Preparation of the isocyanide complexes trans-[ReCl(CNR)(dppe)2](R = Me or But) and their reactions with acid to give carbyne complexes. X-Ray crystal structure of trans-[ReCl(CNHMe)(dppe)2][BF4]

The complexes trans-[ReCl(CNR)(dppe)2](1, R = Me or But) have been prepared by replacement of dinitrogen in trans-[ReCl(N2)(dppe)2]. The alkyl isocyanide ligands in complexes (1) undergo electrophilic attack at the nitrogen atom by mineral acid (HBF4), forming the carbyne complexes trans-[ReCl(CNHR)(dppe)2][BF4](2, R = Me or But) and spectroscopic data for these complexes are given.The X-ray structure of trans-[ReCl(CNHMe)(dppe)2][BF4] has been determined and shows that the CNMe angle is 123(2)°, the Re–C (carbyne) bond length is 1.80(3)Å, and the C(carbyne)–N bond length is 1.35(3)Å.