Supramolecular 2D/3D Isomerism in a Compound Containing Heterometallic CuII2CoII Nodes and Dicyanamide Bridges

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• 作者：Saptarshi Biswas ; Carlos J. G贸mez-Garc铆a ; Juan M. Clemente-Juan ; Samia Benmansour ; Ashutosh Ghosh
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：March 3, 2014
• 年：2014
• 卷：53
• 期：5
• 页码：2441-2449
• 全文大小：440K
• 年卷期：v.53,no.5(March 3, 2014)
• ISSN：1520-510X

文摘

Three new heterometallic copper(II)鈥揷obalt(II) complexes [(CuL²)₂Co{dca}₂]路H₂O(1), [(CuL¹)₂Co{dca}₂]_n (2a), and [(CuL¹)₂Co{dca}₂]_n (2b) [dca^{鈥?/sup> = dicyanamide = N(CN)₂鈥?/sup>] have been synthesized by reacting the 鈥渕etallo-ligand鈥?[CuL1] or [CuL2] with cobalt(II) perchlorate and sodium dicyanamide in methanol鈥搘ater medium (where H₂L1 = N,N鈥?bis(salicylidene)-1,3-propanediamine and H₂L2 = N,N鈥?bis(伪-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 [(CuL1)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 渭_1,5-dca鈥?/sup> 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鈥搊rbit coupling in the central Co(II) ion.}