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arXiv · 2511.03513

Group 13 Metals as L-Type Ligands for Transition Metals

Abstract

Low-valent Group 13 fragments can serve as neutral two-electron L-type metalloligands to transition-metal (TM) centers, enabling heterometallic M-TM platforms with bonding and reactivity patterns distinct from classical CO, phosphine, and carbene ligation. This chapter develops a unifying, descriptor-based view of aluminylene Al(I), gallylene Ga(I), and indylene In(I) donors, and contrasts them with the limited L-type behavior of Tl(I). We map synthetic gateways to isolable M(I) donors, analyze their sigma-donation/pi-acceptance profiles, and extract periodic design rules in which the sigma-donor strength decreases Al > Ga > In, whereas Tl(I) has not yet been convincingly shown to engage in neutral L-type Tl->TM coordination. Borderline cases that blur L-, X-, and Z-type classifications are also examined to clarify descriptors and guide consistent usage across the series. This contribution links ligand sterics/electronics, ambiphilicity at M(I), and the chosen TM fragment to guide the rational design of M-TM platforms that harness Group-13 M(I) donors for small-molecule activation and cooperative catalysis.

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Hellen Videa, M. Angeles Fuentes, Antonio J. Martinez-Martinez. 2025-11-05. Group 13 Metals as L-Type Ligands for Transition Metals. https://doi.org/10.1007/430_2026_105

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