From Pseudo-octahedral to Pseudo-trigonal Bipyramidal

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From Pseudo-octahedral to Pseudo-trigonal Bipyramidal Configuration: Syntheses and Molecular Structures of 4-t-Bu2,6-[(EtO)2P(O)]2C6H2BiCl2 and [1(Bi),3(P)-Bi(Cl)OP(O)(OEt)-5-t-Bu-7P(O)(OEt)2]C6H2 Katja Peveling,† Markus Sch€urmann,† Sonja Herres-Pawlis,† Cristian Silvestru,‡ and Klaus Jurkschat*,† † ‡

Lehrstuhl f€ur Anorganische Chemie II der Technischen Universit€at Dortmund, 44227-Dortmund, Germany Facultatea de Chimie s-i Inginerie Chimica, Universitatea Babes--Bolyai, 400028-Cluj-Napoca, Romania

bS Supporting Information ABSTRACT: The syntheses and molecular structures in solution and in the solid state of the intramolecularly coordinated organobismuth derivatives 4-t-Bu-2,6-[(EtO)2P(O)]2C6H2BiCl2 (1) and [1(Bi),3(P)-Bi(Cl)OP(O)(OEt)-5-t-Bu-7-P(O)(OEt)2]C6H2 (2) are reported. Compound 1 crystallizes in the triclinic space group P1 with two pairs of crystallographically independent molecules per unit cell. Each bismuth atom shows a distorted Ψ-octahedral CCl2O2Bi configuration with the chlorine and oxygen atoms mutually trans. The intramolecular Bi 3 3 3 O distances range between 2.378(5) and 2.414(5) Å. The phosphabismole derivative 2 forms a head-to-tail dimer via intermolecular PdOfBi interactions. Compound 2 crystallizes as a racemic mixture of (SP,ABi) and (RP, CBi) isomers. DFT calculations reveal the high s-character of the lone electron pairs at the bismuth atoms in compounds 1 and 2.

’ INTRODUCTION Recent developments in the chemistry of organobismuth(III) compounds have revealed that aryl groups containing one or two built-in donor ligands such as 2-(MeOCR2)C6H4 (R = Me,1
4 CF35), 2-(R2NCH2)C6H4 (R = Me,6 Et7), 2,6-(Me2NCH2)2C6H3,6,8,9a
9c 2,6-[MeN(CH2CH2)2NCH2]2C6H3,8 2,6-(ROCH2)2C6H3 (R = Me,10 tBu10
12a), and 2-(MeOCH2)-6-(Me2NCH2)C6H3,12b respectively, can provide efficient protection of the metal atom. The protection is both steric and also by reducing the Lewis acidity though intramolecular EfBi (E = N, O) interactions observed both in the solid state and in solution. Such ligands are an attractive alternative to the bulky aryl groups such as 2,6-R2C6H3 (R = Mes,13
17 2,6-i-Pr2C6H316), 2,4,6-R3C6H2 [(Me3Si)2CH,18,19 Ph20,21], 2,6-[(Me3Si)2CH]24-(Me3Si)3C-C6H2,22
25 and 2,6-Mes2-4-t-Bu-C6H2.17 The N,C, N- and O,C,O-chelating pincer-type ligands 2,6-(Me2NCH2)2C6H3 (a) and 2,6-(ROCH2)2C6H3 (b), respectively (Chart 1), raised considerable interest, and their use afforded the isolation of unusual species such as the first peroxido-substituted derivative [{2,6-(Me2NCH2)2C6H3}2Bi]2(O2),26 the organobismuth(III) sulfides cyclo-[{2,6-(Me2NCH2)2C6H3}BiS]26 and cyclo-[{2,6(t-BuOCH2)2C6H3}BiS],12 the carbon disulfide-substituted derivative {2,6-(Me2NCH2)2C6H3}BiS2CS,9b the hydroxido-substituted derivative 2,6-(Me2NCH2)2C6H3Bi(OH)(O3SCF3),9a and the aryloxy-substituted compounds 2,6-(Me2NCH2)2C6H3Bi(OC6H3Me2-2,6)2 and 2,6-(Me2NCH2)2C6H3Bi(OC6H3i-Pr2r 2011 American Chemical Society

Chart 1

2,6)2.9c Most recently, the bulky pincer-type ligand c (Chart 1) has been employed for the synthesis of a monomeric organobismuth compound RBi (R = 2,6-bis{N-(20 ,60 -dimethylphenyl) ketimino}phenyl).12c Also recently, organobismuth compounds containing even two N,C,N-coordinating pincer-type ligands 2,6-(Me2NCH2)2C6H3 have been reported.9d Within our interest in hypercoordinated main group organometallic compounds containing the O,C,O-coordinating pincer-type ligands 4-t-Bu-2,6-[(RO)2P(O)]2C6H2
(R = Et, i-Pr) (Chart 2, d), so far we have investigated derivatives of silicon,27
32a germanium,32b Received: June 24, 2011 Published: September 16, 2011 5181

dx.doi.org/10.1021/om200544r | Organometallics 2011, 30, 5181–5187

Organometallics

ARTICLE

Chart 2

Scheme 1

tin,30,33
37 lead,38,39a and antimony.39b A common feature of these compounds is, in an Arbuzov-type reaction, the elimination of alkyl halide under various conditions to afford intramolecularly PdOfM coordinated phosphole-type compounds with, for instance, M = SiPh2, SnPh2, and PbPh2 (Chart 2, e). In the course of our ongoing systematic studies on phosphorus-containing O,C,O-coordinating pincer-type ligands and their organoelement derivatives (Chart 2, d) we report herein the synthesis and characterization in solution and in the solid state of the monoorganobismuth(III) dichloride [4-t-Bu-2,6{(EtO)2P(O)}2C6H2]BiCl2 (1) and the benzoxaphosphabismole [1(Bi),3(P)-Bi(Cl)OP(O)(OEt)-5-t-Bu-7-P(O)(OEt)2]C6H2 (2).

’ RESULTS AND DISCUSSION The reaction in thf at
50 °C of BiCl3 with in situ generated 4-t-Bu-2,6-[(EtO)2P(O)]2C6H2Li (ratio 1.33:1.00) provided the monoorganobismuth(III) dichloride 4-t-Bu-2,6-[(EtO)2P(O)]2C6H2BiCl2, 1, as a colorless crystalline material that is stable to light, oxygen, and moisture and well soluble in organic solvents such as diethyl ether, dichloromethane, chloroform, and toluene (Scheme 1). Compound 1 crystallized in the triclinic space group P1 with two pairs of crystallographically independent molecules 1a and 1b in the unit cell. The molecules 1a and 1b exhibit rather similar geometric parameters, and consequently, only the molecular structure of molecule 1a is depicted in Figure 1. Selected bond distances and angles of both 1a and 1b are given in Table 1. The bismuth atom in compound 1 shows a pseudo-octahedral configuration with the O(1)/O(2), Cl(1)/Cl(2), and C(1)/lone pair, respectively, mutually trans. The Cl(1)
Bi(1)
Cl(2)/Cl(3)
Bi(2)
Cl(4) bond angles of 167.9(1)° (1a)/168.7(1)° (1b) differ from the ideal value of 180°. This is traced to both the stereochemical activity of the lone electron pair at the bismuth atom and the intermolecular Bi(1) 3 3 3 O(30 A)/O(300 A) interactions. The chlorine atoms are bent toward the C(1)/C(21) atoms. The O(1)
Bi(1)
O(2)/O(3)
Bi(2)
O(4) angles of 154.4(2)o (1a)/153.5(2)o (1b) also differ from 180°, which is the result of ligand constraint. The intramolecular PdOfBi interactions at O(1)
Bi(1)/O(2)
Bi(1) and O(3)
Bi(2)/O(4)
Bi(2) distances of 2.378(5)/ 2.382(5) (1a) and 2.381(5)/2.414(5) Å (1b) are slightly longer

Figure 1. Molecular structure of 1a (ORTEP drawing with 20% probability ellipsoids) with the labeling scheme for the atom positions. Hydrogen atoms are omitted for clarity.

Table 1. Selected Bond Distances [Å] and Angles [deg] for Compound 1 molecule 1a

molecule 1b

Bi(1)
C(1)

2.261(6)

Bi(2)
C(21)

2.234(6)

Bi(1)
Cl(1)

2.674(3)

Bi(2)
Cl(3)

2.630(2)

Bi(1)
Cl(2)

2.665(2)

Bi(2)
Cl(4)

2.672(2)

Bi(1)
O(1)

2.378(5)

Bi(2)
O(3)

2.381(5)

Bi(1)
O(2)

2.382(5)

Bi(2)
O(4)

2.414(5)

P(1)
O(1)

1.499(5)

P(3)
O(3)

1.500(5)

P(1)
O(10 ) P(1)
O(100 )

1.540(6) 1.564(7)

P(3)
O(30 ) P(3)
O(300 )

1.557(4) 1.548(6)

P(2)
O(2)

1.510(5)

P(4)
O(4)

1.495(5)

P(2)
O(20 )

1.558(7)

P(4)
O(40 )

1.554(8)

P(2)
O(200 )

1.563(5)

P(4)
O(400 )

1.557(6)

Cl(3)
Bi(2)
Cl(4) C(21)
Bi(2)
Cl(3)

168.73(7) 83.6(2)

Cl(1)
Bi(1)
Cl(2) C(1)
Bi(1)
Cl(1)

167.9(8) 85.6(2)

C(1)
Bi(1)
Cl(2)

83.0(2)

C(21)
Bi(2)
Cl(4)

86.4(2)

C(1)
Bi(1)
O(1)

77.1(2)

C(21)
Bi(2)
O(3)

76.7(2)

C(1)
Bi(1)
O(2)

77.3(2)

C(21)
Bi(2)
O(4)

76.8(2)

O(1)
Bi(1)
O(2)

154.4(2)

O(3)
Bi(2)
O(4)

153.5(2)

O(1)
Bi(1)
Cl(1)

86.5(2)

O(3)
Bi(2)
Cl(3)

91.9(1)

O(1)
Bi(1)
Cl(2)

83.0(2)

O(3)
Bi(2)
Cl(4)

91.0(3)

O(2)
Bi(1)
Cl(1) O(2)
Bi(1)
Cl(2)

91.2(1) 90.0(1)

O(4)
Bi(2)
Cl(3) O(4)
Bi(2)
Cl(4)

86.5(1) 86.0(1) 118.4(3)

P(1)
O(1)
Bi(1)

117.0(3)

P(3)
O(3)
Bi(2)

P(1)
C(2)
C(1)

117.2(6)

P(3)
C(22)
C(21)

117.3(6)

C(2)
C(1)
Bi(1)

119.5(5)

C(22)
C(21)
Bi(2)

120.3(5)

P(2)
O(2)
Bi(1)

117.1(3)

P(4)
O(4)
Bi(2)

116.9(3)

P(2)
C(2)
C(1)

118.1(6)

P(4)
C(26)
C(21)

117.3(6)

C(6)
C(1)
Bi(1)

119.3(5)

C(26)
C(21)
Bi(2)

120.9(5)

than the sum of the corresponding covalent radii of oxygen and bismuth (∑rcov(Bi,O) 2.18 Å).40a They compare well with those 5182

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Organometallics observed in [2,6-(t-BuOCH2)2C6H3]BiCl2 [2.376(3)/2.459 (3) Å]10 but are considerably shorter than the intramolecular O
Bi distances of 2.493(3)/2.501(3) Å reported for the centrosymmetric μ-chlorido-bridged dimer [{2,6-(MeOCH2)2C6H3} BiCl2]2. Notably, in the latter compound the donor oxygen atoms are cis with an O
Bi
O angle of 127.5(1)°.10 Even longer O
Bi distances were observed in [{3-F-2-{(Me2CO)2B}C6H3}BiCl2]n [2.583(2) Å]41 and the organobismuth dichloride tetrahydrofurane complex [PhBiCl2(THF)]n [2.608(7) Å].42 Both compounds are μ-chlorido-bridged polymers. The intramolecular PdOfBi coordination in compound 1 is also reflected by the IR spectrum, showing a vibration at νPdO 1177 cm
1, which is at lower frequency than the νPdO (1255 cm
1) of the protonated ligand 3-t-Bu-1,5-[(EtO)2P(O)]2C6H3. The Bi(1)
Cl(1)/Bi(1)
Cl(2) and Bi(2)
Cl3)/Bi(2)
Cl(4) distances in 1 of 2.674(3)/2.665(2) and 2.630(2)/2.672(2) Å, respectively, are also longer than the sum of the covalent radii of bismuth and chlorine (∑rcov(Bi,Cl) 2.51 Å).40a They are slightly shorter as compared to the related pincer ligand-containing organobismuth dichlorides [2,6-(t-BuOCH2)2C6H3]BiCl2 [2.6863(11)/2.6872(11) Å],10 [2,6-(Me2NCH2)2C6H3]BiCl2 [2.701(1)/2.706(1) Å],43 and [2,6-[MeN(CH2CH2)2NCH2]2C6H3]BiCl2 [2.6866(15)/2.7024(15) Å].8 The μ-chloridobridged polymeric methylbismuth dichloride (MeBiCl2)n shows Bi
Cl distances of 2.741(2) and 2.755(2) Å.44 It should be noted here that for the centrosymmetric dimer [{2,6-(MeOCH2)2C6H3}BiCl2]2 significant differences were observed between terminal [2.6595(1) Å] and bridging [2.8873(1)/2.8850(1) Å] Bi
Cl bond lengths.10 A similar behavior was found for the polymeric [PhBiCl2(THF)]n [Bi
Clterminal 2.543(3) Å, trans to oxygen; Bi
Clbridging 2.655(2)/2.933(2) Å].42 In the crystal, alternating 1a and 1b molecules form an infinitive zigzag chain via intermolecular PO(Et)fBi interactions [Bi(1) 3 3 3 O(30 a) 3.426(5)/Bi(1) 3 3 3 O(300 a) 3.311(4) Å; Bi(2) 3 3 3 O(20 ) 3.300(6)/Bi(2) 3 3 3 O(200 ) 3.309(6) Å], which involve the ethoxy oxygen atoms from only one of the two phosphoryl groups per pincer ligand (Supporting Information, Figures S1, S2). The distances are shorter than the sum of the van der Waals radii of oxygen and bismuth (cf. ∑rvdW(Bi,O) 3.8 Å).40a The 31P NMR spectrum of compound 1 showed a single resonance at δ 57.9 that is considerably high-frequency shifted as compared to the chemical shift of δ 18.9 (in CDCl3) observed for the protonated ligand 3-t-Bu-1,5-{(EtO)2P(O)}2C6H3. It indicates both phosphorus atoms to be equivalent and the coordination of the phosphoryl groups to the bismuth atom. Moreover, only one set of resonances was observed in the 1H and 13C spectra, and, therefore, a similar molecular structure in solution to that observed in the solid state (see subsequent discussion) might be considered for 1. The attempts to obtain salt-like species of the type [{4-t-Bu2,6-{(EtO)2P(O)}2C6H2}BiCl]+X
(X = PF6, BF4) by reacting compound 1 with Tl[PF6] or Ag[BF4] have failed. The reaction of 1 with LiAlH4 did not provide the organobismuth dihydride, 4-t-Bu-2,6-{(EtO)2P(O)}2C6H2BiH2. Instead, cleavage of the Bi
C bond was observed. In this context it has to be mentioned that, by employing the bulky noncoordinating carboranate anion CB11H12
, the salt [{2,6-(t-BuOCH2)2C6H3}BiCl]+[CB11H12]
was isolated and completely characterized,11 while the reduction of (2,6-Mes2C6H3)2BiCl with LiAlH4 afforded the corresponding diorganobismuth(III) hydride, [2,6-Mes2C6H3]2BiH.14 The 31P NMR spectrum of a solution of the organobismuth dichloride 1 in CDCl3 that had been kept for two months at

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Figure 2. Molecular structure of the (RP,CBi)-2 dimer (ORTEP drawing with 20% probability ellipsoids) with the labeling scheme for the atom positions [symmetry equivalent atoms (1
x, y, 0.5
z) are given by “A”]. Hydrogen atoms are omitted for clarity.

Table 2. Selected Bond Distances [Å] and Angles [deg] for Compound 2 Bi(1)
C(1) Bi(1)
Cl(1)

2.234(4) 2.603(1)

Bi(1)
O(2A)

Bi(1)
O(1)

2.422(3)

Bi(1)
O(20 )

2.278(3)

P(1)
O(1)

1.482(3)

P(2)
O(2)

1.486(3)

P(1)
O(10 )

1.565(3)

P(2)
O(20 )

1.523(3)

1.572(3)

P(2)
O(200 )

1.577(3)

00

P(1)
O(1 )

2.426(2)

C(1)
Bi(1)
Cl(1)

87.6(1)

O(1)
Bi(1)
O(20 )

C(1)
Bi(1)
O(1)

76.5(1)

C(1)
Bi(1)
O(20 )

78.3(1)

O(1)
Bi(1)
Cl(1)

86.1(1)

O(20 )
Bi(1)
Cl(1)

92.7(1)

82.6(1)

Cl(1)
Bi(1)
O(2A)

168.8(6)

C(1)
Bi(1)
O(2A)

154.8(9)

P(1)
O(1)
Bi(1)

116.2(1)

P(2)
O(20 )
Bi(1)

120.3(2)

P(1)
C(2)
C(1)

116.1(3)

P(2)
C(6)
C(1)

117.5(3)

C(2)
C(1)
Bi(1)

121.6(3)

C(6)
C(1)
Bi(1)

118.6(3)

50 °C showed three resonances, at δ 57.9 (integral 4%, 1), 49.4 (integral 48%), and 54.9 (integral 48%). The two latter signals are assigned to the benzoxaphosphabismole 2 (see Scheme 1). Colorless, single crystals of 2 suitable for X-ray diffraction analysis were obtained by slow evaporation of the solvent from its solution in ethyl acetate. The molecular structure of compound 2 is shown in Figure 2, and selected molecular parameters are listed in Table 2. In compound 2 both one phosphorus atom and the bismuth atom are chiral centers, and consequently, four isomers are possible. The crystal of 2 contains a 1:1 mixture of (SP,ABi) and (RP,CBi) isomers (taking into account the intramolecular OfBi coordination the chirality at the bismuth atom in the resulting pseudo-trigonal bipyramidal environment is described in term of ABi and CBi isomers45). Discrete centrosymmetric head-to-tail dimers are formed by isomers of the same type, i.e., (SP,ABi/SP,ABi)-2 and (RP,CBi/RP, CBi)-2, via intermolecular PdOfBi interactions at a Bi(1)
O(2A) 5183

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Organometallics Scheme 2

distance of 2.426(2) Å. This distance is as long as the intramolecular Bi(1)
O(1) coordinative bond of 2.422(3) Å, but considerably shorter than the intramolecular Bi(1)
O(1) and Bi(1)
O(2) distances observed in the organobismuth dichloride 1 (see Table 1). The Bi(1)
O(20 ) distance of 2.278(3) Å for the benzoxaphosphabismole 2 is longer than that reported for the related [2-{MeOC(Me)2}C6H4]Bi[C6H4{C(CF3)2O}-2] [2.193(7) Å].4 The Bi(1)
Cl(1) bond distance in 2 of 2.604(1) Å is slightly shorter than the Bi
Cl distances observed in 1. The presence of two different PdO groups is nicely reflected by the IR spectrum, showing two vibrations νPdO at 1174 and 1187 cm
1. The Bi(1) atom in the benzoxaphosphabismole 2 exhibits a pseudo-octahedral configuration with the Cl(1) and O(2A), and O(1) and O(20 ) atoms mutually trans. The fifth coordination site is occupied by the C(1) atom, and the sixth position by the lone electron pair. As for compound 1, the Cl(1)
Bi(1)
O(2A) angle of 168.8(1)° deviates from the ideal angle of 180°. As in the case of the organobismuth dichloride 1, in the solid-state structure of the benzoxaphosphabismole 2 secondary, weaker intermolecular bismuth
oxygen interactions at Bi(1) 3 3 3 O(10 a)/Bi(1) 3 3 3 O(100 a) distances of 3.650(3)/3.306(3) Å are observed that are shorter than the sum of the van der Waals radii of bismuth and oxygen (cf. ∑rvdW(Bi,O) 3.8 Å).40a This results in a layer architecture developed along the c-axis in which a (SP,ABi/SP,ABi)-2 isomer is connected to four (RP,CBi/RP,CBi)-2 isomers and vice versa (Supporting Information, Figures S3
S5). These intermolecular bismuth
oxygen interactions are, together with the stereochemical activity of the lone electron pair at the bismuth atom, responsible for the small Cl(1)
Bi(1)
O(2A) angle as mentioned above. Another notable feature in the structure of compound 2 is the almost perfect stacking of the two aromatic rings above each other with a torsion angle C(7)
C(4)
C(4A)
C(7A) of 59.7(3)°. This is in contrast to the related benzoxaphosphastannole derivatives {[1(Sn),3(P)-Cl(X)SnOP(O)(OEt)-5-t-Bu-7P(O)(OEt)2]C6H2}2 (X = Ph, Cl),34,36 for which trans-configurated dimers have been found in the solid state. In solution, however, the NMR data for the representative with X = Cl were interpreted in terms of a cis
trans equilibrium. The 31P NMR spectra of compound 2 in CDCl3 (81.01 MHz) at room temperature and in CH2Cl2 (161.97 MHz) at
70 °C showed two equally intense resonances at δ 49.4 (ν1/2 = 2 Hz) and 54.9 (ν1/2 = 1 Hz), and δ 49.7 (ν1/2 = 2 Hz) and 55.0 (ν1/2 = 4 Hz), respectively. Both the 1H and 13C NMR spectra displayed three sets of resonances for the ethyl protons and carbon atoms, respectively. These results indicate the epimerization shown in Scheme 2 to be fast on the 1H, 13C, and 31P NMR time scales. In the related benzoxaphosphasilole [1(P),3(Si)-P(O)(OEt)OSiPhMe-6-t-Bu-4-P(O)(OEt)2]C6H2 the epimerization is slow on the NMR time scales.29 DFT Calculations. DFT calculations reveal the molecular structures of compounds 1 and 2 found in the solid state to be

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close to the calculated ones (see Supporting Information, Tables S1, S2). Most importantly, the lone electron pair at the bismuth atom possesses high s-character for both the organobismuth dichloride 1 (92%) and the benzoxaphosphabismole derivative 2 (93%). Each of the two intramolecular PdOfBi interactions in compound 1 contributes approximately 56 kcal/mol to the stabilization of the molecule. The Wiberg bond indices are 0.23 (Bi
O) and 0.47/0.46 (Bi
Cl). For compound 2, the difference between the P
O
Bi and the PdOfBi oxygen
bismuth bonds is very pronounced: the energy of the former is 79 kcal/mol, whereas that of the latter is approximately 50 kcal/mol. This value is in accordance with those reported for other compounds stabilized by O,C,O-coordinating pincer-type ligands.39c The difference between the two O
Bi interactions is also reflected by the Wiberg bond indices of 0.30 (P
O
Bi) and 0.18 (PdOfBi). With respect to the stereochemical activity of the lone electron pair it should be mentioned that, according to a recent tutorial review,40b this lone electron pair can gain a directional component by mixing with a bismuth p-orbital via antibonding states. The latter result from the orbital interaction with p-orbitals of hard donor atoms.

’ CONCLUSIONS In this report we have extended the family of organoelement compounds of the type 4-t-Bu-2,6-[(RO)2P(O)]2C6H2E (R = Et, i-Pr; E = main group element moiety) by the first representative with E = BiCl2. Like the related silicon, tin, and lead representatives, the organobismuth dichloride undergoes intramolecular O
C bond cleavage and cyclization to give a benzoxaphosphabismole. This is in contrast to the results recently reported by Dostal et al.,46 according to which the related organobismuth compound 2-(Me2NCH2)-6-(t-BuOCH2)C6H3BiCl2 does not undergo ether cleavage. Given the structure-directing property of the phosphonyl moiety, the sterically more protected isopropoxy-substituted organobismuth dichloride 4-t-Bu-2,6[(i-PrO)2P(O)]2C6H2BiCl2 will be synthesized and its reactivity toward mild reducing reagents such as K-selectride and silver salts of noncoordinating anions will be studied. ’ EXPERIMENTAL SECTION General Procedures. All solvents were dried and purified by standard procedures. All reactions were carried out under an argon atmosphere using Schlenk techniques. The IR spectra (cm
1) were recorded on a Bruker IFS 28 spectrometer. Bruker DPX-300 and DRX-400 spectrometers were used to obtain 1H (400.13 MHz), 13C (100.63 MHz), and 31P (121.49 MHz, 161.98 MHz) NMR spectra. 1H, 13C, and 31P NMR chemical shifts δ are given in ppm and were referenced against Me4Si (1H, 13C) and H3PO4 (85%, 31P), respectively. The NMR spectra were recorded at room temperature unless otherwise stated. Elemental analyses were performed on a LECO-CHNS-932 analyzer. Electron impact mass spectra were recorded on a Finnigan MAT 8200 mass spectrometer. Synthesis of [4-t-Bu-2,6-{(EtO)2P(O)}2C6H2]BiCl2 (1). Bismuth trichloride, BiCl3 (2.44 g, 7.74 mmol), was added in small portions to a cooled (
50 °C) solution of [4-tBu-2,6-{(EtO)2P(O)}2C6H2]Li (2.39 g, 5.80 mmol) in THF (100 mL). The reaction mixture was stirred for 16 h, during which it was warmed to room temperature. Then it was filtered to remove LiCl and unreacted starting material. After the solvent of the filtrate had been removed in vacuo, recrystallization of the residue from diethyl ether gave compound 1 as a colorless solid. Yield: 2.73 g 5184

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Organometallics (69%), mp 129
131 °C. Anal. Calcd for C18H31BiCl2O6P2 (MW 685.25): C, 31.5; H, 4.6. Found: C, 31.7; H, 4.5. 1H NMR (400 MHz, C6D6): δ 0.99 [9H, s, C(CH3)3], 1.03 (12H, t, P-OCH2CH3, 3J(1H
1H = 7.4 Hz), 4.20
4.45 (8H, m, P-OCH2CH3), 8.25 (2H, m, C6H2). 13C NMR (100.6 MHz, C6D6): δ 16.2 (d, P-OCH2CH3, 3J(13C
31P) = 6 Hz), 30.7 [s, C(CH3)3], 35.2 [s, C(CH3)3], 65.5 (d, P-OCH2CH3, 2J(13C
31P) = 4 Hz), 130.8 (dd, Ar-C2,6, 1J(13C
31P) = 187 Hz, 3J(13C
31P) = 19 Hz), 137.6 (dd, Ar-C3,5, 2J(13C
31P) = 15 Hz, 4J(13C
31P) = 4 Hz), 152.2 (t, Ar-C4, 3J(13C
31P) = 12 Hz), 224.5 (t, Ar-C1, 2J(13C
31P) = 24 Hz). 31P NMR (162 MHz, C6D6): δ 57.9. IR (KBr, cm
1): 1177(s) (νPdO). Mass spectrum: m/e (relative intensity, %) 651 (35) [MH+
Cl], 650 (22) [M+
Cl], 649 (100) [M+
Cl
H], 483 (14) [M+
2Cl
OEt
Et
t-Bu].

ARTICLE

Table 3. Data Collection and Structure Refinement Details for Compounds 1 and 2 1

Synthesis of [1(Bi),3(P)-Bi(Cl)OP(O)(OEt)-5-t-Bu-7-P(O)(OEt)2]C6H2 (2). A solution of 1 (2.14 g, 3.12 mmol) in CHCl3 (100 mL) was stirred at room temperature for 39 days. Purification by flash chromatography (silica gel/ethyl acetate) provided a crude reaction product that was recrystallized from ethyl acetate to give compound 2 as a colorless, crystalline material. Yield: 1.36 g (70%), mp 210
212 °C (dec). Anal. Calcd for C16H26BiClO6P2 (620.74): C, 31.0; H, 4.2. Found: C, 31.0; H, 4.2. 1H NMR (400.13 MHz, CD2Cl2): δ 1.07 (3H, t, P-OCH2CH3, 3J(1H
1H = 7.4 Hz), 1.31 (3H, t, P-OCH2CH3, 3 1 J( H
1H) = 7.4 Hz), 1.32 (3H, t, P-OCH2CH3, 3J(1H
1H) = 7.4 Hz), 1.40 [9H, s, C(CH3)3], 3.65
3.75 (1H, complex pattern, P-OCH2CH3), 3.79
3.89 (1H, complex pattern, P-OCH2CH3), 4.06
4.20 (2H, complex pattern, P-OCH2CH3), 4.20
4.34 (2H, complex pattern, P-OCH2CH3), 8.26 (1H, d, C6H2, 3J(1H
31P) = 12.0 Hz), 8.38 (1H, d, C6H2, 3J(1H
31P) = 12.0 Hz). 13C NMR (100.6 MHz, CDCl3): δ 16.3 (complex pattern, P-OCH2CH3), 31.3 [s, C(CH3)3], 35.7 [s, C(CH3)3], 62.5 (d, P-OCH2CH3, 2J(13C
31P) = 4 Hz), 64.4 (d, P-OCH2CH3, 2 13 J( C
31P) = 4 Hz), 64.6 (d, P-OCH2CH3, 2J(13C
31P) = 4 Hz), 129.5/137.0 (dd/dd, Ar-C2/ C6, 1J(13C
31P) = 184/178 Hz, 3 13 J( C
31P) = 17 Hz), 135.4/137.4 (dd/dd, Ar-C3/C5, 2J(13C
31P) = 13 Hz, 4J(13C
31P) = 4 Hz), 153.3 (t, Ar-C4, 3J(13C
31P) = 13 Hz), 218.6 (t, Ar-C1, 2J(13C
31P) = 20 Hz). 31P NMR (81.01 MHz, CDCl3): δ 49.0 (ν1/2 = 2 Hz), 54.5 (ν1/2 = 1 Hz). 31P NMR (81.01 MHz, CDCl3): δ 49.0 (ν1/2 = 2 Hz) and 54.5 (ν1/2 = 1 Hz); (162.97 MHz, CH2Cl2,
70 °C): δ 49.7 (ν1/2 = 2 Hz), 55.0 (ν1/2 = 4 Hz). IR (KBr, cm
1): 1187(s, νPdO), 1174(s, νPdO). Mass spectrum: m/e (relative intensity, %) 619 (11) [M+
H], 585 (8) [M+
Cl], 584 (36) [M+
Cl
H], 540 (17) [M+
Cl
OEt], 483 (12) [M+
Cl
OEt
t-Bu]. Reaction of Compound 1 with TlPF6. To a solution of compound 1 (0.39 g, 0.57 mmol) in THF (10 mL) was added TlPF6 (0.20 g, 0.57 mmol). After the reaction mixture had been magnetically stirred for 18 h the colorless residue was filtered. The solvent of the filtrate was evaporated in vacuo, and the residue dissolved in C6D6. A 31P NMR spectrum (161.98 MHz) showed two resonances at δ 17.6 (18%, 3-t-Bu-1,5-[P(O)(OEt)2]2C6H3) and 58.7 (82%, 2). Reaction of Compound 1 with AgPF6. To a solution of compound 1 (0.10 g, 0.15 mmol) in toluene (10 mL) was added AgPF6 (0.04 g, 0.16 mmol). After stirring the reaction mixture at room temperature in the dark for eight days, a 31P NMR spectrum (C7H8/ D2Ocappillary) showed resonances at δ
18.4 [t, 1J(31P
19F) 963 Hz, 20%, not assigned],
7.1 [d, 1J(31P
19F) 920 Hz, 6%, not assigned], 18.4 (9%, 3-t-Bu-1,5-[P(O)(OEt)2]2C6H3), 56.7 (8%, not assigned), 58.8 (57%, 1). Apparently, under the experimental conditions employed, partial hydrolysis of the PF6
anion took place. Reaction of Compound 1 with LiAlH4. To a solution of compound 1 (0.10 g, 0.15 mmol) in Et2O (20 mL) was added at room temperature a suspension of LiAlH4 in Et2O (2.5 mL, c = 2.9  10
2 mol/L). The color of the solution turned from colorless to green, and a black precipitate appeared. A 31P NMR spectrum (121.49 MHz, Et2O/ D2Ocapillary) of the solution showed resonances at δ 3.0 (19%, not

2

formula

C18H31BiCl2O6P2

C32 H52 Bi2 Cl2 O12 P4

fw cryst syst

685.25 triclinic

1241.48 orthorhombic

cryst size, mm

0.180  0.15  0.15 0.15  0.15  0.15 mm

space group

P1

Pbcn

a, Å

10.7908(2)

14.0009(2)

b, Å

15.4793(5)

14.0776(2)

c, Å

17.8283(6)

22.1290(3)

α, deg

113.3954(9)

90

β, deg γ, deg

93.3927(18) 100.0151(17)

90 90

V, Å3

2664.23(13)

4361.61(11)

Z

4

4

Fcalcd, Mg/m3

1.708

1.891

μ, mm
1

6.966

8.381

F(000)

1336

2400

θ range, deg

2.94 to 25.31

3.43 to 27.48

index ranges


11 e h e 11,
18 e k e 18,


18 e h e 18,
17 e k e 17,


21 e l e 21


28 e l e 28

no. of reflns collcd

30 363

26 122

completeness to θmax

92.8%

98.2%

no. of indep reflns/Rint

9025/R(int) = 0.049 4918/R(int) = 0.042

no. of reflns obsd

5442

3351

none 559

none 241

with (I > 2σ(I)) absorpn correction no. of refined params GooF (F2)

0.876

0.994

R1 (F) (I > 2σ(I))

0.0385

0.0301

wR2 (F2) (all data)

0.0901

0.0901

(Δ/σ)max

0.001

0.001

largest diff peak/hole, e/Å3 1.267 and
1.813

0.847 and
1.167

assigned), 6.0 (1%, not assigned), 19.0 (34%, 3-t-Bu-1,5-[P(O)(OEt)2]2C6H3), and
151.9 (46%, not assigned). Crystallography. Single crystals of compounds 1 and 2 were obtained by slow evaporation of their solutions in diethyl ether and ethyl acetate, respectively. Intensity data for the colorless crystals were collected on a Nonius KappaCCD diffractometer with graphite-monochromated Mo Kα (0.71073 Å) radiation at 291(1) (1) and 173(1) (2) K, respectively. The data collection for 1 and 2 covered almost the whole sphere of reciprocal space with 360 frames (1) and with 2 sets at different k-angles with 198 frames (2) via ω-rotation (Δ/ω = 1°) at two times 20 s per frame. The crystal-to-detector distances were 3.4 cm (1, 2) with a detector
θ offset of 5° (1). Crystal decays were monitored by repeating the initial frames at the end of data collection. The data were not corrected for absorption effects. Analyzing the duplicate reflections there were no indications for any decay. The structures were solved by direct methods with SHELXS9747 [1] and successive difference Fourier syntheses. Refinements applied full-matrix least-squares methods with SHELXL9748 [2]. The H atoms were placed in geometrically calculated positions using a riding model with isotropic temperature factors constrained at 1.2 for non-methyl and at 1.5 for methyl groups times Ueq of the carrier C atom. 5185

dx.doi.org/10.1021/om200544r |Organometallics 2011, 30, 5181–5187

Organometallics In 1 disordered tert-butyl and ethoxy groups were found disordered over two sites with occupancies of 0.3 (C(80 ), C(90 ), C(100 ), 0.4 C(360 ), 0.6 C(36)) and 0.7 (C(8), C(9), C(10)). Atomic scattering factors for neutral atoms and real and imaginary dispersion terms were taken from International Tables for X-ray Crystallography.49 The figures were created by SHELXTL.50 Crystallographic data are given in Table 3; selected bond distances and angles, in Table 1. CCDC-802068 (1) and CCDC-802069 (2) contain the supplementary crystallographic data for this paper. These data can be obtained free of charge at www.ccdc.cam.ac.uk/conts/retrieving.html [or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (internat.) +44-1223/336-033; e-mail: deposit@ ccdc.cam.ac.uk]. Computational Details. The geometry optimizations were started from the geometry of the solid-state structures using the BP86 pure functional51,52 and the Ahlrichs def2-TZVP basis set,53 which includes an effective core potential on Bi as implemented in Turbomole.54 Stationary points have been characterized with frequency analysis and show the correct number of negative eigenvalues (zero for a local minimum). On the basis of the geometry obtained with the BP86/def2-TZVP method, a NBO analysis55 was performed with this method using NBO 5.0 as implemented in Gaussian09 Rev. B.01.56

’ ASSOCIATED CONTENT

bS

Supporting Information. Figures representing the optical isomers in the crystal of 2, as well as the supramolecular architectures in the crystals of compounds 1 and 2, and additional information on the DFT calculations. This material is available free of charge via the Internet at http://pubs.acs.org.

’ AUTHOR INFORMATION Corresponding Author

*E-mail: [email protected]. Funding Sources

This work contains part of the Ph.D. thesis of K.P., TU Dortmund, 2003. Part of this work was first presented at the XXIInd GermanPolish Colloquium on Organometallic Chemistry, September 24
27, 2000, Bad Frankhausen, Germany, book of abstracts, p 10.

’ ACKNOWLEDGMENT We thank the Deutsche Forschungsgemeinschaft DFG for financial support. S.H.-P. thanks the FCI for a Liebig fellowship and the Bundesministerium f€ur Bildung und Forschung (MoSGrid, 01IG09006) for financial support. Calculation time at the ARMINIUS Cluster at the PC2 Paderborn and the SuGI Cluster at the Regionales Rechenzentrum K€oln (RRZK) is gratefully acknowledged. C.S. acknowledges TU Dortmund for a Gambrinus fellowship. ’DEDICATION Dedicated to Prof. Dr. Hans Joachim Breunig on the occasion of his retirement. ’ REFERENCES (1) Yamamoto, Y.; Chen, X.; Akiba, K. J. Am. Chem. Soc. 1992, 114, 7906. (2) Yoshida, S.; Yasui, M.; Iwasaki, F.; Yamamoto, Y.; Chen, X.; Akiba, K. Acta Crystallogr. Sect. B 1994, 50, 151.

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