Synthesis and magnetostructural characterization of dinuclear copper(II) complexes with the diazine ligand, 3,6-bis(di-2-pyridylmethyl)pyridazine

Abstract

The crystal structures of [CuJbdpdz) Br,]-2CH3CN 1, [Cu,(bdpdz)C13(H,0)]CI~3.5H,0 2 and [Cu,(bdpdz),] [CIO,], 3 were determined by X-ray analysis, where bdpdz represents the binucleating ligand 3,6-bis(di-2-pyridylmethyl) pyridazine, formed by the reaction of 3.6-dichloropyridazine and di-2pyridylmethyllithium. Compounds 1 and 2 consist of discrete binuclear units, in which copper atoms are linked by the diazine bridge and two halide ions. The pyridazine acts as a hexadentate ligand. In complex 2 the two copper(ii) ions have a distorted octahedral co-ordination geometry, 4 + 2. Compound 3 also consists of discrete binuclear units, in which the copper centres are linked by two organic ligands. Here bdpdz acts as a pentadentate ligand, with one of the diazine nitrogen atoms not bonded. The two copper(i1) ions have a square pyramidal co-ordination geometry, 4 + 1. The magnetic susceptibility was investigated in the temperature range 300-5 K. These measurements reveal an antiferromagnetic interaction for all three compounds (-W = 98.1 for 1, 79.6 for 2 and 6.4 cm-' for 3). The lack of a diazine bridge, N-N, for the perchlorate salt 3 substantially reduces the antiferromagnetic interaction. 61 9( 17) Results Structural Description of [Cu2(bdpdz)Br,]-2CH3CN 1 .-* Supplementary data available (No. SUP 56923,4 pp.): phase diagram.

Synthesis, crystal structures and properties of the novel mononuclear copper(II) and tetranuclear cobalt(II) complexes with 3,6-bis-(3,5-dimethylpyrazolyl)-pyridazine

“…In most cases, bridging azide groups take end-to-end (EE, l-1,3) and end-on (EO, l-1,1) coordination modes. The pyridazine and it's derivatives as the functional ligands have shown much useful function, such as application in magnetic exchange effects [4][5][6][7][8][9], pharmaceutical importance [10][11][12] and antimicrobial [13][14][15]. 3,6-bis-(3,5-dimethylpyrazolyl)-pyridazine (L) is one of the pyridazine derivatives, which as a function ligand has shown versatile properties in respect of the formation of monouclear and polynuclear complexes due to the formation of the five-membered metallacycles stabilizing the configurations around the metal center [16].…”

Bridging ligands comprising two or more di-2-pyridylmethyl or amine arms: Alternatives to 2,2′-bipyridyl-containing bridging ligands

“…[49] In an earlier report, copper(II) chloride and bromide complexes were described in which two chloride or two bromide anions bridge the copper centres supported by coordination to 19a. [45] The authors concluded that 19a is not a particularly efficient bridge for facilitating magnetic interaction through the N-N diazine bridge, when it acts as a hexadentate ligand generating octahedral species and that the efficiency is even lower when the ligand is pentadentate and does not bond through both N-N atoms. A related dinuclear copper(I) complex was also reported by the same researchers but not structurally characterised.…”

“…Ligands based on a pyridazine core were first reported in 1993 and 1997, namely compounds 19a and 19b, from reaction of 3,6-dichloropyridazine with di-(2-pyridyl)methyllithium or (6-methyl-2-pyridyl)(2-pyridyl)methyllithium, respectively. [45,49] Manzur and co-workers studied the magnetism of binuclear copper(II) complexes with 19b, which present six-membered chelate rings around the metal centres; in these complexes the copper centres are bridged by both the diazine ligand and hydroxide, leading to quite short metal-metal distances. [49] In an earlier report, copper(II) chloride and bromide complexes were described in which two chloride or two bromide anions bridge the copper centres supported by coordination to 19a.…”

Structural and magnetic characterization of 1-D complexes constructed from pyrazole-3,5-dicarboxylate bridging multi copper(II) centers

“…Although a wide range of the 2J values (À35 to À1304 cm À1 ) is found for mixed l-diazine with l-OH or l-halogeno bridging dinuclear copper(II) complexes [30][31][32][33], most of them show a strong anti-ferromagnetic interaction through the l-azine-bridge. A weak anti-ferromagnetic coupling (2J = À10.3 cm À1 ) was observed for a diazine-bridged dinuclear copper(II) complex [34].…”