AMINOCARBYNE COUPLING REACTIONS LEADING TO THE BIS(AMINO)ACETYLENE COMPLEXES TRANS-[MF(ETA-2-MEHNCCNHME)-(PH2PCH2CH2PPH2)2][BF4] (M=MO OR W) AND CLEAVAGE OF THE ACETYLENIC-TRIPLE BOND - A REFORMULATION, AND X-RAY STRUCTURE OF THE MO COMPOUND

Reactions of [Et2OH][BF4] with the aminocarbyne complexes trans-[M(CNHMe)(CNMe)(dppe)2][BF4] (M=Mo or W; dppe = Ph2PCH2CH2PPh2) give the corresponding bis(amino)acetylene compounds trans-[MF(eta2-MeHNC=CNHMe)(dppe)2][BF4] (the molecular structure of the Mo complex being authenticated by an X-ray analysis). Previously this was formulated as trans-[M(CNHMe)2(dppe)2][BF4]2 and, unknowingly, it had provided the first example of reductive coupling of isocyanide ligands. Base-induced CC cleavage (by Li Bu(n)) of the bis(amino)acetylene to two isocyanide ligands has been recognized to form quantitatively trans-[M(CNMe)2(dppe)2] for the first time.