# Al(ii) transfer harnessing a well-defined cadmium precursor

## TL;DR

This paper explores how a cadmium-based template can control the release and transfer of Al(ii) fragments in chemical reactions.

## Contribution

The study introduces a new method for selective Al(ii) transfer using a covalent Al/Cd framework.

## Key findings

- The trimetallic compound [({N(TMS)2})(Cp*)Al]2Cd selectively transfers Al(ii) fragments through cadmium extrusion.
- Reactivity with radicals, dichalcogenides, and benzophenone derivatives confirms the formation of Al(ii) radicals.
- Nuclearity-dependent reactivity is observed, with a dimeric compound promoting cadmium transfer instead.

## Abstract

Low-valent aluminum chemistry continues to expand the boundaries of main-group reactivity, yet the selective generation and transfer of Al(ii) fragments remain underexplored. Controlled Al(ii) transfer may establish a basis for selective substrate alumination and subsequent functionalization. More broadly, findings in the field offer conceptual guidance for the development of synthetically and potentially catalytically relevant main-group platforms. Here, we now show that heterometals can act as structural templates that tame and direct Al(ii) reactivity within covalent Al/Cd frameworks. The trimetallic compound [({N(TMS)2})(Cp*)Al]2Cd (1tri; Cp* = C5Me5) proved as an excellent candidate, selectively transferring aluminum complex fragments through cadmium extrusion. This reactivity was verified through reactions with free radicals, dichalcogenides, and benzophenone (-derivatives), the latter representing spin-trapped versions of the fleeting Al(ii) radical [({N(TMS)2})(Cp*)Al]˙. In contrast, [{N(TMS)2}(Cp*)Al–Cd{N(TMS)2}] (1bi) retains cadmium and instead promotes cadmium transfer, i.e. to form chalcogenophenolates, underscoring its nuclearity-dependent reactivity. Corroborating these experimental observations, DFT studies provide insight into the formation pathways, electronic structure, and stability of the resulting compounds.

A cadmium template enables controlled Al(ii) release from a trimetallic Al/Cd platform while also supporting Cd-centered transfer when nuclearity shifts.