Electronic absorption spectra for copper(II) polyamine complexes

1970 ◽  
Vol 23 (5) ◽  
pp. 981 ◽  
Author(s):  
GR Hedwig ◽  
JL Love ◽  
HKJ Powell
Keyword(s):  
Aqueous Solution ◽  
Field Strength ◽  
Absorption Spectra ◽  
Chain Length ◽  
Electronic Absorption ◽  
Thermodynamic Stability ◽  
Electronic Absorption Spectra ◽  
Ultraviolet Absorption ◽  
Ligand Field ◽  
Nitrogen Donor

The preparations and visible and ultraviolet absorption spectra are reported for a series of copper(11) complexes with linear and cyclic aliphatic ligands which each have four nitrogen donor atoms. Data are compared with that for 16 analogous complexes. For linear polyamines of different chain length the ligand field strength, as denoted by vmax (visible), is found to increase with increasing thermodynamic stability of the copper(11) complex in aqueous solution. For linear and cyclic ligands the ligand field strength is a maximum for complexes containing a combination of five- and six-membered chelate rings.

Niobocene Dichloride and Niobocene Diiodide: Electronic Absorption Spectra and Electron Spin Resonance

1998 ◽  
Vol 63 (5) ◽  
pp. 628-635 ◽  
Author(s):  
Jana Holubová ◽  
Zdeněk Černošek ◽  
Ivan Pavlík
Keyword(s):  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Point Group ◽  
Esr Spectra ◽  
Ligand Field ◽  
Orbital Interaction ◽  
Symmetry Point Group ◽  
Spin Orbital ◽  
Halide Ligands

The effect of the halide ligand on the bonding of niobium in niobocene dichloride and niobocene diiodide was investigated. The electronic absorption spectra of the two compounds in the range of d-d transitions were resolved into four bands corresponding to transitions of the d1 electron between five frontier orbitals in a molecule of symmetry point group C2v. The energies of the frontier molecular orbitals were determined relatively to the energy of the orbitals in the spherically symmetric ligand field formed by the appropriate halide ligands. The effect of the halide ligands on the spin-orbital interaction of the HOMO orbital is discussed qualitatively on the basis the ESR spectra.

LIGHT ABSORPTION STUDIES: PART XI ELECTRONIC ABSORPTION SPECTRA OF NITROBENZENES

1958 ◽  
Vol 36 (10) ◽  
pp. 1350-1361 ◽  
Author(s):  
W. F. Forbes
Keyword(s):  
Absorption Spectra ◽  
Electronic Absorption ◽  
Light Absorption ◽  
Electronic Absorption Spectra ◽  
Ultraviolet Absorption ◽  
Electronic Interactions ◽  
Absorption Studies

The spectra of nitrobenzenes are discussed in terms of previously proposed hypotheses relating electronic interactions and ultraviolet absorption spectra.

Spectral and electrochemical study of coordination molecules Cu4OX6L4: 3-Methylpyridine and 4-Methylpyridine Cu4OBrnCl(6−n)L4 complexes

2006 ◽  
Vol 60 (1) ◽  
Author(s):  
G. Ondrejovič ◽  
A. Kotočová
Keyword(s):  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Far Infrared ◽  
High Energy ◽  
Low Energy ◽  
Ligand Field ◽  
Cyclic Voltammograms ◽  
Energy Bands ◽  
Trigonal Bipyramidal

AbstractThe tetranuclear Cu4OBrnCl(6-n)L4 complexes, where L = 3-methylpyridine (3-Mepy), 4-methylpyridine (4-Mepy) and n=0–6 with trigonal bipyramidal coordination of copper(II) were prepared and their infrared and electronic absorption spectra as well as cyclic voltammograms in nitromethane solutions were measured. The polyhedra in Cu4OBrnCl(6−n) (3-Mepy)4 molecules are less distorted comparing with those of 4-Mepy analogues as indicated by infrared Cu4O absorptions, far infrared Cu—Br, Cu—Cl, and Cu—N absorptions, d—d bands in electronic spectra and potentials, measured by cyclic voltammetry. The 3-Mepy complexes exhibit strong single infrared Cu4O absorptions, while for related 4-Mepy complexes doubly split Cu4O bands were observed. Two strongly overlapped d—d bands in electronic absorption spectra of the 3-and 4-Mepy complexes in nitromethane were resolved by Gaussian fitting. The 4-Mepy ligand produces slightly stronger ligand field than its 3-Mepy analogue. The maxima of high-energy d—d bands are in a linear correlation with the number of bromide ligands. The correlations for corresponding low-energy bands are considerably deviated from linearity. The halfwave potentials of the complexes in nitromethane correlate with both the number of bromides and the data of electronic absorption spectra suggesting that the reducing electron at the electrode process enters the half-filled d z 2 orbital of the copper(II) atom. The origin of a difference between the 3-and 4-Mepy complexes in their spectral and electrochemical properties is also discussed.

Correlation of absorption spectra and structure of some Co(II)– and Ni(II)–2,2′-biquinoline complexes

1967 ◽  
Vol 45 (20) ◽  
pp. 2335-2345 ◽  
Author(s):  
G. H. Faye ◽  
J. L. Horwood
Keyword(s):  
Field Theory ◽  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Transition ◽  
Near Infrared ◽  
Magnetic Measurements ◽  
Electronic Absorption Spectra ◽  
General Interest ◽  
Ligand Field ◽  
Ligand Field Theory

Co(II)– and Ni(II)–2,2′-biquinoline (Biq) complexes of the type MBiqCl2 and MBiq(NO3)2 have been isolated. Electronic absorption spectra in the visible and near infrared, as well as magnetic measurements, show that CoBiqCl2 is essentially tetrahedral, whereas NiBiqCl2 and the MBiq(NO3)2 complexes are pseudo-octahedral. In acetone solution Co(II) forms a bis-Biq complex that is probably five coordinate, whereas the Ni(II) analogue is probably an octahedral species with a cis configuration. Elementary ligand field theory has been used to interpret the absorption spectra, and certain electronic transition assignments have been made that may be of general interest.

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