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Cyanocobalt(III) complexes of penta- and tetradentate-coordinated macrocyclic hexaamines


Bernhardt, PV and Kilah, NL, Cyanocobalt(III) complexes of penta- and tetradentate-coordinated macrocyclic hexaamines, Acta Crystallographica Section C: Crystal Structure Communications, 61, (5) pp. m245-m249. ISSN 0108-2701 (2005) [Refereed Article]

Copyright Statement

Copyright 2005 International Union of Crystallography

DOI: doi:10.1107/S0108270105009261


The pendent-arm macrocyclic hexaamine trans-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diamine (L) may coordinate in tetra-, penta- or hexadentate modes, depending on the metal ion and the synthetic procedure. We report here the crystal structures of two pseudo-octahedral cobalt(III) complexes of L, namely sodium trans-cyano(trans-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diamine)cobalt(III) triperchlorate, Na[Co(CN)(C13H30N6)](ClO4)3 or Na{trans-[CoL(CN)]}(ClO4)3, (I), where L is coordinated as a pentadentate ligand, and trans-dicyano(trans-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diamine)cobalt(III) trans-dicyano(trans-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diaminium)cobalt(III) tetraperchlorate tetrahydrate, [Co(CN)2(C14H32N6)][Co(CN)2(C14H30N6)](ClO4)44H2O or trans-[CoL(CN)2]trans-[Co(H2L)(CN)2](ClO4)44H2O, (II), where the ligand binds in a tetradentate mode, with the remaining coordination sites being filled by C-bound cyano ligands. In (I), the secondary amine Co-N bond lengths lie within the range 1.944 (3)-1.969 (3) , while the trans influence of the cyano ligand lengthens the Co-N bond length of the coordinated primary amine [Co-N = 1.986 (3) ]. The Co-CN bond length is 1.899 (3) . The complex cations in (II) are each located on centres of symmetry. The Co-N bond lengths in both cations are somewhat longer than in (I) and span a narrow range [1.972 (3)-1.982 (3) ]. The two independent Co-CN bond lengths are similar [1.918 (4) and 1.926 (4) ] but significantly longer than in the structure of (I), again a consequence of the trans influence of each cyano ligand. Formula: Na[Co(CN)(C13H30N6)](ClO4)3 and [Co(CN)2(C14H32N6)][Co(CN)2(C14H30N6)](ClO4)44H2O

Item Details

Item Type:Refereed Article
Research Division:Chemical Sciences
Research Group:Inorganic chemistry
Research Field:Transition metal chemistry
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the chemical sciences
UTAS Author:Kilah, NL (Dr Nathan Kilah)
ID Code:87081
Year Published:2005
Web of Science® Times Cited:2
Deposited By:Chemistry
Deposited On:2013-11-07
Last Modified:2013-12-12

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