Second sphere coordination complexes via hydrogen bonding: Synthesis, spectroscopic characterisation of [trans-Co(en)2Cl2]CdX4 (X=Br or I) and single crystal X-ray structure determination of [trans-Co(en)2Cl2]CdBr4

✍ Scribed by Raj Pal Sharma; Rajni Sharma; Ritu Bala; Juan M. Salas; Miguel Quiros

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 251 KB
• Volume: 794
• Category: Article
• ISSN: 0022-2860
• DOI: 10.1016/j.molstruc.2006.02.053

✦ Synopsis

In an effort to explore [trans-Co(en) 2 Cl 2 ] C as anion receptor for tetrabromocadmate and tetraiodocadmate ion, green coloured single crystals of [trans-Co(en) 2 Cl 2 ]CdBr 4 I and [trans-Co(en) 2 Cl 2 ]CdI 4 II have been obtained by slowly mixing the separately dissolved transdichlorobis(ethylenediamine)cobalt(III) chloride with potassium tetrabromocadmate and tetraiodocadmate in aqueous medium in 2:1 molar ratio. The newly synthesized complex salt was characterized on the basis of elemental analysis and spectroscopic techniques (IR, UV/visible, 1 H and 13 C NMR). Single crystal X-ray structure determination of [trans-Co(en) 2 Cl 2 ] 2 CdBr 4 revealed that it crystallizes in the orthorhombic space group Pbca with aZ18.6201(10), bZ12.0872(6), cZ24.0877(12) A ˚, VZ5421.3(5) A ˚3, ZZ8, RZ0.0727. Supramolecular hydrogen bonding networks between ionic groups: bromide ions of tetrabromocadmate group and NH groups of coordinated ethylenediamine molecules, i.e. N-H/Br K interactions by second sphere coordination besides electrostatic forces of attraction have been observed. This suggests that [trans-Co(en) 2 Cl 2 ] C is a promising anion receptor for the tetrabromocadmate.