Synthesis and Structure of Magnesium and Group 13 Metal Bis

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Organometallics 2010, 29, 1622–1628 DOI: 10.1021/om100019c

Synthesis and Structure of Magnesium and Group 13 Metal Bis(thiophosphinoyl)methanediide Complexes Wing-Por Leung,* Chi-Ling Wan, and Thomas C. W. Mak Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, People’s Republic of China Received January 7, 2010

Metalations of bis(diphenylthiophosphinoyl)methane, CH2(PPh2dS)2, with equimolar BunLi or Bun2Mg in THF afforded [Li{(SdPPh2)2CH}(THF)(Et2O)] (1) and [MgC(PPh2dS)2(THF)]2 (2), respectively. Compound 1 with a group 13 metal chloride MCl3 (M = Al, Ga, In) gave the methanediide complex [MCl{C(PPh2dS)2}]2 (M = Al (3), Ga (4), In (5)). Compounds 3-5 are believed to be formed by ligand transfer reaction followed by dehydrochlorination. X-ray structures of 1-5 have been determined. It was found that the magnesium complex 2 has a similar structure to the group 13 metal analogues 3-5.

Introduction The chemistry of group 13 metal organometallic complexes, especially the organoaluminium compounds, has been widely explored on account of their uses in polymerization catalysis. Various ligands containing N-donor sites have been used to stabilize these metal complexes.1 For example, the imino and sulfur derivatives of bis(diphenylphosphino)methane have been studied extensively in the past few decades. Dilithium methanediide complexes [Li2C(PPh2dX)2] (X = NSiMe3, S) have been prepared and structurally characterized.2,3 The coordination chemistry of bis(iminophosphorano)- and bis(thiophosphinoyl)methanediide complexes has developed *Corresponding author. E-mail: [email protected]. (1) Selected reviews and examples of group 13 metal complexes with N-donors: (a) Barker, J.; Blacker, N. C.; Phillips, P. R.; Alcock, N. W.; Errington, W.; Wallbridge, M. G. H. J. Chem. Soc., Dalton Trans. 1996, 431. (b) Coles, M. P.; Jordan, R. F. J. Am. Chem. Soc. 1997, 119, 8125. (c) Coles, M. P.; Swenson, D. C.; Jordan, R. F. Organometallics 1997, 16, 5183. (d) Qian, B.; Ward, D. L.; Smith, M. R. S.III. Organometallics 1998, 17, 3070. (e) Bruce, M.; Gibson, V. C.; Redshaw, C.; Solan, G. A.; White, A. J. P.; Williams, D. J. Chem. Commun. 1998, 2523. (f) Cosledan, F.; Hitchcock, P. B.; Lappert, M. F. Chem. Commun. 1999, 705. (g) Chang, C.-C.; Ameerunisha, M. S. Coord. Chem. Rev. 1999, 189, 199. (h) Dagorne, S.; Jordan, R. F. Organometallics 1999, 18, 4619. (i) Hair, G. S.; Battle, S. L.; Decken, A.; Cowley, A. H.; Jones, R. A. Inorg. Chem. 2000, 39, 27. (j) Dagorne, S.; Guzei, I. A.; Coles, M. P.; Jordan, R. F. J. Am. Chem. Soc. 2000, 122, 274. (k) Hardman, N. J.; Power, P. P. Inorg. Chem. 2001, 40, 2474. (l) Carmalt, C. J.; Mileham, J. D.; White, A. J. P.; Williams, D. J.; Steed, J. W. Inorg. Chem. 2001, 40, 6035. (m) Stender, M.; Eichler, B. E.; Hardman, N. J.; Power, P. P.; Prust, J.; Noltemeyer, M.; Roesky, H. W. Inorg. Chem. 2001, 40, 2794. (n) Wingerter, S.; Pfeiffer, M.; Stey, T.; Bolboaca, M.; Kiefer, W.; Chandrasekhar, V.; Stalke, D. Organometallics 2001, 20, 2730. (o) Gardinier, J. R.; Gabbaï, F. P. New J. Chem. 2001, 25, 1567. (p) Wang, Z.-X.; Li, Y.-X. Organometallics 2003, 22, 4900. (q) Kenney, A. P.; Yap, G. P. A.; Richeson, D. S.; Barry, S. T. Inorg. Chem. 2005, 44, 2926. (r) Jones, C.; Junk, P. C.; Platts, J. A.; Stasch, A. J. Am. Chem. Soc. 2006, 128, 2206. (s) Kempter, A.; Gemel, C.; Fischer, R. A. Inorg. Chem. 2008, 47, 7279. (t) Chai, Z.-Y.; Zhang, C.; Wang, Z.-X. Organometallics 2008, 27, 1626. (2) (a) Kasani, A.; Kamalesh Babu, R. P.; McDonald, R.; Cavell, R. G. Angew. Chem., Int. Ed. 1999, 38, 1483. (b) Ong, C. M.; Strphan, D. W. J. Am. Chem. Soc. 1999, 121, 2939. (3) Cantat, T.; Ricard, L.; Le Floch, P.; Mezailles, N. Organometallics 2006, 25, 4965. pubs.acs.org/Organometallics

Published on Web 02/26/2010

rapidly. Numerous main group, transition metal, and rare earth metal complexes of this kind were synthesized.4-6 However, only a few examples of group 13 methanediide complexes are known. Cavell and co-workers have reported the first example of bis(iminophosphorano)methanediide complexes [(AlR2)2{μ2-C(Ph2PdNSiMe3)2-κ2N,N0 }] (R = Me, Bu).7,8 The aluminum methanediide complex [(AlBu)2Ph2P(S)SPPh2(S)2(AlBu)2] has a related ligand.9 These compounds are bridging bi- and tetrametallic complexes, respectively. Moreover, the gallium and indium methanediide complexes were unknown. Herein, we report the synthesis of a series of metal (M = Al, Ga, In, and Mg) bis(thiophosphinoyl)methanediide complexes, in which there is direct interaction between the metal and the methanediide carbon. (4) (a) Leung, W.-P.; Wang, Z.-X.; Li, H.-W.; Mak, T. C. W. Angew. Chem., Int. Ed. 2001, 40, 2501. (b) Hull, K. L.; Noll, B. C.; Henderson, K. W. Organometallics 2006, 25, 4072. (c) Orzechowski, L.; Jansen, G.; Harder, S. J. Am. Chem. Soc. 2006, 128, 14676. (d) Orzechowski, L.; Harder, S. Organometallics 2007, 26, 5501. (5) (a) Cavell, R. G.; Kamalesh Babu, R. P.; Kasani, A.; McDonald, R. J. Am. Chem. Soc. 1999, 121, 5805. (b) Kamalesh Babu, R. P.; McDonald, R.; Decker, S. A.; Klobukowski, M.; Cavell, R. C. Organometallics 1999, 18, 4226. (c) Kasani, A.; McDonald, R.; Cavell, R. G. Chem. Commun. 1999, 1993. (d) Kamalesh Babu, R. P.; McDonald, R.; Cavell, R. G. Chem. Commun. 2000, 481. (e) Jones, N. D.; Lin, G.; Gossage, R. A.; McDonald, R.; Cavell, R. G. Organometallics 2003, 22, 2832. (f) Cantat, T.; Mezaillies, N.; Ricard, L.; Jean, Y.; Le Floch, P. Angew. Chem., Int. Ed. 2004, 43, 6382. (g) Cantat, T.; Demange, M.; Mezaillies, N.; Ricard, L.; Jean, Y.; Le Floch, P. Organometallics 2005, 24, 4838. (h) Cantat, T.; Ricard, L.; Mezailles, N.; Le Floch, P. Organometallics 2006, 25, 6030. (6) (a) Kasani, A.; Ferguson, M.; Cavell, R. G. J. Am. Chem. Soc. 2000, 122, 726. (b) Cantat, T.; Jaroschik, F.; Nief, F.; Ricard, L.; Mezaillies, N.; Le Floch, P. Chem. Commun. 2005, 5178. (c) Cantat, T.; Jaroschik, F.; Ricard, L.; Le Floch, P.; Nief, F.; Mezaillies, N. Organometallics 2006, 25, 1329. (d) Cantat, T.; Arliguie., T.; No€el, A.; Thuery, P.; Ephritikhine, M.; Le Floch, P.; Mezaillies, N. J. Am. Chem. Soc. 2009, 131, 963. (7) Aparna, K.; McDonald, R.; Ferguson, M.; Cavell, R. G. Organometallics 1999, 18, 4241. (8) Cavell, R. G.; Aparna, K.; Kamalesh Babu, R. P.; Wang, Q. J. Mol. Catal. A: Chem. 2002, 189, 137. (9) Robinson, G. H.; Self, M. K.; Pennington, W. T; Sangokoya, S. A. Organometallics 1988, 7, 2424. r 2010 American Chemical Society

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Scheme 1

Scheme 2

Figure 1. Molecular structure of 1 with 30% thermal ellipsoids.

Results and Discussion Synthesis of Lithium and Magnesium Bis(thiophosphinoyl) Complexes. The acidity of the methylene protons in bis(diphenylthiophosphinoyl)methane, CH2(PPh2dS)2, is enhanced by the thiophosphinoyl groups and therefore can be deprotonated by bases. Reaction of CH2(PPh2dS)2 with one equivalent of BunLi in THF at 0 °C afforded the monolithium complex [Li{(SdPPh2)2CH}(THF)(Et2O)] (1), while that with equimolar Bun2Mg in THF at 60 °C afforded the magnesium methanediide complex [MgC(PPh2dS)2(THF)]2 (2) (Scheme 1). Double deprotonation of related bis(phosphorus)-stabilized compounds is usually done by lithium alkyl.2,3,10 Magnesium methanediide complexes [{(Ph2Pd NSiMe3)(Ph2PdE)}CMg]2 (E=S, NSiMe3) containing magnesium atoms that bridge the methandiide carbon have been reported recently.11 To our knowledge, compound 2 is the first example of a methandiide carbon bonded to one magnesium atom. Synthesis of Group 13 Metal Bis(thiophosphinoyl) Complexes. Group 13 bis(thiophosphinoyl)methanediide metal chlorides [MCl{C(PPh2dS)2}]2 (M = Al (3), Ga (4), In (5)) have been synthesized from the reaction of MCl3 with two equivalents of 1 in Et2O at 0 °C (Scheme 2). On the basis of the structures and spectroscopic data of products obtained, it is proposed that the intermediate [MCl2{C(PPh2dS)2}] (10) Chen, J.-H.; Guo, J.; Li, Y.; So, C.-W. Organometallics 2009, 28, 4617. (11) Guo, J.; Lee, J.-S.; Foo, M.-C.; Lau, K.-C.; Xi, H.-W.; Lim, H. W.; So, C.-W. Organometallics 2010, 29, 939.

(M = Al (3a), Ga (4a), In (5a)) formed underwent further dehydrochlorination to give compounds 3-5. The monolithium complex 1 acts both as a ligand transfer reagent and as a base for dehydrochlorination. Similar dehydrochlorination has been reported in the synthesis of bisgermavinylidene from the reaction of GeCl2 dioxane with [Li{CH(PPh2dNSiMe3)2}(THF)].4a Until now, only the aluminum methandiide complex [{(Ph2PdNSiMe3)(Ph2PdS)}CAlMe]2 with one Al-C bond has been synthesized and structurally characterized.11 Spectroscopic Properties. Compounds 1 and 3-5 were isolated as colorless crystalline solids, while compound 2 is a yellow crystalline solid. Compound 1 is extremely air and moisture sensitive. The 1H NMR and 13C NMR spectra of 1 displayed signals assignable to the bis(thiophosphinoyl)methanide ligand, together with solvated THF and Et2O molecules. The 1H NMR spectrum of 1 showed a triplet at δ 2.23 ppm (JP-H = 1.8 Hz) for the methanide proton on the P-C-P backbone with coupling to two equivalent phosphorus nuclei. These indicate considerable delocalization throughout the SPCPS backbone of the ligand. This is also consistent with the 31P NMR, which showed one singlet at δ 37.61 ppm. The 13C NMR spectrum of 1 is normal. Compound 2 is an extremely air-sensitive solid. Although no signal was observed for the carbenic carbon in the 13C NMR spectrum of 2, the absence of signals assignable to the methylene protons in compound 2 was confirmed by 1H NMR spectroscopy. The 31P NMR spectrum of 2 displays two singlets at δ 14.05 and 34.96 ppm, which does not correspond to the solid-state X-ray structure. The variabletemperature 31P NMR of 2 in d8-THF has been carried out in the range from 60 to -60 °C. The two peaks did not coalesce at temperature up to 60 °C. The 31P-31P EXSY NMR spectrum of 2 in d8-THF has also been recorded. There were no cross-peaks in the spectrum; therefore no exchange between the two phosphorus atoms was present. We propose that the phosphorus atoms within the molecule might have two different environments in solution. The 1H and 13C NMR spectra of 3-5 showed a similar pattern and displayed one set of signals due to the ligand. There is one sharp singlet [δ 32.24 (3); δ 31.86 (4); δ 31.87 ppm (5)] in all of their 31P NMR spectra. This indicates that

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Table 1. Crystallographic Data for Compounds 1 and 2 1 formula

C33H39LiO2P2S2 fw 600.64 color colorless cryst syst triclinic space group P1 a (A˚) 10.4369(18) 10.6649(18) b (A˚) c (A˚) 17.073(3) R (deg) 81.831(4) β (deg) 73.596(3) γ (deg) 69.205(3) 1702.4(5) V (A˚3) Z 2 -3 1.172 dcalcd (g cm ) 0.277 μ (mm-1) F(000) 636 cryst size (mm) 0.50 0.40 0.30 2θ range (deg) 1.24 to 25.00 index ranges -12 e h e 9, -12 e k e 12, -20 e l e 20 no. of rflns collected 9291 no. of indep rflns 5975 R1, wR2 (I >2(σ)I) 0.0785, 0.2216 R1, wR2 (all data) 0.1015, 0.2406 2 1.075 goodness of fit, F no. of data/restraints/params 5975/9/361 0.739 to -0.426 largest diff peaks (e A˚-3)

2 C58H56Mg2O2P4S4 3 2THF 1229.98 yellow monoclinic P21/c 10.420(4) 13.181(5) 23.464(9) 90 96.986 90 3199(2) 2 1.277 0.315 1296 0.40 0.30 0.20 1.75 to 28.05 -13 e h e 13, -16 e k e 17, -26 e l e 30 21 358 7736 0.0666, 0.1645 0.1906, 0.2355 1.012 7736/10/361 0.468 to -0.302

the phosphorus atoms in these compounds are in the same environment. X-ray Structures. The molecular structure of 1 is shown in Figure 1. Selected bond distances (A˚) and angles (deg) of 1 are listed in Table 2. Compound 1 is a monomeric lithium complex. The Li(1) coordinates to the ligand with S,S0 chelation to form a six-membered ring. The lithium is bonded to a THF and a Et2O molecule to adopt a tetrahedral geometry. It is rare that a lithium atom is coordinated to two different ether molecules in a coordinated compound. The Li-S bond distances of 2.422(1) and 2.421(1) A˚ in 1 are comparable to those of 2.474(8) and 2.473(8) A˚ in [Li{(SdPPh2)2N}(THF)2].12 The P-S bond distances [1.993(2), 1.993(2) A˚] and the P-C bond distances [1.712(4), 1.711(4) A˚] in 1 are different from those of CH2(PPh2dS)2 [P-S: 1.944 A˚; P-C: 1.829 A˚].13 These suggest that charge delocalization within the SPCPS skeleton is present. The P(2)-C(13)-P(1) angle of 126.8(3)° is larger than that of 118.4(2)° in CH2(PPh2dS)2. The molecular structure of 2 is shown in Figure 2. Selected bond distances (A˚) and angles (deg) of 2 are listed in Table 2. Compound 2 is a dimeric species with two magnesium methanediide molecules bonded side-by-side via the sulfur atoms in a head-to-tail fashion. The magnesium metal center is bonded to the methanediide carbon atom, two thio sulfur atoms from an adjacent ligand, and a THF molecule to give a tetrahedral geometry. The angles at the three coordinated methanediide carbon atoms [119.0(3)°, 115.4(2)°, 115.0(2)°; P bond angles = 349.4°] support the existence of a sp2hybridized carbon. The Mg(1)-C(1A) bond distance (2.156(5) A˚) is significantly shorter than the reported Mg-C single bond distances of [HC(Ph2PdNSiMe3)2Mg(μ-Cl)]2 (12) Chem, F.; Kapon, M.; Woollins, D.; Eisen, M. S. Organometallics 2009, 28, 2391. (13) Carmalt, C. J.; Cowley, A. H.; Decken, A.; Lawson, Y. G.; Norman, N. C. Acta Crystallogr., Sect. C: Cryst. Struct. Commun. 1996, 52, 931.

Table 2. Selected Bond Distances (A˚) and Angles (deg) for Compounds 1 and 2 [Li{(SdPPh2)2CH}(THF)(Et2O)] (1) Li(1)-O(1) Li(1)-O(2) Li(1)-S(1) Li(1)-S(2)

1.941(1) 1.960(1) 2.422(1) 2.421(1)

P(1)-C(13) P(1)-S(1) P(2)-C(13) P(2)-S(2)

1.712(4) 1.993(2) 1.711(4) 1.993(2)

O(1)-Li(1)-O(2) O(1)-Li(1)-S(1) O(1)-Li(1)-S(2) O(2)-Li(1)-S(1) O(2)-Li(1)-S(2) S(2)-Li(1)-S(1)

101.9(5) 117.3(5) 104.7(5) 108.5(5) 116.5(5) 108.1(4)

C(13)-P(1)-S(1) C(13)-P(2)-S(2) P(1)-S(1)-Li(1) P(2)-S(2)-Li(1) P(2)-C(13)-P(1)

118.6(2) 117.1(2) 102.9(2) 106.6(3) 126.8(3)

[MgC(PPh2dS)2(THF)]2 3 2THF (2) Mg(1)-O(1) Mg(1)-C(1A) Mg(1)-S(1) Mg(1)-S(2)

2.061(4) 2.156(5) 2.455(2) 2.459(2)

P(1)-C(1) P(1)-S(1) P(2)-C(1) P(2)-S(2)

1.708(5) 2.026(2) 1.702(5) 2.039(2)

O(1)-Mg(1)-C(1A) O(1)-Mg(1)-S(1) C(1A)-Mg(1)-S(1) O(1)-Mg(1)-S(2) C(1A)-Mg(1)-S(2) S(1)-Mg(1)-S(2)

114.0 (2) 95.0(1) 117.7(1) 95.0(1) 121.7(1) 108.0(1)

C(1)-P(1)-S(1) C(1)-P(2)-S(2) P(1)-S(1)-Mg(1) P(2)-S(2)-Mg(1) P(2)-C(1)-P(1) P(2)-C(1)-Mg(1A) P(1)-C(1)-Mg(1A)

118.3(2) 117.5(2) 96.7(1) 97.0(1) 119.0(3) 115.0(2) 115.4(2)

(2.460(8) A˚) and HC(Ph2PdNSiMe3)2MgI(THF) (2.573(6) A˚)14 as well as those of magnesium methandiide complexes [{(Ph2PdNSiMe3)(Ph2PdE)}CMg]2 (E = S (average 2.241); NSiMe3 (average 2.235 A˚))].11 This value also shows good agreement with the calculated Mg-C bond (2.08-2.10 A˚) of MgdCH2.15 The relatively short P-C bond length of 1.705 A˚ suggests that the thiophosphinoyl arms help to stabilize the electron density on the carbon center. Compounds 3-5 are isostructural, and their molecular structures are illustrated in Figures 3-5. Selected bond distances (A˚) and angles (deg) of 3-5 are shown in Table 4. All of 3-5 are dimeric species bearing structural resemblance to [MgC(PPh2dS)2(THF)]2 (2). The metal center is bonded to the chlorine atom instead of a THF molecule, a methanediide carbon, and two thio sulfur atoms from an adjacent ligand, leading to a tetrahedral environment. It is noteworthy that compounds 3-5 possess an inversion center i, so that half of the structures is centrosymmetric to the other half. The sum of angles of 351.9°, 350.4°, and 352.4° in 3, 4, and 5 around the C(1) atom is indicative of a sp2 carbon. The average metal-sulfur bond and metal-chloride bond distances increase down the group [M-S: 2.286 (3), 2.298 (4), 2.480 (5); M-Cl: 2.169(1) (3), 2.219(2) (4), 2.410(1) A˚ (5)]. There is also an interesting trend in the M-C contact lengths. The Al-C bond distance [1.975(2) A˚] and Ga-C bond distance [1.972(4) A˚] are very close to each other, while the In-C bond distance [2.173(3) A˚] is much longer. These M-C bond distances are in between the M-C single and double bond length values [M-C: 2.032 (Al), 2.032 (Ga), 2.212 (In); MdC: 1.927 (Al), 1.927 (Ga), 2.107 A˚ (In)].16 In addition, they are relatively shorter than the similar M-C bond in N-heterocyclic carbene complexes [Al-C: (14) Wei, P.; Stephan, D. W. Organometallics 2003, 22, 601. (15) Bare, W. D.; Citra, A.; Trindle, C.; Andrews, L. Inorg. Chem. 2000, 39, 1204. (16) Pauling, L. The Nature of The Chemical Bond and The Structure of Molecules and Crystals: An Introduction of Modern Structural Chemistry; Cornell University Press: Ithaca, NY, 1976; pp 221-264.

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2.031-2.124, Ga-C: 2.071-2.131, In-C: 2.200-2.267 A˚].17 Also, the Al-C bond distance is shorter than the Al-C (17) (a) Arguengo, A. J.III; Dias, H. V. R.; Calabrese, J. C.; Davidson, F. J. Am. Chem. Soc. 1992, 114, 9724. (b) Li, X.-W.; Su, J.; Robinson, G. H. Chem. Commun. 1996, 2683. (c) Francis, M. D.; Hibbs, D. E.; Hursthouse, M. B.; Jones, C.; Smithies, N. A. J. Chem. Soc., Dalton Trans. 1998, 3249. (d) Abernethy, C. D.; Cole, M. L.; Jones, C. Organometallics 2000, 29, 4852. (e) Baker, R. J.; Farley, R. D.; Jones, C.; Kloth, M.; Murphy, D. M. Chem. Commun. 2002, 1196. (f) Shih, W.-C.; Wang, C.-H.; Chang, Y.-T.; Yap, G. P. A.; Ong, T.-G. Organometallics 2009, 28, 1060. (g) Ghadwal, R. S.; Roesky, H. W.; Herbst-Irmer, R.; Jones, P. G. Z. Anorg. Allg. Chem. 2009, 635, 431.

single bond distance of 2.119 A˚ in [(AlMe2)2{μ2C(Ph2PdNSiMe3)2-κ4C,C0 ,N,N0 }]7 and that of 2.097(4) A˚ in [Al(Me2)C(PPh2dS)(PPh2dSfAlMe3)].18 It is found that the Al-C bond distance of 5 is very similar to that of [{(Ph2PdNSiMe3)(Ph2PdS)}CAlMe]2 (1.976(1) A˚).11 In compound 3, the average Al-S bond distance of 2.286 A˚ is comparatively shorter than those in [{Me2Si(μ-NBut)2Pd (18) Self, M. F.; Lee, B.; Sangokoya, S. A.; Pennington, W. T.; Robinson, G. H. Polyhedron 1990, 9, 313.

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S(NPh)-κN-κS}AlMe2] (2.352(1) A˚),19 [Al(Me2)C(PPh2dS)(PPh2dSfAlMe3)] (2.388(2), 2.460(2) A˚),18 and [(AlMe3)(SdPPh2CH2CH2PPh2dS)(AlMe3)] (2.506(3) A˚).18 The AlCl bond distance of 2.169(1) A˚ is comparable to those of 2.126 A˚ in [{HC(CMeNAr)2}AlCl2],1m 2.152(1) A˚ in [{(Me3SiNCH2CH2)2NMe}AlCl],20 and 2.149 A˚ in [{HC(Ph2Pd NMes)2}AlCl2].21 The average Ga-S bond distance of 2.298 A˚ in 4 is similar to that of 2.273 A˚ in [GaCl2{N(Ph2PdS)2}]22 but shorter than those of 2.398 A˚ in [GaMe2{N(Ph2PdS)2}]23 and 2.3886(9) A˚ in [GaMe2{(SdPPh2)N(C9H10NCdS}].23 The Ga-Cl bond (2.219(2) A˚) has a similar bond length to the corresponding bond in [GaCl2{N(Ph2PdS)2}] (2.169 A˚),22 [{CH(Ph2PdNSiMe3)2}GaCl2] (2.200 A˚),24 and [{HC(CMeNAr)2}GaCl2] (2.223 A˚).1m In the case of 5, the average In-S bond distance of 2.481 A˚ agrees with that of 2.485 A˚ in [InI2{N(Ph2PdS)2}]25 but is shorter than those in [InCl{N(Pri2PdS)2}2] (2.5715 A˚)26 and [κ3-N,N0 ,S-{4,5-P(S)Ph2}2(μ-tz)]InMe2]2] (2.780(1) A˚).27 It is believed that the higher indium coordination number in the latter two compounds lengthens the In-S bond. The InCl bond distance of 2.410(1) A˚ is comparable to those of 2.410(2) A˚ in [InCl{N(Pri2PdS)2}2]26 and 2.396 A˚ in [{HC(CMeNAr)2}InCl2].1m (19) Haagenson, D. C.; Moser, D. F.; Stahl, L. Inorg. Chem. 2002, 41, 1245. (20) Emig, N.; Nguyen, H.; Krautscheid, H.; Reau, R.; Cazaux, J.-B.; Bertrand, G. Organometallics 1998, 17, 3599. (21) Hill, M. S.; Hitchcock, P. B.; Karagouni, S. M. A. J. Organomet. Chem. 2004, 689, 722. Montiel-Palma, V.; Huitr (22) Mu~ noz-Hern andez, M.-A.; on-Rattinger, E.; Cortes-Llamas, S.; Tiempos-Flores, N.; Grevy, J.-M.; Silvestru, C.; Power, P. P. Dalton Trans. 2005, 193. (23) Montiel-Palma, V.; Huitr on-Rattinger, E.; Cortes-Llamas, S.; Garcı´ a-Montalvo, V.; L Mu~ noz-Hern andez, M.-A.; opez- Honorato, E.; Silvestru, C. Eur. J. Inorg. Chem. 2004, 3743. (24) Ong, C. M.; McKarns, P.; Stephan, D. W. Organometallics 1999, 18, 4197. (25) Abbati, G. L.; Aragoni, M. C.; Arca, M.; Devillanova, F. A.; Fabretti, A. C.; Garau, A.; Isaia, F.; Lippolis, V.; Verani, G. Dalton Trans. 2003, 1515. (26) Darwin, K.; Gilby, L. M.; Hodge, P. R.; Piggott, B. Polyhedron 1999, 18, 3729. (27) Moya-Cabrera, M.; Jancik, V.; Castro, R. A.; Herbst-Irmer, R.; Roesky, H. W. Inorg. Chem. 2006, 45, 5167.

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In these three compounds, the P-S bonds [2.062 (3), 2.053 (4), 2.058 A˚ (5)] are lengthened and the P-C bonds [1.723 (3), 1.715 (4), 1.721 A˚ (5)] are shortened relative to the free ligand [(SdPPh2)2CH2]; this is consistent with π-delocalization around the MS2P2C ring.

Conclusion To summarize, lithium and magnesium thiophosphinoyl complexes were readily prepared from CH2(PPh2dS)2. The monolithium salt is a versatile precursor to access the first series of group 13 bis(thiophosphinoyl)methanediide complexes. There is an unusual direct interaction between the metal and methanediide carbon in the magnesium and group 13 metal complexes. Reactivity studies that explore this interaction are being pursued in our laboratory.

Experimental Section General Procedures. All manipulations were carried out under an inert atmosphere of dinitrogen gas by standard Schlenk techniques. Solvents were dried over and distilled from CaH2 (CH2Cl2) and Na (Et2O, toluene, and THF). CH2(PPh2dS)2 was prepared according to the literature procedures.3 BunLi (1.6 M in hexane), Bun2Mg (1.0 M in heptane), AlCl3, GaCl3, and InCl3 were purchased from Aldrich Chemical Co. and used without further purification. The 1H, 13C, and 31P NMR spectra were recorded on Br€ uker DPX-300 or Br€ uker DPX-400 spectrometers. The NMR spectra were recorded in C6D6 and THF-d8, and the chemical shifts δ are relative to SiMe4 and 85% H3PO4 for 1H, 13C, and 31P, respectively. [Li{(SdPPh2)2CH}(THF)(Et2O)] (1). BunLi (4.40 mL, 7.04 mmol, 1.6 M solution in hexane) was added slowly to a solution of CH2(PPh2dS)2 (3.12 g, 6.96 mmol) in THF (50 mL) at 0 °C. The temperature of the reaction mixture was raised to ambient temperature and stirred for 15 h. Volatiles were removed under reduced pressure, and the residue was extracted with Et2O. After filtration and concentration of filtrate, 1 was obtained as colorless crystals. Yield: 3.48 g (83%). Mp: 169.2-172.1 °C. Anal. Found: C, 65.36; H, 6.54. Calcd for C33H39LiO2P2S2: C, 65.99; H, 6.54. 1H NMR (400 MHz, C6D6): δ 1.05 (t, 3H, Et2O, J = 7.0 Hz), 1.17-1.20 (m, 4H, THF), 2.23 (t, 1H, CH, JP-H = 1.8 Hz), 3.19-3.25 (q, 2H, Et2O, J = 7.0 Hz), 3.39-3.42, (m, 4H, THF), 6.97-7.05 (m, 12H, Ph), 8.15-8.20 (m, 8H, Ph).

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Table 3. Crystallographic Data for Compounds 3-5

formula fw color cryst syst space group a (A˚) b (A˚) c (A˚) R (deg) β (deg) γ (deg) V (A˚3) Z dcalcd (g cm-3) μ (mm-1) F(000) cryst size (mm) 2θ range (deg) index ranges no. of rflns collected no. of indep rflns R1, wR2 (I > 2(σ)I) R1, wR2 (all data) goodness of fit, F2 no. of data/restraints/params largest diff peaks (e A˚-3)

3

4

5

C25H20AlClP2S2 508.90 colorless monoclinic P21/c 11.5467(16) 19.957(3) 12.4806(17) 90 105.873(2) 90 2766.4(6) 4 1.222 0.447 1048 0.40 0.30 0.20 1.83 to 25.00 -10 e h e 13 -19 e k e 23 -14 e l e 14 14 857 4867 0.0388, 0.0973 0.0537, 0.1036 0.993 4867/0/280 0.458 to -0.233

C50H40Cl2Ga2P4S4 1103.28 colorless monoclinic P21/c 11.557(8) 19.892(14) 12.418(8) 90 106.293(11) 90 2740(3) 2 1.337 1.381 1120 0.40 0.30 0.20 1.84 to 25.00 -13 e h e 13 -23 e k e 23 -14 e l e 8 14 297 4819 0.0524, 0.1126 0.0875, 0.1235 0.901 4819/0/280 0.834 to -0.523

C25H20ClInP2S2 596.74 colorless monoclinic P21/c 11.6775(17) 20.458(3) 12.5404(19) 90 108.184(2) 90 2846.3(7) 4 1.393 1.193 1192 0.40 0.30 0.20 1.84 to 25.00 -13 e h e 13 -20 e k e 24 -14 e l e 14 15 234 5013 0.0323, 0.0785 0.0425, 0.0826 0.978 5013/0/280 0.805 to -0.386

Table 4. Selected Bond Distances (A˚) and Angles (deg) for Compounds 3-5 [MCl{C(PPh2dS)2}]2 M = Al (3)

M = Ga (4)

M = In (5)

M(1)-C(1A) M(1)-Cl(1) M(1)-S(1) M(1)-S(2) P(1)-C(1) P(1)-S(1) P(2)-C(1) P(2)-S(2)

1.975(2) 2.169(1) 2.281(1) 2.291(1) 1.722(2) 2.062(1) 1.724(2) 2.062(1)

1.972(4) 2.219(2) 2.294(2) 2.302(2) 1.710(5) 2.054(2) 1.720(5) 2.051(2)

2.173(3) 2.410(1) 2.477(1) 2.485(1) 1.723(3) 2.059(1) 1.718(3) 2.057(1)

C(1A)-M(1)-Cl(1) C(1A)-M(1)-S(1) Cl(1)-M(1)-S(1) C(1A)-M(1)-S(2) Cl(1)-M(1)-S(2) S(1)-M(1)-S(2) C(1)-P(1)-S(1) C(1)-P(2)-S(2) P(1)-S(1)-M(1) P(2)-S(2)-M(1) P(1)-C(1)-P(2) P(1)-C(1)-M(1A) P(2)-C(1)-M(1A)

112.58(8) 116.03(7) 100.81(4) 116.95(8) 100.29(4) 107.91(4) 115.69(8) 114.99(9) 101.27(4) 101.71(3) 116.8(1) 118.0(1) 117.1(1)

112.0(1) 117.4(1) 99.94(7) 117.9(1) 99.60(6) 107.12(6) 116.3(2) 115.4(2) 101.05(8) 101.73(7) 117.8(3) 116.9(2) 115.7(2)

112.2(1) 119.1(1) 99.68(3) 119.19(8) 99.61(3) 103.70(3) 116.9(1) 116.5(1) 99.14(4) 99.41(4) 121.1(2) 115.4(2) 115.8(2)

C{1H} NMR (75.5 MHz, C6D6): δ 15.68 (Et2O), 20.05 (t, PCP, JP-C = 101.0 Hz), 25.65 (THF), 66.15 (Et2O), 68.55 (THF), 128.17 (m-Ph), 129.88 (p-Ph), 132.18 (t, o-Ph, 2JP-C= 5.4 Hz), 140.49 (d, ipso-Ph, 1JP-C = 93.3 Hz). 31P{1H} NMR (121.5 MHz, C6D6): δ 37.61. [MgC(PPh2dS)2(THF)]2 (2). Bun2Mg (1.33 mL, 1.33 mmol, 1.0 M solution in heptane) was added slowly to a solution of CH2(PPh2dS)2 (0.60 g, 1.33 mmol) in THF (70 mL). The reaction mixture was stirred at 60 °C for 15 h. The precipitate was filtered. The yellow filtrate was concentrated under reduced pressure to yield yellow crystals of 2. Yield: 0.54 g (66%). Mp: 208 °C (dec). Anal. Found: C, 63.87; H, 6.08. Calcd for C58H56Mg2O2P4S4 3 THF: C, 64.31; H, 5.58. 1H NMR (300 MHz, THF-d8): δ 6.98-7.27 (m, 24H, Ph), 7.72-7.82 (m, 13

16H, Ph). 13C{1H} NMR (75.5 MHz, THF-d8): δ 26.39 (THF), 68.23 (THF), 127.36, 127.44, 127.52, 128.22, 128.63, 130.25, 131.84, 132.20, 139.53, 140.77 (Ph). 31P{1H} NMR (121.5 MHz, THF-d8): δ 14.05, 34.98. [AlCl{C(PPh2dS)2}]2 (3). A solution of 1 (0.63 g, 1.05 mmol) in Et2O (20 mL) was added slowly to the solution of AlCl3 (0.07 g, 0.52 mmol) in Et2O (20 mL) at 0 °C with stirring. The resultant white suspension was raised to ambient temperature and stirred for 48 h. Volatiles were removed under reduced pressure. The residue was extracted with CH2Cl2 and filtered. Addition of THF to the filtrate and concentration gave 3 as colorless crystals. Yield: 0.25 g (93%). Mp: 244.2 °C (dec). Anal. Found: C, 57.95; H, 3.79. Calcd for C25H20AlClP2S2 3 1 /6CH2Cl2: C, 57.78; H, 3.92. 1H NMR (300 MHz, THF-d8): δ 7.29-7.39 (m, 12H, Ph), 7.90-7.97 (m, 8H, Ph). 13C{1H} NMR (75.5 MHz, THF-d8): δ 128.66 (t, m-Ph, 3JP-C = 6.3 Hz), 131.71 (s, p-Ph), 132.58 (t, o-Ph, 2JP-C = 5.3 Hz), 134.34 (d, ipso-Ph, 1 JP-C = 85.3 Hz). 31P{1H} (121.5 MHz, THF-d8): δ 32.24. [GaCl{C(PPh2dS)2}]2 (4). A solution of 1 (0.63 g, 1.05 mmol) in Et2O (20 mL) was added slowly to the solution of GaCl3 (0.10 g, 0.57 mmol) in Et2O (20 mL) at 0 °C with stirring. The resultant white suspension was raised to ambient temperature and stirred for 48 h. Volatiles were removed under reduced pressure. The residue was extracted with CH2Cl2 and filtered. After adding THF to the filtrate, it was concentrated and allowed to stand for a week to give the title compound as colorless crystals. Yield: 0.06 g (21%). Mp: 279.7 °C (dec). Anal. Found: C, 53.95; H, 3.95. Calcd for C50H40Ga2Cl2P4S4 3 1 /4CH2Cl2: C, 53.67; H, 3.63. 1H NMR (400 MHz, THF-d8): δ 7.29-7.40 (m, 12H, Ph), 7.90-7.95 (m, 8H, Ph). 13C{1H} NMR (100.6 MHz, THF-d8): δ 128.66 (t, m-Ph, 3JP-C = 6.3 Hz), 131.71 (s, p-Ph), 132.58 (t, o-Ph, 2JP-C = 5.4 Hz), 134.48 (d, ipso-Ph, 1 JP-C = 85.6 Hz). 31P{1H} (162.0 MHz, THF-d8): δ 31.86. [InCl{C(PPh2dS)2}]2 (5). A solution of 1 (0.66 g, 1.10 mmol) in Et2O (20 mL) was added slowly to the solution of InCl3 (0.11 g, 0.53 mmol) in Et2O (20 mL) at 0 °C with stirring. The resultant white suspension was raised to ambient temperature and stirred for 48 h. Volatiles were removed under reduced pressure. The residue was extracted with CH2Cl2 and filtered. Addition of THF to the filtrate and concentration gave 5 as

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colorless crystals. Yield: 0.20 g (64%). Mp: 227.5 °C (dec). Anal. Found: C, 49.04; H, 3.27. Calcd for C25H20InClP2S2 3 1 /4CH2Cl2: C, 49.07; H, 3.34. 1H NMR (400 MHz, THF-d8): δ 7.08-7.41 (m, 12H, Ph), 7.90-7.96 (m, 8H, Ph). 13C{1H} NMR (100.6 MHz, THF-d8): δ 128.66 (t, m-Ph, 3JP-C = 6.4 Hz), 131.71 (s, p-Ph), 132.58 (t, o-Ph, 2JP-C = 5.4 Hz), 134.47 (d, ipso-Ph, 1JP-C = 85.9 Hz). 31P{1H} (162.0 MHz, THF-d8): δ 31.87 X-ray Crystallography. Single crystals were sealed in Lindemann glass capillaries under nitrogen. X-ray data of 1-5 were collected on a Bruker SMART CCD diffractrometer with a Mo KR sealed tube, ω scan mode with an increment of 0.3°. Crystal data of 1-5 are summarized in Tables 1 and 3. The structures were solved by direct phase determination using the SHELXL97 program package28 and refined by full-matrix least-squares (28) Sheldrick, G. M. SHELX-97, Program for Crystal Structure Refinement from Diffraction Data; University of G€ottingen: G€ottingen, Germany, 1997.

Leung et al. with anisotropic thermal parameters for the non-hydrogen atoms. Hydrogen atoms were introduced in their idealized positions and included in structure factor calculations with assigned isotropic temperature factor calculations. Full details of the crystallographic analysis of 1-5 are given in the Supporting Information.

Acknowledgment. This work was supported by the Chinese University of Hong Kong Direct Grant (Project No.2060353). Supporting Information Available: Details on the X-ray crystal structures, including ORTEP diagrams and tables of crystal data and structure refinement, atomic coordinates, bond lengths and angles, and anisotropic displacement parameters for 1-5. This material is available free of charge via the Internet at http://pubs.acs.org.

Synthesis and Structure of Magnesium and Group 13 Metal Bis

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