Tartrato complexes

Schwendt, P, P. Svancarek, L. Kuchta, and J. Marek. 1998. A new coordination mode for the tartrato ligand. Synthesis of vanadium(V) oxo peroxo tartrato complexes and the x-ray crystal structure of K2[ V0(02)(L-tartH2) 2( j.-H20)] 5H20. Polyhedron 17 2161-2166. 

Cp2TiMe2 reacts selectively with a variety of dialkyltartrates with protonolytic cleavage of one of its Ti-Me bonds to form the respective binuclear [Cp2TiMe]2(/r-tartrato) complexes. The complexes were characterized by X-ray crystal structure analyses. A comparison of the characteristic structural parameters are indicative of an increased metal-oxygen 7r-interaction in the order Ti < Hf < Zr, which may explain the different chemical behavior observed in this series of compounds.1582... 

Structural and spectral properties of tartrato complexes of yanadium(V) from quantum chemical calculations... 

The catalytic activity of the VO(stearate)2-L/o tartrate system with the suggested presence of a dinuclear oxidovanadium(IV) tartrato complex leads to an enanti-oselective oxidative coupUng polymerization of 2,3-dihy-droxynaphthalene [13]. Very recently, the second harmonic generation and spin-dimer behavior were observed for oxovanadium(IV) tartrates [14], In addition, a study appeared on an interaction of tartratovanadates with chiral Fe(II) and Ni(II) tris(2,2 -bipyridine) complexes manifesting itself with the solid state by packing into homochiral layers in the crystal structure [15]. 

The following dinuclear and tetranuclear tartrato complexes of vanadium(V) previously isolated from... 

While the tetranuclear anion [17] always contains tar-trato gronps of the same enantiomeric form, formation of the dinuclear complexes is stereospecific [16]. Continuous effort to understand the stereospecific aspecfs of vanadium(V) tartrato complexes leads us to take a closer look at their spectral properties. Hence, this work is aimed to complement the aforementioned studies and provide deeper understanding of the experimental observations. 

At present, the density functional theory (DFT) prevails in calculations of the structural and spectral parameters of transition metal complexes [18]. For this reason, and thanks to our previous positive experience with simulation and interpretation of the UV-Vis, IR, electronic and vibrational circular dichroism (BCD and VCD) spectra of chiral vanadium complexes [19], we decided to use the DFT methods as the main tool in the present work as weU. We shall present the calculated molecular stractures, vibrational and electronic spectra, as well as the V chemical shifts of the chosen anions of the vanadium(V) tartrato complexes. Where applicable, results are confronted with the available experimental data, with the aim to assess the reliability of the individual methods for future calculations of a similar kind. 

Tellurium(IV) sulfato complexes of composition 2(2Te02 S03),MHS04-2H20 have been reported,46 from which the anhydrous compounds were obtained by calcination. Carboxylic acids have also been found to form anionic complexes with tellurium(IV) and polonium(IV). For example, the silver salts of the citrato- and tartrato-tellurates(IV) have been described47 as insoluble in water but soluble in nitric acid. 

Mixed dinuclear complexes of tartrates and 2,2 -bipyridyl or 1,10-phenanthroline and chromium(III) have been prepared 934,935 the typical structure is illustrated below (213). Stereochemical correlations have been carried out by oxidatively cleaving the tartrate bridge (214,215).936 The crystal structure of sodium hydrogen bis(//-meso-tartrato)bis(2,2 -bipyridyl)dichromate(III) heptahydrate has been reported.937... 

E.s.r. spectra have been reported114 for several oxalato-chromium(m) complexes and the thermal decomposition products of Cr2(C204)3,6H20 characterized by X-ray powder photography.115 The stability constants for 1 1. 1 2. and 1 3 chromium(m) formato-116 and tartrato-117 complexes have been determined, and the constitution and charge of 1 1 and 1 2 chromium(m) complexes with aspartic acid and asparagine reported.118... 

A slightly different type of chemical correlation is that recently achieved (138) on the two diastereoisomeric D-tartrato-bridged dimeric cobalt(III) complexes ... 

The standard method for resolution of coordination complexes involve crystallization of salts with chiral anions such as tartrate, ((+)-tartrato)antimonate(IlI) [19], or tn s-(cysteinesulphinato)cobaltate [20], or rf-[Co(en)2(N02)2] as a chiral cation... 

Fig. 13-11. The structures of two oxo acid complexes of Sb111. (a) The Sb(C204)3 ion projected on a plane approximately perpendicular to the basal plane of the pentagonal pyramid, (b) Geometry of the Sb111 tartrato-bridged binuclear complex ion of tartar emetic. [Reproduced by permission from reference 67.]...

Keywords Vanadium(V) complexes Tartrato ligand DFT calculations Spectral properties Chirality... 

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