Self-assembled polynuclear complexes of copper with aliphatic diethanolamines: combined experimental and computational study of structures and properties

Massimiliano Ceci

Key information

Authors:

Massimiliano Ceci (Massimiliano Ceci)

Supervisors:

Dmytro Nesterov (Dmytro Nesterov); Riccardo Pettinari

Published in

July 9, 2024

Abstract

Five novel polynuclear coordination compounds are reported, featuring N-tert-butyldiethanolamine (H2tBuDea) as an aminoalcohol along with cyclic and branched aliphatic carboxylate co-ligands, namely dinuclear (1) [Cu2(HtBuDea)2(cy6a)2] (H-cy6a = cyclohexanecarboxylic acid), unprecedented hexanuclear (2 and 3) [Cu6(H2CO3)(tBuDea)4(La)4] (H-La = 3,3-dimethylbutanoic or cyclopropanoic acid, respectively), and decanuclear (4 and 5) [Cu10(OH)2(tBuDea)6(Lb)6] (H-Lb = iso-butyric or 2-ethylbutanoic acid, respectively) compounds. All the compounds were characterized by FTIR, thermogravimetric analysis, and single-crystal X-ray diffraction analysis (SCXRD). DFT and CASSCF/NEVPT2 computational studies were performed towards structures refinement and modelling of their properties. The hexanuclear architectures 2 and 3 feature the entrapment of carbon dioxide upon complex formation, and the studies were aimed at determining the reversibility of CO2 binding. The molecular topology of the structures 4 and 5 is characterized by a novel decanuclear {Cu10(µ3-O)6(µ-O)10} molecular structure type. The specific intermolecular interactions in 5 result in a very large unit cell (a = b = 43.507 Å, c = 12.6687 Å) and large porous cavities in the lattice. The complexes have been tested as catalysts towards oxidation of alkanes under mild conditions using H2O2, tBuOOH and m-CPBA as terminal oxidants (m-CPBA = meta-chloroperoxybenzoic acid).