Naslov
The role of methanol molecule in supramolecular assembling of [MoO2L(CH3OH)] · CH3OH and [MoO2L(CH3OH)] Schiff base type complexes

Autori
Katava, Robert ; Pavlović, Gordana ; Cindrić, Marina ;

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts / - , 2015

Skup
29th European Crystallographic Meeting ;

Mjesto i datum
Rovinj, Hrvatska, 23.08.2015. - 28.08.2015

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
dioxidomolybdenum(VI) complexes ; catalysts ; supramolecular architecture

Sažetak
Investigations of Schiff base molybdenum(VI) complexes have been stimulated by discovery of molybdenum in a number of redox enzymes1 and their efficiency as catalysts both in heterogeneous and homogenous reactions2. Reactions of tridentate O, N, O Schiff base ligands H2L with [MoO2(acac)2] afforded a series of distorted octahedral cis-MoO22+ complexes of the type [MoO2L(CH3OH)] · CH3OH (1-4) and [MoO2L(CH3OH)] (5). Coordinated CH3OH molecule, positioned trans to oxido oxygen atom, could be readily removed from first coordination sphere of molybdenum(VI) cation, yielding a [MoO2(L)] intermediate responsible for catalytic activation of substrates during Lewis acid catalyzed transformations. The supramolecular architecture of complexes is dominated by two types of hydrogen bonds (HB): O−H···O and C−H···O. The supramolecular motif shaped by O−H···O HB in 2, 3 and 4 differs in comparison with that formed by the same type of HB in 1. The infinite chains in 2, 3 and 4 are shaped via the O−H···O HB which include the coordinated methanol oxygen atom, MeOH solvent molecule and the oxido oxygen atom of the complex molecule (Fig. 1a). On the contrary, the supramolecular dimers in 1 are formed by two molecules of solvent CH3OH and two complex molecules via the phenolate oxygen atom and oxygen atom from coordinated CH3OH (Fig.1b). Formed dimers are condensed with both sides with complex molecules via C−H···O intermolecular hydrogen bond which form centrosymmetric puckered 15-membered ring. (Figure 1b). Since the complex 4 does not contain solvent molecule of crystallization, the main supramolecular synthon formed via O−H···O hydrogen bond is centrosymmetric dimer between the –OH group of coordinated methanol and the oxygen donor atom of five-membered chelate ring of another complex molecule (Fig. 1c). The determination of supramolecular role of MeOH molecules is essential in the context of complexes solubility and their catalytic activity in the conditions of epoxidation.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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