| SM ISO690:2012|
MELNYK, Silvia; BENNISTON, Andrew; ARAUZO, A.; BARTOLOME, Bartolome; BARTOLOME, Juan; TURTA, Constantin. Synthesis and study of a calcium(II)-based molecular rod decorated with manganese(II) butterfly-like complex. In: The International Conference dedicated to the 55th anniversary from the foundation of the Institute of Chemistry of the Academy of Sciences of Moldova. 28-30 mai 2014, Chișinău. Chișinău, Republica Moldova: Institutul de Chimie al AȘM, 2014, p. 93.
|The International Conference dedicated to the 55th anniversary from the foundation of the Institute of Chemistry of the Academy of Sciences of Moldova 2014|
Conferința "The International Conference dedicated to the 55th anniversary from the foundation of the Institute of Chemistry of the Academy of Sciences of Moldova" |
Chișinău, Moldova, 28-30 mai 2014
Biological water splitting occurs at the oxygen-evolving complex (OEC) of photosystem II (PSII). Nowadays the laboratory synthesis of an artificial OEC has been the objective of many synthetic chemists. Particular attention has been given to mixed manganese-calcium compounds aimed at mimicking the OEC of PSII , not only because they are used by Nature to oxidize water but also because manganese and calcium are cheap and environmentally friendly. Fig. 1. Partial crystal packing diagram for 1 displaying the manganese complexes decorating the calcium(II)-based rod.. Fig. 2. Frequency dependence of the out-ofphase susceptibility of 1, as a function of temperature at H = 1500 Oe. In efforts to construct heterometallic Mn-Ca clusters our attention focussed on using preorganised [Mn2O2(bipy)4](ClO4)3 (bipy = 2,2’-bipyridyl) with the intention of forming an accretion with Ca(CHCl2COO)2. The structure comprises a multiple calcium(II) carboxylate bridged rod-like structure which is decorated with [Mn(bipy)2(OH2)]2+ subunits. The synthesised complex with the general formula [Mn(bipy)2Ca2(CHCl2COO)6(H2O)(CH3OH)] (1) (Fig.1) was studied by cyclic voltammetry, magnetochemistry, IR, mass- and UV-visible spectroscopy. The redox behaviour for the complex was investigated in H2O and MeCN. In the latter solvent the oxidation of the manganese ions appears to be facilitated by the presence of the calcium ions. Magnetic measurements show that the Mn moment is isotropic, with g = 1.99(1) and S = 5/2, confirming it is in the 2+ oxidation state. Field induced slow magnetic relaxation processes are detected at low temperatures