SYNTHESIS OF A NEW MULTIDENTATE PHOSPHANE LIGAND C6H2(CH2PPH2)(4)-1,2,4,5 - X-RAY STRUCTURE OF A DINUCLEAR RUTHENIUM(II)-BRIDGED COMPLEX - PPH3))(2)(C6H2(CH2PPH2)(4)-1,2,4,5-P,P',P'',P''')]

The tetrakis(phosphane oxide) C6H2(CH2P(O)Ph-2](4)-1,2,4,5 (5), has be en prepared in high yield from the Arbuzov reaction of C6H2(CH2Br)(4)- 1,2,4,5 (4), with excess (7 equiv.) of Ph2POEt. Subsequent reduction o f 5 with HSiCl3 (12 equiv.) in C6H4Cl2-1,2 afforded the new tetraphosp hane C6H2(CH2PPh2)(4)-1,2,4,5 (6), in high yield. The reaction of 6 wi th [RuCl2(PPh3)(4)] in Ch(2)Cl(2) afforded the green dinuclear rutheni um(II) coordination complex [{RuCl2(PPh3))(2)(C6H2-ruthenium(II) coord ination complex Cl2(PPh3))(2)\C6H2-(Ch(2)PPh(2))(4)-1,2,4,5-P,P',P '', P'''}].0.5 CH2Cl2 (8), in 39% isolated yield. The solid-state molecula r geometry of 8, determined by X-ray analysis, shows that the tetrapho sphane is ortho-P,P'-chelated to each of the two [(RuCl2)-Cl-II(PPh3)] units.