Bis-hypodentate coordination in a classical Werner-type complex: Synthesis and structure of [Co(en-N,N)2(enH-N)2]Br5·H2O

David B. Cordes, Ryan R. Tarak, Shay M. McDonald, Scott A. Cameron, Charles R. Clarke, Allan G. Blackman

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

The synthesis, characterisation (elemental analysis, 1H and 13C NMR, UV–Vis), X-ray crystal structure and pKa values of the bis-hypodentate complex cis-[Co(en-N,N')2(enH-N)2]Br5·H2O are reported. Reaction of cis-[Co(en-N,N')2Cl2]+ in neat ethylenediamine for 1 min followed by acid quenching and cation exchange chromatography gives cis-[Co(en-N,N')2(enH-N)2]Br5·H2O on crystallisation of the product from water containing added LiBr. X-ray structural characterisation of the complex as the dihydrate confirms both the presence of two hypodentate ethylenediamine ligands protonated at the terminal N atoms, and their cis disposition. The complex displays pKa values of 7.36 ± 0.06 and 7.96 ± 0.06 (I = 1.0 M, NaClO4), and undergoes base hydrolysis to give cis-[Co(en-N,N')2(OH)2]+ over the [OH-] range 0.10–0.50 M. No evidence for the formation of [Co(en-N,N')3]3+ in this reaction was obtained.

Original languageEnglish
Pages (from-to)1227-1230
Number of pages4
JournalPolyhedron
Volume52
Early online date26 Jun 2012
DOIs
Publication statusPublished - Mar 2013

Fingerprint

Dive into the research topics of 'Bis-hypodentate coordination in a classical Werner-type complex: Synthesis and structure of [Co(en-N,N)2(enH-N)2]Br5·H2O'. Together they form a unique fingerprint.

Cite this