Chemical and physical properties of triangular bridged metal complexes

Powder synthesis from metal-organic precursors.

Organometallic Chemistry of the Lanthanides

The oxidation state of iridium ions in an oxide film grown electrochemically on an Ir metal reflector electrode in aqueous 0.5M H2SO4 electrolyte can be rapidly and reversibly modulated by voltage pulses of 1 V amplitude according to the reaction: Ir(OH)n(transparent) ⇄IrOx(OH)n−x(colored)+xH++xe. This valency interconversion produces a marked change in light absorption throughout the visible wavelength region and occurs without change in film thickness. Color‐bleach cycles exhibit reflectance contrast changes, ΔR/R, and charging times, τ, suitable for electrochromic display devices, e.g., for a film 700 A thick: ΔR/R=60% at λ=546 nm and τ≈40 msec. The fast write‐erase times are made possible by the highly porous and hydrated nature of the oxide film. The charge (∼20 mC cm−2) and energy (∼20 mJ cm−2) are comparable with those for other electrochromic oxide systems, e.g., the tungsten bronzes. Advantages of the iridium oxide system include: (i) fast response; (ii) stability of the colored written state in ...

Electrochromism in anodic iridium oxide films

A brief account of the methods generally employed for the synthesis of metal alkoxides has been presented. Successful elucidation of the structural features of simple alkoxides on the basis of a coordination model involving alkoxy bridges has prompted a detailed study of a variety of bimetallic alkoxides during the last two decades followed by the extension of the work to a novel series of ter- and tetra-metallic alkoxides during the last two years. Most of these polymetallic alkoxides (including derivatives of strongly electropositive alkali, alkaline earth metals and lanthanons) are stable to heat and can be volatilized unchanged. After listing the typical properties and reactions of these alkoxy derivatives, their hydrolytic reactions are briefly discussed. The uses of metallic alkoxides for ceramic materials and the potential applications of bimetallic alkoxides in this direction are discussed.

J. D. E. McIntyre

Papers

Mixed valence in the trimeric oxo- and nitridoiridium sulfates