om8004756_si_003.cif (42.44 kB)

Reactions of [Mo(CBr)(CO)2{HB(pzMe2)3}] (pz = pyrazol-1-yl) with Amines: Synthesis of Amino, Pyridinium, and Thiolato Carbyne Complexes

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posted on 08.09.2008, 00:00 by Richard L. Cordiner, Anthony F. Hill, Jörg Wagler
The reactions of the bromocarbyne complex [Mo(CBr)(CO)2{HB(pzMe2)3}] (pz = pyrazol-1-yl) with a range of secondary and heterocyclic amines have been investigated and found in each case to proceed via simple nucleophilic halide substitution to provide N-functionalized carbyne derivatives, some of which are not available via conventional approaches. With diethylamine or piperazine the simple dialkyaminocarbyne complexes [Mo(CNEt2)(CO)2{HB(pzMe2)3}] or [Mo{CN(C2H4)2NH}(CO)2{HB(pzMe2)3}] were obtained. With 4-N,N-dimethylaminopyridine the pyridiniumcarbyne salt [Mo(CNC5H4NMe2-4)(CO)2{HB(pzMe2)3}]Br was obtained; pyridine provided a complex intractable mixture and collidine failed to react. N-Methylimidazole provided the imidazolium derivative [Mo(CNC3H3NMe)(CO)2{HB(pzMe2)3}]Br, while N-(trimethylsilyl)imidazole gave the neutral imidazolyl derivative [Mo(CNC3H3N)(CO)2{HB(pzMe2)3}] and N,N′-bis(trimethylsilyl)imidazolium bromide. The sulfenamide HN(SPh)2 afforded the thiolatocarbyne complex [Mo(CSPh)(CO)2{HB(pzMe2)3}] rather than the expected aminocarbyne complex [Mo{CN(SPh)2}(CO)2{HB(pzMe2)3}], while HN(PPh2S)2 failed to react. The complex 1 is unreactive toward 1,8-diazabicycloundecene (DBU); however prolonged heating results in the formation of [DBUH][Mo(O)3{HB(pzMe2)3}] via base-induced hydrolysis/oxidation.