Solvato-polymorph of [(η6-C6H6)RuCl (L)]PF6 (L = (2,6-dimethyl-phenyl-pyridin-2-yl methylene amine)

A half-sandwich complex salt of ruthenium containing the Schiff base ligand, 2, 6-dimethyl-N-(pyridin-2-ylmethylene)aniline has been synthesized and structurally characterized. The complex salt 1, [(eta(C6H6)-C-6)RuCl(C5H4NCH=N(2,6-(CH3)(2)C6H3)]PF6 was obtained from the reaction of the ruthenium arene precursor, [(eta(6)-C6H6)Ru(mu-Cl)Cl](2) with the Schiff base in a 1:2 ratio followed by treatment with NH4PF6. Its acetone solvate 2, [(eta(6)-C6H6)RuCl(C5H4NCH=N (2, 6- (CH3)(2)C6H3)]PF6, (CH3)(2)CO was obtained by recrystallization of 1 from a solution of hexane and acetone. 1 and 2 crystallize in the monoclinic P2(1)/c and P2(1)/n space groups as blocks and as prisms respectively. The ruthenium centers in 1 and 2 are coordinated to the bidentate Schiff base, to a chloride atom, and to the arene ring to give a pseudo octahedral geometry around them. The whole arrangement is referred to as the familiar three-legged piano stool in which the Schiff base and the Cl atom serve as the base while the arene ring serve as the apex of the stool. Polymorph 2 has an acetone molecule in the asymmetric unit. Of interest is the similar behavior of the solvate on heating which shows the crystals shuttering at about 531.6 and 523.4 K for 1 and 2 respectively. (C) 2016 Elsevier B.V. All rights reserved.