Title

Dinuclear Rhenium Complexes with a Bridging Helicene-bis-bipyridine Ligand: Synthesis, Structure, and Photophysical and Chiroptical Properties

Publication Date

11-1-2020

Document Type

Article

Department

Chemistry

Publication Title

ChemPlusChem

Volume

85

Issue

11

DOI

10.1002/cplu.202000559

First Page

2446

Last Page

2454

Abstract

By attaching pyridine groups to a diaza[6]helicene, a helical, bis-ditopic, bis-N N-coordinating ligand can be accessed. Dinuclear rhenium complexes featuring this bridging ligand, of the form [{Re(CO)3Cl}2(N N−N N)], have been prepared and resolved to give enantiopure complexes. These complexes are phosphorescent in solution at room temperature under one- and two-photon excitation. Their experimental chiroptical properties (optical rotation, electronic circular dichroism and circularly polarized emission) have been measured. They show, for instance, emission dissymmetry factors of c.a. ±3x10−3. Quantum-chemical calculations indicate the importance of stereochemistry on the optical activity, pointing towards further design improvements in such types of complexes.

Funding Number

859752 – HEL4CHIROLED – H2020‐MSCA‐ITN‐2019

Funding Sponsor

National Science Foundation

Keywords

circularly polarized luminescence, helicenes, N ligands, rhenium, two-photon absorption

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