Abstract
A series of ruthenium hydride compounds containing substituted bidentate pyrrole-imine ligands were synthesized and characterized. Reacting RuHCl(CO)(PPh 3 ) 3 with one equivalent of [C 4 H 3 NH(2-CH=NR)] in ethanol in the presence of KOH gave compounds {RuH(CO)(PPh 3 ) 2 [C 4 H 3 N(2-CH=NR)]} where trans-Py-Ru-H 1, R = CH 2 CH 2 C 6 H 9 ; cis-Py-Ru-H 2, R = Ph-2-Me; and cis-Py-Ru-H 3, R = C 6 H 11 . Heating trans-Py-Ru-H 1 in toluene at 70°C for 12 hr resulted a thermal conversion of the trans-Py-Ru-H 1 into its cis form, {RuH(CO)(PPh 3 ) 2 [C 4 H 3 N(2-CH=NCH 2 CH 2 C 6 H 9 )]} (cis-Py-Ru-H 1) in very high yield. The 1 H NMR spectra of trans-Py-Ru-H 1, cis-Py-Ru-H 2, cis-Py-Ru-H 3, and cis-Py-Ru-H 1 all show a typical triplet at ca. δ–11 for the hydride. The trans and cis form indicate the relative positions of pyrrole ring and hydride. The geometries of trans-Py-Ru-H 1, cis-Py-Ru-H 1, and cis-Py-Ru-H 3 are relatively similar showing typical octahedral geometries with two PPh 3 fragments arranged in trans positions.