Nature of the coordination bond in metal complexes of substituted pyridine derivatives. I. The substituent effect on the coordination bond

1968 ◽  
Vol 46 (2) ◽  
pp. 131-138 ◽  
Author(s):  
Patrick T. T. Wong ◽  
D. G. Brewer
Keyword(s):  
Free Energy ◽  
Bond Strength ◽  
Metal Complexes ◽  
Infrared Spectra ◽  
Substituent Effect ◽  
Coordination Bond ◽  
Spectroscopic Methods ◽  
Pyridine Derivatives ◽  
Coordination Center ◽  
Substituted Pyridines

The nature of the coordination bond in some metal complexes of 4-substituted pyridines has been investigated by thermodynamic and infrared spectroscopic methods. The effects of the substituents upon the coordination bond strength in the copper(II) complexes of these ligands have been found by direct measurement of the heats of coordination. These effects have been further described by the substituent effect upon the change in free energy of the coordination center in the ligands. A new parameter, Rπ, measuring the relative π bonding in the complexes of 4-substituted pyridines has been introduced. For this purpose a series of complexes of the types [M(4—R—C5H4N)2Cl2] and [(4—R—C5H4N)•HCl] (R = CH3, CH2OH, H, COCH3, CONH2, COOCH3, CN; M = Cu(II), Zn(II)) has been isolated, and the infrared spectra of these complexes and the free ligands have been examined.

The nature of the coordination bond in metal complexes of substituted pyridine derivatives. III. 4-Methylpyridine complexes of some divalent transition metal ions

1968 ◽  
Vol 46 (20) ◽  
pp. 3137-3141 ◽  
Author(s):  
D. G. Brewer ◽  
P. T. T. Wong ◽  
M. C. Sears
Keyword(s):  
Infrared Spectroscopy ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Ions ◽  
Coordination Bond ◽  
Pyridine Derivatives ◽  
Normal Coordinate ◽  
Substituted Pyridines ◽  
Solid Complexes ◽  
Nitrogen Bond

Previous papers in this series investigated the nature of the coordination bond in copper(II) and zinc(II) complexes of 4-substituted pyridines by infrared spectroscopy. In this paper, the investigation has been extended to complexes of 4-methylpyridine with cobalt(II), manganese(II), and nickel(II). The geometry of the solid complexes is assigned, and the force constants associated with the metal–nitrogen bond were calculated from a normal coordinate analysis. The validity of the previously introduced Rπ parameter in these systems is discussed.

Nature of the Coordination Bond in Metal Complexes of Substituted Pyridine Derivatives. VI. Electronic Spectra of Some Complexes of Copper(II)

1971 ◽  
Vol 49 (1) ◽  
pp. 102-104 ◽  
Author(s):  
Miss M. Tong ◽  
D. G. Brewer
Keyword(s):  
Metal Complexes ◽  
Electronic Spectra ◽  
Spectroscopic Data ◽  
Coordination Bond ◽  
Pyridine Derivatives ◽  
Pyridine Complexes ◽  
Infrared Measurements

The electronic spectra of some substituted pyridine complexes of copper(II) have been studied. The effects of bonding on the spectroscopic data are discussed, and compared with the Rπ values determined from infrared measurements.

The nature of the coordination bond in metal complexes of substituted pyridine derivatives. V. 4-Methylpyridine complexes of Zn(II), Cd(II), and Hg(II)

1970 ◽  
Vol 48 (24) ◽  
pp. 3786-3789 ◽  
Author(s):  
M. C. Sears ◽  
W. V. F. Brooks ◽  
D. G. Brewer
Keyword(s):  
Force Field ◽  
Metal Complexes ◽  
Field Model ◽  
Coordination Bond ◽  
Pyridine Derivatives ◽  
Divalent Ions ◽  
Normal Coordinate ◽  
Valence Force ◽  
Valence Force Field ◽  
Zinc Cadmium

In this paper, an attempt is made to interpret the π-bonding between a 4-methylpyridine ligand and the divalent ions of zinc, cadmium, and mercury, using the previously introduced Rπ parameter. To do this, the ν12 mode in the complexes is assigned and confirmed by a normal coordinate analysis based on a valence force field model.

Nature of the coordination bond in metal complexes of substituted pyridine derivatives. II. The far infrared spectra and metal–ligand force constants of copper complexes of 4-substituted pyridines

1968 ◽  
Vol 46 (2) ◽  
pp. 139-148 ◽  
Author(s):  
Patrick T. T. Wong ◽  
D. G. Brewer
Keyword(s):  
Infrared Spectra ◽  
Copper Complexes ◽  
Far Infrared ◽  
Coordination Bond ◽  
Force Constants ◽  
Nitrogen Ligand ◽  
Substituted Pyridines ◽  
Ligand Coordination ◽  
Chlorine Bond ◽  
Metal Ligand

Infrared spectra, including the lower frequency region, of copper (II) complexes of the type [CuL2Cl2], where L = 4-methylpyridine, 4-carbinylpyridine, pyridine, 4-acetylpyridine, 4-pyridinecarboxamide, 4-carbomethoxypyridine, and 4-cyanopyridine have been measured. The substituent effect upon the copper–nitrogen (ligand) and copper–chlorine stretching frequencies has also been examined. It was found that the substituents on the pyridine ring not only affected the nature of copper–nitrogen bond, but also the copper–chlorine bond. It appears that an entirely delocalized system exists, involving the chlorine atoms and the substituents in the complexes. Force constants associated with the coordination bond between copper and the nitrogen of the ligands have been calculated by means of an IBM 1620 computer. By comparison of the copper–nitrogen stretching frequencies with the corresponding force constants, and the heats of coordination, it may be concluded that the magnitude of the metal–ligand stretching frequency is directly related to the metal–ligand coordination bond strength for the systems under study.

scholarly journals Exploration of Free Energy Surface and Thermal Effects on Relative Population and Infrared Spectrum of the Be6B11− Fluxional Cluster

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 112
Author(s):  
Carlos Emiliano Buelna-Garcia ◽  
José Luis Cabellos ◽  
Jesus Manuel Quiroz-Castillo ◽  
Gerardo Martinez-Guajardo ◽  
Cesar Castillo-Quevedo ◽  
...  
Keyword(s):  
Free Energy ◽  
Infrared Spectrum ◽  
Infrared Spectra ◽  
Thermal Effects ◽  
Global Minimum ◽  
Energy Surface ◽  
Weighted Sums ◽  
Free Energy Surface ◽  
Temperature Dependent ◽  
Relative Population

The starting point to understanding cluster properties is the putative global minimum and all the nearby local energy minima; however, locating them is computationally expensive and difficult. The relative populations and spectroscopic properties that are a function of temperature can be approximately computed by employing statistical thermodynamics. Here, we investigate entropy-driven isomers distribution on Be6B11− clusters and the effect of temperature on their infrared spectroscopy and relative populations. We identify the vibration modes possessed by the cluster that significantly contribute to the zero-point energy. A couple of steps are considered for computing the temperature-dependent relative population: First, using a genetic algorithm coupled to density functional theory, we performed an extensive and systematic exploration of the potential/free energy surface of Be6B11− clusters to locate the putative global minimum and elucidate the low-energy structures. Second, the relative populations’ temperature effects are determined by considering the thermodynamic properties and Boltzmann factors. The temperature-dependent relative populations show that the entropies and temperature are essential for determining the global minimum. We compute the temperature-dependent total infrared spectra employing the Boltzmann factor weighted sums of each isomer’s infrared spectrum and find that at finite temperature, the total infrared spectrum is composed of an admixture of infrared spectra that corresponds to the spectra of the lowest-energy structure and its isomers located at higher energies. The methodology and results describe the thermal effects in the relative population and the infrared spectra.

Spectra-structure correlations from the infrared spectra of some transition metal complexes of 8-hydroxyquinoline

1989 ◽  
Vol 213 ◽  
pp. 133-144 ◽  
Author(s):  
Carola Engelter ◽  
Graham E. Jackson ◽  
Cheryl L. Knight ◽  
David A. Thornton
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Infrared Spectra ◽  
Structure Correlations

ChemInform Abstract: INFRARED SPECTRA OF METAL COMPLEXES OF OCTAETHYLCHLORINE ANALOGS OF CHLOROPHYLL AND HEME D

1975 ◽  
Vol 6 (33) ◽  
pp. no-no
Author(s):  
H. OGOSHI ◽  
E. WATANABE ◽  
Z. YOSHIDA ◽  
J. KINCAID ◽  
K. NAKAMOTO
Keyword(s):  
Metal Complexes ◽  
Infrared Spectra

ChemInform Abstract: INFRARED SPECTRA OF SOME BIVALENT METAL COMPLEXES OF MANDELIC ACID

1974 ◽  
Vol 5 (8) ◽  
Author(s):  
P. V. KHADIKAR ◽  
R. L. AMERIA ◽  
M. G. KEKRE ◽  
S. D. CHAUHAN
Keyword(s):  
Metal Complexes ◽  
Infrared Spectra ◽  
Mandelic Acid ◽  
Bivalent Metal ◽  
Bivalent Metal Complexes
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