Journal Article

FZJ-2021-02725

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Investigation of Structural Changes of Cu(I) and Ag(I) Complexes Utilizing a Flexible, Yet Sterically Demanding Multidentate Phosphine Oxide Ligand

Kirst, C. ; Zoller, F. (Corresponding author)FZJ* ; Bräuniger, T. ; Mayer, P. ; Fattakhova-Rohlfing, D.FZJ* ; Karaghiosoff, K.

2021
American Chemical Society Washington, DC

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Please use a persistent id in citations: http://hdl.handle.net/2128/28093  doi:10.1021/acs.inorgchem.0c03334

Abstract: The syntheses of a sterically demanding, multidentate bis(quinaldinyl)phenylphosphine oxide ligand and some Cu(I) and Ag(I) complexes thereof are described. By introducing a methylene group between the quinoline unit and phosphorus, the phosphine oxide ligand gains additional flexibility. This specific ligand design induces not only a versatile coordination chemistry but also a rarely observed and investigated behavior in solution. The flexibility of the birdlike ligand offers the unexpected opportunity of open-wing and closed-wing coordination to the metal. In fact, the determined crystal structures of these complexes show both orientations. Investigations of the ligand in solution show a strong dependency of the chemical shift of the CH2 protons on the solvent used. Variable-temperature, multinuclear NMR spectroscopy was carried out, and an interesting dynamic behavior of the complexes is observed. Due to the introduced flexibility, the quinaldinyl substituents change their arrangements from open-wing to closed-wing upon cooling, while still staying coordinated to the metal. This change in conformation is completely reversible when warming up the sample. Based on 2D NMR spectra measured at −80 °C, an assignment of the signals corresponding to the different arrangements was possible. Additionally, the copper(I) complex shows reversible redox activity in solution. The combination of structural flexibility of a multidentate ligand and the positive redox properties of the resulting complexes comprises key factors for a possible application of such compounds in transition-metal catalysis. Via a reorganization of the ligand, occurring transition states could be stabilized, and selectivity might be enhanced.

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Contributing Institute(s):

1. Werkstoffsynthese und Herstellungsverfahren (IEK-1)

Research Program(s):

1. 1232 - Power-based Fuels and Chemicals (POF4-123) (POF4-123)

Appears in the scientific report 2021

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF < 5 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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