932712-95-3Relevant academic research and scientific papers
Imidazole → imidazolidine. Preparation by reduction of [Os (H) (CO) (PPh3)2 (PyaiR)]+ / 0 with NaBH4 and characterisation of the products (PyaiR = 1-alkyl-2-{3′-(pyridylazo)}imidazole)
Mondal,Mathur,Slawin,Woollins,Sinha
, p. 1472 - 1481 (2007)
The reaction of 2-(3′-pyridylazo)imidazole (PyaiH) or 1-alkyl-2-(3′-pyridylazo)imidazole (PyaiR) with [Os (H) (Cl) (CO) (PPh3)3] in THF or MeCN has synthesized stable red coloured [Os (H) (CO) (PPh3)2 (Pyai)] (2a) or [Os (H) (CO) (PPh3)2 (PyaiR)] (PF6) (2b-2d). While the reaction of PyaiR and [Os (H) (Cl) (CO) (PPh3)3] in dry n-heptane has separated shining green compound and has been identified azo-anion radical, [Os(Cl)(CO)(PPh3)2(PyaiR-{radical dot})] (4b-4d). The reaction performance in n-hexane or toluene is very poor. Upon addition of Cl2 in MeCN to CH2Cl2 solution of 2 or 4 the colour has changed sharply to red-violet and has isolated [Os (Cl) (CO) (PPh3)2 (PyaiR)]+ (3). The reaction of 2 in ethanol with NaBH4 suspension under dinitrogen has reduced coordinated imidazole group to imidazolidine (5). One of the structures of azo-imidazolidinate-hydrido-osmium-carbonyl, [Os(H)(CO)(PPh3)2(PyaiH2)] (5a), is characterized by X-ray diffraction study. Other spectroscopic studies (IR, UV-Vis, NMR) are used to identify the structure of all the complexes. Electrochemistry shows two consecutive anodic peaks (Epa) and suggest irreversible oxidations Os(III)/Os(II), Os(IV)/Os(III) along with azo reductions.
