4,6-tBu3C6H2.



of 4 with PhNCS in 75% yield (Scheme 8).12 The reaction may proceed in the following manner: initial formation of a four-membered metallaheterocycle as a result of a [2 + 2] cycloaddition between PhNCS and 4 concomitant with KCl loss followed by PhNCP-2,4,6-tBu3C6H2 elimination to yield the monomeric terminal sulfido intermediate [η 5 -1,3(Me3C)2C5H3]2ThS, which stabilizes itself by dimerization to form 14 (Scheme 8). Table 1 lists relevant bond angles and distances of 14, and its molecular structure is depicted in Figure 13. The Th−S distance of 2.668(1) Å can be related to those observed in {[η 5 -1,2,4-(Me 3 C) 3 C 5 H 2 ]2 Th} 2 (μ-S) 2 [2.713(2) Å and 2.726(2) Å].9 A similar cycloaddition− elimination reaction of 4 can be established for the reaction with p-tolylCHO, which initially yields a monomeric terminal oxido intermediate [η5-1,3-(Me3C)2C5H3]2ThO, which consequently forms the dimer {[η5-1,3(Me3C)2C5H3]2Th}2(μ-O)2 (15) in 78% yield (Scheme 9 and Figure 14). The Th−O distances are 2.135(9) and 2.195(8) Å (Table 1), which are in the same range as those


G


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Inorganic Chemistry established for {[η 5 -1,2,4-(Me 3 C) 3 C 5 H 2 ] 2 Th} 2 (μ-O) 2 [2.176(6) and 2.174(6) Å].8c

(Scheme 10). The average Th−O distance in complex 16 of 2.170(2) Å (Table 1 and Figure 15) may be compared to that found in [η5-1,2,4-(Me3C)3C5H2]2Th[(OCPh2)2] [2.182(2) Å].7j



Nevertheless, in the presence of suitable substrates, the phosphinidiide moiety can also be exchanged; e.g., when 4 is exposed to Ph 2 CO, the thorium pinacolate [η 5 -1,3(Me3C)2C5H3]2Th[(OCPh2)2] (16), the phosphaindane 3,3Me2-5,7-tBu2C8H5P (17), and KCl are formed (Scheme 10).

In contrast to the reactivity of the thorium imido (η5C5Me5)2ThN(mesityl)(DMAP) toward thiazole,8i no deprotonation occurs between 4 and thiazole; instead, a fivemembered metallaheterocycle [η5-1,3-(Me3C)2C5H3]2Th[SCHCHN(CHP-2,4,6-tBu3C6H2)] (18) is formed in 85% yield (Scheme 11). We propose that the thiazole initially



Variations of the amount of Ph2CO do not alter the product formation. This reaction outcome can be rationalized by an initial coordination of one molecule of Ph2CO to 4, which induces KCl loss, but because of the two bulky phenyl substituents, the carbon atom of the CO group can no longer be attacked by the P atom of the phosphinidene moiety. This contrasts the reactivity of 4 with that of p-tolylCHO (vide supra). Consequently, Ph2CO substitutes the phosphinidene moiety to establish a metal η2-ketone intermediate,7j which immediately attacks a second molecule of Ph2CO to furnish 16 (Scheme 10). The phosphaindane 17 is formed by C−H bond activation within the unstable phosphinidene 2,4,6-tBu3C6H2P

reacts with 4 in a [2 + 2] cycloaddition to give KCl and a fourmembered metallaheterocycle, which then converts via C−S cleavage to a zwitterionic intermediate and spontaneously forms 18 (Scheme 11). DFT studies reveal that thiazole initially coordinates to 4′ to give the intermediate COM18. In the next step, the thiazole reacts with the thorium phosphinidene moiety of COM18 via the concerted [2 + 2] transition state TS18a to yield the four-membered heterocyclic complex INT18a (Figure 16). However, this intermediate rearranges to a η4-thiazole-coordinated complex INT18b, which further participates in a C−S bond cleavage reaction H


Article

Inorganic Chemistry Scheme 12. Synthesis of Complexes 19−22

Figure 16. Energy profile (kcal/mol) for the reaction of 4′ + C3H3NS (computed at T = 298 K). [Th] = [η5-1,3-(Me3C)2C5H3]2Th. Ar = 2,4,6-tBu3C6H2.

18, whereas the structures of 20-22 are provided in the Supporting Information. The Th−N distances are 2.436(3) Å

to spontaneously form 18. The transformation from COM18 to 18 proceeds via two intermediates (INT18a and INT18b) and three transition states (TS18a, TS18b, and TS18c). Furthermore, the formation of 18 is energetically favorable [ΔG(298 K) = −49.2 kcal/mol] with an overall reaction barrier of ΔG⧧(298 K) = 26.4 kcal/mol (relative to COM18), which agrees with the experimentally observed formation of 18 at ambient temperature. The molecular structure of 18 is shown in Figure 17, and selected bond distances and angles are


for 19, 2.454(2) Å for 20, 2.480(4) Å for 21, and 2.439(4) Å for 22, the Th−C distances are 2.455(4) Å for 19, 2.431(2) Å for 20, 2.434(4) Å for 21, and 2.441(4) Å for 22, and the Th− P distances are 2.917(1) Å for 19, 2.975(2) Å for 20, 3.023(2) Å for 21, and 2.981(2) Å for 22. We previously extensively investigated the reactivity of the thorium imido [η5-1,2,4-(Me3C)3C5H2]2ThN(p-tolyl) toward organic azides,8f but a different reaction outcome is now observed for 4 when it is exposed to Ph3CN3 at room temperature. Surprisingly, no five-membered thorium metallacycle is isolated; instead, the thorium pseudophosphinimido9 chloride complex [η 5 -1,3-(Me 3 C) 2 C 5 H 3 ] 2 Th(N = P2,4,6-tBu3C6H2)(Cl) (23) is formed in 78% yield besides Gomberg’s dimer Ph3CCH(C2H2)2CCPh2 (Scheme 13). Analogous to the reactivity of the thorium phosphinidene [η51,2,4-(Me3C)3C5H2]2ThP-2,4,6-tBu3C6H2 toward Ph3CN3,9 complex 4 may initially participate in a [2 + 1] cycloaddition with one molecule of Ph3CN3 to give a three-membered


listed in Table 1. The Th−S distance is 2.715(1) Å, whereas the Th−N distance is 2.351(2) Å. Nevertheless, when 1methylimidazole, 4-(dimethyamino)pyridine (DMAP), quinoline, and isoquinoline are used as substrates, analogous to the reactivity of the thorium imido complexes,8i the phosphido complexes [η5-1,3-(Me3C)2C5H3]2Th(PH-2,4,6-tBu3C6H2)[2(1-MeC 3 H 2 N 2 )] (19), [η 5 -1,3-(Me 3 C) 2 C 5 H 3 ] 2 Th(PH2,4,6- t Bu 3 C 6 H 2 )[2-(4-Me 2 N)C 5 H 3 )] (20), [η 5 -1,3(Me 3 C) 2 C5 H 3 ] 2 Th(PH-2,4,6- t Bu 3 C 6 H 2 )[2-(1-N-C 9 H 6 N)] (21), and [η5-1,3-(Me3C)2C5H3]2Th(PH-2,4,6-tBu3C6H2)[1(2-N-C9H6N)] (22) are formed in 92%, 82%, 95%, and 88% yields, respectively, as a result of deprotonation reactions (Scheme 12). The molecular structure of 19 is shown in Figure I


Article

Inorganic Chemistry Scheme 13. Synthesis of Complex 23



heterocyclic complex, subsequently converting to 23 and [Ph3CN2K] (Scheme 13). [Ph3CN2K] may then form KN3 and the diazene derivative Ph3CNNCPh3, when exposed to a second molecule of Ph3CN3. However, (Ph3CN)2 is also subjected to further degradation to yield Gomberg’s dimer Ph3CCH(C 2H2)2CCPh213 and N2 (Scheme 13). An alternative mechanism may be envisioned in which a fivemembered thorium metallacycle (A or B) initially forms in the reaction of Ph3CN3 with 4. However, the metallacyclic intermediate A or B spontaneously releases N2 to furnish a three-membered metallacycle, from which 23 and [Ph3CK] emerge (Scheme 13). [Ph3CK] can also participate in the reaction by attacking a second molecule of Ph3CN3 to yield KN 3 and Gomberg’s dimer Ph 3 CCH(C 2 H 2 ) 2 CCPh 2 (Scheme 13). Complex 23 was studied by several spectroscopic techniques, and a singlet at δ = 505.4 ppm attributed to the pseudophosphinimido ligand is found in its 31P{1H} NMR spectrum. Furthermore, 23 was structurally authenticated (Figure 19), and relevant bond distances and angles can be found in Table 1. The Th−Cl distance is 2.698(3) Å, which is in line with those established for 4 and 5, while the Th−N distance of 2.247(6) Å (Table 1) is essentially identical with that established for [η 5-1,2,4-(Me 3C)3 C5H2 ]2Th(NP2,4,6-tBu3C6H2)(N3) [2.273(9) Å].9 Moreover, compound 4 reacts with selenium (Se) to form the dimeric selenido complex {[η5-1,3-(Me3C)2C5H3]2Th}2(μSe)2 (24) and the diphosphene derivative (2,4,6-tBu3C6H2P)2 (Scheme 14), and 24 was isolated in 77% yield. A plausible reaction sequence can be postulated based on the reactivity of

the thorium imido [η5-1,2,4-(Me3C)3C5H2]2ThN(p-tolyl) toward Se;8g complex 4 initially converts with Se to lose KCl and yield a four-membered metallaheterocycle, which eliminates 2,4,6-tBu3C6H2PSe to form the monomeric selenido [η5-1,3-(Me3C)2C5H3]2ThSe, which further dimerizes to 24. However, the intermediate 2,4,6-tBu3C6H2PSe is unstable,14 and therefore it reacts with a second molecule of 4 to furnish a four-membered metallaheterocycle, followed by elimination of the diphosphene (2,4,6-tBu3C6H2P)2 to yield the monomeric thorium selenido species [η5-1,3-(Me3C)2C5H3]2ThSe, which then also dimerizes to 24 (Scheme 14). Figure 20 shows the ORTEP of 24, whereas relevant bond distances and J


Article

Inorganic Chemistry



angles are provided in Table 1. The Th−Se distances are 2.827(2) and 2.822(2) Å, while the angle of Se−Th−Se is 83.3(1)°. Nevertheless, phosphinidiide replacement occurs in the reaction of 4 with Ph2S2 to form the sulfido complex [η51,3-(Me3C)2C5H3]2Th(SPh)2 (25) in 91% yield and the phosphaindane 17 (Scheme 15). The latter is the result of C−

isothiocyanates, aldehydes, thiazoles, quinolines, pyridines, imidazoles, and elemental Se, resulting in metallacycles, phosphole derivatives, imidos, metallaheterocycles, sulfidos, oxidos, phosphidos, and selenidos. However, when the sterically encumbered benzophenone Ph2CO is used as the substrate, phosphinidene 2,4,6-tBu3C6H2P displacement occurs to form the metallaoxirane intermediate [η 5 -1,3(Me3C)2C5H3]2Th(η2-Ph2CO), which is too reactive to be observed spectroscopically, but it converts with a second molecule of Ph2CO to the thorium pinacolate 16. Furthermore, complex 4 participates in a rather elaborate reaction sequence with Ph3CN3 to yield the pseudophosphinimido 23 besides Gomberg’s dimer Ph3CCH(C2H2)2CCPh2, N2, and KN3. The replacement of the 1,2,4-tri-tert-butylcyclopentadienyl ligand by the less bulky 1,3-di-tert-butylcyclopentadienyl ligand also results in a distinctively different reactivity of 4 compared to that of [η5-1,2,4-(Me3C)3C5H2]2ThP-2,4,6-tBu3C6H2. For example, [η 5 -1,2,4-(Me 3 C) 3 C 5 H 2 ] 2 ThP-2,4,6- t Bu 3 C6 H 2 shows no reactivity toward alkynes,9 whereas [2 + 2] cycloaddition occurs for complex 4, which we attribute to the different steric demands of both ligands. Moreover, while monoinsertion of the isonitriles into the ThPR moiety of the phosphinidene thorium complex [η5-1,2,4(Me3C)3C5H2]2ThP-2,4,6-tBu3C6H2 cleanly affords the metallaaziridines,9 complex 4 reacts with cyclohexylisonitrile via double insertion followed by C−H bond activation to metallaheterocycle 10. Further studies on the intrinsic reactivity of the actinide phosphinidenes and phosphinidiides are ongoing and will be detailed in due course.


H bond activation within the released 2,4,6-tBu3C6H2P (Scheme 15). Compound 25 was successfully structurally characterized (Figure 21), and Table 1 provides the reader with selected bond distances and angles. The Th−S distances of 2.757(1) and 2.733(1) Å and the S−Th−S angle of 114.2(1)° are rather unremarkable.

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CONCLUSIONS In conclusion, a comprehensive survey of the reactivity patterns associated with an alkali-metal halide-masked terminal phosphinidene actinide metallocene 4 was conducted. The 5f orbitals contribute to the covalent bonding of the Th P(2,4,6-tBu3C6H2) moiety, as was inferred by DFT studies. This allows complex 4 to serve as a [η 5 -1,3(Me3C)2C5H3]2ThII synthon in the reaction with Ph2S2, which leads to the displacement of the coordinated phosphinidiide. Furthermore, complex 4 also exhibits a rich reactivity toward alkynes and a variety of heterounsaturated molecules such as nitriles, isonitriles, carbodiimides, imines,

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EXPERIMENTAL SECTION

General Procedures. All reactions and product manipulations were carried out under an atmosphere of dry dinitrogen with rigid exclusion of air and moisture using standard Schlenk or cannula techniques or in a glovebox. All organic solvents were freshly distilled from sodium benzophenone ketyl immediately prior to use. [η5-1,3(Me3C)2C5H3]2ThCl2 (1),8d [η5-1,3-(Me3C)2C5H3]2ThMe2 (2),8d 2,4,6-tBu3C6H2PH2,15 and 2,4,6-tBu3C6H2PHK16 were prepared according to literature methods. All other chemicals were purchased from Aldrich Chemical Co. and Beijing Chemical Co. and used as received unless otherwise noted. IR spectra were recorded in KBr K


Article

Inorganic Chemistry pellets on an Avatar 360 Fourier transform infrared spectrometer. 1H, 13 C{1H}, and 31P{1H} NMR spectra were recorded on a Bruker AV 400 spectrometer at 400, 100, and 162 MHz, respectively. All chemical shifts are reported in δ units with reference to the residual protons of the deuterated solvents, which served as internal standards, for proton and carbon chemical shifts, and to external 85% H3PO4 (0.00 ppm) for phosphorus chemical shifts. Melting points were measured on an X-6 melting point apparatus and were uncorrected. Elemental analyses were performed on a Vario EL elemental analyzer. Note: Natural thorium (primary isotope 232Th) is a weak α-emitter (4.012 MeV) with a half-life of 1.41 × 1010 years; manipulations and reactions should be carried out in monitored fume hoods or in an inert-atmosphere drybox in a laboratory equipped with α- and βcounting equipment. Preparation of [η5-1,3-(Me3C)2C5H3]2Th(Cl)Me (3). Method A. A benzene (15 mL) solution of 1 (658 mg, 1.0 mmol) was added to a benzene (10 mL) solution of 2 (617 mg, 1.0 mmol) with stirring at room temperature. After this solution was stirred at room temperature for 2 days, the solution was filtered. The volume of the filtrate was reduced to 10 mL, and colorless microcrystals of 3 were isolated after this solution was stored at room temperature for 2 days. Yield: 1096 mg (86%). Mp: 123−125 °C (dec). 1H NMR (C6D6): δ 6.59 (d, J = 2.0 Hz, 2H, ring CH), 6.07 (m, J = 8.0 Hz, 4H, ring CH), 1.36 (s, 18H, C(CH3)3), 1.30 (s, 18H, C(CH3)3), 0.80 (s, 3H, CH3). 13C{1H} NMR (C6D6): 149.2 (ring C), 149.1 (ring C), 116.6 (ring C), 111.1 (ring C), 110.2 (ring C), 62.0 (CH3), 33.3 (C(CH3)3), 33.1 (C(CH3)3), 31.9 (C(CH3)3), 31.8 (C(CH3)3). IR (KBr, cm−1): ν 2960 (s), 2904 (s), 2868 (s), 1464 (s), 1398 (s), 1259 (s), 1091 (s), 1020 (s), 798 (s). Anal. Calcd for C27H45ClTh: C, 50.90; H, 7.12. Found: C, 50.83; H, 7.19. Method B. NMR Scale. A C6D6 (0.3 mL) solution of 1 (6.6 mg, 0.01 mmol) was slowly added to a J. Young NMR tube charged with 2 (6.2 mg, 0.01 mmol) and C6D6 (0.2 mL). The resonances due to 3 were observed by 1H NMR spectroscopy (100% conversion) after this solution was stored at room temperature for 3 days. Preparation of 4·4C6H6. Solid 2,4,6-tBu3C6H2PHK (316 mg, 1.0 mmol) was slowly added to a benzene (20 mL) solution of 3 (637 mg, 1.0 mmol) with stirring at room temperature. After the solution was stirred at room temperature overnight, the solvent was removed. The residue was extracted with n-hexane (10 mL × 3) and filtered. The volume of the filtrate was reduced to 10 mL, and orange crystals of 4·4C6H6 were isolated when this solution was stored at room temperature for 2 days. Yield: 852 mg (78%). Mp: 123−125 °C (dec). 1H NMR (C6D6): δ 7.32 (s, 4H, phenyl), 7.15 (s, 24H, C6H6), 6.53 (s, 4H, ring CH), 6.50 (s, 4H, ring CH), 6.47 (s, 4H, ring CH), 2.00 (s, 36H, C(CH3)3), 1.68 (s, 36H, C(CH3)3), 1.64 (s, 36H, C(CH3)3), 1.26 (s, 18H, C(CH3)3). 13C{1H} NMR (C6D6): δ 153.1 (phenyl C), 149.0 (phenyl C), 146.9 (d, JP−C = 46.0 Hz, phenyl C), 142.4 (phenyl C), 128.0 (C6H6), 120.5 (ring C), 114.6 (ring C), 113.9 (ring C), 113.7 (ring C), 110.3 (ring C), 38.5 (C(CH3)3), 34.1 (C(CH3)3), 33.8 (C(CH3)3), 33.5 (C(CH3)3), 32.8 (C(CH3)3), 32.7 (C(CH3)3), 31.9 (C(CH3)3), 31.8 (C(CH3)3). 31P{1H} NMR (C6D6): δ 108.8. IR (KBr, cm−1): ν 2960 (s), 2902 (s), 2866 (s), 1595 (s), 1462 (s), 1390 (s), 1361 (s), 1249 (s), 1020 (s), 810 (s). Anal. Calcd for C112H166Cl2K2P2Th2: C, 61.49; H, 7.65. Found: C, 61.52; H, 7.61. Preparation of 5·C6H6. Method A. A benzene (10 mL) solution of 18-c-6 (53 mg, 0.2 mmol) was added to a benzene (10 mL) solution of 4 (188 mg, 0.1 mmol) with stirring at room temperature. After the solution was stirred at room temperature overnight, the solution was filtered. The volume of the filtrate was reduced to 10 mL, and orange crystals of 5·C6H6 were isolated when this solution was stored at room temperature for 2 days. Yield: 236 mg (92%). Mp: 148−150 °C (dec). 1H NMR (C6D6): δ 7.58 (s, 2H, phenyl), 7.15 (s, 6H, C6H6), 6.91 (m, 2H, ring CH), 6.62 (m, 2H, ring CH), 6.38 (m, 2H, ring CH), 3.13 (s, 24H, CH2), 2.30 (s, 18H, C(CH3)3), 1.77 (s, 18H, C(CH3)3), 1.69 (s, 18H, C(CH3)3), 1.44 (s, 9H, C(CH3)3). 13 C{1H} NMR (C6D6): δ 152.7 (phenyl C), 145.0 (phenyl C), 142.8 (phenyl C), 129.3 (ring C), 128.0 (C6H6), 119.8 (ring C), 115.1 (ring C), 111.7 (ring C), 111.1 (ring C), 69.9 (OCH2), 38.7 (C(CH3)3),

33.9 (C(CH3)3), 33.8 (C(CH3)3), 33.8 (C(CH3)3), 33.7 (C(CH3)3), 33.3 (C(CH3)3), 33.2 (C(CH3)3), 32.2 (C(CH3)3); the carbon atom of ThPC was not observed. 31P{1H} NMR (C6D6): δ 133.5. IR (KBr, cm−1): ν 2958 (s), 2897 (s), 2864 (s), 1402 (s), 1259 (s), 1107 (s), 1020 (s), 798 (s). Anal. Calcd for C62H101ClKO6PTh: C, 58.18; H, 7.95. Found: C, 58.15; H, 8.01. Method B. NMR Scale. A C6D6 (0.3 mL) solution of 18-c-6 (5.3 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 5 were observed by 1H NMR spectroscopy (100% conversion in 10 min). Preparation of [η5-1,3-(Me3C)2C5H3]2Th[P(2,4,6-tBu3C6H2)CMeCPh] (6a) and [η5-1,3-(Me3C)2C5H3]2Th[P(2,4,6-tBu3C6H2)CPhCMe] (6b). Method A. A toluene (10 mL) solution of PhCCMe (24 mg, 0.2 mmol) was added to a toluene (10 mL) solution of 4 (188 mg, 0.1 mmol) with stirring at room temperature. After the solution was stirred at room temperature overnight, the solvent was removed. The residue was extracted with nhexane (10 mL × 3) and filtered. The volume of the filtrate was reduced to 5 mL. After this solution was stored at room temperature for 1 week, orange microcrystals were isolated. Yield: 147 mg (75%). The NMR spectrum recorded in C6D6 showed the presence of two isomers in a 4:1 ratio. 6a. 1H NMR (C6D6): δ 7.64 (d, J = 2.2 Hz, 2H, phenyl), 7.31 (t, J = 7.6 Hz, 2H, phenyl), 7.05 (d, J = 7.4 Hz, 2H, phenyl), 6.96 (t, J = 7.6 Hz, 1H, phenyl), 6.58 (t, J = 2.7 Hz, 2H, ring CH), 6.48 (s, 2H, ring CH), 6.15 (t, J = 2.7 Hz, 2H, ring CH), 1.82 (s, 18H, C(CH3)3), 1.65 (d, J = 2.8 Hz, 3H, CH3), 1.45 (s, 18H, C(CH3)3), 1.39 (s, 18H, C(CH3)3), 1.29 (s, 9H, C(CH3)3). 13C{1H} NMR (C6D6): δ 220.2 (d, JP−C = 13.0 Hz, ThC), 159.4 (d, JP−C = 3.0 Hz, phenyl C), 153.9 (phenyl C), 150.6 (phenyl C), 148.0 (phenyl C), 147.1 (phenyl C), 142.0 (d, JP−C = 29.0 Hz, phenyl C), 137.1 (d, JP−C = 55.1 Hz, PCC), 128.7 (phenyl C), 126.8 (phenyl C), 123.0 (ring C), 122.2 (d, JP−C = 4.5 Hz, ring C), 115.4 (ring C), 113.1 (ring C), 112.4 (ring C), 38.8 (CH3), 33.6 (C(CH3)3), 33.6 (C(CH3)3), 33.5 (C(CH3)3), 33.2 (C(CH3)3), 32.8 (C(CH3)3), 32.4 (C(CH3)3), 31.1 (C(CH3)3), 20.3 (C(CH3)3). 31P{1H} NMR (C6D6): δ 64.0. 6b. 1H NMR (C6D6): δ 7.18 (d, J = 2.6 Hz, 2H, phenyl), 6.89 (t, J = 7.6 Hz, 2H, phenyl), 6.75 (t, J = 7.3 Hz, 1H, phenyl), 6.62 (d, J = 7.3 Hz, 2H, phenyl), 6.44 (t, J = 2.7 Hz, 2H, ring CH), 6.31 (t, J = 2.5 Hz, 2H, ring CH), 6.15 (t, J = 2.8 Hz, 2H, ring CH), 2.55 (s, 3H, CH3), 1.78 (s, 18H, C(CH3)3), 1.53 (s, 18H, C(CH3)3), 1.43 (s, 18H, C(CH3)3), 1.25 (s, 9H, C(CH3)3). 13C{1H} NMR (C6D6): δ 214.4 (d, JP−C = 11.0 Hz, ThC), 158.5 (phenyl C), 149.2 (phenyl C), 148.6 (phenyl C), 146.8 (phenyl C), 141.8 (d, JP−C = 27.0 Hz, phenyl C), 140.3 (phenyl C), 136.4 (d, JP−C = 57.0 Hz, PCC), 128.6 (phenyl C), 126.6 (phenyl C), 124.1 (ring C), 121.3 (ring C), 112.8 (ring C), 112.5 (ring C), 110.8 (ring C), 38.7 (CH3), 34.8 (C(CH3)3), 34.4 (C(CH3)3), 34.4 (C(CH3)3), 33.4 (C(CH3)3), 32.5 (C(CH3)3), 32.5 (C(CH3)3), 31.4 (C(CH3)3), 28.2 (C(CH3)3). 31P{1H} NMR (C6D6): δ 68.7. Anal. Calcd for C53H79PTh: C, 65.01; H, 8.13. Found: C, 64.98; H, 8.08. The unambiguous assignment of the NMR resonances corresponding to 6a and 6b was not a trivial task. However, isomers 6a and 6b were obtained in different ratios (ca. 4:1), and therefore their NMR resonances feature different intensities, and we employed this information for the assignment of the respective NMR resonances. In addition, complexes 6a and 6b were not isolated as pure materials on a synthetic scale because of their very similar solubilities. However, a few orange crystals of 6a·0.5C6H14 suitable for X-ray diffraction analysis were selected from those microcrystals that recrystallized from an n-hexane solution at room temperature. Method B. NMR Scale. A C6D6 (0.3 mL) solution of PhCCMe (2.4 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 6a and 6b were observed by 1H NMR spectroscopy (100% conversion) when this solution was stored at room temperature overnight. The ratio of 6a/6b is ca. 4:1. The sample was monitored periodically by 1H NMR spectroscopy, but no changes in the 1H NMR spectrum were observed upon heating at 100 °C for 1 week, indicating that the mixture of 6a and 6b could not be converted to a single isomer. L


Article

Inorganic Chemistry Preparation of [η5-1,3-(Me3C)2C5H3]2Th[1-(2,4,6-tBu3C6H2)-2C6H4-5-PhC4HP] (7). Method A. A toluene (5 mL) solution of 1,4diphenylbutadiyne (41 mg, 0.2 mmol) was added to a toluene (10 mL) solution of 4 (188 mg, 0.1 mmol) with stirring at room temperature. After the solution was stirred at room temperature overnight, the solvent was removed. The residue was extracted with benzene (10 mL × 3) and filtered. The volume of the filtrate was reduced to 5 mL, and yellow crystals of 7 were isolated when this solution was stored at room temperature for 1 week. Yield: 175 mg (82%). Mp: 219−221 °C (dec). 1H NMR (C6D6): δ 7.79 (m, 3H, phenyl), 7.64 (d, 1H, J = 11.6 Hz, phenyl), 7.52 (d, J = 8.4 Hz, 1H, phenyl), 7.32 (d, J = 7.6 Hz, 2H, phenyl), 7.07 (m, 3H, phenyl and CHC), 6.91 (m, 2H, phenyl), 6.56 (t, J = 2.2 Hz, 2H, ring CH), 6.29 (t, J = 2.6 Hz, 2H, ring CH), 6.24 (t, J = 2.6 Hz, 2H, ring CH), 1.62 (s, 18H, C(CH3)3), 1.32 (s, 9H, C(CH3)3), 1.26 (s, 18H, C(CH3)3), 1.26 (s, 18H, C(CH3)3). 13C{1H} NMR (C6D6): δ 214.6 (phenyl C), 208.1 (d, JP−C = 15.4 Hz, ThCCP), 158.6 (d, JP−C = 11.0 Hz, phenyl C), 153.2 (phenyl C), 152.3 (phenyl C), 152.1 (phenyl C), 148.6 (d, JP−C = 74.9 Hz, ThCCP), 145.0 (phenyl C), 144.8 (phenyl C), 140.2 (phenyl C), 139.9 (phenyl C), 138.4 (phenyl C), 138.2 (phenyl C), 137.8 (phenyl C), 132.4 (d, JP−C = 41.3 Hz, phenyl C), 131.1 (d, JP−C = 6.1 Hz, phenyl C), 127.5 (ring C), 127.0 (d, JP−C = 3.7 Hz, ring C), 125.9 (ring C), 124.5 (d, JP−C = 8.9 Hz, ring C), 123.7 (ring C), 112.5 (ThCCHCPh), 111.9 (d, JP−C = 16.0 Hz, ThCCHCPh), 40.1 (d, JP−C = 3.6 Hz, C(CH3)3), 35.3 (C(CH3)3), 33.7 (C(CH3)3), 33.7 (C(CH3)3), 33.1 (C(CH3)3), 33.1 (C(CH3)3), 32.1 (C(CH3)3), 31.1 (C(CH3)3). 31P{1H} NMR (C6D6): δ 9.9. IR (KBr, cm−1): ν 2960 (s), 2902 (s), 2866 (s), 1595 (s), 1462 (s), 1390 (s), 1361 (s), 1249 (s), 817(s). Anal. Calcd for C60H81PTh: C, 67.65; H, 7.66. Found: C, 67.72; H, 7.63. Method B. NMR Scale. A C6D6 (0.3 mL) solution of 1,4diphenylbutadiyne (4.0 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 7 were observed by 1H NMR spectroscopy (100% conversion) when this solution was stored at room temperature overnight. Preparation of {[η5 -1,3-(Me 3C) 2 C5H 3] 2Th[NC(Ph)(P2,4,6-tBu3C6H2)](ClK)}2 (9). Method A. This compound was obtained as orange crystals from the reaction of 4 (188 mg, 0.1 mmol) and PhCN (21 mg, 0.2 mmol) in toluene (15 mL) at room temperature and recrystallization from an n-hexane solution by a procedure similar to that described in the synthesis of 7. Yield: 183 mg (88%). Mp: 223−225 °C (dec). 1H NMR (C6D6): δ 7.38 (s, 4H, phenyl), 6.97 (m, 8H, phenyl), 6.89 (m, 2H, phenyl), 6.51 (s, 4H, ring CH), 6.38 (s, 4H, ring CH), 6.33 (s, 4H, ring CH), 1.71 (s, 36H, C(CH3)3), 1.56 (s, 36H, C(CH3)3), 1.43 (s, 36H, C(CH3)3), 1.40 (s, 18H, C(CH3)3). 13C{1H} NMR (C6D6): δ 207.0 (d, JP−C = 55.3 Hz, ThNC), 155.2 (phenyl C), 148.7 (phenyl C), 148.4 (phenyl C), 145.6 (phenyl C), 138.5 (d, JP−C = 62.9 Hz, phenyl C), 128.5 (phenyl C), 126.4 (phenyl C), 125.5 (ring C), 121.0 (ring C), 113.4 (ring C), 112.3 (ring C), 110.9 (ring C), 38.9 (C(CH3)3), 34.9 (C(CH3)3), 33.9 (C(CH3)3), 33.8 (C(CH3)3), 33.3 (C(CH3)3), 32.8 (C(CH3)3), 32.6 (C(CH3)3), 31.9 (C(CH3)3); one carbon atom of phenyl was not observed. 31P{1H} NMR (C6D6): δ 102.3. IR (KBr, cm−1): ν 2958 (s), 2902 (s), 1591 (s), 1462 (s), 1388 (s), 1359 (s), 1311 (s), 1195 (s), 821 (s). Anal. Calcd for C102H152N2Cl2K2P2Th2: C, 58.86; H, 7.36; N, 1.35. Found: C, 58.82; H, 7.39; N, 1.31. Method B. NMR Scale. A C6D6 (0.3 mL) solution of PhCN (2.1 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 9 were observed by 1H NMR spectroscopy (100% conversion) when this solution was stored at room temperature overnight. Preparation of [η5-1,3-(Me3C)2C5H3][η5-κP,κN-1-Me2C{CH2C(NC 6 H 11 )C(NHC 6 H 11 )(P-2,4,6- t Bu 3 C 6 H 2 )}-3-(Me 3 C)C 5 H 3 ]Th (10). A toluene (5 mL) solution of C6H11NC (44 mg, 0.4 mmol) was added to a toluene (10 mL) solution of 4 (188 mg, 0.1 mmol) with stirring at room temperature. After the solution was stirred at room temperature overnight, the solvent was removed. The residue was extracted with n-hexane (10 mL × 3) and filtered. The volume of the filtrate was reduced to 5 mL, and orange crystals of 10 were isolated

when this solution was stored at room temperature for 2 weeks. Yield: 177 mg (82%). Mp: 206−208 °C (dec). 1H NMR (C6D6): δ 7.34 (d, J = 2.9 Hz, 2H, phenyl), 6.73 (t, J = 2.9 Hz, 1H, ring CH), 6.62 (t, J = 2.8 Hz, 1H, ring CH), 6.50 (t, J = 2.6 Hz, 1H, ring CH), 6.19 (t, J = 2.7 Hz, 1H, ring CH), 6.11 (t, J = 2.6 Hz, 1H, ring CH), 5.96 (t, J = 2.8 Hz, 1H, ring CH), 3.67 (m, 1H, CH2CHCH2), 3.07 (d, J = 14.4 Hz, 1H, C(CH3)2CH), 2.97 (dd, J = 8.0 and 2.8 Hz, 1H, NH), 2.68 (d, J = 14.4 Hz, 1H, C(CH3)2CH), 2.55 (m, 1H, CH2CHCH2), 2.11 (s, 9H, C(CH3)3), 2.06 (m, 2H, CH2), 1.94 (m, 2H, CH2), 1.88 (s, 7H, CH2 and C(CH3)2), 1.84 (s, 9H, C(CH3)3), 1.64 (s, 14H, CH2, C(CH3)2, and C(CH3)3), 1.54 (s, 9H, C(CH3)3), 1.51 (s, 11H, CH2 and C(CH3)3), 1.39 (s, 17H, CH2 and C(CH3)3). 13C{1H} NMR (C6D6): δ 149.7 (phenyl C), 146.3 (phenyl C), 144.5 (phenyl C), 143.1 (ring C), 141.0 (ring C), 137.8 (ring C), 129.3 (ring C), 125.6 (ring C), 122.8 (d, JP−C = 4.7 Hz, ring C), 118.6 (ring C), 113.6 (ring C), 112.3 (d, JP−C = 6.2 Hz, ring C), 110.1 (ring C), 67.8 (CC), 65.6 (C(CH3)2CH2), 59.7 (CH2CHCH2), 43.9 (CH2CHCH2), 39.4 (C(CH3)2), 39.3 (C(CH3)3), 38.9 (C(CH3)2), 38.7 (C(CH3)3), 38.2 (C(CH3)2), 37.4 (C(CH3)3), 35.2 (C(CH3)3), 34.9 (C(CH3)3), 34.7 (C(CH3)3), 34.6 (C(CH3)3), 33.7 (C(CH3)3), 33.6 (C(CH3)3), 33.5 (C(CH3)3), 33.2 (C(CH3)3), 31.6 (C(CH3)3), 29.9 (CH2), 27.0 (CH2), 26.6 (CH2), 26.2 (CH2), 25.8 (CH2), 21.4 (CH2); one carbon atom of phenyl and one carbon atom of CC were not observed. 31 1 P{ H} NMR (C6D6): δ 44.8. IR (KBr, cm−1): ν 2962 (s), 2927 (s), 1400 (s), 1259 (s), 1091 (s), 1018 (s), 798 (s). Anal. Calcd for C58H93N2PTh: C, 64.42; H, 8.67; N, 2.59. Found: C, 64.45; H, 8.63; N, 2.61. Preparation of [η 5-1,3-(Me 3 C) 2 C5 H3 ] 2 Th[N(C6 H 11 )C(P2,4,6-tBu3C6H2)N(C6H11)] (11). Method A. This compound was obtained as green crystals from the reaction of 4 (188 mg, 0.1 mmol) and N,N′-dicyclohexylcarbodiimide (DCC; 41 mg, 0.2 mmol) in toluene (15 mL) at room temperature and recrystallization from an nhexane solution by a procedure similar to that described in the synthesis of 7. Yield: 182 mg (85%). Mp: 211−213 °C (dec). 1H NMR (C6D6): δ 7.58 (s, 2H, phenyl), 6.60 (s, 2H, ring CH), 6.43 (s, 2H, ring CH), 6.17 (s, 2H, ring CH), 4.53 (m, 1H, NH), 3.38 (m, 1H, NH), 3.07 (m, 2H, CH2), 2.01 (s, 18H, C(CH3)3), 1.94 (m, 4H, CH2), 1.72 (m, 4H, CH2), 1.58 (m, 10H, CH2), 1.44 (s, 9H, C(CH3)3), 1.37 (s, 18H, C(CH3)3), 1.30 (s, 18H, C(CH3)3). 13 C{1H} NMR (C6D6): δ 178.5 (d, J = 210.7 Hz, NCP), 156.8 (d, J = 5.1 Hz, phenyl C), 150.5 (phenyl C), 148.7 (phenyl C), 147.3 (ring C), 140.7 (d, J = 77.2 Hz, phenyl C), 121.3 (ring C), 115.0 (ring C), 114.4 (ring C), 113.8 (ring C), 58.9 (d, J = 36.9 Hz, NCH(CH2)2), 57.4 (NCH(CH2)2), 39.6 (C(CH3)3), 37.9 (C(CH3)3), 35.0 (CH2), 33.9 (C(CH3)3), 33.8 (C(CH3)3), 33.7 (C(CH3)3), 33.7 (CH2), 32.4 (C(CH3)3), 32.4 (C(CH3)3), 31.8 (C(CH3)3), 27.3 (CH2), 26.2 (CH2), 26.2 (CH2), 26.1 (CH2). 31P{1H} NMR (C6D6): δ 19.1. IR (KBr, cm−1): ν 2958 (s), 2928 (s), 1593 (s), 1462 (s), 1400 (s), 1386 (s), 1359 (s), 1249 (s), 1107 (s), 1020 (s), 808 (s). Anal. Calcd for C57H93N2PTh: C, 64.02; H, 8.77; N, 2.62. Found: C, 64.08; H, 8.79; N, 2.61. Method B. NMR Scale. A C6D6 (0.3 mL) solution of DCC (4.1 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 11 were observed by 1H NMR spectroscopy (100% conversion) when this solution was stored at room temperature overnight. Preparation of [η 5 -1,3-(Me 3 C) 2 C 5 H 3 ] 2 Th[N( i Pr)C(P2,4,6-tBu3C6H2)N(iPr)] (12). Method A. This compound was obtained as green crystals from the reaction of 4 (188 mg, 0.1 mmol) and (iPrN)2C (26 mg, 0.2 mmol) in toluene (15 mL) at room temperature and recrystallization from an n-hexane solution by a procedure similar to that described in the synthesis of 7. Yield: 154 mg (78%). Mp: 205−206 °C (dec). 1H NMR (C6D6): δ 7.51 (s, 2H, phenyl), 6.44 (s, 2H, ring CH), 6.33 (s, 2H, ring CH), 6.18 (s, 2H, ring CH), 4.93 (m, 1H, CH(CH3)2), 3.59 (m, 1H, CH(CH3)2), 2.00 (s, 18H, C(CH3)3), 1.76 (d, J = 6.0 Hz, 6H, CH(CH3)2), 1.43 (s, 9H, C(CH3)3), 1.30 (s, 18H, C(CH3)3), 1.26 (s, 18H, C(CH3)3), 1.02 (d, J = 6.3 Hz, 6H, CH(CH3)2). 13C{1H} NMR (C6D6): δ 152.8 (phenyl C), 152.1 (d, J = 255.5 Hz, NCP), 149.8 (phenyl C), 146.1 (phenyl C), 142.6 (d, J = 65.0 Hz, phenyl C), 142.6 (ring C), 121.8 (ring C), M


Article

Inorganic Chemistry

−107.4.],9 were observed by NMR spectroscopy (100% conversion) after the sample was stored at room temperature overnight. Preparation of {[η5-1,3-(Me3C)2C5H3]2Th}2(μ-O)2 (15). Method A. This compound was obtained as colorless crystals from the reaction of 4 (188 mg, 0.1 mmol) and p-tolylCHO (24 mg, 0.2 mmol) in toluene (15 mL) at room temperature and recrystallization from a benzene solution by a procedure similar to that described in the synthesis of 7. Yield: 94 mg (78%). Mp: >300 °C (dec). 1H NMR (C6D6): δ 6.80 (s, 4H, ring CH), 6.45 (s, 8H, ring CH), 1.49 (s, 72H, C(CH3)3). 13C{1H} NMR (C6D6): δ 122.0 (ring C), 115.2 (ring C), 114.0 (ring C), 33.1 (C(CH3)3), 32.7 (C(CH3)3). IR (KBr, cm−1): ν 2960 (s), 1400 (s), 1384 (s), 1259 (s), 1091 (s), 1020 (s), 802 (s). Anal. Calcd for C52H84O2Th2: C, 51.82; H, 7.02. Found: C, 51.84; H, 7.09. Method B. NMR Scale. A C6D6 (0.3 mL) solution of p-tolylCHO (2.4 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 15, along with those of p-tolylCHP-2,4,6-tBu3C6H2 [1H NMR: δ 8.21 (d, 1H, J = 25.2 Hz, CHP), 7.40 (d, 2H, J = 7.8 Hz, phenyl), 6.86 (d, 2H, J = 7.8 Hz, phenyl), 2.00 (d, J = 1.0 Hz, 3H, CH3), 1.61 (s, 18H, C(CH3)3), 1.35 (s, 9H, C(CH3)3). 31P{1H} NMR (C6D6): δ 251.3.],18 were observed by NMR spectroscopy (100% conversion) after the sample was stored at room temperature overnight. Preparation of [η5-1,3-(Me3C)2C5H3]2Th[(OCPh2)2] (16). Method A. This compound was obtained as colorless crystals from the reaction of 4 (188 mg, 0.1 mmol) and Ph2CO (73 mg, 0.4 mmol) in toluene (15 mL) at room temperature and recrystallization from a benzene solution by a procedure similar to that described in the synthesis of 7. Yield: 156 mg (82%). Mp: 175−177 °C (dec). 1H NMR (C6D6): δ 7.41 (d, J = 7.1 Hz, 8H, phenyl), 7.02 (m, 8H, phenyl), 6.94 (m, 4H, phenyl), 6.47 (s, 4H, ring CH), 6.40 (s, 2H, ring CH), 1.29 (s, 36H, C(CH3)3). 13C{1H} NMR (C6D6): δ 148.8 (phenyl C), 147.3 (phenyl C), 130.7 (phenyl C), 126.8 (phenyl C), 126.3 (ring C), 114.8 (ring C), 113.2 (ring C), 110.5 (OC), 33.2 (C(CH3)3), 32.1 (C(CH3)3). IR (KBr, cm−1): ν 2960 (s), 1597 (s), 1442 (s), 1400 (s), 1386 (s), 1361 (s), 1014 (s), 812 (s). Anal. Calcd for C52H62O2Th: C, 55.67; H, 6.57. Found: C, 55.72; H, 6.59. Method B. NMR Scale. A C6D6 (0.3 mL) solution of Ph2CO (7.3 mg, 0.04 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 16, along with those of 17 [1H NMR (C6D6): δ 7.46 (dd, J = 3.8 and 1.5 Hz, 2H, phenyl), 4.39 (ddd, J = 181.6, 11.9, and 7.9 Hz, 1H, PH), 1.59 (d, J = 3.6 Hz, 1H CH2), 1.56 (s, 9H, (CH3)3C), 1.34 (s, 3H, (CH3), 1.31 (s, 9H, (CH3)3C), 1.29 (d, J = 3.6 Hz, 1H CH2), 1.11 (s, 3H, (CH3). 31P{1H} NMR (C6D6): δ −79.5.],9 were observed by NMR spectroscopy (100% conversion) after the sample was stored at room temperature overnight. Reaction of 4 with Ph2CO. NMR Scale. A C6D6 (0.2 mL) solution of Ph2CO (3.6 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.3 mL). Resonances of 16, along with those of unreacted 4 and 17, were observed by 1H NMR spectroscopy (50% conversion based on 4) after the sample was stored at room temperature overnight. Preparation of [η5-1,3-(Me3C)2C5H3]2Th[SCHCHN(CHP2,4,6-tBu3C6H2)] (18). Method A. This compound was obtained as yellow crystals from the reaction of 4 (188 mg, 0.1 mmol) and thiazole (17 mg, 0.2 mmol) in toluene (15 mL) at room temperature and recrystallization from a benzene solution by a procedure similar to that described in the synthesis of 7. Yield: 161 mg (85%). Mp: 241− 243 °C (dec). 1H NMR (C6D6): δ 8.62 (d, J = 15.6 Hz, 1H, CHP), 7.61 (s, 2H, phenyl), 7.39 (d, J = 6.1 Hz, 1H, SCHCHN), 6.26 (m, 2H, ring CH), 6.15 (m, 2H, ring CH), 6.06 (d, J = 6.2 Hz, 1H, SCHCHN), 5.94 (m, 2H, ring CH), 1.75 (s, 18H, C(CH3)3), 1.34 (s, 27H, C(CH3)3), 1.08 (s, 18H, C(CH3)3). 13C{1H} NMR (C6D6): δ 186.5 (d, JP−C = 45.9 Hz, CHP), 156.3 (SCHCHN), 150.3 (phenyl), 149.0 (phenyl), 145.9 (SCHCHN), 138.7 (d, JP−C = 52.0 Hz, phenyl), 133.4 (d, JP−C = 30.7 Hz, phenyl), 121.4 (ring C), 113.3 (ring C), 112.9 (ring C), 111.7 (ring C), 111.2 (ring C), 38.7 (C(CH3)3), 35.0 (C(CH3)3), 34.4 (C(CH3)3), 34.3 (C(CH3)3), 33.5 (C(CH3)3), 32.9 (C(CH3)3), 32.2 (C(CH3)3), 32.1 (C(CH3)3).

120.8 (ring C), 117.3 (ring C), 113.1 (ring C), 67.8 (NCH(CH3)2), 51.8 (NCH(CH3)2), 34.7 (C(CH3)3), 34.4 (CH(CH3)2), 33.4 (C(CH3)3), 32.2 (C(CH3)3), 32.1 (C(CH3)3), 32.0 (C(CH3)3), 31.4 (C(CH3)3), 25.8 (CH(CH3)2), 25.0 (C(CH3)3), 24.5 (C(CH3)3). 31P{1H} NMR (C6D6): δ 20.3. IR (KBr, cm−1): ν 2960 (s), 2904 (s), 1599 (s), 1386 (s),1361 (s), 1224 (s), 1176 (s), 1018 (s), 808 (s). Anal. Calcd for C51H85N2PTh: C, 61.92; H, 8.66; N, 2.83. Found: C, 61.87; H, 8.68; N, 2.81. Method B. NMR Scale. A C6D6 (0.3 mL) solution of (iPrN)2C (2.6 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 12 were observed by 1H NMR spectroscopy (100% conversion) when this solution was stored at room temperature overnight. Preparation of [η5-1,3-(Me3C)2C5H3]2Th[N(Ph)C(NPh)N(Ph)] (13). Method A. This compound was obtained as yellow crystals from the reaction of 4 (188 mg, 0.1 mmol) and PhCHNPh (72 mg, 0.4 mmol) in toluene (15 mL) at room temperature and recrystallization from a benzene solution by a procedure similar to that described in the synthesis of 7. Yield: 141 mg (82%). Mp: 143− 145 °C (dec). 1H NMR (C6D6): δ 7.48 (d, J = 7.6 Hz, 2H, phenyl), 7.28 (t, J = 7.6 Hz, 4H, phenyl), 7.02 (t, J = 7.6 Hz, 2H, phenyl), 6.96 (d, J = 7.8 Hz, 5H, phenyl), 6.78 (t, J = 7.1 Hz, 2H, phenyl), 6.61 (s. 2H, ring CH), 6.50 (s. 1H, ring CH), 6.35 (s. 3H, ring CH), 6.25 (s. 1H, CHPh), 1.32 (s, 18H, C(CH3)3), 1.13 (s, 18H, C(CH3)3). 13 C{1H} NMR (C6D6): δ 154.8 (phenyl C), 153.3 (phenyl C), 151.0 (phenyl C), 148.9 (phenyl C), 144.8 (phenyl C), 128.9 (phenyl C), 127.1 (phenyl C), 120.4 (phenyl C), 118.8 (ring C), 116.3 (ring C), 115.4 (ring C), 113.3 (ring C), 112.4 (ring C), 65.7 (CHPh), 33.6 (C(CH3)3), 33.4 (C(CH3)3), 32.3 (C(CH3)3), 31.6 (C(CH3)3). IR (KBr, cm−1): ν 2960 (s), 2902 (s), 2864 (s), 1591 (s), 1489 (s), 1359 (s), 1249 (s), 1087 (s), 1026 (s), 806 (s). Anal. Calcd for C45H58N2Th: C, 62.92; H, 6.81; N, 3.26. Found: C, 62.89; H, 6.80; N, 3.21. Method B. NMR Scale. A C6D6 (0.3 mL) solution of PhCHNPh (7.2 mg, 0.04 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 13, along with those of PhCHP-2,4,6-tBu3C6H2 [1H NMR (C6D6): δ 8.19 (d, J = 25.4 Hz, 1H, CHP), 7.63 (s, 2H, phenyl), 7.45 (dd, 2H, J = 7.4 Hz, JP−H = 2.7 Hz, phenyl), 7.03 (m, 2H, phenyl), 6.96 (m, 1H, phenyl), 1.59 (s, 18H, C(CH3)3), 1.35 (s, 9H, C(CH3)3). 31P{1H} NMR (C6D6): δ 257.3.],17 were observed by NMR spectroscopy (100% conversion) after the sample was stored at room temperature overnight. Reaction of 4 with PhCHNPh. NMR Scale. A C6D6 (0.2 mL) solution of PhCHNPh (3.6 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.3 mL). Resonances of 13, along with those of unreacted 4 and PhCH P-2,4,6-tBu3C6H2, were observed by 1H NMR spectroscopy (50% conversion based on 4) after the sample was stored at room temperature overnight. Preparation of 14·C6H6. Method A. This compound was obtained as colorless crystals from the reaction of 4 (188 mg, 0.1 mmol) and PhNCS (27 mg, 0.2 mmol) in toluene (15 mL) at room temperature and recrystallization from a benzene solution by a procedure similar to that described in the synthesis of 7. Yield: 99 mg (75%). Mp: >300 °C (dec). 1H NMR (C6D6): δ 7.15 (s, 6H, C6H6), 6.76 (s, 4H, ring CH), 6.23 (s, 8H, ring CH), 1.53 (s, 72H, C(CH3)3). 13C{1H} NMR (C6D6): δ 128.0 (C6H6), 121.0 (ring C), 115.5 (ring C), 112.2 (ring C), 33.7 (C(CH3)3), 33.0 (C(CH3)3). IR (KBr, cm−1): ν 2960 (s), 1545 (m), 1402 (s), 1386 (s), 1089 (m), 1020 (s), 800 (s). Anal. Calcd for C58H90S2Th2: C, 52.95; H, 6.90. Found: C, 52.92; H, 6.89. Method B. NMR Scale. A C6D6 (0.3 mL) solution of PhNCS (2.7 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 14, along with those of PhNCP-2,4,6-tBu3C6H2 [1H NMR: δ 7.60 (d, 2H, J = 2.0 Hz, phenyl), 6.94 (d, 2H, J = 7.7 Hz, phenyl), 6.83 (t, 2H, J = 7.5 Hz, phenyl), 6.70 (m, 1H, J = 7.4 Hz, phenyl), 1.79 (s, 18H, C(CH3)3), 1.23 (s, 9H, C(CH3)3). 31P{1H} NMR (C6D6): δ N


Article

Inorganic Chemistry P{1H} NMR (C6D6): δ 144.3. IR (KBr, cm−1): ν 2960 (s), 1400 (s), 1384 (s), 1261 (s), 1091(s), 1020 (s), 798 (s). Anal. Calcd for C47H74NPSTh: C, 59.54; H, 7.87; N, 1.48. Found: C, 59.52; H, 7.89; N, 1.51. Method B. NMR Scale. A C6D6 (0.3 mL) solution of thiazole (1.7 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 18 were observed by 1H NMR spectroscopy (100% conversion) when this solution was stored at room temperature overnight. Preparation of [η5-1,3-(Me3C)2C5H3]2Th(PH-2,4,6-tBu3C6H2)[2-(1-MeC3H2N2)] (19). Method A. This compound was obtained as yellow crystals from the reaction of 4 (188 mg, 0.1 mmol) and 1methylimidazole (17 mg, 0.2 mmol) in toluene (15 mL) at room temperature and recrystallization from a benzene solution by a procedure similar to that described in the synthesis of 7. Yield: 174 mg (92%). Mp: 132−134 °C (dec). 1H NMR (C6D6): δ 7.58 (d, J = 1.6 Hz, 2H, phenyl), 6.79 (d, J = 1.2 Hz, 1H, CHCH), 6.73 (d, J = 1.6 Hz, 1H, CHCH), 6.33 (t, J = 2.4 Hz, 2H, ring CH), 6.27 (t, J = 2.8 Hz, 2H, ring CH), 6.13 (t, J = 3.2 Hz, 2H, ring CH), 5.02 (d, JP−H = 207.2 Hz, 1H, PH), 3.13 (s, 3H, NCH3), 1.99 (s, 18H, C(CH3)3), 1.45 (s, 9H, C(CH3)3), 1.22 (s, 18H, C(CH3)3), 1.13 (s, 18H, C(CH3)3). 13C{1H} NMR (C6D6): δ 213.7 (d, JP−C = 10.7 Hz, ThCN), 152.0 (d, JP−C = 4.6 Hz, phenyl C), 148.0 (phenyl C), 145.7 (phenyl C), 144.3 (CHCH), 141.6 (CHCH), 130.7 (phenyl C), 124.4 (ring C), 120.7 (d, JP−C = 4.6 Hz, ring C), 116.0 (ring C), 113.1 (ring C), 111.3 (ring C), 38.8 (NCH3), 35.7 (C(CH3)3), 34.5 (C(CH3)3), 33.6 (C(CH3)3), 33.6 (C(CH3)3), 33.3 (C(CH3)3), 32.5 (C(CH3)3), 32.2 (C(CH3)3), 32.0 (C(CH3)3). 31 1 P{ H} NMR (C6D6): δ 1.2. IR (KBr, cm−1): ν 2960 (s), 2930 (s), 1593 (m), 1462 (s), 1384 (s), 1361 (s), 1259 (s), 1099 (s). 1022 (s), 802 (s). Anal. Calcd for C48H77N2PTh: C, 61.00; H, 8.21; N, 2.96. Found: C, 60.96; H, 8.19; N, 3.02. Method B. NMR Scale. A C6D6 (0.3 mL) solution of 1methylimidazole (1.6 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 19 were observed by 1H NMR spectroscopy (100% conversion) when this solution was stored at room temperature overnight. Preparation of [η5-1,3-(Me3C)2C5H3]2Th(PH-2,4,6-tBu3C6H2)[2-(4-Me2N)C5H3)] (20). Method A. This compound was isolated as brown crystals from the reaction of 4 (188 mg, 0.1 mmol) and DMAP (25 mg, 0.2 mmol) in toluene (15 mL) at room temperature and recrystallization from a benzene solution by a procedure similar to that described in the synthesis of 7. Yield: 167 mg (82%). Mp: 200− 202 °C (dec). 1H NMR (C6D6): δ 8.32 (d, J = 6.3 Hz, 1H, DMAP), 7.61 (s, 2H, phenyl), 7.18 (d, J = 1.8 Hz, 1H, DMAP), 6.21 (d, 2H, J = 2.4 Hz, ring CH), 6.17 (s, 2H, ring CH), 6.08 (t, 2H, ring CH), 6.02 (dd, J = 6.3 and 2.4 Hz, 1H, DMAP), 4.80 (d, JP−H = 199 Hz, 1H, PH), 2.30 (s, 6H, N(CH3)2), 2.05 (s, 18H, C(CH3)3), 1.45 (s, 9H, C(CH3)3), 1.36 (s, 18H, C(CH3)3), 1.22 (s, 18H, C(CH3)3). 13 C{1H} NMR (C6D6): δ 225.4 (d, JP−C = 3.3 Hz, ThC) 154.6 (aryl C), 151.0 (aryl C), 151.0 (aryl C), 147.5 (d, JP−C = 46.9 Hz, aryl C) 146.5 (aryl C), 145.3 (aryl C), 144.3 (aryl C), 143.1 (aryl C), 120.4 (d, JP−C = 4.2 Hz, ring C), 114.4 (ring C), 113.4 (d, JP−C = 4.9 Hz, ring C), 111.3 (ring C), 109.1 (ring C), 38.7 (d, JP−C = 7.6 Hz, N(CH3)2), 34.5 (C(CH3)3), 33.7 (C(CH3)3), 33.6 (C(CH3)3), 33.5 (C(CH3)3), 33.4 (C(CH3)3), 32.7 (C(CH3)3), 32.6 (C(CH3)3), 32.5 (C(CH3)3). 31P{1H} NMR (C6D6): δ −36.3. IR (KBr, cm−1): ν 2960 (s), 1585 (s), 1400 (s), 1259 (s), 1091 (s), 1020 (s), 802 (s). Anal. Calcd for C51H81N2PTh: C, 62.17; H, 8.29; N, 2.84. Found: C, 62.15; H, 8.31; N, 2.81. Method B. NMR Scale. A C6D6 (0.3 mL) solution of DMAP (2.4 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 20 were observed by 1H NMR spectroscopy (100% conversion) when this solution was stored at room temperature overnight. Preparation of [η5-1,3-(Me3C)2C5H3]2Th(PH-2,4,6-tBu3C6H2)[2-(1-N-C9H6N)] (21). Method A. This compound was obtained as orange crystals from the reaction of 4 (188 mg, 0.1 mmol) and quinoline (26 mg, 0.2 mmol) in toluene (15 mL) at room 31

temperature and recrystallization from an n-hexane solution by a procedure similar to that described in the synthesis of 7. Yield: 188 mg (95%). Mp: 177−179 °C (dec). 1H NMR (C6D6): δ 8.03 (d, 1H, J = 7.8 Hz, quinoline), 7.59 (m, 3H, quinoline and phenyl), 7.51 (t, 1H, J = 7.6 Hz, quinoline), 7.38 (d, 1H, J = 6.6 Hz, quinoline), 7.14 (m, 2H, quinoline), 6.15 (s, 2H, ring CH), 6.07 (d, 2H, J = 2.6 Hz, ring CH), 6.03 (s, 2H, ring CH), 4.99 (d, 1H, JP−H = 193.4 Hz, PH), 1.94 (s, 18H, C(CH3)3), 1.43 (s, 9H, C(CH3)3), 1.25 (s, 18H, C(CH3)3), 1.12 (s, 18H, C(CH3)3). 13C{1H} NMR (C6D6): δ 151.3 (aryl C), 147.8 (aryl C), 146.5 (aryl C), 146.2 (aryl C), 143.6 (aryl C), 136.0 (aryl C), 130.2 (aryl C), 130.1 (aryl C), 130.0 (aryl C), 128.5 (aryl C), 128.3 (aryl C), 120.7 (ring C), 120.4 (ring C), 114.4 (ring C), 113.5 (ring C), 112.3 (ring C), 38.6 (C(CH3)3), 34.5 (C(CH3)3), 33.6 (C(CH3)3), 33.5 (C(CH3)3), 33.5 (C(CH3)3), 32.7 (C(CH3)3), 32.5 (d, JP−C = 2.1 Hz, C(CH3)3), 32.0 (C(CH3)3); two carbon atoms were not observed. 31P{1H} NMR (C6D6): δ −50.7. IR (KBr, cm−1): ν 2960 (s), 2904 (s), 2868 (s), 1587 (m), 1462 (s), 1392 (s), 1361 (s), 1259 (s), 1089 (s). 1020 (s), 802 (s). Anal. Calcd for C53H78NPTh: C, 64.16; H, 7.92; N, 1.41. Found: C, 64.12; H, 7.89; N, 1.43. Method B. NMR Scale. A C6D6 (0.3 mL) solution of quinoline (2.6 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 21 were observed by 1H NMR spectroscopy (100% conversion) when this solution was stored at room temperature overnight. Preparation of [η5-1,3-(Me3C)2C5H3]2Th(PH-2,4,6-tBu3C6H2)[1-(2-N-C9H6N)] (22). Method A. This compound was obtained as orange crystals from the reaction of 4 (188 mg, 0.1 mmol) and isoquinoline (26 mg, 0.2 mmol) in toluene (15 mL) at room temperature and recrystallization from a benzene solution by a procedure similar to that described in the synthesis of 7. Yield: 175 mg (88%). Mp: 170−172 °C (dec). 1H NMR (C6D6): δ 8.67 (d, 1H, J = 8.0 Hz, quinoline), 8.48 (d, 1H, J = 6.0 Hz, quinoline), 7.62 (d, 2H, J = 1.6 Hz, phenyl), 7.46 (m, 1H, quinoline), 7.39 (d, 1H, J = 7.8 Hz, quinoline), 7.32 (m, 1H, quinoline), 7.14 (d, 1H, J = 7.8 Hz, quinoline), 6.38 (s, 2H, ring CH), 6.28 (d, 2H, J = 2.2 Hz, ring CH), 6.24 (t, 2H, J = 2.6 Hz, ring CH), 5.10 (d, 1H, JP−H = 205.7 Hz, PH), 2.06 (s, 18H, C(CH3)3), 1.46 (s, 9H, C(CH3)3), 1.15 (s, 18H, C(CH3)3), 0.98 (s, 18H, C(CH3)3). 13C{1H} NMR (C6D6): δ 240.8 (d, JP−C = 9.1 Hz, ThCN), 151.7 (d, JP−C = 7.9 Hz, aryl C), 148.0 (aryl C), 145.9 (aryl C), 145.7 (d, JP−C = 46.1 Hz, aryl C), 144.1 (aryl C), 138.3 (aryl C), 135.5 (aryl C), 134.9 (aryl C), 134.6 (aryl C), 131.7 (aryl C), 123.8 (ring C), 120.8 (d, JP−C = 4.9 Hz, ring C), 114.7 (ring C), 113.6 (ring C), 111.3 (ring C), 38.9 (C(CH3)3), 34.5 (C(CH3)3), 33.7 (C(CH3)3), 33.6 (C(CH3)3), 33.4 (C(CH3)3), 33.2 (C(CH3)3), 32.4 (C(CH3)3), 32.1 (C(CH3)3); other carbon atoms overlapped. 31P{1H} NMR (C6D6): δ −14.9. IR (KBr, cm−1): ν 2960 (s), 2930 (s), 2902 (s), 2866 (s), 1593 (m), 1462 (s), 1384 (s), 1361 (s), 1259 (s), 1099 (s). 1022 (s), 802 (s). Anal. Calcd for C53H78NPTh: C, 64.16; H, 7.92; N, 1.41. Found: C, 64.15; H, 7.88; N, 1.39. Method B. NMR Scale. A C6D6 (0.3 mL) solution of isoquinoline (2.6 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 22 were observed by 1H NMR spectroscopy (100% conversion) when this solution was stored at room temperature overnight. Preparation of [η5-1,3-(Me3C)2C5H3]2Th(NP2,4,6-tBu3C6H2)(Cl) (23). Method A. A toluene (5 mL) solution of Ph3CN3 (114 mg, 0.4 mmol) was added to a toluene (10 mL) solution of 4 (188 mg, 0.1 mmol) with stirring at room temperature. During the reaction, KN3 was formed and deposited as a colorless precipitate, which exhibited a characteristic IR stretch at 2167 cm−1. After the solution was stirred at room temperature overnight, the solvent was removed. The residue was extracted with benzene (10 mL × 3) and filtered. The volume of the filtrate was reduced to 5 mL, and purple crystals of 23 were isolated when this solution was stored at room temperature for 1 week. Yield: 142 mg (78%). Mp: 137−139 °C (dec). 1H NMR (C6D6): δ 7.37 (s, 2H, phenyl), 6.71 (t, J = 2.5 Hz, 2H, ring CH), 6.33 (t, J = 2.7 Hz, 2H, ring CH), 6.25 (t, J = 2.8 Hz, 2H, ring CH), 1.61 (s, 18H, C(CH3)3), 1.45 (s, 18H, C(CH3)3), O


Article

Inorganic Chemistry

using the SADABS program.20 All structures were solved by direct methods and refined by full-matrix least squares on F2 using the SHELXL program package.21 All of the hydrogen atoms were geometrically fixed using the riding model. The measured crystal of 11 was twinned, and only one domain was used for the refinement, resulting in high residual electron density. Moreover, the crystals of 11 and 15 were not of high quality, and therefore the C−C bond distances are only of moderate precision. The crystal and experimental data for 4−7, 9−16, and 18−26 are summarized in the Supporting Information. Selected bond distances and angles are listed in Table 1. Computational Methods. All calculations were carried out with the Gaussian 09 program (G09),22 employing the B3PW91 functional, plus a polarizable continuum model (PCM) (denoted as B3PW91PCM), with the standard 6-31G(d) basis set for the carbon, hydrogen, nitrogen, sulfur, and phosphorus elements and a quasirelativistic 5f-in-valence effective-core potential (ECP60MWB) treatment with 60 electrons in the core region for thorium and the corresponding optimized segmented ((14s13p10d8f6g)/ [10s9p5d4f3g]) basis set for the valence shells of thorium,23 to fully optimize the structures of the reactants, complexes, transition states, intermediates, and products and also to mimic the experimental toluene solvent conditions (dielectric constant ε = 2.379). All stationary points were subsequently characterized by vibrational analyses, from which their respective zero-point (vibrational) energies were extracted and used in the relative energy determinations; in addition, frequency calculations were also performed to ensure that the reactant, complex, intermediate, product, and transition state structures resided at minima and first-order saddle points, respectively, on their potential energy hypersurfaces.

1.33 (s, 9H, C(CH3)3), 1.22 (s, 18H, C(CH3)3). 13C{1H} NMR (C6D6): δ 159.9 (JP−C = 74.4 Hz, phenyl C), 153.5 (phenyl C), 149.1 (phenyl C), 148.8 (phenyl C), 125.8 (ring C), 122.5 (ring C), 116.0 (ring C), 112.2 (ring C), 111.7 (ring C), 38.4 (C(CH3)3), 35.6 (C(CH3)3), 33.4 (C(CH3)3), 33.0 (C(CH3)3), 32.3 (C(CH3)3), 32.1 (C(CH3)3), 31.9 (C(CH3)3), 31.5 (C(CH3)3). 31P{1H} NMR (C6D6): δ 505.4. IR (KBr, cm−1): ν 2958 (s), 2902 (s), 2866 (s), 2094 (s), 1593 (s), 1491 (s), 1462 (s), 1361 (s), 1249 (s), 1147 (s). 1122 (s), 829 (s). Anal. Calcd for C44H71NClPTh: C, 57.91; H, 7.84; N, 1.53. Found: C, 57.87; H, 7.89; N, 1.51. Method B. NMR Scale. A C6D6 (0.3 mL) solution of Ph3CN3 (11.4 mg, 0.04 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 23, along with those of Ph3CCH(C2H2)2CCPh2 [1H NMR (C6D6): δ 7.29 (m, 3H, phenyl), 7.00 (m, 22H, phenyl), 6.43 (d, J = 9.8 Hz, 2H, CH), 5.92 (d, J = 9.8 Hz, 2H, CH), 4.92 (s, 1H, CH).],9 were observed by 1H NMR spectroscopy (100% conversion) after the sample was stored at room temperature overnight. Reaction of 4 with Ph3CN3. NMR Scale. A C6D6 (0.2 mL) solution of Ph3CN3 (5.7 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.3 mL). Resonances of 23, along with those of unreacted 4 and Ph3CCH(C2H2)2CCPh2, were observed by 1H NMR spectroscopy (50% conversion based on 4) after the sample was stored at room temperature overnight. Preparation of {[η5-1,3-(Me3C)2C5H3]2Th}2(μ-Se)2 (24). Method A. Solid Se (24 mg, 0.3 mmol) was added to a stirred toluene (20 mL) solution of 4 (188 mg, 0.1 mmol). After the solution was stirred at room temperature for 2 days, the solvent was removed. The residue was extracted with benzene (10 mL × 3) and filtered. The volume of the filtrate was reduced to 5 mL, and yellow crystals of 24 were isolated when this solution was stored at room temperature for 1 day. Yield: 103 mg (77%). Mp: >300 °C (dec). 1H NMR (C6D6): δ 6.90 (s, 4H, ring CH), 6.17 (s, 8H, ring CH), 1.56 (s, 72H, C(CH3)3). 13 C{1H} NMR (C6D6): δ 123.1 (ring C), 115.4 (ring C), 113.0 (ring C), 33.9 (C(CH3)3), 32.9 (C(CH3)3). IR (KBr, cm−1): ν 2953 (s), 1460 (s), 1388 (s), 1249 (s), 1089 (s), 1022 (s), 812 (s). Anal. Calcd for C52H84Se2Th2: C, 46.92; H, 6.36. Found: C, 46.89; H, 6.39. Method B. NMR Scale. Se (1.6 mg, 0.02 mmol) was added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.5 mL). Resonances of 24, along with those of (2,4,6-tBu3C6H2P)2 [1H NMR (C6D6): δ 7.59 (s, 4H, phenyl), 1.57 (s, 36H, C(CH3)3), 1.29 (s, 18H, C(CH3)3). 31P{1H} NMR (C6D6): δ 493.3.],19 were observed by 1H NMR spectroscopy (100% conversion) when this solution was stored at room temperature for 2 days. Preparation of [η5-1,3-(Me3C)2C5H3]2Th(SPh)2 (25). Method A. This compound was obtained as colorless crystals from the reaction of 4 (188 mg, 0.1 mmol) and Ph2S2 (44 mg, 0.2 mmol) in toluene (15 mL) at room temperature and recrystallization from a benzene solution by a procedure similar to that described in the synthesis of 7. Yield: 146 mg (91%). Mp: 150−152 °C (dec). 1H NMR (C6D6): δ 7.79 (d, J = 8.1 Hz, 4H, phenyl), 7.11 (t, J = 7.7 Hz, 4H, phenyl), 6.92 (t, J = 7.4 Hz, 2H, phenyl), 6.22 (d, J = 2.7 Hz, 4H, ring CH), 6.13 (d, J = 2.7 Hz, 2H, ring CH), 1.34 (s, 36H, C(CH3)3). 13C{1H} NMR (C6D6): δ 151.9 (phenyl C), 143.2 (phenyl C), 133.8 (phenyl C), 128.9 (phenyl C), 125.2 (ring C), 116.2 (ring C), 113.4 (ring C), 34.0 (C(CH3)3), 32.2 (C(CH3)3). IR (KBr, cm−1): ν 2960 (s), 2902 (s), 2868 (s), 1577 (s), 1464 (s), 1359 (s), 1248 (s), 1080 (s), 1024 (s), 831 (s). Anal. Calcd for C38H52S2Th: C, 56.70; H, 6.51. Found: C, 56.72; H, 6.49. Method B. NMR Scale. A C6D6 (0.3 mL) solution of Ph2S2 (4.4 mg, 0.02 mmol) was slowly added to a J. Young NMR tube charged with 4 (19 mg, 0.01 mmol) and C6D6 (0.2 mL). Resonances of 25, along with those of 17, were observed by 1H NMR spectroscopy (100% conversion) when this solution was stored at room temperature overnight. X-ray Crystallography. Single-crystal X-ray diffraction measurements were carried out on a Rigaku Saturn CCD diffractometer at 100(2) K using Mο Kα radiation (λ = 0.71073 Å) or Cu Kα radiation (λ = 1.54184 Å). An empirical absorption correction was applied

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ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.8b03091. Crystal parameters for compounds 4−7, 9−16, and 18− 26 and computational studies (PDF) Cartesian coordinates of all stationary points optimized at the B3PW91-PCM level (XYZ) Accession Codes

CCDC 1873323−1873340 and 1873342−1873343 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/ data_request/cif, or by emailing [email protected]. uk, or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.

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AUTHOR INFORMATION

Corresponding Authors

*E-mail: [email protected] (G.Z.). *E-mail: [email protected] (W.D.). *E-mail: [email protected] (M.D.W.). ORCID

Guohua Hou: 0000-0002-3571-456X Guofu Zi: 0000-0002-7455-460X Marc D. Walter: 0000-0002-4682-8749 Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (Grants 21871029, 21472013, 21573021, and 21672024) and the Deutsche Forschungsgemeinschaft P


Article

Inorganic Chemistry

Sci. 2011, 2, 1320−1325. (n) Graham, T. W.; Udachin, K. A.; Zgierski, M. Z.; Carty, A. J. Synthesis and Structural Characterization of the First Thermally Stable, Neutral, and Electrophilic Phosphinidene Complexes of Vanadium. Organometallics 2011, 30, 1382−1388. (o) Rankin, M. A.; Cummins, C. C. Terminal phosphinidene formation via tantalaziridine complexes. Dalton Trans 2012, 41, 9615−9618. (p) Searles, K.; Carroll, P. J.; Mindiola, D. J. Anionic and Mononuclear Phosphinidene and Imide Complexes of Niobium. Organometallics 2015, 34, 4641−4643. (q) Normand, A. T.; Daniliuc, C. G.; Wibbeling, B.; Kehr, G.; Le Gendre, P.; Erker, G. Phosphidoand Amidozirconocene Cation-based Frustrated Lewis Pair Chemistry. J. Am. Chem. Soc. 2015, 137, 10796−10808. (r) Andrews, L.; Cho, H.-G. Matrix Infrared Spectra and Quantum Chemical Calculations of Ti, Zr, and Hf Dihydride Phosphinidene and Arsinidene Molecules. Inorg. Chem. 2016, 55, 8786−8793. (s) Stafford, H.; Rookes, T. M.; Wildman, E. P.; Balázs, G.; Wooles, A. J.; Scheer, M.; Liddle, S. T. Terminal Parent Phosphanide and Phosphinidene Complexes of Zirconium(IV). Angew. Chem., Int. Ed. 2017, 56, 7669−7673. (3) For select papers on other d transition-metal phosphinidene complexes, see: (a) Hitchcock, P. B.; Lappert, M. F.; Leung, W.-P. The First Stable Transition Metal (Molybdenum or Tungsten) Complexes Having a Metal-Phosphorus(III) Double Bond: the Phosphorus Analogues of Metal Aryl- and Alkyl-imides; X-Ray Structure of [Mo(η-C5H5)2(=PAr)] (Ar = C6H2But3-2,4,6). J. Chem. Soc., Chem. Commun. 1987, 1282−1283. (b) Sterenberg, B. T.; Udachin, K. A.; Carty, A. J. Reactivity of Electrophilic Terminal Phosphinidene Complexes: P-P Bond Forming Reactions with Phosphines and Diphosphines. Organometallics 2001, 20, 4463− 4465. (c) Sterenberg, B. T.; Udachin, K. A.; Carty, A. J. Electrophilic “Fischer Type” Phosphinidene Complexes of Molybdenum, Tungsten, and Ruthenium. Organometallics 2001, 20, 2657−2659. (d) Termaten, A. T.; Nijbacker, T.; Schakel, M.; Lutz, M.; Spek, A. L.; Lammertsma, K. Synthesis of Novel Terminal Iridium Phosphinidene Complexes. Organometallics 2002, 21, 3196−3202. (e) Melenkivitz, R.; Mindiola, D. J.; Hillhouse, G. L. Monomeric Phosphido and Phosphinidene Complexes of Nickel. J. Am. Chem. Soc. 2002, 124, 3846−3847. (f) Ehlers, A. W.; Baerends, E. J.; Lammertsma, K. Nucleophilic or Electrophilic Phosphinidene Complexes MLnPH; What Makes the Difference? J. Am. Chem. Soc. 2002, 124, 2831−2838. (g) Termaten, A. T.; Schakel, M.; Ehlers, A. W.; Lutz, M.; Spek, A. L.; Lammertsma, K. N-Heterocyclic Carbene Functionalized Iridium Phosphinidene Complex [Cp*(NHC)Ir = PMes*]: Comparison of Phosphinidene, Imido, and Carbene Complexes. Chem. - Eur. J. 2003, 9, 3577−3582. (h) Termaten, A. T.; Nijbacker, T.; Schakel, M.; Lutz, M.; Spek, A. L.; Lammertsma, K. Synthesis and Reactions of Terminal Osmium and Ruthenium Complexed Phosphinidenes [(η6-Ar)(L)M = PMes*]. Chem. - Eur. J. 2003, 9, 2200−2208. (i) Termaten, A. T.; Aktas, H.; Schakel, M.; Ehlers, A. W.; Lutz, M.; Spek, A. L.; Lammertsma, K. Terminal Phosphinidene Complexes CpR(L)M = PAr of the Group 9 Transition Metals Cobalt, Rhodium, and Iridium. Synthesis, Structures, and Properties. Organometallics 2003, 22, 1827−1834. (j) Sterenberg, B. T.; Udachin, K. A.; Carty, A. J. Terminal Aminophosphinidene Complexes of Iron, Ruthenium, and Osmium. Organometallics 2003, 22, 3927−3932. (k) Sánchez-Nieves, J.; Sterenberg, B. T.; Udachin, K. A.; Carty, A. J. A Thermally Stable and Sterically Unprotected Terminal Electrophilic Phosphinidene Complex of Cobalt and Its Conversion to an η1-Phosphirene. J. Am. Chem. Soc. 2003, 125, 2404−2405. (l) Sterenberg, B. T.; Senturk, O. S.; Udachin, K. A.; Carty, A. J. Reactivity of Terminal, Electrophilic Phosphinidene Complexes of Molybdenum and Tungsten. Nucleophilic Addition at Phosphorus and P-P Bond Forming Reactions with Phosphines and Diphosphines. Organometallics 2007, 26, 925−937. (m) Menye-Biyogo, R.; Delpech, F.; Castel, A.; Pimienta, V.; Gornitzka, H.; Rivière, P. Ruthenium-Stabilized Low-Coordinate Phosphorus Atoms. p-Cymene Ligand as Reactivity Switch. Organometallics 2007, 26, 5091−5101. (n) Aktas, H.; Slootweg, J. C.; Ehlers, A. W.; Lutz, M.; Spek, A. L.; Lammertsma, K. N-Heterocyclic

through the Heisenberg program (Grants WA 2513/6 and WA 2513/8).

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