Structural Elucidation, Aggregation, and Dynamic Behaviour of N, N, N, N‐Copper(I) Schiff Base Complexes in Solid and in Solution: A Combined NMR, X‐ray Spectroscopic and Crystallographic Investigation. Issue 46 (29th October 2021)

• Record Type: Journal Article
• Authors: Gerz, Isabelle; Jannuzzi, Sergio Augusto Venturinelli; Hylland, Knut T.; Negri, Chiara; Wragg, David S.; Øien‐Ødegaard, Sigurd; Tilset, Mats; Olsbye, Unni; DeBeer, Serena; Amedjkouh, Mohamed
• Is Part Of: European journal of inorganic chemistry. Issue 46(2021)
• Page Start: 4762
• Page End: 4775
• Publication Date: 2021-10-29
• Subjects: Aggregation -- Copper -- NMR spectroscopy -- X-ray absorption spectroscopy -- X-ray emission spectroscopy; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.202100722
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract: A series of Cu(I) complexes of bidentate or tetradentate Schiff base ligands bearing either 1‐ H ‐imidazole or pyridine moieties were synthesized. The complexes were studied by a combination of NMR and X‐ray spectroscopic techniques. The differences between the imidazole‐ and pyridine‐based ligands were examined by 1 H, 13 C and 15 N NMR spectroscopy. The magnitude of the 15 Nimine coordination shifts was found to be strongly affected by the nature of the heterocycle in the complexes. These trends showed good correlation with the obtained Cu−Nimine bond lengths from single‐crystal X‐ray diffraction measurements. Variable‐temperature NMR experiments, in combination with diffusion ordered spectroscopy (DOSY) revealed that one of the complexes underwent a temperature‐dependent interconversion between a monomer, a dimer and a higher aggregate. The complexes bearing tetradentate imidazole ligands were further studied using Cu K‐edge XAS and VtC XES, where DFT‐assisted assignment of spectral features suggested that these complexes may form polynuclear oligomers in solid state. Additionally, the Cu(II) analogue of one of the complexes was incorporated into a metal‐organic framework (MOF) as a way to obtain discrete, mononuclear complexes in the solid state. Abstract : A series of N, N, N, N Cu(I) Schiff base complexes was studied by NMR and X‐ray spectroscopic techniques. In solution, the aggregation behaviour was investigated by DOSY and variable‐temperature NMR. 15 N NMR studies shed light on the Cu−N interactions in the complexes. XAS and XES, supported by DFT calculations, highlighted the complexes' tendencies to form polynuclear species in the solid state.