title: Ferro- to antiferromagnetic crossover angle in diphenoxido- and carboxylato-bridged trinuclear Ni(II)₂-Mn(II) complexes: experimental observations and theoretical rationalization.
abstract: Three new trinuclear heterometallic Ni(II)-Mn(II) complexes have been synthesized using a [NiL] metalloligand, where H2L = N,N'-bis(salicylidene)-1,3-propanediamine. The complexes [(NiL)2Mn(OCnn)2(CH3OH)2]·CH3OH (1), [(NiL)2Mn(OPh)2(CH3OH)2][(NiL)2Mn(OPh)2]·H2O (2), and [(NiL)2Mn(OSal)2(CH3OH)2]·2[NiL] (3) (where OCnn = cinnamate, OPh = phenylacetate, OSal = salicylate) have been structurally characterized. In all three complexes, in addition to the double phenoxido bridge, the two terminal Ni(II) atoms are linked to the central Mn(II) by means of a syn-syn bridging carboxylate, giving rise to a linear structure. Complexes 1 and 2 with Ni-O-Mn angles of 97.24 and 96.43°, respectively, exhibit ferromagnetic interactions (J(Ni-Mn) = +1.38 and +0.50 cm(-1), respectively), whereas 3 is antiferromagnetic (J(Ni-Mn) = -0.24 cm(-1)), having an Ni-O-Mn angle of 98.51°. DFT calculations indicate that there is a clear magneto-structural correlation between the Ni-O-Mn angle and J(Ni-Mn) values, which is in agreement with the experimental results.
authors.affiliation: Department of Chemistry, University College of Science, University of Calcutta , 92, A.P.C. Road, Kolkata 700 009, India.
authors.forename: Piya
authors.initials: P
authors.lastname: Seth
authors.forename: Albert
authors.initials: A
authors.lastname: Figuerola
authors.forename: Jesús
authors.initials: J
authors.lastname: Jover
authors.forename: Eliseo
authors.initials: E
authors.lastname: Ruiz
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Ghosh