Crystal Structure and Magnetic Properties of an Oxamato‐Bridged Heterobimetallic Tetranuclear [NiIICuII]2 Complex of the Rack Type. Issue 3 (15th December 2017)

• Record Type: Journal Article
• Authors: Reis, Natalia V.; Barros, Wdeson P.; Oliveira, Willian X. C.; Pereira, Cynthia L. M.; Rocha, Willian R.; Pinheiro, Carlos B.; Lloret, Francesc; Julve, Miguel; Stumpf, Humberto O.
• Other Names: Le Guennic Boris guestEditor.; Chastanet Guillaume guestEditor.; Pillet Sébastien guestEditor.; Clérac Rodolphe guestEditor.
• Is Part Of: European journal of inorganic chemistry. Issue 3/4(2018)
• Page Start: 477
• Page End: 484
• Publication Date: 2017-12-15
• Subjects: Copper -- Nickel -- Oxamate -- Heterometallic complexes -- Crystal structure -- Magnetic properties; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201700821
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : This work discusses a new heterobimetallic nickel(II)–copper(II) complex of the formula [Ni(tpa)Cu(opba)]2 · 6H2 O (1 ) {H4 opba = N, N′ ‐1, 2‐phenylenebis(oxamic acid) and tpa = tris(2‐pyridylmethyl)amine}. The molecular structure of1 consists of neutral tetranuclear species with a 4 R rack‐type architecture featuring two Ni II Cu II dinuclear units connected through two out‐of‐plane oxo(carboxylate‐oxamate) atoms from the opba ligands. The crystal packing of1 exhibits a supramolecular 1D arrangement of tetranuclear entities connected by hydrogen bonds and π–π stacking interactions. The dc magnetic properties of1 were interpreted according to its dimer‐of‐dimer structure; the spin Hamiltonian being defined as { H = – J [ S Ni1 · S Cu1 + S Ni1 ⁱ · S Cu1 ⁱ – j eff (SCu1 · S Cu1 ⁱ )]}. The analysis of the magnetic data shows the occurrence of a strong intradimer antiferromagnetic coupling between the Ni II and Cu II ions [ J = –115.2(4) cm –1 ] and a weak interdimer antiferromagnetic coupling between the Cu II ions [ j eff = –1.12(7) cm –1 ]. DFT‐type calculations were performed to visualize the exchange pathway through the oxamate bridge and substantiate the value of J . Abstract : The nature of the ground singlet spin state in the new heterotetranuclear complex [Ni(tpa)Cu(opba)]2 · 6H2 O is explained by the occurrence of a strong antiferromagnetic coupling between the Ni II and Cu II ions [ J = –115.2(4) cm –1 ] and a weak antiferromagnetic coupling between the Cu II ions [ j eff = –1.12(7) cm –1 ] within the tetranuclear unit.