Volume 85, Issue 11 p. 2518-2527
Full Paper

Targeted Synthesis of NIR Luminescent Rhenium Diimine cis,trans-[Re(urn:x-wiley:21926506:media:cplu202000597:cplu202000597-math-0001 )(CO)2(L)2]n+ Complexes Containing N-Donor Axial Ligands: Photophysical, Electrochemical, and Theoretical Studies

Dr. J. R. Shakirova

Dr. J. R. Shakirova

Department of Chemistry, St. Petersburg State University, Universitetskii pr. 26, 198504 St. Petersburg, Russia

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S. Nayeri

S. Nayeri

Department of Chemistry, Sharif University of Technology, P.O. Box, 11155-3516 Tehran, Iran

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S. Jamali

S. Jamali

Department of Chemistry, Sharif University of Technology, P.O. Box, 11155-3516 Tehran, Iran

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Dr. Vitaly V. Porsev

Dr. Vitaly V. Porsev

Department of Chemistry, St. Petersburg State University, Universitetskii pr. 26, 198504 St. Petersburg, Russia

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Dr. Vladislav V. Gurzhiy

Dr. Vladislav V. Gurzhiy

Department of Chemistry, St. Petersburg State University, Universitetskii pr. 26, 198504 St. Petersburg, Russia

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Oleg V. Levin

Oleg V. Levin

Department of Chemistry, St. Petersburg State University, Universitetskii pr. 26, 198504 St. Petersburg, Russia

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Prof. I. O. Koshevoy

Prof. I. O. Koshevoy

Department of Chemistry, University of Eastern Finland, 80101 Joensuu, Finland

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Prof. S. P. Tunik

Corresponding Author

Prof. S. P. Tunik

Department of Chemistry, St. Petersburg State University, Universitetskii pr. 26, 198504 St. Petersburg, Russia

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First published: 09 November 2020
Citations: 7

Graphical Abstract

NIR out of the microwave: A series of NIR-emitting rhenium diimine complexes, [Re(NN)(CO)2(L)2]+(L=NCMe, aromatic N-donor ligands) have been synthesized by activating standard precursors with UV irradiation and microwave heating. The obtained chromophores display strong absorption in the visible area of the electronic spectrum and NIR emission with emission wavelengths ranging from 711 to 800 nm. DFT calculations showed dominant contribution of the 3MLCT (dπ(Re)→π*(urn:x-wiley:21926506:media:cplu202000597:cplu202000597-math-0007 )) character to the emissive excited state.

Abstract

The combined action of ultraviolet irradiation and microwave heating onto acetonitrile solution of [Re(urn:x-wiley:21926506:media:cplu202000597:cplu202000597-math-0002 )(CO)3(NCMe)]OTf (urn:x-wiley:21926506:media:cplu202000597:cplu202000597-math-0003 =phenantroline and neocuproine) afforded cis,trans-Re(urn:x-wiley:21926506:media:cplu202000597:cplu202000597-math-0004 )(CO)2(NCMe)2]+ acetonitrile derivatives. Substitution of relatively labile NCMe with a series of aromatic N-donor ligands (pyridine, pyrazine, 4,4’-bipyridine, N-methyl-4,4’-bipyridine) gave a novel family of the diimine cis,trans-[Re(urn:x-wiley:21926506:media:cplu202000597:cplu202000597-math-0005 )(CO)2(L)2]+ complexes. Photophysical studies of the obtained compounds in solution revealed unusually high absorption across the visible region and NIR phosphorescence with emission band maxima ranging from 711 to 805 nm. The nature of emissive excited states was studied using DFT calculations to show dominant contribution of 3MLCT (dπ(Re)→π*(urn:x-wiley:21926506:media:cplu202000597:cplu202000597-math-0006 )) character. Electrochemical (CV and DPV) studies of the monocationic diimine complexes revealed one reduction and one oxidation wave assigned to reduction of the diimine moiety and oxidation of the rhenium center, respectively.

Conflict of interest

The authors declare no conflict of interest.