NEW RUTHENIUM VINYLIDENE COMPLEXES AS INTERMEDIATES FOR THE ACCESS TOSIGMA-ACETYLIDE AND UNSYMMETRICAL TRANS-DIYNYL, ALKYNYL METAL-COMPLEXES - CRYSTAL-STRUCTURES OF [(PH2PCH2PPH2)2(CL)RU=C=CH2]PF6 AND [(PH2PCH2PPH2)2(CL)RUC=CH] COMPLEXES

cis-RuCl2(dppm)2 (1) (dppm = Ph2PCH2PPh2) reacts with acetylene to giv e trans-(dppm)2-ClRu+=C=CH2 (3) and with terminal alkynes to give tran s-(dppm)2ClRu+=C=CHR4 cations. These vinylidenes 3 and 4 are readily d eprotonated using DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) to give tra ns-(dppm)2ClRuC=CH(5) and trans-(dppm)2ClRu-C=CR6. The substitution of chloride from 6 with diyne HC=CC=CC(OSiMe3)Ph2 and a base gives acces s to unsymmetrical complexes trans-(dppm)2(RC=CRuC=CC=CC(OSiMe3)Ph2) 8 . These derivatives have been fully characterized by IR, H-1, C-13{H-1 }, C-13, and P-31{H-1} NMR and single crystal X-ray diffraction for 3 and 5. Complex 3 crystallizes in the orthorhombic space group Pna2(1) with Z = 4 in a unit cell of dimensions a = 22.602(3) angstrom, b = 11 .850(2) angstrom, c = 19.235(6) angstrom with a final R value of 3.9 % . Crystals of 5 are monoclinic, space group I2/a, with a = 22.003(2) a ngstrom, b = 9.715(1) angstrom, c = 22.205(3) angstrom, beta = 112.38( 2)-degrees and Z = 4, with a final R value of 2.7 %.