September 1, 2019 at 8:16 pm

Chemistry Colloquium | Switchable Molecular Tweezers: A Prototype of Molecular Machine to Control Luminescence, Magnetic or Redox Properties, Sept. 16

Guillaume Vives, portrait

Guillaume Vives

Ohio University’s Chemistry and Biochemistry Colloquium Series presents Dr. Guillaume Vives on “Switchable Molecular Tweezers: A Prototype of Molecular Machine to Control Luminescence, Magnetic or Redox Properties,” Monday, Sept. 16, at 4:10 p.m. in Walter Hall 145.

Vives is an Associate Professor in the Department of Chemistry at Sorbonne University.

The host is Dr. Eric Masson.

Abstract: In the field of nanosciences, the control at the molecular level of physical or chemical properties remains an important challenge.1 Designing modular systems for the reversible switching of optical or magnetic properties via a mechanical motion is an innovative approach. Among switchable systems, molecular tweezers2 offer the possibility of a double control of the physical properties due to the successive closing and guest intercalation.

We have developed switchable tweezers based on a terpyridine ligand functionalized in 6 and 6” positions by Metal-salen complexes. The open tweezers adopt a ‘W’ shaped conformation that can be switched to a ‘U’ shaped one by a coordination stimulus bringing into proximity the two functional salen complexes. By using Pt(II) or Cu(II)-salen complexes a drastic modulation of the luminescence3 and magnetic4 properties respectively was achieved demonstrating the versatility of our mechanical switch. More recently, we exploited the modularity of our platform to combine ion triggered mechanical motion with redox activity of Ni(II)-salen complexes. A remarkable six level switch5 was achieved by combining three orthogonal stimuli: i) metal coordination of the terpyridine moiety to open/close the tweezers ii) reversible oxidation of the Ni-salen complexes and iii) guest binding to oxidized Ni-salen coupled to valence-tautomerism. The synthesis of terpy(Ni-salen)2 tweezers and the study of their six-level switch will be highlighted.

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