Structural diversity of dimethylgallium naphthalene-2,3-dicarboxylate/pyridine systems

Abstract

Group 13 organometallic complexes are versatile building blocks of supramolecular architectures, offering wide structural and functional diversity. While organoaluminum systems have been extensively explored as nodes or chiral metalloligands in the construction of coordination frameworks, their heavier congeners remain far less investigated. Herein, we examined the reactivity of a new macrocyclic organogallium derivative of 2,3-naphthalenedicarboxylic acid (naphtha-H₂), [(Me₂Ga)₂(naphtha)]₂ (1), toward selected mono-and bifunctional pyridine Lewis bases, as well as the chiral metalloligand [Me₂Al(CN)]₂ (where CN = deprotonated cinchonine). The results show that, in the presence of neutral Lewis bases, the macrocyclic structure of the parent complex 1 undergoes cleavage accompanied by rearrangement into various four-coordinate pyridine adducts, which, in the case of 4,4′-bipyridine (bipy), leads to the formation of a new 1D coordination polymer [(Me₂Ga)₂(naphtha)(bipy)]_n. Moreover, we show that the reaction of 1 with the chiral organoaluminum N,N′-ditopic metalloligand [Me₂Al(CN)]₂ proceeds via an intriguing transalkylation pathway, affording an original complex [(MeAl)₂(naphtha)(CN)₂(GaMe₃)₂]. Together with our previous studies on the organoaluminum analogue of 1, this work provides new insight into how the nature of the Group 13 metal center governs Lewis acidity of organometallic complexes and their reactivity toward N,N′-ditopic linkers.