Assembly of dinuclear copper(ii) secondary building units into polymeric complexes: crystal structures and magnetic properties

Abstract

Four Cu(II) complexes, the one-dimensional [Cu(HL 1 ) 2 (CuCl 4 )] n (1), {[Cu 2 (L 1 ) 2 (N(CN) 2 )(CH 3 OH)](ClO 4 )} n (2), dinuclear [Cu 2 (L 2 ) 2 Cl 2 ] (3), and two-dimensional layered [Cu 2 (L 2 ) 2 (N(CN) 2 ) 2 ] n (4) were synthesized by Cu(II) salts (CuCl 2 •2H 2 O or Cu(ClO 4 ) 2 •6H 2 O), alkanol bidentate ligands trans-2-(1-pyrazolyl)cyclohexanol (HL 1 ) or3,5-dimethyl-N-hydroxyethyl-pyrazolyl (HL 2 ) together with sodium dicyanamide. For complex 1, the bridging chlorine atoms of the tetrahedral [CuCl 4 ] 2− moieties are located at the Jahn-Teller axis of the elongated octahedral Cu(II), forming an alternate elongated-octahedral-tetrahedral Cu(II) chain complex.For complexes 2, 3 and 4, the alkyl oxygen atoms of the deprotonated ligands HL 1 and HL 2 bridge two Cu(II) ions, yielding a dinuclear Cu(II) unit [Cu 2 (L x ) 2 ] 2+ (x = 1, 2), and one-or two-dimensional complexes via bridging dicyanamide ligands. Complex 1 shows weak ferromagnetic coupling, whilst complexes 2-4 display strong antiferromagnetic coupling or are even nearly diamagnetic due to the large Cu-O-Cu bond angles.

A family of ligand and anion dependent structurally diverse Cu(ii) Schiff-base complexes and their catalytic efficacy in an O-arylation reaction in ethanolic media

“…The selection of suitable metal salts and multidentate ligands is very important as they play dominant roles in the control and adjustment of the architecture of coordination complexes. [39][40][41][42] The coordination chemistry of Schiff-base ligands is particularly interesting as the selection of suitable amines and aldehydes/ ketones, which can afford steric and electronic inuence originating from different substituent groups, may create structural and functional variations. [43][44][45][46] These types of structural diversity have a signicant impact in the elds of catalysis, 47,48 magnetism, 49,50 and DNA cleavage studies.…”

3,5-disusbtituted-N-hydroxyalkylpyrazole Cu(II) compounds: Anion effect on dimensionality, supramolecular structure and magnetic properties

“…Lastly, the magnetic properties and magneto-structural correlations for 1 and 5a were discussed. Although there are some reported papers studying the reactivity of HL with copper(II) salts [44][45][46], the coordination chemistry of pyrazolyl ligands seems to be really sensible to reaction conditions such as solvent or working ratios, and we are able to report four new compounds which have not been previously described (2-5b), one of them showing a particularly unusual architecture. For compounds 1-4, it has been possible to obtain crystals suitable for X-ray diffraction.…”

“…Moreover, recrystallization of 5a in MeOH yields [Cu(MeCO2)(µ-L)]2•6H2O (5b) (Scheme 1). Although crystal structure of compound 1 has been previously reported [46], in the present work its synthetic route is different, as it is obtained as a minority product in the synthesis of 2. Moreover, its supramolecular structure is discussed in deep.…”

Structure, DFT Calculations, and Magnetic Characterization of Coordination Polymers of Bridged Dicyanamido-Metal(II) Complexes

“…The adaption of these configurations seem to be more common and unified in this class of compounds [15,62,63,65,72,73]. As a consequence of the long intramolecular distances between paramagnetic metal ions linked by µ 1,5 -dca coordination modes, the complexes 1 and 2 display weak antiferromagnetic coupling (small |J| values) [63,65,[72][73][74][75][76].…”