One-Dimensional Organometallic Materials

This lecture note gives an analysis of electronic structure effects for a new class of molecular solids, i. e. one-dimensional organometal­ lic systems formed by transition-met. l atoms that are embedded in a matrix of macrocyclic organic ligands. These systems as well as orga­ nic metals have focused considerable interest due to the potential formation of high-mobility charge carriers. For the present author it is difficult to participate in this restriction on a single physical property (i. e. high electronic conductivities, technical applications, etc. ). The lecture note is hopefully a small contribution to enhance the general understanding of certain electronic properties in organo­ metallic polymers. Those problems have been considered in the first place that seem to form a theoretical deficit in one specific field of solid-state chemistry. For the reader it will become evident that this contribution is a compromise always guided and limited by boundaries: i) An attempt to present problems to a ·chemical· audience which have their roots in solid-state physics. ii) The model calculations are limited by the currently available computational facilities. This ·boundary· implies that the compu­ tational data a~e subject to severe theoretical approximations. iii) Theorists have often a strong tendency to identify their numeri­ cal results and models with physical effects. Also this lecture note is not free of this almost universal trend. Nevertheless the author hopes that this text leads to some insight into a rather modern research field. M. e. B6hm I.

Contenu

and Historical Review.- References (Introduction).- II. Experimental Results and Global Band Structure Properties.- II.1 One-Dimensional Building Principles in Organometallic Solids and General Band (Electronic) Structure Properties.- II.2 Electric Conductivities of Partially Oxidized Organometallic 1D Systems.- II.3 Electron Paramagnetic Resonance (EPR) Data of Organometallic Solids of Class I.- References (Section II).- III. Theoretical Methods; Crystal Orbital (CO) Approaches.- III.1 A (Semiempirical) Crystal Orbital Formalism.- Appendix III.1.- III.2 Nonlocal Hartree-Fock Exchange in Narrow-Band Materials.- III.3 Electronic Correlations and Relaxations in One-Dimensional (Organometallic) Polymers.- III.4 A Simple Electrostatic Model for Interchain Interactions in Quasi 1D Solids.- References (Section III).- IV. Model Calculations in the Framework of a (Semiempirical) Crystal Orbital Approach.- IV.1 Neighborstrand Interactions in One-Dimensional Tight-Binding Models. The (Tetrathiosquarato)nickel(II) System.- IV.2 Band Structure Properties of One-Dimensional Polydecker Sandwich Systems.- IV.3 Partially Oxidized Transition-Metal Polymers; Stabilization of Mixed Valence States.- IV.4 The Band Structure of One-Dimensional (Tetrazaporphyrinato)Cobalt(II).- IV.5 The Band Structure of the One-Dimensional (Bisglyoximato)Ni(II) System.- IV.6 Band Structures of (Porphyrinato)Ni(II) Systems.- IV.7 The 1D Band Structure of Tetrathiotetracene.- IV. 8 The Band Structure of Polyferrocenylene;.- References (Section IV).- V. Outlook.- Appendix (Abbreviations).