Mononuclear and heterometallic dinuclear, trinuclear and dimer-of-dinuclear complexes derived from single- and double-compartment Schiff base ligands having a less utilized diamine

With the aim of exploring metal complexes from single-/double-compartmental acyclic Schiff base ligands having a less utilized diamine counterpart, this work presents the syntheses, characterization, crystal structures and diffuse reflectance spectra of two mononuclear compounds, [CuIIL1]·MeOH and [NiIIL1], and six heteronuclear complexes [CuII(acetone)L1(UVIO2)(NO3)2]·1.5CH3COCH3 (1), [CuII(H2O)L3(UVIO2)(NO3)2]·MeCN (2), [NiIIL1(UVIO2)(NO3)2]·CH3COCH3 (3), [{CuIIL1AgI(NO3)}2] (4), [{CuIIL2AgI(NO3)}2] (5) and [(CuIIL2)2CdII(ClO4)2] (6), where H2L1, H2L2 and H2L3 are the [1+2] condensation products of 2,2-dimethyl-1,3-diaminopropane and, respectively, 2-hydroxyacetophenone, salicylaldehyde and 3-ethoxysalicylaldehyde. The crystal structures of [CuIIL1]·MeOH and 1–6 have been determined. Compounds 1–3 are diphenoxo-bridged dinuclear copper(II)/nickel(II)-uranyl(VI) systems, compounds 4 and 5 are dimer-of-dinuclear [CuIIAgI]2 systems where two diphenoxo-bridged dinuclear CuIIAgI units are interlinked by an AgI–C (η2 arene) bond and silver(I)⋯silver(I) interaction (in 4) or by CuII⋯O (nitrate) semi-coordination and silver(I)⋯silver(I) interaction (in 5), and compound 6 is a trinuclear linear CuIICdIICuII system where copper(II) and cadmium(II) are bridged by a bis(μ-phenoxo)-μ-perchlorate moiety. Diffuse reflectance spectra of 1–6 and the corresponding mononuclear copper(II)/nickel(II) compounds have been recorded and it has been explored how much the d–d band position of copper(II) is correlated with the shifting of the copper(II) center from the least-squares basal plane. Salient features in the structures have been discussed.

Syntheses, characterization, crystal structures and diffuse reflectance spectra of two mononuclear copper(II)/nickel(II) and six heterometallic dinuclear CuII(UVIO2)/NiII(UVIO2), trinuclear CuIICdIICuII and dimer-of-dinuclear [CuIIAgI]2 compounds derived from single-/double-compartment Schiff base ligands, where the aldehyde components are salicylaldehyde, 2-hydroxyacetophenone or 3-ethoxysalicylaldehyde and the diamine component is 2,2-dimethyl-1,3-diaminopropane, have been described. A spectroscopic (d–d band of copper(II)) correlation has been highlighted.Figure optionsDownload as PowerPoint slide