Crystal structures of tri-chlorido-(4-methyl-piperidine)gold(III) and two polymorphs of tri-bromido(4-methyl-piperidine)-gold(III).

Tri-chlorido-(4-methyl-piperidine)-gold(III), [AuCl(CHN)], , crystallizes in with = 8. Tri-bromido-(4-methyl-piperidine)-gold(III), [AuBr(CHN)], , crystallizes as two polymorphs, in with = 4 (imposed mirror symmetry) and , which is isotypic to . The Au-N bonds to Cl are somewhat shorter than those to Br, and the Au-Cl bonds to N are longer than those to N, whereas the Au-Br bonds to N are slightly shorter than the bonds. The methyl and Au groups ( = halogen) occupy equatorial positions at the six-membered ring. The packing of all three structures involves chains of mol-ecules with offset stacking of the Au moieties associated with short Au⋯ contacts; for and these are reinforced by N-H⋯ hydrogen bonds, whereas for there are no classical hydrogen bonds and the chains are inter-connected by Br⋯Br contacts.