Activation of C-CN bond of propionitrile:: An alternative route to the syntheses of 5-substituted-1H-tetrazoles and dicyano-platinum(II) species

Reaction of trans-[Pt(N4CR)(2)(PPh3)(2)] 1 (R = Me 1a, Et 1b, Ph 1c, CH2CH2Ph 1d) with propionitrile under reflux gives trans-[Pt(CN)(2)(PPh3)(2)] 2 along with 5-substitued-1H-tetrazoles N4CR 3 (R = Me 3a, Et 3b, Ph 3c, CH2CH2Ph 3d) in moderated to good yield, respectively. Treatment of cis-[Pt(N-3)(2)(PPh3)(2)] 5 with alkynes HC equivalent to CR' 6 (R' = Ph 6a, p-MeC6H4 6b) under focused microwave irradiation leads, upon azide replacement, to the formation of the dialkynyl complexes trons-[Pt(C equivalent to CR')(2)(PPh3)(2)] 7 (R' = Ph 7a, p-MeC6H4 7b) which also furnish the dicyano-platinum complex 2 in refluxing propionitrile. In both cases, the reactions leading to the formation of 2 proceed via an unusual oxidative addition, involving NC-C bond cleavage of two propionitrile molecules, and a reductive elimination process. (C) 2008 Elsevier Ltd. All rights reserved.