Trimipraminium maleate

Abstract

The title compound [systematic name: 3-(10,11-dihydro-5H-dibenzo[b,f]azepin-5-yl)-N,N,2-trimethylpropan-1-aminium hydrogen maleate], C20H27N2+·C4H3O4−, 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)°. Intermolecular N—H...O and intramolecular O—H...O hydrogen bonds pack the ions into chains along [101]. Additional weak intermolecular 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.