title: Loops, chains, sheets, and networks from variable coordination of Cu(hfac)2 with a flexibly hinged aminoxyl radical ligand.
abstract: One pair of reactants, Cu(hfac)(2) = M and the hinge-flexible radical ligand 5-(3-N-tert-butyl-N-aminoxylphenyl)pyrimidine (3PPN = L), yields a diverse set of five coordination complexes: a cyclic loop M(2)L(2) dimer; a 1:1 cocrystal between an M(2)L(2) loop and an ML(2) fragment; a 1D chain of M(2)L(2) loops linked by M; two 2D M(3)L(2) networks of (M-L)(n) chains cross-linked by M with different repeat length pitches; a 3D M(3)L(2) network of M(2)L(2) loops cross-linking (M-L)(n)-type chains with connectivity different from those in the 2D networks. Most of the higher dimensional complexes exhibit reversible, temperature-dependent spin-state conversion of high-temperature paramagnetic states to lower magnetic moment states having antiferromagnetic exchange within Cu-ON bonds upon cooling, with accompanying bond contraction. The 3D complex also exhibited antiferromagnetic exchange between Cu(II) ions linked in chains through pyrimidine rings.
authors.affiliation: Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA.
authors.forename: Martha
authors.initials: M
authors.lastname: Baskett
authors.forename: Armando
authors.initials: A
authors.lastname: Paduan-Filho
authors.forename: Nei Fernandes
authors.initials: NF
authors.lastname: Oliveira
authors.forename: A
authors.initials: A
authors.lastname: Chandrasekaran
authors.forename: Joel T
authors.initials: JT
authors.lastname: Mague
authors.forename: Paul M
authors.initials: PM
authors.lastname: Lahti