LIGHT ABSORPTION STUDIES: PART VII. CONCERNING THE RELATION BETWEEN THE INFRARED CARBONYL STRETCHING BANDS AND ULTRAVIOLET SPECTRA (B-BANDS) IN RING SUBSTITUTED ACETOPHENONES

1957 ◽  
Vol 35 (5) ◽  
pp. 488-499 ◽  
Author(s):  
W. F. Forbes ◽  
W. A. Mueller
Keyword(s):  
Light Absorption ◽  
Ultraviolet Spectra ◽  
Substituent Group ◽  
Absorption Studies

The B-bands of a number of ring substituted acetophenones were determined. The observed changes are discussed in relation to the nature and position of the substituent group and are compared with the corresponding changes observed in the infrared carbonyl stretching bands.

LIGHT ABSORPTION STUDIES: PART VIII. THE SECONDARY BAND OF ACETOPHENONES AND BENZOIC ACIDS IN ULTRAVIOLET SPECTRA

1957 ◽  
Vol 35 (9) ◽  
pp. 1049-1059 ◽  
Author(s):  
W. F. Forbes ◽  
W. A. Mueller ◽  
Audrey S. Ralph ◽  
J. F. Templeton
Keyword(s):  
Absorption Spectra ◽  
Solvent Effects ◽  
Light Absorption ◽  
High Intensity ◽  
Benzoic Acids ◽  
Ultraviolet Spectra ◽  
Absorption Studies ◽  
Similar Character ◽  
High Intensity Band ◽  
Primary Band

The absorption spectra of some acetophenones and benzoic acids have been measured in different solvents in the region 220–400 mμ. The two major bands are compared and it is found that steric interactions which considerably alter the high-intensity band have less and somewhat different effects on the secondary band. Solvent effects and the changes observed on substitution indicate that the weaker band (C-band) is essentially of similar character to the high intensity primary band (B-band). A unifying hypothesis to account for the observed changes is presented.

LIGHT ABSORPTION STUDIES: PART XV. THE ULTRAVIOLET ABSORPTION SPECTRA OF ANISOLES

1959 ◽  
Vol 37 (8) ◽  
pp. 1305-1314 ◽  
Author(s):  
J. C. Dearden ◽  
W. F. Forbes
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Atom ◽  
Absorption Spectra ◽  
Hydroxy Group ◽  
Light Absorption ◽  
Spectral Properties ◽  
Ultraviolet Absorption ◽  
Steric Interactions ◽  
Absorption Studies ◽  
Methoxy Groups

Anisoles, compared with phenols, possess similar spectral properties, except that properties determined mainly by the hydrogen atom of the hydroxy group are modified. In this way, comparison of the ultraviolet absorption spectra of phenols and anisoles permits, for example, the study of the spectral effects of hydrogen bonding and the study of steric interactions involving the hydroxy and methoxy groups.

LIGHT ABSORPTION STUDIES: PART II. ULTRAVIOLET ABSORPTION SPECTRA OF SUBSTITUTED BENZOIC ACIDS AND PHENYL BENZOATES

1955 ◽  
Vol 33 (12) ◽  
pp. 1829-1839 ◽  
Author(s):  
W. F. Forbes ◽  
M. B. Sheratte
Keyword(s):  
Absorption Spectra ◽  
Light Absorption ◽  
Ultraviolet Absorption ◽  
Steric Effects ◽  
Benzoic Acids ◽  
Absorption Studies ◽  
Substituted Benzoic Acids ◽  
Electronic And Steric Effects

The spectra of a number of substituted benzoic acids, acetanilides, and phenyl benzoates are discussed in terms of the electronic and steric effects of substituents.

LIGHT ABSORPTION STUDIES: PART XII. ULTRAVIOLET ABSORPTION SPECTRA OF BENZALDEHYDES

1958 ◽  
Vol 36 (10) ◽  
pp. 1362-1370 ◽  
Author(s):  
J. C. Dearden ◽  
W. F. Forbes
Keyword(s):  
Absorption Spectra ◽  
Light Absorption ◽  
Electronic Spectra ◽  
Spectral Properties ◽  
Ultraviolet Absorption ◽  
Benzene Derivatives ◽  
Formyl Group ◽  
Steric Interactions ◽  
Absorption Studies ◽  
Acetyl Group

The electronic spectra of benzaldehydes in the region 220–360 mμ are recorded and discussed in terms of previously stated hypotheses. The formyl group is shown to endow benzene derivatives with spectral properties similar to those of the acetyl group in acetophenones, except that steric interactions are slightly modified.

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.

LIGHT ABSORPTION STUDIES: PART XVIII. THE ULTRAVIOLET ABSORPTION SPECTRA OF BROMOBENZENES

1961 ◽  
Vol 39 (5) ◽  
pp. 1131-1142 ◽  
Author(s):  
W. F. Forbes
Keyword(s):  
Spectral Data ◽  
Absorption Spectra ◽  
Light Absorption ◽  
Bromine Atom ◽  
Ultraviolet Absorption ◽  
Steric Effects ◽  
Benzene Derivative ◽  
Previous Part ◽  
Absorption Studies ◽  
Band Spectra

The ultraviolet absorption spectra of bromobenzene in various solvents, and the spectra of a series of substituted bromobenzenes in cyclohexane solution, are reported. The B-band spectral data confirm the hypotheses postulated for the B-band spectra of chlorobenzenes in the previous part of this series of papers. That is, the bromine atom usually gives rise to greater steric effects than the chlorine atom and the apparent mesomeric interaction as judged from these spectra increases with the size of the halogen substituent.Both bromobenzene and chlorobenzene C-band intensities are unusually small, and this is assumed to account for the frequent C-band similarity between the spectrum of a mono-substituted benzene derivative PhX, where X = OH, OCH3, NH2, and the spectrum of the corresponding chloro- or bromo-substituted PhX derivative.

LIGHT ABSORPTION STUDIES: PART XIV. THE ULTRAVIOLET ABSORPTION SPECTRA OF PHENOLS

1959 ◽  
Vol 37 (8) ◽  
pp. 1294-1304 ◽  
Author(s):  
J. C. Dearden ◽  
W. F. Forbes
Keyword(s):  
Hydrogen Bonding ◽  
Spectral Analysis ◽  
Absorption Spectra ◽  
Excited States ◽  
Light Absorption ◽  
Steric Effects ◽  
Benzene Derivatives ◽  
Substituted Phenols ◽  
Absorption Bands ◽  
Absorption Studies

A spectral analysis of benzene derivatives is extended to substituted phenols. The discussion emphasizes hydrogen bonding and steric effects which occur in phenols. Some of the phenolic absorption bands are ascribed to locally excited states.

LIGHT ABSORPTION STUDIES: PART VI. THE EFFECTIVE INTERFERENCE VALUES OF NON-BONDED ATOMS IN SOLUTION. PART I. SOME PRELIMINARY OBSERVATIONS

1956 ◽  
Vol 34 (11) ◽  
pp. 1542-1552 ◽  
Author(s):  
W. F. Forbes ◽  
W. A. Mueller
Keyword(s):  
Potential Energy ◽  
Light Absorption ◽  
Interatomic Distance ◽  
Neutral Solution ◽  
Absorption Data ◽  
Absorption Studies ◽  
Minimum Interference

The application of light absorption data to determine minimum interference radii of various atoms in solution is examined. Three separate methods are suggested and the relation between potential energy and interatomic distance of two non-bonded atoms is discussed. The values obtained in neutral solution are as follows: H, 0.95 ± 0.1 Å; O (in C=O), 1.0 ± 0.15 Å; and CH3, 1.7 ± 0.2 Å.

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