Schwamm Ryan J, Bhide Malavika A, Nichol Gary S, Cowley Michael J
School of Chemistry, The University of Edinburgh Joseph Black Building, David Brewster Road Edinburgh EH9 3FJ UK
Chem Sci. 2025 Apr 15. doi: 10.1039/d4sc06894g.
Reversible interactions of organic substrates with transition metal compounds are a hallmark of their chemistry and its catalytic applications, but remain uncommon for low-valent p-block compounds. We report here the preparation of amidophosphine-supported gallium(i) compounds that exhibit equilibria between monomeric gallylene and dimeric digallene (Ga[double bond, length as m-dash]Ga) states. The monomer-dimer equilibrium is controlled by the steric and electronic properties of the phosphine donor in the ligand employed. Regardless of their preference for monomeric or dimeric state, reactions of the Ga(i) systems with B(CF) affords monomeric gallylene adducts, whilst reactions with ethene produce 1,2-digallacyclobutanes formal [2 + 2] cycloadditions. These ethene additions are reversible, with the digallacyclobutanes releasing ethene upon heating or treatment with Lewis acids to regenerate the gallium(i) species.
有机底物与过渡金属化合物之间的可逆相互作用是其化学性质及其催化应用的一个标志，但对于低价p族化合物来说仍然不常见。我们在此报告了膦酰胺支持的镓（I）化合物的制备，这些化合物在单体镓烯和二聚双镓烯（Ga=Ga）状态之间表现出平衡。单体-二聚体平衡由所用配体中膦供体的空间和电子性质控制。无论它们对单体或二聚体状态的偏好如何，Ga（I）体系与B（CF）的反应都会生成单体镓烯加合物，而与乙烯的反应则会产生1,2-二镓环丁烷——形式上的[2+2]环加成反应。这些乙烯加成反应是可逆的，二镓环丁烷在加热或用路易斯酸处理时会释放乙烯，以再生镓（I）物种。
