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Two new Mn(II) and Co(II) coordination polymers with azide and zwitterionic dicarboxylate ligands L 1 and L 2 (L 1 = [4-((1-carboxylatobenzyl)pyridimium-3-yl) benzoic acid] chloride, L 2 = [1,1′-bis(4-carboxylatobenzyl)-4,4′-bipyridinium] dichloride) were synthesized and structurally and magnetically characterized. They are formulated as [Mn 3 (L 1 ) 4 (N 3 )(CH 3 CH 2 OH)(H 2 O)]ClO 4 ·4H 2 O ( 1 ) and [Co 3 (L 2 ) 4 (N 3 ) 2 (H 2 O) 2 ]·4NO 3 ( 2 ). Compound 1 contains two different linear trinuclear [Mn 3 (COO) 8 (CH 3 CH 2 OH) 2 ] 2 − and [Mn 3 (COO) 6 (H 2 O) 2 (N 3 ) 2 ] 2 − units built from the mixed bridges of ( μ -COO) 2 ( μ 2 -O carboxylate ). The trinuclear units are alternately linked into 1D chains by L 1 . Compound 2 contains linear trinuclear [Co 3 (N 3 ) 2 (COO) 4 (H 2 O) 2 ] units built from the mixed bridges ( μ -COO) 2 ( μ -H 2 O). Magnetic studies demonstrated that the mixed triple bridges are antiferromagnetic in compounds 1 and 2 . [ABSTRACT FROM AUTHOR]

A new cobalt(II) coordination polymer formulated as [Co2(N3)4(L)] n ·4n H2O (1) (L=tetrakis(3-pyridyloxymethylene) methane) was synthesized by a diffusion method, and structurally and magnetically characterized. In compound 1, the Co(II) chains with double end-to-end (EE) azide bridges are interlinked by the tetrapyridyl ligands into a three-dimensional framework. With both Co(II) and L as 4-connecting nodes, the structure represents the first real example of the 4-connected net topology with point symbol (62·74)(64·7·9)2. Magnetic studies demonstrated that the double EE azide bridges transmit antiferromagnetic interactions along the chain. [ABSTRACT FROM AUTHOR]

The reactions of manganese(ii) acetate or perchlorate, sodium azide or sodium cyanate, and the zwitterionic dicarboxylate ligand 1,4-bis(4-carboxylatopyridinium-1-methylene)benzene (L) under different conditions yielded three different Mn(ii) coordination polymers with mixed carboxylate and azide (or cyanate) bridges: {[Mn (L1)0.5(N3)(OAc)]·3H2O}n(1), {[Mn4(L1)(N3)8(H2O)4(CH3OH)2]·[L1]}n(2), and {[Mn3(L1)(NCO)6(H2O)4]·[L1]·[H2O]2}n(3). The compounds exhibit diverse structures and magnetic properties. In 1, the 1D uniform anionic [Mn(N3)(COO)2]nchains with the (μ-EO-N3)(μ-COO)2triple bridges (EO = end-on) are interlinked by the dipyridinium L ligands into highly undulated 2D layers. Magnetic studies on 1reveal that the mixed triple bridges induce antiferromagnetic coupling between Mn(ii) ions. Compounds 2and 3consist of 1D neutral polymeric chains and co-crystallized zwitterions, and the chains are formed by the L ligands interlinking linear polynuclear units. The polynuclear unit in 2is tetranuclear with (μ-EO-N3)2as central bridges and (μ-EO-N3)2(μ-COO) as peripheral bridges, while that in 3is trinuclear with (μ-NCO)2(μ-COO) bridges. Magnetic studies demonstrate that the magnetic coupling through the mixed azide/isocyanate and carboxylate bridges in 2and 3is antiferromagnetic. An expression of magnetic susceptibility based on a 2-Jmodel for linear tetranuclear systems of classical spins has been deduced and applied to 2. [ABSTRACT FROM AUTHOR]

A novel 2D coordination polymer consisting of ferromagnetic Ni(ii) chains with alternating double EO-azide bridges and (EO-azide)bis(carboxylate) triple bridges exhibits solvent-modulated metamagnetism, and the reversible dehydration/hydration processes are accompanied by significant changes in critical temperature, critical field and hysteresis. [ABSTRACT FROM AUTHOR]

Abstract: A new lanthanide(III) coordination polymer with mixed m-phenylenediacrylate (mpda) and formate bridges, [Nd(mpda)(HCOO)(H2O)] n was synthesized by a solvothermal reaction involving the in situ formation of formate from N,N-dimethyl formamide. The three-dimensional metal-organic framework contains μ3-formate-bridged Nd(III) layers pillared by the mpda ligand and exhibits an unprecedented 3,7-connected topology with Schläfli symbol (4,62)2(42,6)(47,64,810). The magnetic properties are typical of the Nd(III) 4 I 9/2 ground state perturbed by ligand field and probable antiferromagnetic exchange through triple μ2-oxygen bridges. [Copyright &y& Elsevier]

A new cobalt(II) coordination polymer formulated as {[Co 3 (L) 6 (C 8 N 2 H 6)(H 2 O)]∙(H 2 O) 4 } n (1) (L = 4-(tetrazol-5-yl)phenyl-4,2′:6′,4″-terpyridine), has been synthesized by a solvothermal method and characterized structurally and magnetically. Compound 1 contains the linear trinuclear [Co 3 (tetrazolate) 6 (H 2 O) 2 ] units built from (μ -N-N-tetrazolate) 3 bridges between Co(II) ions, which are interlinked by the L ligands to generate a 2D square double layer coordination framework. It was demonstrated that the triple tetrazolate bridges mediate antiferromagnetic interaction between Co(II) ions in 1. The first (μ -N-N-tetrazolate) 3 -bridged Co(II) magnetic system derived from a terpyridine-based tetrazolate bridging ligand (L) was obtained. And the triple μ -N-N-tetrazolate bridges transmit antiferromagnetic interactions between Co(II) ions in the trinuclear unit. Unlabelled Image • First (μ -N-N-tetrazolate) 3 -bridged magnetic system derived from a terpyridine-based tetrazolate ligand L • A new example of the Co(II) systems with triple μ -N-N-tetrazolate bridges • First square double layer network based on the Co 3 units connecting by L • Magnetic properties investigated, revealing antiferromagnetic interactions in the trinuclear unit [ABSTRACT FROM AUTHOR]