L.B. Rogers

Bio: L.B. Rogers is an academic researcher from Purdue University. The author has contributed to research in topic(s): Bond energy & Pyridine. The author has an hindex of 1, co-authored 1 publication(s) receiving 37 citation(s).

Effect of metal ion and ligand on thermal stability of metal amine complexes

Abstract: A series of transition-metal (II) pyridine complexes, [M(py) 2 X 2 where M  Cu 2+ , N 2+ , Co 2+ , Mn 2+ , Zn 2+ , and X  Cl − , NO 3 − , NCS − ,] and two series of copper (II) chloride complexes with mono- and dimethyl substituted pyridines and with 4-substituted pyridines were studied by differential thermal analysis. The thermal stability was correlated with thermodynamic constants determined in solution and with bond energies determined by far infra-red spectroscopy. In the transition-metal series thermal stability increased with increasing stability in solution. In the copper series the opposite trend was found. As base strength of the ligand increased the thermal stability decreased. This can be best explained by an oxidation-reduction reaction occurring during decomposition.

Heterogeneous reactions of solid nickel(II) complexes, III

Abstract: The stoichiometry of thermal decomposition was studied for the following compounds: Ni(pyNO)Cl2H2O (I), (pyNO=pyridine N-oxide), Ni(2-MepyNO)Cl2·2H2O (II), Ni(3-MepyNo)Cl2·2H2O (III) and Ni(4-MepyNO)2Cl2·C2H5OH (IV). The heating of the compounds led first to the release of H2O molecules (or C2H5OH molecules), with the formation of Ni(pyNO)Cl2 (V), Ni(2-MepyNO)Cl2(VI), Ni(3-MepyNO)Cl2 (VII) and Ni(4-MepyNO)2Cl2 (VIII). In the next stage, decomposition of the heterocyclic liugands set in. The compositions and spectral and magnetic properties of these complexes indicate their dimeric (II, III, IV, VIII) of polymeric (I, V, VI, VII) structure with coordinated molecules of H2O (or C2H5OH).

Study of the adsorption of organic molecules on clay minerals by differential thermal analysis

Abstract: DTA was adapted to study the types of associations between water molecules, exchangeable metallic cations and organic molecules or ions formed on clay surfaces. Comparison between curves recorded in the absence or presence of air show that in the latter case strong diagnostic exothermic peaks are obtained and the analysis is more sensitive for identification of the different associations. The location of the peaks serves to differentiate between adsorbed and non-adsorbed organic matter, a neutral free organic molecule, cationic organic matter or a neutral molecule coordinated to transition metal. DTA study of the adsorption of aliphatic and aromatic amines by montmorillonite is described in detail, in order to demonstrate how this technique is applicable for the study of surface reactions.

Thermal decomposition of complexes of palladium(II) chloride with substituted pyridines

Abstract: The thermal decomposition of solid complexes of palladium(II) chloride with pyridine and several methyl and dimethylpyridines has been studied using differential scanning calorimetry. In general, a linear relationship exists between the pKb values of the ligands and the activation energies for decomposition of the complexes. The variation of initiation temperatures for the decomposition with ligand basicities is interpreted in terms of a possible trans effect.

Thermal analysis of metal complexes, III

Abstract: On the basis of the thermal investigation of MpynX z mixed complexes (where M=Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+; py=pyridine; orα-, Β- andγ-picoline; X=Cl−, Br−, I−, OCN−, SCN−, NO 3 − , SO 4 2− ; andn=2,3,4,6;z=1,2), factors influencing the stability of the metal-pyridine-N bond have been determined. On the basis of the measured magnetic susceptibilities the symmetry of the coordina tion sphere of the central atom has been established in the intermediate products formed by the thermal decomposition of cobalt(II) complexes.