The formation of complexes between electron donors and acceptors has long been recognized a s an important phenomenon. Many of themolecular complexes are colored and give rise to new absorption bands in the electronic spectra. These molecular complexes have been investigated by employing a variety of physical methods such as optical spectroscopy, magnetic resonance spectroscopy, calorimetry, dielectric measurements, and X-ray diffraction. Studies of donor-acceptor complexes are of value in understanding various types of reaction mechanisms, including molecular phenomena in biological systems. Some of the relatively recent developments in the study of molecular complexes are: the classification of donors and acceptors by Mulliken [l], vibrational spectroscopy, particularly in the very-low-frequency region [2,3], estimation of the per cent charge transfer by dipole moment measurements [4–6], studies of weak interactions (contact pairs) [7], spectra and thermodynamics of complexes in vapor phase [8,...

Spectroscopy of electron donor-acceptor systems

Determination of trace amounts of copper and zinc in edible fats and oils by acid extraction and atomic absorption spectrophotometry.

Amines are alkyl or aryl derivatives of ammonia and exhibit alkaline reactions in many solvents. Therefore, in the past years, amines have mainly been determined by acid base titrations in aqueous and nonaqueous solutions. Some colorimetric methods are available in the literature for the determination of amino compounds (1-4). Copper sulfate has been used for the determination of ethylenediamine (5). Colorimetric determination of small amounts of aromatic amines by diazotization was reported by Kuritsyn et al. (6). A photometric method for the determination of small amounts of aniline has also been reported (7). DeAtley reported a method for the determination of diphenylamine and its mono nitro derivatives by oxidation with iron(III) in sulfuric acid solution. All these spectrophotometric methods suffer from two limitations: they are less sensitive and cannot be applied for all types of amines. We have, therefore, decided to find a sensitive method for the determination of aliphatic as well as aromatic primary, secondary, and tertiary amines. Small amounts of the amino compounds react with acetyl chloride and ferric ion to produce a greenish violet colored complex. The use of this reaction for the determination of amines is described in this report.

Sensitive method for spectrophotometric determination of amines

Neue Farbreaktionen auf Sulfhydrylgruppen

The relation between the position of the charge transfer band of molecular complexes formed by p-chloranil with benzene derivatives and ionization potentials of the donor molecule was analyzed. Electronic absorption spectra of p-chloranil complexes with donor molecules possessing degenerate molecular orbitals were examined. Unlike complexes with other acceptors, such as 1,3,5-trinitrobenzene and 1,3-dinitrobenzenea, molecular complexes of p-chloranil with analogous donors were classed within a single group.

P.H. Gore

Papers

A spectrophotometric study of the colour reaction between chloranil and aromatic amines