Synthesis and Photoisomerization of Divinyltetramethyldisiloxane and Divinyltetramethyldisilazane Complexes of (η5-C5R5)Rh (R = H, Me). Crystal and Molecular Structure of (η5-C5Me5)Rh[η4-(CH2CH)Me2SiOSiMe2(CHCH2)]

The synthesis and photochemistry of a series of new rhodium complexes of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, (CH2CHSiMe2)2O, and its disilazane analogue (CH2CHSiMe2)2NH are reported. The divinyldisiloxane or divinyldisilazane ligands in (η5-C5R5)Rh[η4-(CH2CHSiMe2)2X] (R = H, Me; X = O, NH; type 1 complexes) are coordinated through the vinyl groups as for a diene. The structure of (η5-C5Me5)Rh[η4-(CH2CHSiMe2)2O] was established crystallographically. The two coordinated double bonds are arranged with their Si substitutents in a cis orientation with respect to the metal. The strain in the structure is suggested by the scissor geometry of the vinyl CC bonds relative to the C5 plane of the ring, combined with unequal Rh-C and CC bond lengths. Photolysis of (η5-C5R5)Rh(C2H4)2 (R = H, Me) in the presence of (CH2CHSiMe2)2X (X = O, NH) results in the formation of the complexes of type 1, together with an isomer in which the substituents on the coordinated CC bonds are oriented trans at rhodium (2) and speci...