Syntheses, Characterizations, and Coordination Chemistry of the 10-Vertex Phosphadicarbaboranes 6-R-arachno-6,8,9-PC2B7H11 and 6-R-arachno-
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- 作者：Daewon Hong ; Scott E. Rathmill ; Patrick J. Carroll ; and Larry G. Sneddon
- 刊名：Journal of the American Chemical Society
- 出版年：2003
- 出版时间：December 24, 2003
- 年：2003
- 卷：125
- 期：51
- 页码：16058 - 16073
- 全文大小：444K
- 年卷期：v.125,no.51(December 24, 2003)
- ISSN：1520-5126
文摘
The 10-vertex phosphadicarbaboranes, 6-R-arachno-6,8,9-PC2B7H11 (1) (R = Ph 1a or Me 1b)and 6-R-arachno-6,5,7-PC2B7H11 (2) (R = Ph 2a or Me 2b) have been synthesized using in situdehydrohalogenation reactions of RPCl2 (R = Ph or Me) with the arachno-4,5-C2B7H13 and arachno-4,6-C2B7H13 carboranes, respectively. X-ray crystallographic determinations in conjunction with DFT/GIAO/NMR calculations and NMR spectroscopic studies have established that both 1 and 2 have open cagestructures based on an icosahedron missing two vertexes. The two isomeric compounds differ in the positionsof the carbons and bridging hydrogens on the open face. Studies of the reactions of 2a with BH3·THF, S8,and hydrogen peroxide demonstrated that 2a shows strong donor properties yielding the compounds endo-6-H3B-exo-6-Ph-arachno-6,5,7-PC2B7H11 (3), endo-6-S-exo-6-Ph-arachno-6,5,7-PC2B7H11 (4), and endo-6-O-exo-6-Ph-arachno-6,5,7-PC2B7H11 (5) in which the BH3, S, and O substitutents are bonded to an electronlone pair localized at the phosphorus endo-position. The reaction of 2a with an excess of S8 results in theloss of a framework boron to produce the unique open-cage compound 
7,8-{HS(Ph)P}-hypho-7,8-C2B6H11(6). 2a also formed the donor complexes cis-(
1-[6-Ph-arachno-6,5,7-PC2B7H11])2PtBr2 (7) and trans-(1-[6-Ph-arachno-6,5,7-PC2B7H11])2PdBr2 (8) in which the metal fragment is bonded in an 1-fashion at thephosphorus endo-position. In these complexes, 2a is functioning as a two-electron sigma donor to themetals and can thus be considered as an analogue of the PR3 ligands in the classical cis-(PPh3)2PtBr2 andtrans-(PPh3)2PdBr2 coordination complexes. Although 1a did not show the donor properties exhibited by2a, its dianion 6-Ph-6,8,9-PC2B7H92- (1a2-) readily formed 4-coordinated complexes with late transitionmetals including 8-Ph-7-(Ph3P)2-nido-7,8,10,11-PtPC2B7H9 (9), 7-Ph-11-(5-C5H5)-nido-11,7,9,10-CoPC2B7H9(10), and commo-Ni-(7-Ni-8'-Ph-nido-8',10',11'-PC2B7H9)(7-Ni-8-Ph-nido-8,10,11-PC2B7H9) (11).
7,8-{HS(Ph)P}-hypho-7,8-C2B6H11(6). 2a also formed the donor complexes cis-(1-[6-Ph-arachno-6,5,7-PC2B7H11])2PtBr2 (7) and trans-(1-[6-Ph-arachno-6,5,7-PC2B7H11])2PdBr2 (8) in which the metal fragment is bonded in an 1-fashion at thephosphorus endo-position. In these complexes, 2a is functioning as a two-electron sigma donor to themetals and can thus be considered as an analogue of the PR3 ligands in the classical cis-(PPh3)2PtBr2 andtrans-(PPh3)2PdBr2 coordination complexes. Although 1a did not show the donor properties exhibited by2a, its dianion 6-Ph-6,8,9-PC2B7H92- (1a2-) readily formed 4-coordinated complexes with late transitionmetals including 8-Ph-7-(Ph3P)2-nido-7,8,10,11-PtPC2B7H9 (9), 7-Ph-11-(5-C5H5)-nido-11,7,9,10-CoPC2B7H9(10), and commo-Ni-(7-Ni-8'-Ph-nido-8',10',11'-PC2B7H9)(7-Ni-8-Ph-nido-8,10,11-PC2B7H9) (11).