| SM ISO690:2012|
BOUROSH, Paulina; KRAVTSOV, Viktor; DRAGANCEA, Diana. Dinuclear manganese(II) complexes with hydrazone ligands. In: Materials Science and Condensed Matter Physics. Editia a 7-a, 16-19 septembrie 2014, Chișinău. Chișinău, Republica Moldova: Institutul de Fizică Aplicată, 2014, p. 186.
|Materials Science and Condensed Matter Physics
Editia a 7-a, 2014
Conferința "Materials Science and Condensed Matter Physics" |
Chișinău, Moldova, 16-19 septembrie 2014
Manganese complexes in general and dinuclear Mn(II) compounds in pa1iicular, with N/O donor ligands have received considerable attention in recent years. This is due to several reasons: unique stmctural features with interesting magnetic prope1iies, manganese containing active sites of enzymes in bioinorganic chemistiy, recognized relevance in homogenous and heterogenous catalysis [ 1]. In the course of our research on polydentate Schiff-base manganese complexes, we repo1i herein two dinuclear Mn(II) complexes with hydrazone Schiff base ligands derived from condensation of o-vanillin with 2-hydroxybenzohydrazide (H3L1 ) or semicarbazide (H2L2). Reaction of Mn(NO3)2·4H2O with the H3L1 ligand, in the presence of sodium azide (1 : 1 : 1 mole ratio), at room temperature in methanol yield the dinuclear manganese(!!) complex [Mn(H2L1 )(CH3OH)(N3)]2 (1). Compound [Mn(HL2)(CH3OH)(Cl)h (2) was synthesized in similar way using MnCh·4H2O as staiiing salt. Compounds c1ystallize in the ti·iclinic space group P-1, in 1 : a=9.0686(8), b= l 0.6318(10), c= l 1.067(1) A, a=65.284(9), β =66.371(9), y=72.475(9)0 , V= 876.5(1) A3, in 2: a=9.0358(6), b=9.5245(6), c=9.7973(8) A, a= l 12.835(7), β=115.911(7), y=93.287(6)0 , V=672.27(8) A3. The X-ray study shown, that in the crystals both dinuclear complexes reside around inversion centers. The monoanionic teti·adentate ligands coordinates to one of the metal via the keto oxygen and the azometine niti·ogen, and via 3-methoxy moiety to another metal. The deprotonated phenolic oxygen atom bridges two metals. Thus, each ligand fo1ms three metallocycles: two five membered and one six-membered. Two ligands fo1m penta-coordinated sunounding in the basal plane of the metals while methanol and the azide anion in 1, and methanol and chloride anions in 2 complete the coordination polyhedron of Mn(II) up to pentagonal bipyramid with OsN2 and OsN1Ch. donor sets, respectively. The metal-donor atom distances in 1 ai·e in the ranges Mnl-O 2.172(2) - 2.261(3), Mnl-N are 2.270(4) and 2.290(3) A, and Mnl-O in 2 ai·e in the ranges 2.179(2) - 2.395(2), Mnl-N = 2.325(3) and Mnl-Cl 2.539(1) A. The metal-··metal separation ai·e 3.417 in 1 and 4.421 A in 2.