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(N3)2(PPh3)2] 5 with alkynes HCCR′ 6 (R′ = Ph 6a, p-MeC6H46b) under focused microwave irradiation leads, upon azide replacement, to the formation of the dialkynyl complexes trans-[Pt(CCR′)2(PPh3)2] 7 (R′ = Ph 7a, p-MeC6H47b) 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.

Reaction of the tetrazolato complexes trans-[Pt(N4CR)2(PPh3)2] (R = alkyl, aryl) with EtCN gives trans-[Pt(CN)2(PPh3)2] along with the corresponding 5-substitued-1H-tetrazoles N4CR, via an unusual NC–C bond cleavage of propionitrile.Figure optionsDownload as PowerPoint slide