Trimipraminium maleate

Abstract

The title compound [systematic name: 3-(10,11-dihydro-5H-dibenzo[b,f] azepin-5-yl)-N,N,2-trimethyl-propan-1-aminium hydrogen maleate], C 20H27N2+·C4H 3O4-, a maleate salt of trimipramine, crystallizes with four independent cation-anion pairs in the asymmetric unit. The trimipramine cation contains a seven-membered azepine ring with two fused benzene rings whose mean planes are separated by 51.7 (1)°. Inter-molecular N - H⋯O and intra-molecular O - H⋯O hydrogen bonds pack the ions into chains along [101]. Additional weak inter-molecular C - H⋯O interactions help to influence the twist angles of the mean planes of the benzene rings fused to the azepine ring in the cation. A geometry-optimized MOPAC AM1 theoretical calculation supports these observations.