Z. Dega‐Szafran, A. Katrusiak, M. Szafran
Feb 28, 2009
Citations
0
Influential Citations
12
Citations
Journal
Journal of Molecular Structure
Abstract
Crystal structure of the 1:1 complex of 1,4-dimethylpiperazine di-betaine (1,4-dimethyl-1,4-dicarboxymethylpiperazinium, inner salt, DBPZ) with meso -tartaric acid ( meso -TA) has been determined by X-ray diffraction. The crystals are triclinic, space group P 1 ¯ . meso -TA and DBPZ are linked by the COOH···OOC hydrogen bonds of 2.536(2) A into infinite chains, which are interconnected through the O H···O C hydrogen bonds of 2.693(2) A. The molecules of DBPZ· meso -TA complex are located on two independent inversion centers, but the crystal is nearly isostructural with the chiral complex of l -tartaric acid [(+)TA] with DBPZ (triclinic, space group P 1). In both these structures the piperazine ring has a chair conformation with the axial CH 3 groups and the equatorial CH 2 COO − substituents. The solid-state FTIR spectrum is consistent with the X-ray results. In the structure of the isolated DBPZ· meso -TA complex optimized at the B3LYP/6-31G(d,p) level of theory, the hydrogen-bonded aggregates of DBPZ and meso -TA molecules (the O···O distance of 2.442 A) are folded.