Synthesis, crystal structure and some reactions of the ruthenacarborane complex [Ru(CO) 2(MeCCPh)( η5-7,8-C 2B 9H 11] ,

Abstract

The alkyne complex [Ru(CO) 2(MeCCPh)( η 5-7,8-C 2B 9H 11] ( 3c) has been prepared and its structure determined by X-ray crystallography. The ruthenium is co-ordinated on one side by the nido-7,8-C 2B 9H 11 fragment in a pentahapto manner, and on the other by the two CO molecules and the alkyne [Ru–C av.=2.305, C–C=1.228(3) Å. Treatment of 3c with PEt 3 and Ph 2PCH 2PPh 2 in CH 2Cl 2 affords the ylid complexes [Ru{C(Me)C(Ph)PEt 3}(CO) 2( η 5-7,8-C 2B 9H 11)] ( 4b) and [Ru{C(Me)C(Ph)P(Ph) 2CH 2PPh 2}(CO) 2( η 5-7,8-C 2B 9H 11)] ( 4c), respectively. The structure of 4b was established by an X-ray diffraction study which revealed that the PEt 3 molecule was attached to the carbon atom of the CPh group. In contrast, reactions between 3c and the donor molecules AsPh 3, SbPh 3 and Ph 2P(S)CH 2P(S)Ph 2 resulted in displacement of the alkyne and formation of the complexes [Ru(CO) 2(L)( η 5-7,8-C 2B 9H 11)] ( 5a, L=AsPh 3; 5b, L=SbPh 3; 5c, L=Ph 2P(S)CH 2P(S)Ph 2). Treatment of 4c with the Ru(CO) 2( η 5-7,8-C 2B 9H 11) fragment yielded the diruthenium complex [Ru 2( μ-Ph 2PCH 2PPh 2)(CO) 4( η 5-7,8-C 2B 9H 11) 2] ( 6). The structure, based on the linking of two Ru(CO) 2( η 5-7,8-C 2B 9H 11) groups by the ligand Ph 2PCH 2PPh 2, was determined by X-ray crystallography. NMR data for the new complexes are reported.