INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
artículos
Título:
Magnetism and Structure in Chains of Copper Dinuclear Paddewheel Units
Autor/es:
PEREC MIREILLE; BAGGIO RICARDO; SARTORIS, ROSANA P.; SANTANA, RICARDO C.; PENA OCTAVIO; CALVO RAFAEL
Revista:
INORGANIC CHEMISTRY
Editorial:
AMER CHEMICAL SOC
Referencias:
Lugar: Washington DC 20036; Año: 2010 vol. 49 p. 695 - 695
ISSN:
0020-1669
Resumen:
An anhydrous copper carboxylate compound of formula [Cu(trans-2-butenoate)2]n has been characterized. X-ray analysis reveals a structure built by paddlewheel units bridged by pairs of Cu¡­O axial bonds to give infinite chains arranged in a new topological motif.Susceptibility measurements in the 10-300 K temperature range, and isothermal magnetization curves at 2, 5, 10 and 50 K with fields up to 5 T, were obtained. EPR spectra of powder samples were measured at 33.9 GHz at 300 K, and at 9.60 GHz at temperatures in the range 90 ¡Ü T ¡Ü 350 K. Fitting the susceptibility data to a chain model of alternating paddlewheel and [Cu(¦Ì-O)2Cu] dinuclear units, yielded exchange interactions J1 = -330.6(1) cm-1 and J2 = 5.9(2) cm-1. The EPR spectra reflect the usual antiferromagnetic dinuclear behavior, with zero field splitting parameters of the excited spin triplet, D = -0.329(3) cm-1 and E ~ 0, plus a central peak not expected for isolated dinuclear units. We interpret this peak as arising from the stochastic spin dynamics of the chain introduced by exchange couplings between spins in neighbor dinuclear units, which averages out the zerotrans-2-butenoate)2]n has been characterized. X-ray analysis reveals a structure built by paddlewheel units bridged by pairs of Cu¡­O axial bonds to give infinite chains arranged in a new topological motif.Susceptibility measurements in the 10-300 K temperature range, and isothermal magnetization curves at 2, 5, 10 and 50 K with fields up to 5 T, were obtained. EPR spectra of powder samples were measured at 33.9 GHz at 300 K, and at 9.60 GHz at temperatures in the range 90 ¡Ü T ¡Ü 350 K. Fitting the susceptibility data to a chain model of alternating paddlewheel and [Cu(¦Ì-O)2Cu] dinuclear units, yielded exchange interactions J1 = -330.6(1) cm-1 and J2 = 5.9(2) cm-1. The EPR spectra reflect the usual antiferromagnetic dinuclear behavior, with zero field splitting parameters of the excited spin triplet, D = -0.329(3) cm-1 and E ~ 0, plus a central peak not expected for isolated dinuclear units. We interpret this peak as arising from the stochastic spin dynamics of the chain introduced by exchange couplings between spins in neighbor dinuclear units, which averages out the zeroD = -0.329(3) cm-1 and E ~ 0, plus a central peak not expected for isolated dinuclear units. We interpret this peak as arising from the stochastic spin dynamics of the chain introduced by exchange couplings between spins in neighbor dinuclear units, which averages out the zero Page 1 of 28 ACS Paragon Plus Environment Submitted to Journal of the American Chemical Society