Inorganic Molecular Dissymmetry

ISBN-13: 9783642671838 / Angielski / Miękka / 2012 / 170 str.

Yoshihiko Saito

Opis

As early as 1874 van't Hoff and Le Bel introduced the concept of antipodes for molecules containing an asymmetric carbon atom. This was the first insight into the spacial arrangement of atoms in a mole- cule. These antipodes exhibit opposite optical rotatory power, but it was not possible to determine specific configuration and direction of the rotatory power. The convention of Fischer, however, gained general acceptance. Eighty years later Bijvoet and his co-workers showed that the Fischer convention happens to be in agreement with reality (I 951). Organic stereochemistry is that of tetrahedral carbon atoms, while stereochemistry of co-ordination compounds mainly concerns octahedrally co-ordinated metal atoms. The stereochemistry of octa- hedrons was founded by Werner. In his magnum opus, Neuere Anschauungen auf dem Gebiete der anorganischen Chemie, are sum- marised his highlights on optical isomerism, beginning with the third edition published in 1913. After about forty years, the author and his co-workers determined the absolute configuration of the tris( ethyl- enediamine )cobaJt(III) ion. Thus an absolute basis was given to dis- cuss the-optical activity and molecular structure of co-ordination compounds. This book deals with the absolute stereochemistry of transition- metal complexes, the charge-density distribution in them and their circular dichroism spectra. The book is directed to students of inor- ganic chemistry and to others seeking a general impression of the recent advances in the field.

Spis treści

I Introduction.- 1 Preamble.- 2 Symmetry.- 3 Isomerism.- 4 Designation of the Absolute Configuration.- 5 Abbreviation of the Ligands.- II X-Ray Diffraction.- 1 Introduction.- 2 Space Lattice.- 3 Symmetry of Crystal Lattices: Space Groups.- 4 Diffraction of X-Rays, Bragg’s Equation.- 5 The Geometrical Structure Factor.- 6 Electron-Density.- 7 Thermal Vibration.- 8 Experimental Procedure.- 9 Process of Crystal Structure Determination.- 10 Neutron Diffraction.- 11 An Example: X-Ray and Neutron Diffraction of (—)589-tris (R-propylenediamine)cobalt(III) Bromide.- 12 Anomalous Scattering.- 13 The Forced, Damped Oscillations of an Electron.- 14 Direct Consequences of Anomalous Scattering.- 15 Complete Expressions for Friedel’s Rule and its Breakdown by Anomalous Scattering.- 16 The Use of Internal Reference Centre.- 17 Neutron Anomalous Scattering.- Appendix II-1.- III Conformational Analysis.- 1 Introduction.- 2 Conformational Energy of a Complex.- A. Bond Stretching Potential.- B. Potential Energy for Bond Angle Distortion.- C. Torsional Potential.- D. Non-Bonded Interactions.- E. Electrostatic Interactions.- 3 Computational Methods for Conformational Analysis.- 4 Geometrical Molecular Models.- 5 Conclusion.- IV Structure and Isomerism of Optically Active Complexes.- 1 Bidentates.- A. Four-Membered Chelate Rings.- B. Five-Membered Chelate Rings.- C. Six-Membered Chelate Rings.- D. Seven-Membered Chelate Rings.- 2 Terdentates.- 3 Quadridentates.- 4 Quinquedentates.- 5 Sexidentates.- V Electron-Density Distribution in Transition Metal Complexes.- 1 Introduction.- 2 Earlier Work.- 3 Charge-Density Distribution in Transition-Metal Complexes: Preamble.- 4 Charge-Density Distribution in Transition-Metal Complexes.- A. [Co(NH3)6][Co(CN)6].- B. [Co(NH3)6] [Cr(CN)6].- C. Asphericity of d-Electron Distribution in [Co(NH3)6][Co(CN)6]and[Co(NH3)6][Cr(CN)6]..- D. K2Na[Co(NO2)6].- E. Charge Distribution in Spinels.- F. Charge Density Distribution in D3 Complexes.- 5 Conclusions.- VI Circular Dichroism.- 1 General Introduction.- 2 Interaction of Light with a Medium Containing Optically Inactive Molecules.- 3 Interaction of Light with a Medium Containing Optically Active Molecules.- 4 Quantum Theories.- 5 Experimental Device; Dichrometer.- 6 Optical Activity of Transition-Metal Complexes.- 7 Circular Dichroism Spectra of tris-Bidentate Complexes.- A. Solution Circular Dichroism.- B. Tests for the Theoretical Models.- C. Solid State Circular Dichroism of tris-Diamine Cobalt(III) Complexes.- D. Calculation of Rotatory Strengths of tris-Bidentate Cobalt(III) Complexes.- 8 Circular Dichroism Spectra of cis-bis-Bidentate Complexes.- 9 Sector Rules and the Circular Dichroism Spectra of Multi dentate Complexes.- A. Sector Rules.- B. Circular Dichroism of Multidentate Complexes.- 10 Conclusion.- Appendix VI-1.- References.