scholarly journals STRUCTURAL AND SPECTRAL STUDIES OF THE MIXED-LIGAND CATION COMPLEX OF LANTHANUM [Lа(L)2bipy2]BPh4 WITH CARBACYLAMIDOPHOSPHATE (CAPH) TYPE LIGAND AND 2,2'-BIPYRIDINE

Author(s):  
M. Struhatska ◽  
I. Olyshevets ◽  
V. Dyakonenko ◽  
V. Ovchynnikov ◽  
S. Shishkina ◽  
...  

A new cationic mixed-ligand complex [Lа(L)2bipy2]BPh4 (where L-= bis(N,N'-diethylamide)(N'-trichloroacetyl)-triamidophosphate anion, bipy = 2,2'-bipyridine) has been synthesized and studied by the means of IR, 1H NMR spectroscopy, thermogravimetric and X-ray structural analyses. Low-frequency shifts of the absorption bands of the carbonyl and phosphoryl groups of phosphorylated ligand in the IR spectra of the complex compared with similar absorption bands in the spectrum of "free" CAPh ligand are Δν(C = O) = 117 cm–1 and Δν(P = O) = 137 cm–1. The analysis of integral signal intensity in the investigated NMR spectra of coordination compounds [Lа(L)2bipy2]BPh4 indicates the molar ratio of ligand : bipyridine : tetraphenylborate anion as a 2:2:1, which corresponds to the proposed structure of the complexes. The compound has been obtained in monocrystalline form. The structure of the complex has been determined by X-ray structural analysis, its ionic structure was proved, and the coordination of two CAPh ligands through the oxygen atoms of the carbonyl and phosphoryl groups was confirmed. Based on the structural data, it was determined that the La3+ ion is octocoordinated (surrounded by four oxygen atoms from two chelated phosphoryl ligands and four nitrogen atoms from two 2,2'-bipyridine molecules). The coordination polyhedron of central ion is interpreted as a square antiprism. Complex cations and tetraphenylborate anions are connected both by electrostatic interaction and by weak intermolecular C – H ∙∙∙ π-contacts between phenyl substituents of BPh4- and molecules of 2,2'-bipyridine. It was established by thermogravimetric analysis that the complex [Lа(L)2bipy2]BPh4 obtained is thermally stable up to a temperature of 150 °C. Significant decomposition of the complex begins at a temperature of 150 °C, occurs in one stage and most intensively continues up to 300 °C. The total weight loss is 78 %.

2003 ◽  
Vol 58 (1) ◽  
pp. 151-154 ◽  
Author(s):  
Rosa Carballo ◽  
Berta Covelo ◽  
Ezequiel M. Vázquez-Lópeza ◽  
Alfonso Castiñeiras ◽  
Juan Niclós

Abstract A new mixed-ligand complex of copper(II) with 1,10-phenanthroline and 2-methyllactate was prepared. [Cu(HmL)2(phen)] ·2H2O (where HmL = monodeprotonated 2-methyllactic acid) was characterized by elemental analysis, IR, electronic and EPR spectroscopy, magnetic measurements at room temperature, thermogravimetric analysis and X-ray diffractometry. The copper atom is in a tetragonally distorted octahedral environment and the 2-methyllactato ligand is bidentately chelating. The presence of lattice water molecules mediates the formation of a three-dimensional network.


1970 ◽  
Vol 25 (1) ◽  
pp. 22-26 ◽  
Author(s):  
G. Sharma ◽  
J. P. Tandon

Stepwise mixed ligand complex formation is observed in the systems containing metal ion, iminodiacetic acid (IMDA) as primary ligand and one of the diamines, such as ethylenediamine (en), 1,2-propanediamine (1,2-pn) and 1,3-propanediamine (1,3-pn) as secondary ligands. Potentionmetric titrations indicate the formation of ternary complexes having a 1:1:1 molar ratio of metal ion to iminodiacetic acid to the secondary ligand. Initially, metal-IMDA (1:1) complex is formed in the lower buffer region prior to the formation of the ternary complex and the addition of the secondary ligand takes place only after the combination with the primary ligand is complete. Formation constants (log KMAB) of the ternary complexes have been calculated and the probable reaction mechanism is suggested. The order of stability in terms of metal ion has been found to be Cu (II) > Ni (II) >Zn (II) >Cd (II) and in terms of secondary ligand as 1,2-pn>en>1,3-pn.


1996 ◽  
Vol 51 (8) ◽  
pp. 1207-1209 ◽  
Author(s):  
Alexander Sladek ◽  
Hubert Schmidbaur

Dimethylsulfide reacts with (triphenylphosphine) gold(I) trifluoromethanesulfonate to give quantitative yields of the mixed ligand complex [(Ph3P)Au(SMe2)]+O3SCF3- (1). The structure of compound 1 has been determined by an X-ray crystal structure analysis. The lattice contains independent anions and (monomeric) cations, which have a linear P-Au-S axis. Attempts to produce a binuclear. dicationic complex through addition of a second equivalent of [(Ph3P)Au]+ failed and lead to decomposition products including [(Ph3P)2Au]+O3SCF3-.


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