Diverse Structures and Magnetism of Cobalt(II) and Manganese(II) Compounds with Mixed Azido and Carboxylato Bridges Induced by Methylpyridinium Carboxylates

Abstract

Herein we present a systematic study of the structures and magnetic properties of six coordination compounds with mixed azide and zwitterionic carboxylate ligands, [M(N(3) )(2) (2-mpc)] (2-mpc=N-methylpyridinium-2-carboxylate; M=Co for 1 and Mn for 2), [M(N(3) )(2) (4-mpc)] (4-mpc=N-methylpyridinium-4-carboxylate; M=Co for 3 and Mn for 4), [Co(3) (N(3) )(6) (3-mpc)(2) (CH(3) OH)(2) ] (5), and [Mn(3) (N(3) )(6) (3-mpc)(2) ] (6; 3-mpc=N-methylpyridinium-3-carboxylate). Compounds 1-3 consist of one-dimensional uniform chains with (μ-EO-N(3) )(2) (μ-COO) triple bridges (EO=end-on); 5 is also a chain compound but with alternating [(μ-EO-N(3) )(2) (μ-COO)] triple and [(EO-N(3) )(2) ] double bridges; Compound 4 contains two-dimensional layers with alternating [(μ-EO-N(3) )(2) (μ-COO)] triple, [(μ-EO-N(3) )(μ-COO)] double, and (EE-N(3) ) single bridges (EE=end-to-end); 6 is a layer compound in which chains similar to those in 5 are cross-linked by a μ(3) -1,1,3-N(3) azido group. Magnetically, the three Co(II) compounds (1, 3, and 5) all exhibit intrachain ferromagnetic interactions but show distinct bulk properties: 1 displays relaxation dynamics at very low temperature, 3 is an antiferromagnet with field-induced metamagnetism due to weak antiferromagnetic interchain interactions, and 5 behaves as a noninnocent single-chain magnet influenced by weak antiferromagnetic interchain interactions. The magnetic differences can be related to the interchain interactions through π-π stacking influenced by different substitution positions in the ligands and/or different magnitudes of intrachain coupling. All of the Mn(II) compounds show overall intrachain/intralayer antiferromagnetic interactions. Compound 2 shows the usual one-dimensional antiferromagnetism, whereas 4 and 6 exhibit different weak ferromagnetism due to spin canting below 13.8 and 4.6 K, respectively.

Diversified architectures of one-dimensional zinc(II) and cadmium(II) coordination polymers incorporating bipyridyl ligands: Syntheses, structures, theoretical studies, fluorescent and nonlinear optical properties

“…The design and construction of CPs is highly influenced by various factors such as the nature of the metal ion, the structural characteristics of the organic ligand, the metalligand ratio, and the possible counter-ion influence [15][16][17][18][19]. Although the infinite one-dimensional (1-D) chain or ladder is the simplest topology of CPs; its packing pattern in the crystal can lead to the formation of fascinating architectures [20][21][22].…”

Two new carboxylate–oxygen bridged trinuclear M(II) (MMn and Co) compounds with zwitterionic dicarboxylate ligands: crystal structures and magnetism

“…Recently, many di-or multicarboxylate ligands have been used to construct metal-organic frameworks (MOFs) or coordination polymers (CPs) which have wide potential applications [9-13]. Our interests lie in the use of a kind of zwitterionic dior multi-carboxyalte ligands and many magnetic systems with mixed azide and carboxylate bridges have been obtained [14][15][16][17]. Here we report the synthesis, structure and magnetic properties of two coordination polymers based on linear trinuclear units obtained from manganese(II)/ cobalt(II), azide and two new zwitterionic dicarboxylate ligands, [4-((1-carboxylatobenzyl)pyridimium-3-yl) benzoic acid] chloride (L 1 ) and [1,1′-bis(4-carboxylatobenzyl)-4,4′-bipyridinium] dichloride (L 2 ) (L 1 and L 2 , Scheme S1) [18,19].…”

Syntheses, crystal structure, and characterization of two Mn(II) CPs based on 4,4′-sulfonyldicarboxylic acid and length modulated bisimidazole ligands

“…The design and construction of coordination polymers (CPs) based on metal ions and multifunctional organic ligands have attracted interest for multifunctional applications in gas and selective molecule adsorption, luminescence, ion exchange, magnetism and catalysis [1][2][3][4][5][6][7][8][9][10] and for intriguing molecular architectures and topological features [11][12][13]. Self-assembly of CPs mainly depends on combination of several factors, such as the nature of the organic ligands used, versatility of the metal coordination geometry and various experimental conditions (pH, temperature, etc.)…”