A rational synthesis of a new discrete anion [trans-CdBr4Cl2]4− and its comparison with newly synthesized anion [CdBr6]4−

Abstract

► Syntheses of two new Co(III) complex salts have been described. ► The new anion [trans-CdBr 4 Cl 2 ] 4− has been isolated for first time. ► Complex salts have been characterized by single crystal X-ray crystallography. ► Non-covalent interactions are playing crucial role in lattice stabilization. Two new cobalt(III) complex salts, [Co(en) 3 ] 2 [CdBr 6 ]·Br 2 ·2H 2 O ( 1 ) and [Co(en) 3 ] 2 [trans-CdBr 4 Cl 2 ]·Br 2 ·2H 2 O ( 2 ) have been synthesized while attempting to synthesize [CdBr 5 ] 3− complex ion. The newly synthesized complex salts have been characterized by elemental analyses, spectroscopic techniques (e.g. UV/Visible, IR and NMR), solubility product, conductance measurements and luminescent studies. Both the complex salts 1 and 2 crystallize in monoclinic crystal system with space group P2 1 / c . Single crystal X-ray structure determination revealed the presence of ionic structures and discrete anions [CdBr 6 ] 4− and [trans-CdBr 4 Cl 2 ] 4− in 1 and 2, respectively. This is the first report of synthesis and single crystal X-ray structure determination of discrete and mixed halogenocadmate(II) anion, [trans-CdBr 4 Cl 2 ] 4− . The crystal lattices of both complex salts are stabilized by N–H⋯Br/Cl, C–H⋯Br/Cl and O–H⋯Br hydrogen bonds besides electrostatic forces of attraction.