Toward Crystal Engineering of Organic Porous Solids: Diammine Salts of Trimesic Acid1

Abstract

We report the synthesis and X-ray crystallographic characterization of three new dibasic organic cation salts of 1,3,5-benzenetricarboxylic acid, trimesic acid. The focus of the study concerns crystal engineering of organic solids with predictable but fine-tuneable porosity. All three salts self-assemble into 2-D grids via interionic hydrogen bonding. Full details of single crystal X-ray diffraction studies of the salts are reported: (1) N,N,N′,N′-tetramethylethylenediammonium dihydrogentrimesate dihydrate, [HMe2NCH2CH2NMe2H]2[1-CO2-3,5(CO2H)2C6H3]·2H2O, a = 12.583(3), b = 15.1177(13), c = 15.407(3), β = 113.466(20), P21/c, d calc(Mg/m3) = 1.42, Z = 4, 3515 unique reflns., R f = 0.061, R w = 0.055; (2) N,N,N′,N′-tetraethylethylenediammonium dihydrogentrimesate, [HEt2NCH2CH2NEt2H]2[1-CO2-3,5(CO2H)2C6H3], a = 6.6196(18), b = 9.243(2), c = 12.360(4), α = 75.16(4), β = 75.88(5), γ = 84.297(22), P1, d calc(Mg/m3) = 1.39, Z = 1, 1844 unique reflns., R f = 0.056, R w = 0.050; (3) N,N,N′,N′-tetramethylethylenediammonium hydrogentrimesate, [HMe2NCH2CH2NMe2H][1,3-(CO2)2-5-(CO2H)C6H3], a = 8.636(4), b = 21.6877(17), c = 9.436(5), β = 114.49(6), P21/c, d calc(Mg/m3) = 1.35, Z = 4, 2820 unique reflns., R f = 0.050, R w = 0.054.