Reactions of manganese and rhenium complexes with organic azides: Preparation of tetraazabutadiene derivatives

Azide complexes M(RN3)(CO)3P2BPh 4 1-3 M = Mn, Re; R = C6H5CH2, 4-CH3C6H4CH2, C6H 5, 4-CH3C6H4, C5H 9; P = PPh(OEt)2, PPh2(OEt) were prepared by allowing tricarbonyl MH(CO)3P2 hydride complexes to react first with Brønsted acid (HBF4, CF3SO3H) and then with organic azide in the dark. In sunlight the reaction yielded tetraazabutadiene M(η2-1,4-R2N4)(CO) 2P2BPh4 4-6 complexes or, with benzyl azide, imine M{η1-NHC(H)Ar}(CO)3P2BPh4 7 (Ar = C6H5, 4-CH3C6H4) derivatives. Tetraazabutadiene M(η2-1,4-R2N 4)(CO)2P2BPh4 complexes were also prepared by reacting dicarbonyl MH(CO)2P3 species first with Brønsted acid and then with an excess of organic azide. Complexes were characterised spectroscopically (IR, 1H, 31P, 13C, 15N NMR data) and by the X-ray crystal structure determination of complex Re{η2-1,4-(C6H 5CH2)2N4}(CO)2{PPh(OEt) 2}2BPh4 (5a). Strong evidence for coordination of the organic azide was obtained from the 15N NMR spectra of labelled M(C6H5CH215NN 15N)(CO)3P2BPh4 derivatives. © The Royal Society of Chemistry 2007.