Chain Compounds Based on Paddle-wheel Copper(II) Carboxylate Bearing Four Nitroxide Radicals

Abstract

Chain compounds of paddle-wheel Cu 2 -clusters of 3-carboxy-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (Hcaproxy) and 4-carboxy-2,2,6,6-tetramethylpiperidinyloxy (Hcatempo) and N,N'-bidentate ligands (L = 4,4 -bipyridine (4,4 -bpy), 1,2-bis(4-pyridyl)ethane (bpe), trans-1,2-bis(4-pyridyl)ethylene (bpel), 4,4 -dipyridyl disulfide (pds), 1,4-diazabicyclo[2.2.2]octane (dabco), and pyrazine (pyz)), [Cu 2 (caproxy) 4 (L)] n , and [Cu 2 (catempo) 4 (L)] n , were synthesized and characterized by elemental analysis, infrared and UV-vis spectra and temperature dependence of magnetic susceptibilities (4.5-300 K). The crystal structures of [Cu 2 (caproxy) 4 (pds)] n , [Cu 2 (catempo) 4 (4,4 -bpy)] n , and [Cu 2 (catempo) 4 (bpe)] n revealed zigzag or linear chains consisting of alternate arrangement of the dinuclear cluster bearing four nitroxide radicals and N,N'-bidentate ligand. Temperature dependence of magnetic susceptibilities showed a considerable antiferromagnetic interaction between the two copper(II) ions within the dinuclear cluster, and weak antiferromagnetic interaction between the dinuclear clusters and/or the radical and dinuclear cluster.

Copper(II) complexes bearing cyclobutanecarboxylate and pyridine ligands: a new series of dinuclear paddle-wheel complexes

“…For the bridging carboxylate, characteristic symmetric and asymmetric vibrations, ν asym (COO -) and ν sym (COO -), can be found at ~ 1607 cm −1 and ~ 1421 cm −1 , respectively. The difference between these bands is 186 cm −1 which is indicative of a bridging binding mode of the carboxylate ligands [2,10,14].…”

“…In the UV-Vis spectra, each complex features a broad absorption at around 700 nm with a low extinction coefficient of around 150 mol −1 dm 3 cm −1 which is characteristic of d-d transitions [10,15]. For 1 and 2, π-π* transitions of the pyridine moieties are found at ~ 255 nm (Figs.…”

“…The vacant axial position can be occupied by various ligands L, whereas pyridines and its derivatives are most frequently used [4][5][6][7]. Due to the robustness and reliability of the preparation with numerous combinations of R and L (see Scheme 1) and due to advantageous coordination geometry in axial direction, such paddle-wheel structures have been used for the synthesis of MOFs, coordination polymers, and related materials [8][9][10].…”

Chemistry of alkaline earth metals: It is not all ionic and definitely not boring!

“…Barium coordination polymers with dinuclear metal ion nodes reminiscent of paddlewheel structures, as the ones known for e.g. [Cu 2 (Ac) 4 ] [118] have been realized with trans-1,2-bis(4pyridyl)ethylene as connecting ligand and thiocyanate as bridging anion between two barium ions (Fig. 30).…”

Preparation and Crystal Structure of Tetrakis(μ-2,4,5-trimethoxybenzoato-κ<i>O</i>:κ<i>O</i>′)bis[(methanol)copper(II)]-<i>N,N</i>-dimethylformamide (1/2) in Relation to Adsorption Property for N₂

“…Dinuclear metal carboxylates have attracted considerable attention due to their potential application for functional materials, such as gas storage, [1][2][3][4] as well as their unique structures and magnetic properties. [5][6][7][8][9][10][11][12] Recently, we reported on the dinuclear copper(II) carboxylate obtained from the reaction of 3,4,5-trimethoxybenzoic acid (H345-tmbz) and copper(II) salt, [Cu2(345-tmbz)4(CH3OH)2]•2dmf (1), which has a syn-synbridged dinuclear cluster with a Cu-Cu distance of 2.6190(6)Å. 11 We also synthesized the dinuclear cluster [Cu2(tbng)4(dmf )2] (tbng -= 3,4,5-tri-O-benzylgallate) (2).…”