Mechanosensitive metal–ligand bonds in the design of new coordination compounds

• Published in: CrystEngComm Vol. 13; no. 13; pp. 4314 - 4323
• Main Authors: Uzarevic, Krunoslav, Rubcic, Mirta, Radic, Maja, Puskaric, Andreas, Cindric, Marina
• Format: Journal Article
• Language: English
• Published: 01.01.2011
• Subjects: Alcohols; Cleavage; Colour; Coordination compounds; Heating; Ligands; Unsaturated
• ISSN: 1466-8033; 1466-8033
• DOI: 10.1039/c0ce00807a

This article describes the selective cleavage of coordination bonds by mechanochemical methods and the further application of the thus obtained precursors for a facile preparation of new coordination compounds. In the class of dioxomolybdenum(vi) coordination compounds, [MoO2L(ROH)], where L stands for a tridentate dianionic ONO ligand and ROH represents different alcohol molecules, mechanical treatment induces an exclusive cleavage of the molybdenum-alcohol bond, which can thus be considered as a mechanosensitive bond. Alcohol removal can also be accomplished by heating. Both grinding and heating resulted in highly reactive, coordinatively unsaturated compounds, an orange amorphous pentacoordinated [MoO2L] (I) and the brown polymeric [MoO2L]n ((I)n), respectively. Even though both I and (I)n are stable at room temperature, they can be interconverted using only solvent-free techniques, a conversion followed by a colour change of the sample. The tendency of such unsaturated complexes to complete their coordination spheres was exploited for the efficient solution and solvent-free syntheses of octahedral molybdenum complexes with selected O- and N-donating ligands. Both approaches herein used, solution and solvent-free, have proved to be superior under specific conditions and their respective advantages and weaknesses are discussed.