Coordination compounds optical

Alfred Werner s research on optically active coordination compounds. G. B. Kauffman, Coord. Chem. Rev., 1974,12, 105-149 (376). 

Optically active coordination compounds. S. Kirschner, Prep. Inorg. React., 1964,1,29-57 (140). 

Lamberth, C. Murphy, D. M. Mingos, D. M. P. Second Harmonic Generation Properties of Some Coordination Compounds Based on Pentadionato and Polyene Ligands. In Organic Materials for Nonlinear Optics II Harm, R. A., Bloor, D., Eds. Royal Society of Chemistry London, 1991 pp 183-189. 

In Chapter 16, we described enantiomorphism in coordination compounds. An optically active compound of this type can sometimes be converted into the racemic mixture even in the solid state. In... 

Mason, S. F. Optical Activity and Molecular Dissymmetiy in Coordination Compounds, In Optical Rotatory Dispersion and Circular Dichroism Ciardelli, F. Salvador , P., Eds. Heyden London 1973 pp. 196-239. 

The resolution of optically active coordination compounds, a feat which shook chemistry to its innermost foundations ,72 gained for the coordination theory the widespread recognition for which Werner had been striving for so long. Nor was the theory s founder neglected, for two years later, largely in recognition of the most brilliant confirmation of [his] stereochemical views ,73 Werner was awarded the Nobel Prize in chemistry for 1913.74... 

As noted previously, the classification of stereoisomers preferred by contemporary organic chemists is the enantiomer-diastereomer dichotomy17 and this may be quite conveniently applied to coordination compounds. Thus, complexes (9a) and (9b) are enantiomers, but (9a) and (9c), and (9b) and (9c), are diastereomers. Older terminology might have led to the description of A and B as optical antipodes and to (A+B) and C as geometrical isomers. 

In describing a stereoisomer, it is perhaps most important initially to define whether or not it is chiral. The origins of chirality (optical activity) in coordination compounds and important experimental results have been recently reviewed.112,113,121,122 The classical example of chirality or enantiomerism in coordination chemistry is that of octahedral complexes of the type [M-(bidentate)3]. These exist in the propeller-like,123 non-superimposable, mirror-image forms (13a) and (13b). Synthesis of this type of complex from M and the bidentate ligand in an achiral environment such as water results in an equimolar mixture of the two stereoisomers. The product... 

The precipitation (Section 10.2) and extraction (Section 10.4) of coordination compounds under controlled conditions and their optical characteristics (Section 10.5) have been exploited, together with a miscellany of other procedures, for detecting selectively small traces of elements in very small volumes of a test sample. Such spot reactions have been painstakingly collected, refined and recorded by Fritz Feigl.83... 

It is worth to mention that both coordination compounds, namely [Ca(7)2]DBTA and [Ca(H20)](12)DBTA form conglomerates with their enantiomers, respectively. Thus, optical resolution of racemic DBTA by preferential crystallization of these coordination complexes is also possible. [26, 27]... 

This volume of the Handbook illustrates the rich variety of topics covered by rare earth science. Three chapters are devoted to the description of solid state compounds skutteru-dites (Chapter 211), rare earth-antimony systems (Chapter 212), and rare earth-manganese perovskites (Chapter 214). Two other reviews deal with solid state properties one contribution includes information on existing thermodynamic data of lanthanide trihalides (Chapter 213) while the other one describes optical properties of rare earth compounds under pressure (Chapter 217). Finally, two chapters focus on solution chemistry. The state of the art in unraveling solution structure of lanthanide-containing coordination compounds by paramagnetic nuclear magnetic resonance is outlined in Chapter 215. The potential of time-resolved, laser-induced emission spectroscopy for the analysis of lanthanide and actinide solutions is presented and critically discussed in Chapter 216. 

A tetrahedral platinum atom was not possible in these molecules, since the isomers were not optically active. The direct linking to the metal of the non-metallic groups added in the formation of these supposed molecular compounds was known as coordination and the resulting molecules were coordination compounds. Molecules that we consider coordination compounds today include hemoglobin and chlorophyll, which are vital to animal and plant life. 

The planar square molecular structure turns out to be common among coordination compounds. The other common structure is octahedral, where the metal is at the center of an eight-sided geometric solid with six vertices, formed by joining two square pyramids at their base. For example, a platinum atom can be linked to four chlorine atoms and two molecules of ammonia in this fashion. If the four chlorine atoms are at the corners of the square, and the ammonia molecules at the apexes, then they form one optical isomer. If one of the ammonia molecules and three of the chlorine atoms form the square, and one chlorine atom and one ammonia molecule occupy the apexes, then we have another optical isomer. The two forms are enantiomers of one another ... 

Billing R. Optical and photoinduced electron transfer in ion pairs of coordination compounds. Coord Chem Rev 1997 159 257-70. 

Optical chirality of molecules is a characteristic measure of stereo-chemical property of biological, pharmaceutical, and metal coordination compounds. Choral structures of amino acids, proteins, DNAs, and various drugs in solutions have been determined from the measurement of circular dichroism (CD). However, small amount of molecules at the liquid-liquid interfaces has never been measured before CLM/CD method [19] and SHG/CD method have been reported [20],... 

Solid-state CD can provide information on solute-solvent interactions when compared with the solution spectra in various solvents. The effects of solvents on the rotatory power are often the results of the formation of some kind of coordination compound between the solvent and the optically active molecules concerned in solution [10,18]. This may affect the optical activity of the molecule by way of conformation alteration in the case of flexible compounds, or through vicinal effects. In contrast, in the solid state, molecules are densely packed and are under a much stronger influence of neighboring molecules. In one sense, this situation can be regarded as an extreme case of the solvent effect [11]. Thus an unusual conformation of a chiral molecule that is unstable in solution may be... 

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