title: Synthesis, structure, and magnetism of non-planar heptanuclear lanthanide(III) complexes.
abstract: The reaction of the hydrazone, 2-methoxy-6-(pyridin-2-yl-hydrazonomethyl) phenol (LH) with lanthanide(iii) nitrate salts in the presence of excess triethylamine afforded the heptanuclear Ln(iii) complexes: [Gd7(L)6(μ3-OH)8(NO3)4(H2O)]·(NO3)3·8CH3CN·H2O (), [Tb7(L)6(μ3-OH)8(NO3)4]·(NO3)3·9CH3CN·2CH3OH·3H2O (), [Dy7(L)6(μ3-OH)8(NO3)4(H2O)]·(NO3)3·7CH3CN·3H2O (), [Ho7(L)6(μ3-OH)8(NO3)4]·(NO3)3·11CH3CN·2CH3OH·2H2O () and [Er7(L)6(μ3-OH)8(NO3)4]·(NO3)3·8CH3CN·2CH3OH (). Single crystal X-ray diffraction studies reveal that these complexes are tri-cationic, possessing three nitrate counter anions. The heptanuclear ensemble is non-planar and consists of six [L](-) and eight μ3-OH ligands. These compounds show an interesting structural motif with two incomplete cubes fused to each other through a common Ln(iii) ion. Compound exhibits a magnetocaloric effect, with (-ΔSm(T) = 27.7 J kg(-1) K(-1) at 3 K and under a field change of 0-7 T), while compound shows slow magnetic relaxation at very low temperatures.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India. vc@iitk.ac.in vc@niser.ac.in.
authors.forename: Joydeb
authors.initials: J
authors.lastname: Goura
authors.forename: James P S
authors.initials: JP
authors.lastname: Walsh
authors.forename: Floriana
authors.initials: F
authors.lastname: Tuna
authors.forename: Vadapalli
authors.initials: V
authors.lastname: Chandrasekhar