64148-47-6Relevant academic research and scientific papers
Synthesis and structures of NCN pincer-type ruthenium and iridium complexes bearing protic pyrazole arms
Toda, Tatsuro,Saitoh, Koki,Yoshinari, Akihiro,Ikariya, Takao,Kuwata, Shigeki
, p. 1188 - 1195 (2017)
The reaction of the 1,3-bis(pyrazol-3-yl)-benzenes 1 with [RuCl(OAc)(PPh3)3] resulted in selective C-H cleavage at the 2-position of 1 to give the protic NCN pincer-type ruthenium(II) complexes [RuCl(R-NCN-LH2)-(PPh3)2] (2; R-NCN-LH2 = 4-R-2,6-bis(5-tert-butyl-1H-pyrazol-3-yl)phenyl). Similar cyclometalation with iridium trichloride followed by addition of triphenylphosphine led to the formation of the iridium(III) analogue [IrCl(But-NCN-LH2)(PPh3)]Cl (5). Treatment of the ruthenium complexes 2 with carbon monoxide afforded the carbonyl complexes [Ru(CO)(R-NCN-LH2)(PPh3)2]Cl (4). On the other hand, the pyridine analogue of 1, 2,6-bis(5-tert-butyl-1H-pyrazol-3-yl)pyridine (NNN-LH2), reacted with iridium trichloride to yield the protic NNN pincer-type complex [IrCl3(NNN-LH3)] (7)., 2,6-bis(5-tert-butyl-1H-pyrazol-3-yl)pyridine (NNN-LH2), reacted with iridium trichloride to yield the protic NNN pincer-type complex [IrCl3(NNN-LH3)] (7).. The stronger ω donation of the NCN pincer-type ligand in comparison with the analogous NNN ligand was suggested by the CO stretching frequencies of the ruthenium carbonyl complexes 4 as well as the M-Cl distances. The catalytic activity of the ruthenium complexes 2a,b toward transfer hydrogenation of a ketone was also evaluated.
