Dinuclear triply bridged copper(II)-carboxylato compounds with different bischelating ligands: Synthesis, crystal structure, spectroscopic and magnetic properties

Synthesis, Crystal Structures and Magnetic Properties of a Linear Trinuclear Cu(II) Complex [Cu3(ClCH2COO)6(bpy)2] and a Dinuclear Complex [Cu2(bpy)2(μ‐OH)(μ‐OH2) (μ‐ClCH2COO)](ClO4)2

“…The spectrum of 2 consists of an asymmetric broad band approximately at 17.00 x 10 3 cm –1 and a lower energy shoulder peak at 14.0 cm –1 . These features are typical and can be assigned to the d xy , d yz ,d xz →d x2‐y2 and d z2 →d x2‐y2 transitions for the square pyramidal geometry of triply‐bridged dinuclear Cu(II) compounds …”

“…The antiferromagnetic interaction observed in the tricopper compound 1 can be understood based on the magneto‐structural correlations established for the triply‐bridged [Cu 2 (RCOO) 3 ] + core in dicopper compounds ,. Table collects the data for such compounds.…”

“…The magnetic data for the known carboxylato‐hydroxo‐aqua triply‐bridged dinuclear Cu(II) complexes, are included in Table . Both Cu(II) sites are five coordinate with slight to moderate deviation from SP geometry.…”

Copper(II) coordination frameworks with 1H-benzimidazole-5,6-dicarboxylic acid: syntheses, crystal structures and magnetic properties

“…For complex 2, the value of l eff at 300 K is 2.2 l B per two Cu(II) atoms which is slightly less than that of two non-interacting Cu(II) atoms. The value gradually rises as the temperature decreases, to reach 2.91 l B at around 20 K. This behavior is typical of ferromagnetically coupled Cu(II) dinuclear compounds [14,17,18]. Below that temperature, l eff decreases to 2.56 l B at about 3 K, which may originate from intermolecular antiferromagnetic interactions or from zero-field splitting of the S = 1 state of the dinuclear species.…”

“…A sharp band at about 3,300 cm -1 for both 1 and 2 is attributed to N-H stretching vibrations [14]. Thermogravimetric analysis was carried out on both complexes in air, with heating to 780°C at a rate of 1°C min -1 under nitrogen atmosphere.…”