Main group transformations

The knowledge base of chemical transformations involving or mediated by transition metal species is vast. However, the corresponding reactivity of compounds derived from the s- and p-block elements is much less studied. Through the 20^th century, concurrent with the increasing maturity of modern analytical methods, seminal works by Wade, Mingos and others afforded insights regarding the unique bonding in ‘electron deficient’ boranes and carboranes, alongside complementary work on electron precise and electron rich cages such as Zintl ions. During this same period, a substantial body of work on inorganic rings, chains, polymers and ceramics emerged while applications of main group materials such as siloxanes and boron nitride were also developed. Nonetheless, the comparative paucity of knowledge regarding reactivity led to the generally accepted folklore that the main group elements were chemically less versatile than their d-block counterparts. However, in the last two decades, a number of advancements has inspired a renaissance in main group chemistry that has dispelled the above dogma.

In recent years, a diverse array of developments and applications of main group compounds and materials have emerged in fields ranging from catalysis to molecular electronics. In quintessential examples of the scientific method, these advances have evolved from a fundamental understanding of the chemistry of low oxidation state and/or low coordinate compounds, Lewis-acid/Lewis-base reactivity, main group heterocycles, free radicals and bonding in main group compounds. The increasing focus on chemical transformations and thus the utility of main group species can be traced to several key findings over the past two decades. Certainly the studies by Power that illustrated that heavier main group elements behave like transition metals was a crucial realisation in small molecule activation. Similarly, the seminal work of Piers on borane mediated hydrosilylation, a decade before the articulation of the concept of frustrated Lewis pair chemistry, foreshadowed the broader emergence of main group species in catalysis.

This themed issue on main group transformations comprises a collection of contributions from some of the leading researchers covering both fundamental and applications-driven research. Included in the volume is a perspective article in addition to several communications and a series of full articles. These manuscripts cover a broad range of chemistry demonstrating a diversity of chemical transformations of main group compounds involving group II to group VI derivatives. Collectively these papers illustrate a broad range of developments and applications of the chemistry of s- and p-block illustrating new strategies to stabilise unusual main group derivatives, new reactivity and offering a new understanding. Other works report the utility of main group species in the activation of small molecules, stoichiometric transformations and catalysis while other contributions are aimed at applications in materials chemistry.

The diverse contributions in this themed issue are further evidence of the renaissance of main group chemistry that is currently on-going. From this breadth of chemistry, it is clear that this field is rapidly evolving and leading to innovation. Clearly it is an exciting time to be a main group chemist!

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