Influence of the Peripheral Ligand Atoms on the Exchange Interaction in Oxalato-Bridged Nickel(II) Complexes: An Orbital Model. Crystal Structures and Magnetic Properties of (H3dien)2[Ni2(ox)5]·12H2O and [Ni2(dien)2(H2O)2(ox)]Cl2
- 1 January 1996
- journal article
- research article
- Published by American Chemical Society (ACS) in Inorganic Chemistry
- Vol. 35 (13) , 3741-3751
- https://doi.org/10.1021/ic951081g
Abstract
Two nickel(II) complexes of formula (H3dien)2[Ni2(ox)5]·12H2O (1) and [Ni2(dien)2(H2O)2(ox)]Cl2 (2) (dien = diethylenetriamine and ox = oxalate dianion) have been synthesized and characterized by single-crystal X-ray diffraction. 1 crystallizes in the orthorhombic system, space group Abnn, with a = 15.386(4) Å, b = 15.710(4) Å, c = 17.071(4) Å, and Z = 4. 2 crystallizes in the monoclinic system, space group P21/c, with a = 10.579(1) Å, b = 7.258(1) Å, c = 13.326(1) Å, β = 93.52(3)°, and Z = 2. The structures of 1 and 2 consist of dinuclear oxalato-bridged nickel(II) units which contain bidentate oxalate (1) and tridentate dien in the fac-conformation (2) as terminal ligands. Both features, oxalato as a peripheral ligand and dien in the fac-conformation (instead of its usual mer-conformation), are unprecedented in the coordination chemistry of nickel(II). The nickel atom is six-coordinated in both compounds, the chromophores being NiO6 (1) and NiN3O3 (2). The Ni−O(ox) bond distances at the bridge (2.072(4) Å in 1 and 2.11(1) and 2.125(9) Å in 2) are somewhat longer than those concerning the terminal oxalate (2.037(5) and 2.035(3) Å in 1). Magnetic susceptibility data of 1 and 2 in the temperature range 4.2−300 K show the occurrence of intramolecular antiferromagnetic coupling with J = −22.8 (1) and −28.8 (2) cm-1 (J being the parameter of the exchange Hamiltonian H = −JSA·SB). The observed value of −J in the investigated oxalato-bridged nickel(II) complexes, which can vary from 22 to 39 cm-1, is strongly dependent on the nature of the donor atoms from the peripheral ligands. This influence has been analyzed and rationalized through extended Hückel calculations.Keywords
This publication has 79 references indexed in Scilit:
- 2,2′-Bipyrimidine (bipym)-bridged dinuclear complexes. Part 4. Synthesis, crystal structure and magnetic properties of [CO2(H2O)8(bipym)][NO3]4, [CO2(H2O)8(bipym)][SO4]2·2H2O and [CO2(bipym)3(NCS)4]J. Chem. Soc., Dalton Trans., 1994
- Oxalato-bridged and related dinuclear copper(II) complexes: theoretical analysis of their structures and magnetic couplingInorganic Chemistry, 1990
- Oxalato and squarato ligands in nickel(II) complexes of tetraazacycloalkanes. Solution and solid-state studies. Crystal and molecular structures of (.mu.-oxalato)bis[(1,7-dimethyl-1,4,7,10-tetraazacyclododecane)nickel(II)] perchlorate dihydrate and of bis[diaquo(1,4,7,10-tetraazacyclododecane)nickel(II)] squarate diperchlorateInorganic Chemistry, 1990
- Charge density and spectra of dichlorotetrakis(thiourea) nickel(II): an ab initio discrete variation X? calculationJ. Chem. Soc., Dalton Trans., 1990
- Dinuclear Complexes with Predictable Magnetic PropertiesAngewandte Chemie International Edition in English, 1985
- Amino acid amides of dithiooxalic acid: spectroscopic, electrochemical, and magnetic properties of copper(II) binuclear complexes and crystal structure of [N,N'-(1,2-dithioxoethane-1,2-diyl)bis(methyl methioninato)]bis(bromocopper(II))Inorganic Chemistry, 1984
- Tunable exchange interaction in .mu.-oxalato copper(II) dinuclear complexesInorganic Chemistry, 1983
- Polymeric coordination compounds of nickel(II), cobalt(II), and zinc(II) with oxalate ions as symmetric tetradentate bridging ligandsTransition Metal Chemistry, 1978
- Crystal structure and magnetic properties of catena-.mu.-sulfato-[N,N'-bis(2-hydroxyethyl)dithiooxamido(2-)-N,O,S:N',O',S']bis[aquacopper(II)]: a chain of copper(II) dinuclear units with a 594 cm-1 singlet-triplet separation and a 5.61 .ANG. copper-copper distanceInorganic Chemistry, 1978
- Crystal and molecular structures of µ-oxalato-di[bisethylenediamine-nickel(II)] dinitrate, µ-oxalato-bis[di-(2-aminoethyl)aminecopper(II)] di-perchlorate, and µ-oxalato-bis[di-(3-aminopropyl)aminezinc(II)] diperchlorateJ. Chem. Soc., Dalton Trans., 1973