Naslov
Supramolecular motifs and solvatomorphism within the compounds [M(bpy)3]2[NbO(C2O4)3]Cl·nH2O (M = Fe2+, Co2+, Ni2+, Cu2+ and Zn2+ ; n = 11, 12). Syntheses, structures and magnetic properties

Autori
Jurić, Marijana ; Perić, Berislav ; Brničević, Nevenka ; Planinić, Pavica ; Pajić, Damir ; Zadro, Krešo ; Giester, Gerald ; Kaitner, Branko

Izvornik
Dalton Transactions (1477-9226) 2008 (2008), 6; 742-754

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
transition metal complexes ; 2 ; 2'-bipyridine ; tris(oxalato)oxoniobate(V) ; synthesis ; crystal structures ; solvatomorphism ; quadruple aryl embrace (QAE) contact ; magnetic susceptibility measurements

Sažetak
Solvatomorphism has been found between two series of complexes of the composition [M(bpy)3]2[NbO(C2O4)3]Cl·nH2O [M = Fe2+ (1, 2), Co2+ (3, 4), Ni2+ (5, 6), Cu2+ (7) and Zn2+ (8, 9) ; bpy = 2, 2′-bipyridine)], crystallizing in the monoclinic space groupP21/c [3, 5, 8 (n = 11)] or in the orthorhombic space groupP212121 [2, 4, 6, 7 (n = 12)]. All the structures contain two symmetry independent [M(bpy)3]2+ cations, one [NbO(C2O4)3]3− anion, one Cl− anion, and crystal water molecules. The cations possess a trigonally distorted octahedral geometry, with an additional tetragonal distortion in 7. Analysis of crystal packing reveals a specific type of supramolecular contact comprising four bipyridine ligands from two neighbouring [M(bpy)3]2+ cations—quadruple aryl embrace (QAE) contact. The contact is realized by the alignment of two molecular two-fold rotation axes, preserving the parallel orientation of the molecular three-fold rotation axes. The resulting two-dimensional honeycomb lattices of [M(bpy)3]2+ cations are placed between the hydrogen bonding layers made of [NbO(C2O4)3]3− and Cl− anions and the majority of the crystal water molecules. The temperature-dependent magnetic susceptibility measurements (1.8–300 K) show a significant orbital angular momentum contribution for 3 and 4 (high-spin Co2+), the influence of zero-field splitting for 5 and 6 (Ni2+) and a substantially paramagnetic Curie behaviour for the Cu2+ compound (7).

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemija

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