作者:Hyungphil Chun、Salah S. Massoud、Ruiwu Wen、Ivan Bernal
DOI:10.1016/s0277-5387(99)00304-6
日期:1999.12
The X-ray structure analysis of mer-trans-[Co(aepn)Cl-2(OH2)](ClO4). H2O (1) (aepn =N-(2-aminoethyl)-1,3 -propanediamine) reveals that the compound crystallizes in an enantiomorphic space group P2(1)2(1)2(1) implying a spontaneous resolution of its racemic solution, known as conglomerate crystallization. Substitutions of the two chloride ligands with bromides result in the isostructural compound mer-trans-[Co(aepn)Br-2(OH2)](ClO4). H2O (2), which also crystallizes as a conglomerate in the space group P2(1)2(1)2(1). Meanwhile, a substitution of the coordinated OH2 of 1 with NH3 gives mer-trans-[Co(aepn)Cl-2(NH3)](ClO4) (3), which crystallizes as a simple racemate in P2(1)/n space group. When N-(3-aminopropyl)-1,3-propanediamine (dpt) is used instead of aepn in the preparation of 1, it gives racemic crystals of mer-trans-[Co(dpt)Cl-2(OH2)](ClO4) (4) whose molecular packing pattern is identical to that of 3. fn the conglomerate structures, the protons of coordinated water ligand are strongly hydrogen-bonded to the oxygen of a water of crystallization to form a spiral packing structures. In the packing structures of 3 and 4, two molecules of opposite chirality are brought together around a crystallographic center of inversion by hydrogen bonds of the protons of the corresponding tridentate amine ligand with oxygens of perchlorate anion. (C) 1999 Elsevier Science Ltd. All rights reserved.