resumo
Dark maroon coloured single crystals of [cis-Co(en)(2)(N(3))(2)][trans-Co(NH(3))(2)(NO(2))(4)] were obtained by slowly mixing the separately dissolved [cis-diazidobis(ethylenediamine)cobalt(III)] nitrate with potassium [trans-diamminetetranitrocobaltate(III)] in aqueous medium in 1:1 molar ratio. The complex salt was characterized by elemental analyses, spectroscopic studies (IR, UV/visible, (1)H and (13)C NMR) and solubility product measurements. The title complex salt crystallises in triclinic space group Pi having cell dimensions, a = 7.4210(2), b = 11.0618(3), c = 12.3763(3) angstrom, alpha = 95.5850(10), beta = 91.4400(10), gamma = 108.9070(10)degrees, V = 954.853 angstrom(3), Z = 2 and R-factor = 5.16%. Single crystal X-ray structure determination revealed an ionic structure consisting of [cis-Co(en)(2)(N(3))(2)](+) and [trans-Co(NH(3))(2)(NO(2))(4)](-). Supramolecular hydrogen bonding networks involving second sphere coordination like [NH(cn)(+)center dot center dot center dot X(anion)(-)] besides electrostatic forces of attraction have been observed to stabilize the crystal lattice. This is the first crystal structure of a salt containing [trans-diamminetetranitrocobaltate(III)] anion and [cis-diazidobis(ethylenediamine)cobalt(III)] cation. The formation of complex salt of definite composition and solubility product measurements show that the cationic cobaltammine [cis-Co(en)(2)(N(3))(2)](+) is a potential anion receptor for complex anion [trans-Co(NH(3))(2)(NO(2))(4)](-) in aqueous medium. (C) 2008 Published by Elsevier B.V.
palavras-chave
SPECTROSCOPIC CHARACTERIZATION; 2ND-SPHERE COORDINATION; CONGLOMERATE CRYSTALLIZATION; ABSOLUTE-CONFIGURATION; CRYSTAL-STRUCTURES; COMPLEXES; RECEPTORS; RECOGNITION; PACKING; TRANS-DIAMMINETETRANITROCOBALTATE(III)
categoria
Chemistry
autores
Sharma, R; Sharma, RP; Brandao, P; Felix, V
nossos autores
Paula Cristina Ferreira da Silva Brandão
Investigador Auxiliar
Vítor Félix
Professor Associado com Agregaçãoagradecimentos
The authors gratefully acknowledge the financial support of UGC vide Grant No. F.12-38/2003(SR) dated 31-03-2003.