Novel copper complexes based on the thiocyanate bridge – Synthesis, X-ray studies and magnetic properties

• Published in: Polyhedron Vol. 30; no. 5; pp. 832 - 840
• Main Authors: Machura, B., Świtlicka, A., Nawrot, I., Mroziński, J., Kruszynski, R.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 24.03.2011
• Subjects: Coordination polymer; Copper; Magnetic measurements; Thiocyanate bridge; X-ray; Thiocyanate bridge; Magnetic measurements; X-ray; Copper; Coordination polymer
• DOI: 10.1016/j.poly.2010.12.024
• ISSN: 0277-5387

Three novel compounds {[Cu(bpzm)(SCN)][Cu(bpzm)(MeOH)][Cu(SCN)4]}n (1a), {[Cu2(bpzm)2(μ-SCN)(SCN)3]}n (1b) and [Cu2(μ-SCN)2(SCN)2(dpa)2] (2) have been obtained and characterized. The compound 1a belongs to a relatively scarce group of mixed-valence CII/CuI coordination polymers with interesting polymeric architecture. It creates infinite two-dimensional structure consisting of layers extending along crystallographic plane (001). Structure 1b consists two crystallographically independent chains, whereas the compound 2 consists of dinuclear [Cu2(dpa)2(μ-SCN)2(SCN)2] units. Variable-temperature magnetic susceptibility measurements show very weak antiferromagnetic interactions between the paramagnetic centres Cu(II) centers inside the dimeric units has been confirmed for structure 2. [Display omitted] ► Three novel copper complexes based on the tiocyanate bridge were synthesized and characterized. ► {[CuII(bpzm)(SCN)][CuII(bpzm)(MeOH)][CuI(SCN)4]}n is a mixed-valence coordination polymer. ► Magnetic measurements confirm weak antiferromagnetic interactions between Cu(II) centers. Three novel compounds {[Cu(bpzm)(SCN)][Cu(bpzm)(MeOH)][Cu(SCN)4]}n (1a), {[Cu2(bpzm)2(μ-SCN)(SCN)3]}n (1b) and [Cu2(μ-SCN)2(SCN)2(dpa)2] (2) have been obtained in one-step self-assembly reaction of copper dichloride, a suitable N–N ligand (bis(pyrazol-1-yl)methane and 2,2′-dipyridylamine) and ammonium thiocyanate. For the reaction involving bis(pyrazol-1-yl)methane, an unprecedented in situ reduction of some Cu(II) ions to Cu(I) has been observed. The compound {[Cu(bpzm)(SCN)][Cu(bpzm)(MeOH)][Cu(SCN)4]}n (1a) belongs to a relatively scarce group of mixed-valence CuII/CuI coordination polymers with interesting polymeric architecture. It creates infinite two-dimensional structure consisting of layers extending along crystallographic plane (001), in which the cations [CuII(bpzm)(SCN)]+ and [CuII(bpzm)(MeOH)]2+ are connected by ions [CuI(SCN)4]3− through single end-to-end thiocyanato bridges. Structure 1b consists two crystallographically independent chains. The chain A has a zig-zag form and extends along the crystallographic direction [001], whereas the second chain is linear and runs along the crystallographic direction [010]. The structure 2 consists of dinuclear [Cu2(dpa)2(μ-SCN)2(SCN)2] units. Variable-temperature magnetic susceptibility measurements show very weak antiferromagnetic interactions between the paramagnetic centres Cu(II) centers inside the crystal lattices of three novel compounds.