Alan Herbert Cowley. 29 January 1934—2 August 2020

Alan Cowley was one of the most creative main group chemists of his generation, and had a central role in what was often described as the renaissance of main group chemistry. Throughout his career Alan always had an eye for what was new. In his early years as an independent researcher, Alan made many fundamental contributions to the chemistry of phosphorus, not only in terms of the synthesis of new compounds but also in their study by employing novel analytical and computational methods. Starting in the 1980s he was at the forefront of emerging research into low-coordinate phosphorus chemistry and made seminal contributions in the areas of multiply bonded species, such as phosphenium ions and diphosphenes, as well as in the transition metal coordination chemistry of phosphinidenes. In the second half of his career, Alan also turned his attention to the study of single source precursors for important solid-state electronic materials, many of which were far superior to known examples. In all of the many areas in which Alan worked, he was a great collaborator with colleagues and researchers across the world, both in chemistry and in other disciplines. This was made all the easier by Alan's charm and easy-going nature, which was also manifest in the interactions he had with his many group members over a period of almost half a century. Alan was a gentleman in every sense and is much missed by friends, colleagues, collaborators and family.

Optimization of a Range-Separated UW12 Hybrid Functional

In a previous paper we presented a new hybrid functional B-LYP-osUW12-D3(BJ) containing the Unsöld-w12 (UW12) hybrid correlation model. In this paper we present a new 15-parameter range-separated hybrid density functional using a power series expansion together with UW12 correlation. This functional is optimised using the survival of the fittest strategy developed for the ωB97X-V functional, fitted to data from the Main Group Chemistry Database (MGCDB84). In addition we optimize a standard hybrid and double hybrid using the same method. We show that our fully self-consistent UW12 hybrid functional WM21-D3(BJ) outperforms both of these functionals and other range-separated hybrid functionals.

Size-control in the synthesis of oxo-bridged phosphazane macrocycles via a modular addition approach

Inorganic macrocycles remain largely underdeveloped compared with their organic counterparts due to the challenges involved in their synthesis. Among them, cyclodiphosphazane macrocycles have shown to be promising candidates for supramolecular chemistry applications due to their ability to encapsulate small molecules or ions within their cavities. However, further developments have been handicapped by the lack of synthetic routes to high-order cyclodiphosphazane macrocycles. Moreover, current approaches allow little control over the size of the macrocycles formed. Here we report the synthesis of high-order oxygen-bridged phosphazane macrocycles via a “3 + n cyclisation” (n = 1 and 3). Using this method, an all-PIII high-order hexameric cyclodiphosphazane macrocycle was isolated, displaying a larger macrocyclic cavity than comparable organic crown-ethers. Our approach demonstrates that increasing building block complexity enables precise control over macrocycle size, which will not only generate future developments in both the phosphazane and main group chemistry but also in the fields of supramolecular chemistry.

Minding our P-block and Q-bands: Synthetic Progress and inroads into main group aspects of corroles and suggestions for fulfilling their potential

Main group chemistry is often considered less “dynamic” than transition metal (TM) chemistry because of predictable VSEPR-based central atom geometries, relatively slower redox switching and lack of electronic d-d transitions....

A Prelude to Biogermylene Chemistry

<p><b>Abstract:</b> The biological applications of germylenes remain an unconceivable domain owing to their unstable nature. We report the isolation of air, water, and culture-medium stable germylene DPMGeOH (<b>3</b>) and its potential biological application (DPM = dipyrromethene ligand). Compound <b>3 </b>exhibits antiproliferative effects comparable to that of cisplatin in human cancer cells. The cytotoxicity of compound <b>3 </b>on normal epithelial cells is minimal and is similar to that of the currently used anti-cancer drugs. These findings provide a framework for a plethora of biological studies using germylenes and have important implications for low-valent main group chemistry.</p>

A Prelude to Biogermylene Chemistry

<p><b>Abstract:</b> The biological applications of germylenes remain an unconceivable domain owing to their unstable nature. We report the isolation of air, water, and culture-medium stable germylene DPMGeOH (<b>3</b>) and its potential biological application (DPM = dipyrromethene ligand). Compound <b>3 </b>exhibits antiproliferative effects comparable to that of cisplatin in human cancer cells. The cytotoxicity of compound <b>3 </b>on normal epithelial cells is minimal and is similar to that of the currently used anti-cancer drugs. These findings provide a framework for a plethora of biological studies using germylenes and have important implications for low-valent main group chemistry.</p>