Reactions of 2-(trimethylsiloxy)phenyl isocyanide with complexes of rhenium in the +1, +3, and +5 oxidation states

2-(Trimethylsiloxy)phenyl isocyanide (1) reacts with trans-[ReCl(N-2)(dppe)(2)] (dppe = 1,2-bis(diphenylphosphino)ethane) in boiling THF to give trans-[Re(Cl)(CNC6H4-2-OSiMe(3))(dppe)(2)] (3). In boiling CH2Cl2 the same reaction proceeds with Si-O bond cleavage to yield trans[Re(Cl)(CNC6H4-2-OH)(dppe)(2)] (4). Si-O bond cleavage was also observed in the reaction of 2,6-bis(trimethylsiloxy)phenyl isocyanide (2) with trans-[ReCl(N-2)(dppe)(2)] in boiling CH2Cl2, which yields trans-{Re(Cl)[CNC6H3(OH)(2)-2,6](dppe)(2)} (5). The Re(II) complex trans[ReCl2(dppe)(2)] (6) was isolated as a side product in the above reactions. The complex mer[ReCl3(NCCH3)(PPh(3))(2)] reacts with 1 in CH2Cl2 to give the isocyanide complex mer-[ReCl3(CNC6H4-2-OH)(PPh(3))(2)] (7) Complex 7 was shown by X-ray crystallography to crystallize with two molecules of chloroform per asymmetric unit. Reaction of fac-[Re(O)-Cl-3(SMe(2))(OPPh(3))] with 2 equiv of I leads to a Re(V) diisocyanide complex which upon Si-O bond cleavage gives the dicarbene complex fac-{Re(O)Cl-3[CN(H)C6H4-2-O](2)} (9). The crystal structure of complex 9, which crystallizes with one molecule of hydrogen-bonded OPPh(3) per asymmetric unit, is reported.