title: Chelating Schiff base assisted azide-bridged Mn(II), Ni(II) and Cu(II) magnetic coordination polymers.
abstract: Four new Mn(II), Ni(II) and Cu(II) coordination polymers [Mn2(L1)(μ(1,1)-N3)2(μ(1,3)-N3)2]n (1), [Ni(L2)2(μ(1,3)-N3)]n(ClO4)n (2), [Cu(L3)(μ(1,1)-N3)(N3)]n (3) and [Cu(L4)(μ(1,1)-N3)2]n (4) (L1 = N,N′-bis(2-pyridylmethylene)ethane-1,2-diamine, L2 = N-(2-pyridylmethylene)methylamine, L3 = N-(2-pyridylmethylene)-3-pyridylamine, L4 = N-(2-pyridylmethylene)-tbutylamine) have been synthesized and characterized by single-crystal X-ray analysis and magnetic measurements. Complex 1 indicates a stoichiometry-dependent structural change (based on Mn:L1:N3 = 2:1:4 molar ratio) and consists of two-dimensional (2-D) (4,4) net layers, in which Mn(II) centers are co-bridged by single end-to-end (EE), double end-on (EO) azide and chelate-bridging L1 ligands. Complex 2 shows a single EE azide-bridged one-dimensional (1-D) Ni(II) chain. Complexes 3 and 4 indicate single EO and double EO azide-bridged 1-D Cu(II) chains, respectively. Complex 1 exhibits weak ferromagnetism due to its intra-layer spin-canting with T(c) = 20 K. Complex 2 shows an unusual intra-chain ferromagnetic coupling and spin-canting behaviour. Both complexes 3 and 4 exhibit intra-chain antiferromagnetic interactions. Magneto-structural parameters for these related complexes were also discussed.
authors.affiliation: Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Singapore. bais@imre.a-star.edu.sg
authors.forename: Shi-Qiang
authors.initials: SQ
authors.lastname: Bai
authors.forename: Chen-Jie
authors.initials: CJ
authors.lastname: Fang
authors.forename: Zheng
authors.initials: Z
authors.lastname: He
authors.forename: En-Qing
authors.initials: EQ
authors.lastname: Gao
authors.forename: Chun-Hua
authors.initials: CH
authors.lastname: Yan
authors.forename: T S Andy
authors.initials: TS
authors.lastname: Hor
mesh_terms: D001386:Azides / Q000737:chemistry*; D002614:Chelating Agents / Q000737:chemistry; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D007477:Ions / Q000737:chemistry; D008280:Magnetics; D008345:Manganese / Q000737:chemistry*; D008968:Molecular Conformation; D009532:Nickel / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D012545:Schiff Bases / Q000737:chemistry*
chemical_list: D001386:Azides; D002614:Chelating Agents; D056831:Coordination Complexes; D007477:Ions; D011108:Polymers; D012545:Schiff Bases; D008345:Manganese; D003300:Copper; D009532:Nickel