title: Synthesis, crystal structure and magnetic studies of tetranuclear hydroxo and ligand bridged [Co4(μ3-OH)2(μ2-dea)2(L-L)4]4Cl·8H2O [L-L = 2,2'-bipyridine or 1,10-phenanthroline] complexes with mixed valence defect dicubane core.
abstract: X-ray crystallography of the title complexes indicates a discrete mixed valence (Co2(II)-Co2(III)) defect dicubane molecular unit where each cobalt nucleus attains a distorted octahedral geometry. The α-diimine (L-L) chelator coordinated to each cobalt ion stops further polymerization or nuclearization. The water molecules in the lattice play a crucial role in the formation of the supramolecular architectures. Magnetic data were analyzed using the effective spin-1/2 Hamiltonian approach and the parameters are, J = 115(6) K, ΔJ = -57.0(1.2) K, g(xy) = 3.001(25), and g(z) = 7.214(7) for 1 and J = 115(12) K, ΔJ = -58.5(2.5) K, g(xy) = 3.34(5), and g(z) = 6.599(12) for 2 suggesting that only the g matrices are prone to the change of α-diimine chelator.
authors.affiliation: Department of Chemistry, Aligarh Muslim University, Aligarh-202002, India. zafarasiddiqi@gmail.com
authors.forename: Zafar A
authors.initials: ZA
authors.lastname: Siddiqi
authors.forename: Armeen
authors.initials: A
authors.lastname: Siddique
authors.forename: M
authors.initials: M
authors.lastname: Shahid
authors.forename: Mohd
authors.initials: M
authors.lastname: Khalid
authors.forename: Prashant K
authors.initials: PK
authors.lastname: Sharma
authors.lastname: Anjuli
authors.forename: Musheer
authors.initials: M
authors.lastname: Ahmad
authors.forename: Sarvendra
authors.initials: S
authors.lastname: Kumar
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Lan
authors.forename: Annie K
authors.initials: AK
authors.lastname: Powell
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008024:Ligands; D060328:Magnetic Phenomena; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010618:Phenanthrolines / Q000737:chemistry*
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D010618:Phenanthrolines; D003035:Cobalt; D015082:2,2'-Dipyridyl; C025205:1,10-phenanthroline