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Supramolecular 2D/3D isomerism in a compound containing heterometallic Cu(II)2Co(II) nodes and dicyanamide bridges.
Inorg Chem ; 53(5): 2441-9, 2014 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-24552535
Three new heterometallic copper(II)-cobalt(II) complexes [(CuL(2))2Co{dca}2]·H2O(1), [(CuL(1))2Co{dca}2]n (2a), and [(CuL(1))2Co{dca}2]n (2b) [dca(-) = dicyanamide = N(CN)2(-)] have been synthesized by reacting the "metallo-ligand" [CuL(1)] or [CuL(2)] with cobalt(II) perchlorate and sodium dicyanamide in methanol-water medium (where H2L(1) = N,N'-bis(salicylidene)-1,3-propanediamine and H2L(2) = N,N'-bis(α-methylsalicylidene)-1,3-propanediamine). The three complexes have been structurally and magnetically characterized. Complex 1 is a discrete trinuclear species in which two metallo-ligands coordinate to a cobalt(II) ion through the phenoxido oxygen atoms along with two terminally coordinated dicyanamide ions. On the other hand, complexes 2a and 2b are one of the very scarce examples of supramolecular isomers since they present the same [(CuL(1))2Co{dca}2] trinuclear units (very similar to the trinuclear core in 1) and differ only in their superstructures. Thus, although each Cu2Co trimer in 2a and 2b is connected to four other Cu2Co trimers through four µ1,5-dca(-) bridges, 2a presents a square two-dimensional structure (each Cu2Co trimer is connected to four in-plane Cu2Co trimers); whereas, 2b shows a triangular three-dimensional lattice (each Cu2Co trimer is connected to three in-plane and one out-of-plane trimers). Variable-temperature magnetic susceptibility measurements show the presence of moderate antiferromagnetic exchange interactions (ferrimagnetic) in all the cases mediated through the double phenoxido bridges that have been fitted with an anisotropic model including spin-orbit coupling in the central Co(II) ion.





Texto completo: Disponível Coleções: Bases de dados internacionais Base de dados: MEDLINE Idioma: Inglês Revista: Inorg Chem Ano de publicação: 2014 Tipo de documento: Artigo País de afiliação: Índia