Nucleophilic Addition Reactions to Allenylidene Complexes of

The complex [Cp*Ru═C═C═CPh2(iPr2PNHPy)][PF6] (2), prepared by reaction of [Cp*Ru(MeCN)(iPr2PNHPy)][PF6] (1) with HC≡CC(OH)Ph2, reacts with ...
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Organometallics 2011, 30, 726–737 DOI: 10.1021/om101013j

Nucleophilic Addition Reactions to Allenylidene Complexes of Ruthenium Bearing Hemilabile P,N Ligands: Isolation of the Vinylcarbene Complex [Cp*RudCHCHdCPh2(iPr2PNHPy)][PF6] Iqbal Hyder, Manuel Jimenez-Tenorio, M. Carmen Puerta,* and Pedro Valerga* Departamento de Ciencia de los Materiales e Ingenierı´a Metal urgica y Quı´mica Inorg anica, Facultad de Ciencias, Universidad de C adiz, 11510 Puerto Real, C adiz, Spain Received October 26, 2010

The complex [Cp*RudCdCdCPh2(iPr2PNHPy)][PF6] (2), prepared by reaction of [Cp*Ru(MeCN)( Pr2PNHPy)][PF6] (1) with HCtCC(OH)Ph2, reacts with primary amines, furnishing the corresponding vinylaminocarbenes, which are better formulated as the azoniabutadienyl derivatives [Cp*Ru{C(NHR)CHdCPh2}(iPr2PNHPy)][PF6] (R = Cy (6a), Me (6b), CH2CtCH (6c)). These species result from the nucleophilic attack of the amine at the CR atom of the allenylidene ligand. At variance with this, the reaction of 2 with cyclic secondary amines such as piperidine, pyrrolidine, and morpholine yields the Schrock-type vinylcarbene complex [Cp*RudCHCHdCPh2(iPr2PNHPy)][PF6] (7), which has been unequivocally characterized by X-ray structure analysis. This vinylcarbene complex is presumably formed by addition of the cyclic amine to the Cγ atom of the allenylidene through the intermediacy of a vinylidene complex. This intermediate vinylidene undergoes a retro-metallo-ene rearrangement, generating 7 plus the product of dehydrogenation of the amine. The reaction of 2 with thiophenol or pentafluorothiophenol afforded the thiocarbenes [Cp*Ru{C(SC6R5)CHdCPh2}(iPr2PNHPy)][PF6] (R = H (8H), F (8F)), which have been structurally characterized. Alternatively, the reaction of 2 with 



i





pyridine-2-thiol or pyrimidine-2-thiol leads to the thiocarbenes [Cp*Ru{κ2C,N-C(SC5H4N)CHdCPh2}(κ1P-iPr2NHPy)][PF6] (9Py) and [Cp*Ru{κ2C,N-C(SC4H3 NN)CHdCPh2}(κ1-P-iPr2NHPy)][PF6] (9Pym). In these compounds a new five-membered chelate ring has formed, and the iPr2NHPy ligand exhibits hemilabile character, changing its coordination mode from κ2P,N to κ1P.

Introduction Vinylcarbenes are known to act as unique intermediates in enyne metathesis.1 Ruthenium vinylcarbene complexes are formed by the reaction of alkynes with alkylidene or methylidene complexes (i.e., Grubbs-type catalysts).2 Vinylcarbenes are more stable than standard alkylidenes, due to conjugation by the vinyl group, and this stabilizing effect has a significant influence on the reactivity. In fact, the first well-defined group 8 metal carbene synthesized was a vinylcarbene, namely [RudCHCHCPh2(Cl)2(PR3)2] (R = Ph, Cy), which was prepared by reaction of [RuCl2(PPh3)3] with 3,3-diphenylcyclopropene.3 Apart from the reaction of alkylidenes with alkynes, there are other methods for producing *To whom correspondence should be addressed. E-mail: pedro.valerga@ uca.es (P.V.); [email protected] (M.C.P.). (1) Diver, S. T. Coord. Chem. Rev. 2007, 251, 671–701. (2) Lippstreu, J. J.; Straub, B. F. J. Am. Chem. Soc. 2005, 127, 7444– 7457. (3) (a) Nguyen, S. T.; Johnson, L. K.; Grubbs, R. H.; Ziller, J. W. J. Am. Chem. Soc. 1992, 114, 3974–3975. (b) Wu, Z.; Nguyen, S. T.; Grubbs, R. H.; Ziller, J. W. J. Am. Chem. Soc. 1995, 117, 5503–5511. (4) Schwab, P.; Grubbs, R. H.; Ziller, J. W. J. Am. Chem. Soc. 1996, 118, 100–110. (5) Niu, X.; Gopal, L.; Masingale, M. P.; Braden, D. A.; Hudson, B. S.; Sponsler, M. B. Organometallics 2000, 19, 649–660. pubs.acs.org/Organometallics

Published on Web 01/14/2011

vinylcarbenes: namely, the reaction of metal hydrides with propargylic halides4,5 and alkene metathesis.6 Vinylcarbenes have also been synthesized via nucleophilic addition to allenylidene intermediates most often generated in situ from propargylic alcohols.7-10 Protonation of neutral dienylmetal complexes is another route to vinylcarbene derivatives. Thus, the complexes [(η5-indenyl)RudCHCHdCRPh(dppm)][BF4] (R = H, Ph; dppm = 1,1-bis(diphenylphosphino)methane) have been obtained via one-pot synthesis by reaction of the monohydride [(η5-indenyl)RuH(dppm)] with HCtCCR(OH)Ph (R = H, Ph) in refluxing toluene followed by the addition of a stoichiometric amount of HBF4 3 OEt2.11 In this sense, the reactivity of allenylidene ligands attached to different (6) (a) Wilhelm, T. E.; Belderrain, T. R.; Brown, S. N.; Grubbs, R. H. Organometallics 1997, 16, 3867–3869. (b) Volland, M. A. O.; Rominger, F.; Eisentrager, F.; Hofmann, P. J. Organomet. Chem. 2002, 641, 220–226. (7) Cadierno, V.; Dı´ ez, J.; Gamasa, M. P.; Gimeno, J. Coord. Chem. Rev. 2004, 248, 1627–1657. (8) Pilette, D.; Ouzzine, K.; Le Bozec, H.; Dixneuf, P. H.; Rickard, C. E. F.; Roper, W. R. Organometallics 1992, 11, 809–817. (9) Esteruelas, M. A.; Lahoz, F. J.; O~ nate, E.; Oro, L. A.; Zeier, B. Organometallics 1994, 13, 4258–4265. (10) Pavlik, S.; Mereiter, K.; Puchberger, M.; Kirchner, K. Organometallics 2005, 24, 3561–3575. (11) Gamasa, M. P.; Gimeno, J.; Martı´ n-Vaca, B. M. Organometallics 1998, 17, 3707–3715. r 2011 American Chemical Society

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ruthenium fragments continues to attract much interest.7,12,13 In our research group we have been studying in detail the reactivity of allenylidene complexes of the type [Cp*RudCdCdCRR0 (P)2]þ ((P)2 = 1,2-bis(disopropylphophino)ethane (dippe),14-17 (PEt3)218,19) and [Cp*RudCdCdCPh2(CO)(PMeiPr2)]þ 20 toward nucleophiles and electrophiles. The reactivity of cationic allenylidene complexes is governed by the electron deficiency of both the CR and Cγ atoms of the unsaturated chain, and this is strongly dependent on the electron density at the metal center. Thus, addition to the Cγ was observed in the case of the electron-rich systems [Cp*RudCdCdCRR0 (P)2]þ ((P)2 = dippe, (PEt3)2).15-19 However, the introduction of a strong π-acceptor ligand such as CO modifies both the electronic and the steric properties of the metallic fragment, and in electronpoor systems of the type [(C5R5)RudCdCdCPh2(CO)(PR3)]þ (R = H, PR3 = PiPr3; R = Me, PR3 = PMeiPr2)20-24 products derived from the regioselective addition to CR of the allenylidene ligand have been isolated. The addition of electrophiles to Cβ of the allenylidene is less frequent and usually leads to dicationic vinylcarbyne derivatives such as [Cp*RutCCHdCRR0 (dippe)]2þ (R = R0 = Ph; R = H, R0 = Ph)15 or [Cp*Rut CCHdCRR0 (PEt3)2]2þ (R = R0 = Ph; R = H, R0 = Ph).19 We have prepared Cp*Ru complexes bearing the P,N-hybrid ligand ((diisopropylphosphino)amino)pyridine (iPr2PNHPy).25 P,Ndonor ligands have a great interest due to their potential hemilabile character because they can furnish complexes that behave as masked 16-electron coordinatively unsaturated species.26 We have now found that the addition of primary amines to the allenylidene complex [Cp*Rud CdCdCPh2(iPr2PNHPy)][PF6] takes place on CR, furnishing vinylaminocarbenes. However, the addition of cyclic secondary amines such as piperidine, pyrrolidine, and morpholine leads in an unprecedented manner to the formation of the stable Schrock-type vinylcarbene complex [Cp*RudCHCHdCPh2(iPr2PNHPy)][PF6], which has been structurally characterized. We have also studied the addition of sulfur-containing molecules to the allenylidene to yield novel vinylthiocarbene complexes. All these results are hereby presented.

Results and Discussion

(12) Cadierno, V.; Gimeno, J. Chem. Rev. 2009, 109, 3512–3560. (13) Byrne, L. T.; Koutsantonis, G. A.; Sanford, V.; Selegue, J. P.; Schauer, P. A.; Iyer, R. S. I. Organometallics 2010, 29, 1199– 1209. (14) de los Rı´ os, I.; Jimenez-Tenorio, M.; Puerta, M. C.; Valerga, P. J. Organomet. Chem. 1997, 549, 221. (15) Bustelo, E.; Jimenez-Tenorio, M.; Puerta, M. C.; Valerga, P.; Mereiter, K. Organometallics 2002, 21, 1903. (16) Bustelo, E.; Jimenez-Tenorio, M.; Puerta, M. C.; Valerga, P. Organometallics 2007, 26, 4300–4309. (17) Bustelo, E.; Jimenez-Tenorio, M.; Puerta, M. C.; Valerga, P. Eur. J. Inorg. Chem. 2001, 2391–2398. (18) Bustelo, E.; Jimenez-Tenorio, M.; Puerta, M. C.; Valerga, P. Organometallics 1999, 18, 4563–4573. (19) Pino-Chamorro, J. A.; Bustelo, E.; Puerta, M. C.; Valerga, P. Organometallics 2009, 28, 1546–1557. (20) Jimenez-Tenorio, M.; Palacios, M. D.; Puerta, M. C.; Valerga, P. J. Organomet. Chem. 2004, 689, 2776–2785. (21) Bernad, D. J.; Esteruelas, M.; L opez, A. M.; Olivan, M.; O~ nate, E.; Puerta, M. C.; Valerga, P. Organometallics 2000, 19, 4327– 4335. (22) Bernad, D. J.; Esteruelas, M.; L opez, A. M.; Modrego, J.; Puerta, M. C.; Valerga, P. Organometallics 1999, 18, 4995–5003. (23) Esteruelas, M.; G omez, A. V.; L opez, A. M.; O~ nate, E. Organometallics 1998, 17, 3567–3573. (24) Esteruelas, M.; G omez, A. V.; L opez, A. M.; Modrego, J.; O~ nate, E. Organometallics 1997, 16, 5826–5835. (25) Macı´ as-Arce, I.; Puerta, M. C.; Valerga, P. Eur. J. Inorg. Chem. 2010, 1767–1776. (26) Grotjahn, D. B. Dalton Trans. 2008, 6497–6508.

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The allenylidene complex [Cp*RudCdCdCPh2(iPr2PNHPy)][PF6] (2) has been prepared by reaction of the acetonitrile complex [Cp*Ru(MeCN)(iPr2PNHPy)][PF6] (1) with HCtCC(OH)Ph2 in 1,2-dichloroethane at 70 °C. This reaction takes place through the formation of an intermediate hydroxyvinylidene complex which undergoes spontaneous thermal dehydration, furnishing the deep purple allenylidene derivative. This is fully consistent with data in the literature7,12,14,17,18 and is supported by the isolation and characterization of the hydroxyvinylidene complexes [Cp*RudCdCHCH2OH(iPr2PNHPy)][Cl] (3)





and [Cp*RudCdCHC(OH)(CH2)4 CH2(iPr2PNHPy)][PF6] (4). These hydroxyvinylidene complexes are derived respectively from the reactions of the chloro complex [Cp*RuCl(iPr2PNHPy)] with propargyl alcohol in CH2Cl2 and of 1 with 1-ethynyl-1-cyclohexanol in 1,2-dichloroethane at 60 °C. At variance with the case of 2, the hydroxyvinylidene complexes 3 and 4 do not undergo dehydration to yield the corresponding allenylidene complexes. It is especially remarkable that 4 was recovered intact upon stirring for 12 h overnight in 1,2-dichloroethane in the presence of acidic alumina, which is known to trigger dehydration in systems which are more reluctant to undergo such a process. Alternatively, the reaction of 1 with 4-pentyn-1-ol in 1,2-dichloroethane yields the carbene complex [Cp*RudC{O(CH2)3 CH2}(iPr2PNHPy)][PF6] (5). This species results from the intramolecular nucleophilic attack of the OH group at the CR-Cβ bond of an intermediate hydroxyvinylidene complex, a process that is well precedented in the literature.10,27,28

Complexes 2-5 display the spectral properties anticipated for allenylidene, vinylidene, and carbene complexes, respectively, being unexceptional. One strong band in the IR spectrum of 2 at 1916 cm-1 is ascribed to the ν(CdCdC) stretching of the cumulated carbon-carbon bonds. The X-ray crystal structure of compound 2 was determined. An ORTEP view of the cation [Cp*RudCdCdCPh2(iPr2PCH2Py)]þ is shown in Figure 1, together with selected bond lengths and angles. The complex cation in 2 adopts a three-legged piano-stool geometry. The diphenylallenylidene ligand appears almost linearly assembled to ruthenium, as indicated by the C11C12-C13 and Ru1-C11-C12 angles of 169.7(2) and 144.09(19)°, respectively. The observed sequence of C-C bond distances across the carbon chain is quite representative of what is expected for an allenylidene ligand having (27) Kopf, H.; Pietraszuk, C.; H€ ubner, E.; Burzlaff, N. Organometallics 2006, 25, 2533–2546. (28) Beddoes, R. L.; Grime, R. W.; Hussain, Z. I.; Whiteley, M. W. J. Organomet. Chem. 1996, 526, 371–378.

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for which the following main resonance structures must be considered:20,22

Figure 1. ORTEP drawing (50% thermal ellipsoids) of [Cp*RudCdCdCPh2(iPr2PNHPy)]þ in 2. Hydrogen atoms have been omitted. Selected bond lengths (A˚) and angles (deg) with estimated standard deviations in parentheses: Ru1-P1 = 2.2977(10), Ru1-N2 = 2.121(2), Ru1-C1 = 2.216(2), Ru1C2 = 2.195(2), Ru1-C3 = 2.239(2), Ru1-C4 = 2.315(2), Ru1-C5 = 2.330(2), Ru1-C11 1.884(2), C11-C12 = 1.265(3), C12-C13 = 1.344(3), P1-N1 = 1.699(2), N2-Ru1-P1 = 79.70(6); C11-C12-C13 = 169.7(2), Ru1-C11-C12 = 174.09(19), C14-C13-C20 = 120.1(2).

substantial contribution of the alkynyl mesomer C of the three different forms

Thus, the bond distances Ru1-C11 = 1.884(2) A˚, C11C12 = 1.265(3) A˚, and C12-C13 = 1.344(3) A˚ compare well with the values found in other allenylidene complexes such as [Cp*RudCdCdCPh2)(PEt3)2][BPh4] (1.876(5), 1.245(7), and 1.352(8) A˚),18 [CpRudCdCdCPh2(PPh2NHPh)2][CF3SO3] (1.889(6), 1.270(8), and 1.356(8) A˚),10 and [CpRudCd CdCMePh(dippe)][BPh4] (1.884(5), 1.257(6), and 1.338(7) A˚).14 The dimensions of the iPr2PNHPy ligand match those found in the carbene complex [Cp*RudCHPh(iPr2PNHPy)][BAr0 4].25 We have studied the reactivity of 2 toward primary and secondary amines, as well as toward thiols. Scheme 1 summarizes the reactions studied in the present work. In the system under study, primary amines such as CyNH2, MeNH2, and HCtCCH2NH2 react with the allenylidene complex 2, adding to the CR-Cβ bond and furnishing the corresponding derivatives [Cp*Ru{C(NHR)CHdCPh2}(iPr2PNHPy)][PF6] (R = Cy (6a), Me (6b), CH2CtCH (6c)). In general, the addition of primary amines to the CR-Cβ bond of allenylidenes yields vinylaminocarbenes,

Structure A corresponds to a vinylaminocarbene, whereas B corresponds to an η1-azoniabutadienyl complex. The X-ray crystal structure of compound 6a was determined. An ORTEP view of the cation [Cp*Ru{C(NHCy)CHd CPh2}(iPr2PCH2Py)]þ is shown in Figure 2, together with selected bond lengths and angles. The Ru1-C11 bond length of 2.038(3) A˚ is longer than the value expected for a RudC bond, i.e. 1.916(7) A˚ in the carbene complex [Cp*RudCHPh(iPr2PNHPy)]þ,25 but is similar to the value of 2.020(4) A˚ reported for the azoniabutadienyl complex [Cp*Ru{C(NHCH2CtCH2)CHdCPh2}(CO)(PMeiPr2)]þ.20 The C11-N3 separation of 1.317(4) A˚ is intermediate between a single and a double carbon-nitrogen bond, whereas C11-C12 = 1.480(4) A˚ corresponds to a single C-C bond. These data suggest that for compound 6a there is a contribution of the azoniabutadienyl resonance structure B, which seems more important than structures A and C. According to this, complexes 6a-c are better formulated as azoniabutadienyl derivatives than as vinylaminocarbenes, just as is the case for the complexes [Cp*Ru{C(NRR0 )CHdCPh2}(CO)(PMeiPr2)]þ (R = R0 = iPr; R = H, R0 = Cy, CH2CtCH), previously reported by our research group.20 The 31P{1H} NMR spectra of 6a-c display broad resonances at 25 °C, which become sharper as the temperature increases. As the temperature is lowered, the resonances remain broad and no decoalescence has been observed down to -80 °C. For this reason, the reported spectral data for these complexes correspond to a temperature of þ80 °C, at which signals appear sharper and better resolved. This behavior has been previously observed by us, and it has been interpreted in terms of the restricted rotation around the C-N bond which originates two possible interconverting diastereoisomers, as in the case of complexes 6a-c:

We have determined that the difference in energy between the two diastereoisomers of the complex [Cp*Ru{C(NHCH2CtCH)CHdCPh2}(CO)(PMeiPr2)]þ was on the order of only 1 ( 0.1 kcal mol-1, whereas the activation energy barrier ΔGq has been estimated to be ca. 13 kcal mol-1.20 It seems reasonable to assume that for 6a-c the activation energy barrier is lower, as NMR data suggest. Whereas the addition of primary amines to 2 leads to azoniabutadienyl derivatives, we have observed an unprecedented

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Scheme 1

287.2 and 146.4 ppm in the 13C{1H} NMR spectrum, as indicated by a gHSQC 2D 1H-13C correlation experiment. No signals attributable to protons or carbon atoms of piperidine were observed. The reactions of 2 with other secondary cyclic amines such as pyrrolidine, morpholine, and substituted piperidines (4-methylpiperidine, 4-benzylpiperidine) led to the same yellow-green compound, although the rate of the reactions was found to be dependent on the nature of the cyclic amine, pyrrolidine being apparently the fastest. No reaction was observed with tetrahydroquinoline. This chemical evidence plus the spectral and analytical data led to the conclusion that in the course of these reactions the final metallic complex is a vinylcarbene complex formulated as [Cp*RudCHCHdCPh2(iPr2PNHPy)][PF6] (7).

Figure 2. ORTEP drawing (50% thermal ellipsoids) of [Cp*Ru{C(NHCy)CHdCPh2}(iPr2PNHPy)]þ in 6a. Hydrogen atoms have been omitted. Selected bond lengths (A˚) and angles (deg) with estimated standard deviations in parentheses: Ru1-P1 = 2.2678(8), Ru1-N1 = 2.137(3), Ru1-C1 = 2.279(3), Ru1C2 = 2.233(3), Ru1-C3 = 2.263(3), Ru1-C4 = 2.270(3), Ru1C5 = 2.262(3), Ru1-C11 = 2.038(3), C11-C12 = 1.480(4), C12-C13 = 1.345(4), C11-N3 = 1.317(4), P1-N2 = 1.704(3), N1-Ru1-P1 = 79.61(7); Ru1-C11-C12 = 119.0(2), Ru1C11-N3 = 123.6(2), C12-C11-N3 = 117.4(3), C11-C12C13 = 133.3(3).

transformation when cyclic secondary amines were used. Thus, the reaction of 2 with piperidine in THF or dichloromethane afforded a greenish yellow solution, from which a yellow-green crystalline material was obtained. This compound showed in the 1H NMR spectrum a doublet of doublets at very low field (15.36 ppm), in the region characteristic for protons attached to the R-carbon atom of a carbene ligand. In a gCOSY 2D spectrum, this proton was shown to be correlated with a doublet signal at 6.94 ppm, with a coupling constant of 13.4 Hz. These relevant signals in the 1H NMR spectrum at 15.36 and 6.94 ppm were respectively correlated with resonances at

This was confirmed by the determination of the X-ray crystal structure of compound 7. An ORTEP view of the cation [Cp*RudCHCHdCPh2(iPr2PCH2Py)]þ is shown in Figure 3, together with selected bond lengths and angles. To our knowledge, this represents the first report of the structure of a half-sandwich ruthenium Schrock-type vinylcarbene complex, since all structure records in the Cambridge Crystallographic Data Centre database for half-sandwich ruthenium vinylcarbenes correspond to Fischer-type derivatives. The complex cation in 7 has the standard three-legged piano-stool structure, with the least-squares plane Ru1-C11-C12-C13 forming an angle of ca. 23° with the plane defined by C11, Ru1, and the centroid of the C5 ring of the Cp* ligand. The vinylcarbene ligand adopts a disposition in which the hydrogen atom of the carbene atom points toward the Cp* group and the diphenyvinyl moiety points away in order to minimize the steric pressure. The Ru1-C11 bond length of 1.913(3) A˚ is longer than the separations observed in other diphenylvinylcarbenes such as

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to an intermediate π-alkynol complex was postulated, with no involvement of allenylidene species. Dixneuf and co-workers have reported the formation of the cationic vinylcarbene complexes [(η6-cymene)RudCHCHdCRR0 (Cl)(PCy3)]þ (RR0 = Ph2, -(CH2)5-) which were characterized in situ by NMR spectroscopy at -30 °C.32 These carbene complexes decompose at room temperature and have been shown to be highly metathesis active. They were generated by intramolecular hydride transfer from allyl or propyl propargyl ethers, with elimination of either acrolein or propanal.

Figure 3. ORTEP drawing (50% thermal ellipsoids) of [Cp*RudCHCHdCPh2(iPr2PNHPy)]þ in 7. Hydrogen atoms have been omitted. Selected bond lengths (A˚) and angles (deg) with estimated standard deviations in parentheses: Ru1-P1 = 2.2874(10), Ru1-N1 = 2.118(3), Ru1-C1 = 2.231(3), Ru1C2 = 2.237(3), Ru1-C3 = 2.331(3), Ru1-C4 = 2.339(3), Ru1-C5 = 2.252(3), Ru1-C11 = 1.913(3), C11-C12 = 1.434(4), C12-C13 = 1.353(4), P1-N2 = 1.697(3); N1-Ru1P1 = 79.14(7), Ru1-C11-C12 = 123.9(5), C11-C12-C13 = 124.9(3).

[RudCHCHdCPh2(Cl)2(tBu2PCH2PtBu2)] (1.838(6) A˚)29 and [RudCHCHdCPh2(Cl)(CO)(PiPr3)2][BF4] (1.874(3) A˚)9 but is essentially identical with the value of 1.916(7) A˚ measured for the Ru-C bond distance in the carbene [Cp*RudCHPh(iPr2PNHPy)][PF6].25 The Ru1-C11-C12 bond angle of 123.9(5)° is fully consistent with sp2 hybridization for the C11 atom. The sequence of bond lengths observed for the Ru1C11-C12-C13 chain and the deviations of the C11-C12 and C12-C13 separations from the mean values described for double and single C-C bonds suggest a certain delocalization of the electron density in the vinylcarbene. The dimensions of the Cp* and iPr2PNHPy ligand are within expected parameters, being unexceptional. Although Fischer-type vinylcarbene complexes are readily formed by addition of alcohols to allenylidene complexes, the formation of a ruthenium vinylcarbene bearing a hydrogen atom at the R-carbon atom starting from a discrete allenylidene complex had never been observed before. In the case of osmium, the complex [OsH(dCdCdCPh2)(CH3CN)2(PiPr3)2][BF4] reacts with primary and secondary alcohols to give the corresponding dehydrogenated alcohol and the hydride-carbene derivative [OsH(dCHCHdCPh2)(CH3CN)2(PiPr3)2][BF4], as result of hydrogen transfer reactions from the alcohol to the CR-Cβ bond of the allenylidene ligand.30 Very recently, our research group has reported the formation of the heterocyclic vinylcarbene species [Cp*Ru{dCHC(NPiPr2CH2CH2NHPiPr2)dCPh2-κ3P,P,C}]þ in the course of the reaction of [Cp*Ru(N2)(dippae)]þ (dippae = 1,2-bis((diisopropylphosphino)amino)ethane) with HCtCC(OH)Ph2.31 However in this case, intramolecular NH addition (29) Volland, M. A. O.; Hansen, S. M.; Rominger, F.; Hofmann, P. Organometallics 2004, 23, 800–816. (30) Bola~ no, T.; Castarlenas, R.; Esteruelas, M. A.; O~ nate, E. J. Am. Chem. Soc. 2007, 129, 8850–8859. (31) Puerta, M. C.; Valerga, P.; Palacios, M. D. Inorg. Chem. 2008, 47, 8598–8600.

The reaction of the 16-electron complex with the propargyl ester affords a vinylidene intermediate which generates the vinylcarbene upon a retro-metallo-ene rearrangement.32 A somewhat related process, very relevant to metathesis catalysis, is the transformation of a diphenylallenylidene ligand into an indenylidene by thermal- or acid-induced activation of an ortho C-H bond of one of the phenyl rings.33,34

In our system, the formation of 7 starting from 2 can be viewed formally as a hydrogenation of the allenylidene ligand. However, complex 2 does not react with H2 even after prolonged exposure. Addition of the cyclic secondary amine to the R-carbon of 2 to yield a vinylaminocarbene (or azoniabutadienyl complex) would have been the anticipated reaction product, as in the case of compounds 6a-c. We have rationalized the formation of the vinylcarbene, assuming that in this particular case the cyclic secondary amine attacks at the γ-position of the allenylidene ligand, very much as it occurs in the case of electron-rich allenylidene complexes. The result is the addition of the amine to the Cβ-Cγ bond of the allenylidene and formation of an intermediate vinylidene complex. A retro-metallo-ene rearrangement, formally analogous to that described above for the complex [(η6-cymene)RudCHCHdCRR0 (Cl)(PCy3)]þ (32) Castarlenas, R.; Eckert, M.; Dixneuf, P. H. Angew. Chem., Int. Ed. 2005, 44, 2576–2579. (33) Lozano-Vila, A. M.; Monsaert, S.; Bajek, A.; Verpoort, F. Chem. Rev. 2010, 110, 4865–4909. (34) Antonucci, A.; Bassetti, M.; Bruneau, C.; Dixneuf, P. H.; Pasquini, C. Organometallics 2010, 29, 4524–4531.

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from propargyl esters, would produce the vinylcarbene complex 7 plus 2,3,4,5-tetrahydropyridine:

A experiment performed using piperidine deuterated at the nitrogen atom showed the presence of deuterium at Cβ of the vinylcarbene, an observation consistent with the formation of the intermediate vinylidene complex. We have also carried out diverse experiments in order to trap and identify the amine-derived product. However, the attempts made did not allow the unequivocal characterization of the organic product. It is known that 2,3,4,5-tetrahydropyridine and its substituted derivatives have a strong tendency to undergo trimerization, furnishing tripiperidines or iso-tripiperidines depending on the conditions. In the presence of water, 2,3,4,5-tetrahydropyridine appears to be in equilibrium with 5-aminopentanal.35,36

The instability of these kinds of piperidine derivatives makes their isolation and purification difficult. In any case, the formation of the vinylcarbene complex 7 at the expense of pyrrolidine, piperidine, or morpholine is fully reproducible. There are known examples of the standard addition of piperidine to the CR-Cβ bond of allenylidene complexes (35) Ogawa, K.; Nomura, Y.; Takeuchi, Y.; Tomoda, S. J. Chem. Soc., Perkin Trans. 1982, 3031–3035. (36) Claxton, G. P.; Allen, L.; Grisar, J. M. Org. Synth. 1977, 56, 118.

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leading to azoniabutadienyl derivatives.22 However, the reactivity pattern observed in our system suggests the possibility that, at least in some instances, an allenylidene ligand can be readily transformed into a Schrock-type vinylcarbene. This is a remarkable finding, given the potential application of such vinylcarbene complexes as catalysts in olefin and enyne metathesis reactions. Following our proposal for the formation of 7, this would imply the initial attack of the cyclic secondary amine at the Cγ of the allenylidene, a process that is known to occur in electron-rich allenylidene complexes.15-19 The general scope of this reaction as a synthetic tool for the preparation of vinylcarbene complexes is currently being explored. The cationic complex 7 has shown so far to be inactive as a catalyst for the benchmark ring closure metathesis reaction of diallyl diethylmalonate (conditions: 5% catalyst load, CH2Cl2, 25 °C). Other cationic vinylcarbene complexes of ruthenium have also been shown to be inactive toward RCM, this being attributed to the fact that they are 18-electron species that require a vacant coordination site in order to become potentially active.1,33 The addition of thiophenol and pentafluorothiophenol to the CR-Cβ bond of the allenylidene ligand in 2 results formally in the formation of the thiocarbene complexes [Cp*Ru{C(SC6R5)CHdCPh2}(iPr2PNHPy)][PF6] (R = H (8H), F (8F)). Both compounds were structurally characterized by single-crystal X-ray diffraction. ORTEP views of the cations [Cp*Ru{C(SPh)CHdCPh2}(iPr2PNHPy)]þ and [Cp*Ru{C(SC 6F 5)CHdCPh 2}(i Pr 2PNHPy)]þ are respectively shown in Figures 4 and 5, together with selected bond lengths and angles. Both cationic complexes show “three-legged piano-stool” structures, as expected. In both structures, the plane defined by C11, S1, and C12 forms a dihedral angle of ca. 41° with the plane defined by C11, Ru1, and the centroid of the C5 ring of the Cp* ligands. Interestingly, the planes defined by one of the phenyl rings (C20-C25) and the carbon atoms of the pentafluorophenyl ring (C26-C31) in 8F are almost perfectly parallel to each other. The Ru1-C11 bond lengths have values of 1.936(4) and 1.947(7) A˚, respectively, for 8H and 8F. These values are similar to the Ru-C separation of 1.913(3) A˚ found in the vinylcarbene complex 7 and are shorter than the separation of 2.065(7) A˚ found for [Cp*Ru{C(SnPr)CHdCPh2}(CO)(PMeiPr2)][BAr0 4].20 On the other hand, the C11-S1 bond distances are consistent with a C-S single bond (1.75-1.79 A˚). As happens with the vinylaminocarbenes, we can consider the following main resonance structures for a vinylthiocarbene:

The observed sequence of bond lengths suggests that the contribution of the structure A is more important, and hence complexes 8H,F can be better considered as thiocarbenes rather than η1-thiabutadienyl derivatives. The resonance for the CR atom appears as a doublet in the 13C{1H} NMR spectrum at 297.2 ppm for 8H and 288.0 ppm for 8F. This represent a shift to lower field with respect to the position of the resonances for the CR atoms in the azoniabutadienyl

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of the reaction of 2 with HSPrn, most likely due to the reaction of the allenylidene with the small amounts of water present. This compound can be easily obtained by reaction of 1 with CO. Its spectral data and X-ray crystal structure have been deposited as part of the Supporting Information. Pyridine-2-thiol is known to react with allenylidene complexes to yield diheterocyclization derivatives resulting from the addition of the SH to the CR-Cβ bond of the allenylidene and attack of the nitrogen atom of the pyridine moiety at Cγ to close a six-membered ring:23



The reaction of 2 with pyridine-2-thiol or pyrimidine-2-thiol also takes place with addition of the SH to the CR-Cβ bond of the allenylidene ligand to furnish thiocarbene complexes. However, in these instances decoordination of the pyridyl substituent of the phosphinopyridine ligand occurs, and the vacancy is replaced by the nitrogen atom of the pyridine-2-thiol or pyrimidine-2-thiol. Hence, the iPr2PNHPy ligand exhibits hemilabile character, changing its coordination mode from κ2P,N to κ1P, resulting in the formation of the carbene complexes 

Figure 4. ORTEP drawing (50% thermal ellipsoids) of [Cp*Ru{C(SPh)CHdCPh2}(iPr2PNHPy)]þ in 8H. Hydrogen atoms have been omitted. Selected bond lengths (A˚) and angles (deg) with estimated standard deviations in parentheses: Ru1-P1 = 2.3059(11), Ru1-N2 = 2.123(3), Ru1-C1 = 2.301(4), Ru1C2 = 2.311(4), Ru1-C3 = 2.255(4), Ru1-C4 = 2.273(4), Ru1-C5 = 2.248(4), Ru1-C11 = 1.937(4), C11-C12 = 1.466(5), C12-C13 = 1.335(5), C11-S1 = 1.746(4), P1-N1 = 1.700(3); N2-Ru1-P1 = 79.38(9), Ru1-C11-C12 = 129.2(3), Ru1-C11-S1 = 115.24(19), C12-C11-S1 = 114.3(3), C11C12-C13 = 131.5(3).





[Cp*Ru{κ2C,N-C(SC5H4N)CHdCPh2}(κ1P-iPr2NHPy)][PF6] (9Py) and [Cp*Ru{κ2C,N-C(SC4H3NN)CHdCPh2}(κ1P-iPr2NHPy)][PF6] (9Pym), which are new five-membered metallacycles:

complexes 6a-c, consistent with the formulation of 8H,F as thiocarbene species. We have studied the reaction of the allenylidene 2 with other thiols. The carbonyl complex [Cp*Ru(CO)(iPr2PNHPy)][PF6] was serendipitously obtained in the course





The X-ray crystal structures of 9Py and 9Pym were deter

mined. ORTEP views of the cations [Cp*Ru{C(SC5H4 N)

Figure 5. ORTEP drawing (50% thermal ellipsoids) of [Cp*Ru{C(SC6F5)CHdCPh2}(iPr2PNHPy)]þ in 8F. Hydrogen atoms have been omitted. Selected bond lengths (A˚) and angles (deg) with estimated standard deviations in parentheses: Ru1P1 = 2.305(2), Ru1-N2 = 2.149(6), Ru1-C1 = 2.270(7), Ru1-C2 = 2.241(8), Ru1-C3 = 2.274(8), Ru1-C4 = 2.287(8), Ru1-C5 = 2.241(8), Ru1-C11 = 1.947(7), C11-C12 = 1.457(10), C12-C13 = 1.342(10), C11-S1 = 1.740(7), P1N1 = 1.697(6); N2-Ru1-P1 = 79.16(16), Ru1-C11-C12 = 124.2(5), Ru1-C11-S1 = 114.5(4), C12-C11-S1 = 120.9(5), C11-C12-C13 = 134.2(7).

CHdCPh2}(iPr2PNHPy)]þ and [Cp*Ru{C(SC5H3NN)CHd CPh2}(iPr2PNHPy)]þ are respectively shown in Figures 6 and 7, together with selected bond lengths and angles. Both complexes adopt the typical “three-legged pianostool” structures, being essentially identical except for the differences in the pyridine and pyrimidine rings. The most

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consistent with their formulation as thiocarbene complexes. The X-ray crystal structures allow the correct interpretation of 31P{1H} NMR data for these compounds. The resonance in the 31P{1H} NMR spectra of both 9Py and 9Pym exhibits a chemical shift of ca. 90 ppm. This represents a very significant high-field shift with respect to the position of the resonances of the other complexes studied in the present work, which are all in the range 126-142 ppm. The differences in chemical shift are due to the different coordination modes of the iPr2PNHPy ligand in each of these complexes. The position of the 31P{1H} NMR resonance of the κ1P-iPr2PNHPy ligand is intermediate between that of a κ2P,N-iPr2PNHPy ligand and the free iPr2PNHPy molecule (49.6 ppm). Finally, the chemical shift for the CR resonances in the 13C{1H} NMR spectra (ca. 290 ppm) is fully consistent for a heterosubstituted carbenic atom. The formation of the metallacyclic thiocarbenes 9Py and 9Pym bears some resemblance to the reaction of the allenylidene complex [TpRud CdCdCPh2(PPh3)2]þ (Tp = hydrotris(pyrazolyl)borate) with NaS2CNMe2 to afford the neutral allenyl metallacycle 

Figure 6. ORTEP drawing (50% thermal ellipsoids) of [Cp*Ru{C(SC5H4N)CHdCPh2}(iPr2PNHPy)]þ in 9Py. Hydrogen atoms have been omitted. Selected bond lengths (A˚ ) and angles (deg) with estimated standard deviations in parentheses: Ru1-P1 = 2.371(2), Ru1-N1 = 2.075(6), Ru1-C1 = 2.254(7), Ru1-C2 = 2.213(7), Ru1-C3 = 2.277(7), Ru1-C4 = 2.286(7), Ru1-C5 = 2.278(7), Ru1-C11 = 1.923(7), C11-C12 = 1.451(10), C12-C13 = 1.361(10), C11-S1 = 1.749(7), P1-N2 = 1.677(6); N1-Ru1-C11=82.8(3), N1-Ru1-P1=91.16(17), Ru1-C11-C12 = 123.8(5), Ru1-C11-S1 = 120.7(4), C12C11-S1 = 114.9(5), C11-C12-C13 = 133.2(7).

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[TpRu{κ2C,S-C(dCdCPh2)SC(NMe2) S}(PPh3)].37 This complex is the result of the nucleophilic addition of one of the sulfur atoms of the dithiocarbamate to CR of the allenylidene and subsequent coordination of the second sulfur to Ru with release of one PPh3. In our case, the isolation of compounds 9Py and 9Pym is very relevant, not only because it demonstrates the hemilabile character of the iPr2PNHPy ligand but also because it suggests that, under the appropriate conditions, decoordination of the pyridyl group might take place. This process would leave a vacant coordination site, enabling the carbene complex to be potentially metathesis active. This is particularly attractive with regard to the vinylcarbene complex 7, which seems to be most promising in this sense.

Conclusions





Figure 7. ORTEP drawing (50% thermal ellipsoids) of [Cp*Ru{C(SC4H3 NN)CHdCPh2}(iPr2PNHPy)]þ in 9Pym. Hydrogen atoms have been omitted. Selected bond lengths (A˚) and angles (deg) with estimated standard deviations in parentheses: Ru1-P1=2.3740(8), Ru1-N1=2.068(2), Ru1-C1=2.251(3), Ru1-C2=2.278(3), Ru1-C3=2.296(3), Ru1-C4=2.284(3), Ru1-C5=2.217(3), Ru1-C11=1.933(3), C11-C12=1.451(10), C12-C13 = 1.361(10), C11-S1 = 1.763(3), P1-N3 = 1.695(2); N1-Ru1-C11 = 83.54(10), N1-Ru1-P1 = 91.07(6), Ru1C11-C12 = 125.25(19), Ru1-C11-S1 = 119.31(14), C12C11-S1 = 113.88(19), C11-C12-C13 = 132.1(2).

relevant feature in these two compounds is the decoordination of the pyridyl group of the iPr2PNHPy ligand, which is now dangling, and the formation of a new five-membered chelate ring. The new Ru1-N1 bond lengths are slightly shorter than those in the thiocarbene complexes 8H,F. This suggests stronger Ru-N bonding in 9Py/9Pym. The Ru-C separations are similar to those in 8H,F and hence are

The reactions of the allenylidene complex [Cp*RudCd CdCPh2(iPr2PNHPy)]þ with primary amines and thiols lead respectively to the formation of azabutadienyl and thiocarbene complexes, resulting from the addition of the N-H or S-H bond to the CR-Cβ bond of the allenylidene ligand. At variance with this, the reaction of 2 with cyclic secondary amines such as piperidine, pyrrolidine, and morpholine leads to the stable Schrock-type vinylcarbene complex [Cp*Rud CHCHdCPh2(iPr2PNHPy)]þ, in a process for which no precedent has been found in the literature. The formation of the vinylcarbene 7 has been rationalized by assuming the attack of piperidine at Cγ of the allenylidene ligand to yield an intermediate vinylidene complex which generates the final product upon a retro-metallo-ene rearrangement and release of 1,2,3,4-tetrahydropyridine. This preparative procedure opens up the possibility of converting allenylidene complexes into vinylcarbenes. Preliminary experiments indicate that complex 7 is not active in ring-closure metathesis (RCM). The creation of a vacant coordination site is required for a carbene to be potentially active in metathesis, and that is feasible with the use of a hemilabile ligand. This has been observed in the course of the reaction of 2 with pyridine-2-thiol or pyrimidine-2-thiol. In these reactions, the iPr2PNHPy ligand (37) Buriez, B.; Cook, D. J.; Harlow, K. J.; Hill, A. F.; Welton, T.; White, A. J. P.; Williams, D. J.; Wilton-Ely, J. D. E. T. J. Organomet. Chem. 1999, 578, 264–267.

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(38) Steinmetz, B.; Schenk, W. A. Organometallics 1999, 18, 943–946.



All synthetic operations were performed under a dry dinitrogen or argon atmosphere following conventional Schlenk techniques. Tetrahydrofuran, diethyl ether, and petroleum ether (boiling point range 40-60 °C) were obtained oxygen- and water-free from an Innovative Technology, Inc. solvent purification apparatus. Dichloromethane and 1,2-dichloroethane were of anhydrous quality and were used as received. All solvents were deoxygenated immediately before use. (Diisopropylphosphinyl)(2-pyridyl)amine and the complexes [Cp*Ru(MeCN)3][PF6] and [Cp*RuCl(iPr2PNHPy)] were prepared according to reported procedures.25,38 IR spectra were recorded in Nujol mulls with a Perkin-Elmer FTIR Spectrum 1000 spectrophotometer. NMR spectra were taken on Varian Inova 400 MHz, Varian Inova 600 MHz, and Varian Gemini 300 MHz equipment. Chemical shifts are given in ppm from SiMe4 (1H and 13C{1H}) or 85% H3PO4 (31P{1H}). 1H and 13C{1H} NMR spectroscopic signal assignments were confirmed by 1H-gCOSY, DEPT, and gHSQC (1H-13C) experiments when required. Microanalyses were performed with a LECO CHNS-932 elemental analyzer at the Servicio Central de Ciencia y Tecnologı´ a, Universidad de Cadiz. [Cp*Ru(MeCN)(iPr2PNHPy)][PF6] (1). To a solution of [Cp*Ru(MeCN)3][PF6] (0.5 g, 1 mmol) in dichloromethane (10 mL) was added the stoichiometric amount of the phosphinoamine iPr2PNHPy (0.21 g, ca. 1 mmol). The resulting mixture was stirred at room temperature for 1 h. Then, the solvent was removed in vacuo, and the resulting solid was washed with several portions of petroleum ether (10 mL each) until a dark yellow solid was obtained. Yield: 0.46 g, 73%. Anal. Calcd for C23H37N3F6P2Ru: C, 43.7; H, 5.90; N, 6.6. Found: C, 43.9; H, 6.18; N, 6.4. 1H NMR (400 MHz, CDCl3, 298 K): δ 0.92-1.02 (m, 12 H, P(CH(CH3)2)2), 1.65 (s, 15 H, C5(CH3)5), 2.23, 2.66 (m, 1 H each, P(CH(CH3)2)2), 2.63 (s, 3 H, CH3CN), 6.24 (d, 2 JHP = 5 Hz, 1 H, NH), 6.59 (t), 6.93 (d), 7.32 (t), 8.07 (d) (1 H each, C5H4N). 31P{1H} NMR (161.89 MHz, CDCl3, 298 K): δ 126.2 (s). 13C{1H} NMR (100.57 MHz, CDCl3, 298 K): δ 3.9 (s, CH3CN), 10.2 (s, C5(CH3)5), 15.7 (d), 17.6 (d), 18.0 (s), 18.1 (s) (P(CH(CH3)2)2), 28.2 (d, 1JCP = 26 Hz, P(CH(CH3)2)), 28.4 (d, 1 JCP = 20 Hz, P(CH(CH3)2)), 86.3 (s, C5(CH3)5), 109.8 (d), 115.3 (s), 137.5 (s), 151.6 (s), 162.4 (d) (C5H4N), 124.9 (CH3CN). [Cp*RudCdCdCPh2(iPr2PNHPy)][PF6] (2). To a solution of 1 (1.26 g, 2 mmol) in 1,2-dichloroethane (8 mL) was added an excess of HCtCC(OH)Ph2 (0.625 g, 3 mmol). The mixture was stirred for 6 h at 70 °C. During this period, the color changed from yellow-orange to dark purple. The resulting solution was filtered through Celite, and the solvent was removed in vacuo. The residue was washed with petroleum ether until a dark purple solid was obtained and then dried in vacuo. Yield: 1.20 g, 77%. Anal. Calcd for C36H44N2F6P2Ru: C, 55.3; H, 5.67; N, 3.6. Found: C, 55.5; H, 5.48; N, 3.5. IR (Nujol, cm-1): ν(NH) 3365, ν(CdCdC) 1916. 1H NMR (400 MHz, CDCl3, 298 K) δ 0.76-0.79 (m, 12 H, P(CH(CH3)2)2), 1.82 (s, 15 H, C5(CH3)5), 2.08, 2.77 (m, 1 H each, P(CH(CH3)2)2), 6.45 (t, 1 H, C5H4N), 6.89 (d, 1 H, NH), 7.16-7.28, 7.43-7.51 (m, 13 H, C5H4N þ C6H5). 31P{1H} NMR (161.89 MHz, CDCl3, 298 K): δ 137.6 (s). 13 C{1H} NMR (100.57 MHz, CDCl3, 298 K): δ 10.9 (s, C5(CH3)5), 15.7 (d), 16.7 (d), 17.2 (d), 17.9 (d) (P(CH(CH3)2)2), 29.3 (d, 1JCP = 20 Hz, P(CH(CH3)2)), 29.7 (d, 1JCP = 19 Hz,

[Cp*RudCdCH{C(OH)(CH2)4CH2}(iPr2PNHPy)][PF6] (4). A mixture containing 1 (0.31 g, 0.49 mmol) and a slight excess of 1-ethynyl-1-cyclohexanol (70 mg, 0.56 mmol) in 1,2-dichloroethane (10 mL) was stirred at 60 °C for 14 h. Upon cooling, the solvent was removed in vacuo, and the resulting brown solid was washed with several portions of petroleum ether. Yield: 0.32 g, 95%. Anal. Calcd for C29H46N2F6OP2Ru: C, 48.7; H, 6.48; N, 3.9. Found: C, 48.9; H, 6.64; N, 3.8. 1H NMR (400 MHz, CDCl3, 298 K): δ 0.98, 1.19, 1.21, 1.28 (m, 3 H each, P(CH(CH3)2)2), 1.11, 1.44, 2.12, (m, 10 H in total, (CH2)5), 1.62 (d, JHP = 1 Hz, 15 H, C5(CH3)5), 2.25, 2.86 (m, 1 H each, P(CH(CH3)2)2), 4.88 (s, 1 H, CdCH), 6.56 (t), 7.20 (d), 7.29 (d), 7.44 (t) (1 H each, C5H4N), 6.96 (s br, 1 H, NH). 31P{1H} NMR (161.89 MHz, CDCl3, 298 K): δ 134.8 (s). 13C{1H} NMR (100.57 MHz, CDCl3, 298 K): δ 10.8 (s, C5(CH3)5), 16.3 (d), 17.4 (d), 17.8 (d), 18.4 (d) (P(CH(CH3)2)2), 22.5, 25.9, 28.9 (s, C(OH)(CH2)5), 29.9 (d, 1JCP = 20 Hz, P(CH(CH3)2)), 30.8 (d, 1JCP = 36 Hz, P(CH(CH3)2)), 76.6 (s, C(OH)(CH2)5), 102.4 (d, JCP = 2 Hz, C5(CH3)5), 110.8 (d), 116.5 (d), 139.6 (s), 152.8 (s), 162.8 (d) (C5H4N), 120.5 (s, RudCdCH), 353.6 (d, 3JCP = 17 Hz, RudC). 

Experimental Section

P(CH(CH3)2)), 100.7 (d, JCP = 2 Hz, C5(CH3)5), 110.8 (d), 115.6 (s), 138.5 (s), 152.6 (s), 155.2 (d) (C5H4N), 125.9, 127.0, 129.2, 130.1, 131.5 (s, C6H5), 144.1 (RuCdCdC), 212.5 (d, 3JCP = 5 Hz, RuCdCdC), 284.5 (d, 3JCP = 16 Hz, RuCdCdC). [Cp*RudCdCHCH2OH(iPr2PNHPy)][Cl] (3). To a solution of [Cp*RuCl(iPr2PNHPy)] (0.24 g, 0.5 mmol) in dichloromethane was added 2-propyn-1-ol (30 μL, ca. 0.5 mmol). The mixture was stirred for 14 h at room temperature. At the end of this time, the solvent was removed in vacuo, and the resulting solid was washed with petroleum ether until an orange microcrystalline solid was obtained. Yield: 0.26 g, 95%. Anal. Calcd for C24H38N2ClOPRu: C, 53.6; H, 7.12; N, 5.2. Found: C, 53.7; H, 7.22; N, 5.1. 1H NMR (400 MHz, CD3COCD3, 298 K) δ 0.94-1.40 (m, 12 H, P(CH(CH3)2)2), 1.81 (s, 15 H, C5(CH3)5), 2.17, 2.84 (m, 1 H each, P(CH(CH3)2)2), 4.04 (d, 3JHH = 8 Hz, 2 H, CH2OH), 4.44 (dd, 3JHH = 8 Hz, 4JHP = 8 Hz, 1 H, CdCH), 6.51 (t, 1 H), 7.38 (m, 2 H), 7.49 (d, 1 H) (C5H4N), 10.8 (s br, 1 H, NH). 31P{1H} NMR (161.89 MHz, CD3COCD3, 298 K): δ 136.2 (s). 13C{1H} NMR (100.57 MHz, CDCl3, 298 K): δ 10.8 (s, C5(CH3)5), 15.6 (d), 16.1 (d), 16.7 (d), 17.4 (d) (P(CH(CH3)2)2), 26.5 (d, 1JCP = 82 Hz, P(CH(CH3)2)), 29.5 (d, 1 JCP = 63 Hz, P(CH(CH3)2)), 52.6 (s, CH2OH), 101.2 (d, JCP = 1 Hz, C5(CH3)5), 111.6 (d), 112.8 (d), 138.4 (s), 152.4 (s), 164.1 (d) (C5H4N), 115.4 (s, RudCdCH), 341.7 (d, 3JCP = 14.5 Hz, RudC). 

changes its coordination mode from chelating κ2P,N to monodentate κ1P, and the allenylidene ligand undergoes addition of the SH bond at the CR-Cβ bond. Subsequent coordination of the pyridyl or pyrimidinyl group to ruthenium produces new five-membered chelate rings and generates the final products, the metallacyclic thiocarbene complexes 9Py and 9Pym.

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[Cp*RudC{O(CH2)3 CH2}(iPr2PNHPy)][PF6] (5). To a solution of 1 (0.28 g, 0.45 mmol) in 1,2-dichloroethane (8 mL) was added an excess of 4-pentyn-1-ol (85 μL, 0.91 mmol). The mixture was stirred at 60 °C for 4 h. Then, the solvent was removed in vacuo, and the residue was washed with diethyl ether and petroleum ether until a light brown solid was obtained. Yield: 0.29 g, 95%. Anal. Calcd for C26H42N2F6OP2Ru: C, 46.2; H, 6.27; N, 4.2. Found: C, 46.4; H, 6.41; N, 4.0. 1H NMR (400 MHz, CD2Cl2, 298 K): δ 0.86, 0.96, 1.13, 1.23 (m, 3 H each, P(CH(CH3)2)2), 1.15, 1.34, 1.75, 1.84, 1.89, 2.07 (m, 1 H each, (CH2)3), 1.70 (d, JHP = 1 Hz, 15 H, C5(CH3)5), 2.20, 2.60 (m, 1 H each, P(CH(CH3)2)2), 4.42, 4.58 (m, 1 H each, OCH2), 6.68 (t), 7.03 (d), 7.46 (d), 8.04 (t) (1 H each, C5H4N). 31P{1H} NMR (161.89 MHz, CD2Cl2, 298 K): δ 136.7 (s). 13C{1H} NMR (100.57 MHz, CD2Cl2, 298 K): δ 10.7 (s, C5(CH3)5), 16.0 (d), 16.9 (d), 17.0 (s), 18.1 (d) (P(CH(CH3)2)2), 16.9, 22.0, 44.5 (s, (CH2)3), 28.8 (d, 1JCP = 35 Hz, P(CH(CH3)2)), 29.0 (d, 1JCP = 16 Hz, P(CH(CH3)2)), 75.2 (s, OCH2), 94.6 (d, JCP = 3 Hz, C5(CH3)5), 110.5 (d), 116.3 (s), 137.9 (s), 152.6 (s), 163.0 (d) (C5H4N), 313.3 (d, 3JCP = 14 Hz, RudC). [Cp*Ru{C(NHR)CHdCPh2}(iPr2PNHPy)][PF6] (R = Cy (6a), Me (6b), CH2CtCH (6c)). To a solution of the allenylidene complex 2 (0.1 g, 0.13 mmol) in 1,2-dichloroethane (8 mL) was

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(dd, 3JHH = 13.4 Hz, 3JHP = 2.7 Hz, 1 H, RudCH). 31P{1H} NMR (161.89 MHz, CD2Cl2, 298 K): δ 142.0 (s). 13C{1H} NMR (100.57 MHz, CD2Cl2, 298 K): δ 10.6 (s, C5(CH3)5), 15.9 (d), 17.3 (d), 18.5 (s), 18.6 (s) (P(CH(CH3)2)2), 29.9 (d, 1JCP = 20 Hz, P(CH(CH3)2)), 30.2 (d, 1JCP = 35.8 Hz, P(CH(CH3)2)), 101.5 (s, C5(CH3)5), 110.9 (s), 116.5 (s), 139.0 (s), 153.7 (s), 163.2 (d) (C5H4N), 128.5, 128.7, 128.9, 129.5, 130.0 (s, (C6H5)2), 142.6 (s, C(C6H5)2), 146.4 (s, RudCHCH), 287.2 (d, 3JCP = 11 Hz, RudCH). [Cp*Ru{C(SC6R5)CHdCPh2}(iPr2NHPy)][PF6] (R = H (8H), F (8F)). To a solution of the allenylidene complex 2 (0.1 g, 0.13 mmol) in 1,2-dichloroethane (8 mL) was added the stoichiometric amount of HSPh (15 μL, 0.13 mmol) or HSC6F5 (0.027 g, 0.13 mmol). The mixture was stirred for 2 h at 50 °C for 8H or for 1 h at room temperature for 8F. During this period, the color changed from dark purple to yellowish red. The solvent was removed in vacuo, and the residue was washed with petroleum ether until a dark red (8H) or yellowish (8F) solid was obtained. The compounds were recrystallized from dichloromethane/petroleum ether, affording crystals suitable for X-ray structure analysis. Data for 8H are as follows. Yield: 0.072 g, 62%. Anal. Calcd for C42H50N2F6P2RuS 3 CH2Cl2: C, 52.9; H, 5.37; N, 2.9. Found: C, 53.0; H, 5.48; N, 2.8. 1H NMR (400 MHz, CDCl3, 298 K): δ 0.70, 1.11-1.42 (m, 12H, P(CH(CH3)2)2), 1.74 (s, 15 H, C5(CH3)5), 2.14, 3.09 (m, 1 H each, P(CH(CH3)2)2), 5.53 (d, 2JHP = 3 Hz, 1 H, NH), 6.14 (t), 6.33 (d), 6.62 (d), 6.93 (d) (C5H4N), 7.02-7.15 (m, 15 H, CHdC(C6H5)2 þ SC6H5), 7.10 (s, CHdC(C6H5)2). 31P{1H} NMR (161.89 MHz, CDCl3, 298 K): δ 131.8 (s). 13C{1H} NMR (75.4 MHz, CDCl3, 298 K): δ 10.6 (s, C5(CH3)5), 16.7, 17.8, 17.9 (s, P(CH(CH3)2)2), 28.6 (d, 1JCP = 17 Hz, P(CH(CH3)2)2), 30.0 (d, 1 JCP = 35 Hz, P(CH(CH3)2)2), 97.8 (s, C5(CH3)5), 110.8 (d), 116.2 (s), 137.7 (s), 151.0 (s), 162.5 (d) (C5H4N), 127.4, 127.6, 128.1, 128.9, 129.9, 130.8, 133.3, 137.0, 138.3 (CHdC(C6H5)2 þ SC5H6), 141.9 (s, CHdC(C6H5)2), 142.3 (s, CHdC(C6H5)2), 297.2 (d, 2 JCP = 8 Hz, RudC). Data for 8F are as follows. Yield: 0.093 g, 74%. Anal. Calcd for C42H45N2F11P2RuS: C, 51.4; H, 4.62; N, 2.9. Found: C, 51.3; H, 4.50; N, 2.8. 1H NMR (400 MHz, CDCl3, 298 K): δ 0.75, 1.24-1.48 (m, 12H, P(CH(CH3)2)2), 1.84 (s, 15 H, C5(CH3)5), 2.20, 3.03 (m, 1 H each, P(CH(CH3)2)2), 5.34 (d, 2 JHP = 4 Hz, 1 H, NH), 6.22 (t), 6.99 (d), 7.01 (d), 7.25 (d) (C5H4N), 6.33, 6.70, 7.06 (m, 10 H, (C6H5)2), 7.10 (s, CHdCPh2). 31 P{1H} NMR (161.89 MHz, CDCl3, 298 K): δ 130.8 (s). 13C{1H} NMR (75.4 MHz, CDCl3, 298 K): δ 10.8 (s, C5(CH3)5), 16.0 (s), 17.0 (d), 17.9 (s), 18.2 (s) (P(CH(CH3)2)2), 28.5 (d, 1JCP = 17.4 Hz, P(CH(CH3)2)2), 31.1 (d, 1JCP = 41.5 Hz, P(CH(CH3)2)2), 99.4 (s, C5(CH3)5), 111.3 (d), 116.6 (s), 138.4 (s), 150.5 (s), 162.8 (d) (C5H4N), 127.3, 127.7, 128.2, 128.5, 128.9, 134.0, 137.6 (C6F5 þ CHdC(C6H5)2), 141.3 (s, CHdC(C6H5)2), 141.8 (s, CHdC(C6H5)2), 288.0 (d, 2JCP = 6.4 Hz, RudC). 



[Cp*Ru{K2C,N-C(SC5H4N)CHdCPh2}(K1P-iPr2NHPy)][PF6] 

added a slight excess of the corresponding amine (0.3 mmol; cyclohexylamine 35 μL, methylamine 10 μL, propargylamine 11 μL). The mixture was stirred for 12 h at room temperature for 6a, for 1 h at 50 °C in the case of 6b, or for 3 h at 50 °C in the case of 6c. During these periods of time, the color changed from dark purple to orange. The solvent was removed in vacuo, and the residue was washed with two 15 mL portions of petroleum ether, affording orange solids. These were recrystallized from dichloromethane/ petroleum ether in all cases. Data for 6a are as follows. Yield: 0.085 g, 76%. Anal. Calcd for C42H57N3F6P2Ru: C, 57.3; H, 6.52; N, 4.8. Found: C, 57.2; H, 6.70; N, 4.5. 1H NMR (400 MHz, C2D2Cl4, 353 K): δ 0.77, 1.21-1.31 (m, 12 H, PCH(CH3)2)2), 1.26, 1.52 (m, 10 H, CH2 from Cy), 1.55 (s, 15 H, C5(CH3)5), 2.23, 2.51 (m, 1 H each, P(CH(CH3)2)), 3.53 (br, CHNH), 5.72 (s, CHdCPh2), 6.01 (d, 2 JHP = 5 Hz, 1 H, NH), 6.29 (t), 6.55 (d), 6.96 (t), 7.63 (d) (1 H each, C5H4N), 6.70, 6.80, 7.13, 7.27 (m, 10 H (C6H5)2), 7.44 (d, 1 H, 3 JHH = 9 Hz, CHNH). 31P{1H} NMR (161.89 MHz, C2D2Cl4, 353 K): δ 134.7 (s). 13C{1H} NMR (75.4 MHz, C2D2Cl4, 298 K): δ 11.0 (s, C5(CH3)5,), 17.3 (d), 17.7 (d), 18.5 (s), 18.7 (d) (P(CH(CH3)2)2), 29.3 (d, 1JCP = 18.6 Hz, PCH(CH3)2), 30.7 (d, 1JCP = 31 Hz, PCH(CH3)2), 25.3, 32.8, 33.3 (s, CH2 from Cy), 59.8 (s, CHNH), 92.3 (s, C5(CH3)5), 110.0 (d), 116.7 (s), 137.4 (s), 152.2 (s), 162.2 (d) (C5H4N), 127.9, 128.2, 128.7, 129.6, 132.3, 139.2 (s, (C6H5)2), 131.2 (s, CHdCPh2), 141.7 (s, CHdCPh2), 254.1 (br, RudC). Data for 6b are as follows. Yield: 0.074 g, 71%. Anal. Calcd for C37H49N3F6P2Ru: C, 54.7; H, 6.08; N, 5.2. Found: C, 55.0; H, 6.23; N, 5.0. 1H NMR (400 MHz, C2D2Cl4, 353 K): δ 0.83, 1.21 (m, 12 H, PCH(CH3)2)2), 1.57 (d, JHP = 1.2 Hz, 15 H, C5(CH3)5), 2.25, 2.62 (m, 1 H each, P(CH(CH3)2)), 2.77 (s, 3 H, NHCH3), 5.23 (s, CHdCPh2), 6.15 (s, 1 H, NH), 6.35 (t), 6.86 (d), 7.12 (t), 7.76 (d) (1 H each, C5H4N), 6.82, 7.17, 7.25 (m, 10 H (C6H5)2), 7.59 (s, 1 H, NHCH3). 31 1 P{ H} NMR (161.89 MHz, C2D2Cl4, 353 K): δ 133.6 (s). 13C{1H} NMR (75.4 MHz, C2D2Cl4, 298 K): δ 10.3 (s, C5(CH3)5,), 16.3, 16.8, 17.5, 17.9 (s, P(CH(CH3)2)2), 28.5 (d, 1JCP = 7.2 Hz, PCH(CH3)2), 29.3 (d, 1JCP = 43.7 Hz, PCH(CH3)2), 38.6 (s, NHCH3), 91.8 (s, C5(CH3)5), 109.1 (s), 116.1 (s), 136.9 (s), 152.0 (s), 161.6 (d) (C5H4N), 127.3, 127.6, 128.1, 129.0, 131.9 (s, (C6H5)2), 138.6 (s, CHdCPh2), 141.3 (s, CHdCPh2), 258.1 (d, 2JCP = 7.5 Hz, m, RudC). Data for 6c are as follows. Yield: 0.070 g, 65%. Anal. Calcd for C39H49N3F6P2Ru: C, 55.9; H, 5.91; N, 5.0. Found: C, 55.6; H, 5.80; N, 4.7. 1H NMR (400 MHz, C2D2Cl4, 353 K): δ 0.83, 1.76-1.61 (m, 12 H, PCH(CH3)2)2), 1.60 (s, 15 H, C5(CH3)5), 2.27, 2.69 (m, 1 H each, P(CH(CH3)2)), 2.46 (t, 4JHH = 2.4 Hz, CH2CtCH), 3.74 (m, 2 H, CH2CtCH), 5.96 (s, 1 H, CHdCPh2), 6.35 (br, 1 H, NH), 6.38 (d), 6.93 (d), 7.13 (t), 7.47 (d) (1 H each, C5H4N), 6.36, 6.83, 7.29 (m, 10 H C6H5), 7.44 (d, 1 H, 3JHH = 9 Hz, CHNH). 31P{1H} NMR (161.89 MHz, C2D2Cl4, 353 K): δ 133.5 (s). 13C{1H} NMR (75.4 MHz, C2D2Cl4, 298 K): δ 10.2 (s, C5(CH3)5,), 16.4, 16.9, 17.4, 17.9 (s, P(CH(CH3)2)2), 28.5 (d, 1 JCP = 15 Hz, PCH(CH3)2), 29.2 (d, 1JCP = 31 Hz, PCH(CH3)2), 40.5 (s, CH2CtCH), 75.6 (s, CH2CtCH), 76.1 (s, CH2CtCH), 92.2 (s, C5(CH3)5), 109.5 (s), 116.1 (s), 137.0 (s), 151.8 (s), 162.0 (d) (C5H4N), 127.4, 127.9, 128.3, 129.1, 131.5 (s, (C6H5)2), 138.1 (s, CHdCPh2), 140.9 (s, CHdCPh2), 258.8 (br, RudC). [Cp*RudCHCHdCPh2(iPr2PNHPy)][PF6] (7). To a solution of the allenylidene complex 2 (0.1 g, 0.13 mmol) was added a slight excess of piperidine (15 μL, 0.2 mmol). The mixture was stirred at room temperature for 3 h. During this time, the color changed from dark purple to greenish yellow. Then the solvent was removed in vacuo, and the residue was washed with several portions of petroleum ether. Recrystallization from dichloromethane/petroleum ether afforded greenish yellow crystals suitable for X-ray structure analysis. Yield: 0.062 g, 62%. Anal. Calcd for C36H46N2F6P2Ru 3 CH2Cl2: C, 51.2; H, 5.57; N, 3.2. Found: C, 51.3; H, 5.61; N, 3.0. 1H NMR (400 MHz, CD2Cl2, 298 K): δ 0.88-1.28 (m, 12 H, P(CH(CH3)2)2), 1.64 (d, JHP = 1 Hz, 15 H, C5(CH3)5), 2.02, 2.67 (m, 1 H each, P(CH(CH3)2)2), 6.57 (t), 7.22 (d), 7.33 (d), 7.56 (t) (1 H each, C5H4N), 6.79 (d br, 2 JHP = 3.5 Hz, 1 H, NH), 6.94 (d, 3JHH = 13.4 Hz, 1 H, RudCHCH), 7.07, 7.21, 7.40, 7.48 (m, 10 H, (C6H5)2), 15.36

Organometallics, Vol. 30, No. 4, 2011

(9Py) and [Cp*Ru{κ2C,N-C(SC4H3 NN)CHdCPh2}(κ1P-iPr2NHPy)][PF6] (9Pym). To a solution of the allenylidene complex 1 (0.1 g, 0.13 mmol) in 1,2-dichloroethane (8 mL) was added the stoichiometric amount of either pyridine-2-thiol or pyrimidine-2thiol (0.13 mmol). The mixture was stirred at 50 °C for 3 h (9Py) or 5 h (9Pym). During this period, the color changed to yellowish red. The solvent was removed in vacuo, and the residue was washed with petroleum ether until dark red solids were obtained. The complexes were recrystallized from dichloromethane/petroleum ether, affording dark red crystals suitable for X-ray structure analysis. Data for 9Py are as follows. Yield: 0.082 g, 72%. Anal. Calcd for C41H49N3F6P2RuS 3 0.5CH2Cl2: C, 53.3; H, 5.39; N, 4.5. Found: C, 53.1; H, 5.44; N, 4.5. 1H NMR (400 MHz, CDCl3, 298 K): δ 0.40, 0.82, 1.24, 1.44 (m, 3 H each, P(CH(CH3)2)2), 1.36 (s, 15 H, C5(CH3)5), 2.06, 2.36 (m, 1 H each, P(CH(CH3)2)2), 5.24 (s br, 1 H, NH), 6.76 (t), 7.02 (d), 7.06 (d), 7.27 (t), 7.38 (m), 7.50 (m), 7.52 (t), 7.66 (m), 9.14 (d) (18 H in total, C(C6H5)2 þ 2 C5H4N), 8.72 (s, 1 H, CHCPh2). 31P{1H} NMR (161.89 MHz, CDCl3, 298 K):

10.376(2) 21.655(4) 17.280(4) 95.54(3) 3864.6(13) 4 1.493 0.685 1784 1.000-0.847 1.88