Katerina A. Vinogradova

Hexanuclear Na(I) complex with 3,5-dimethyl-1 H -pyrazole and its anion

The crystal structure of a hexanuclear Na(I) complex based on 3,5-dimethyl-1H-pyrazole (C5H8N2) and its anion is determined (space group P21/c, a = 12.2194(5) Å, b = 24.1554(9) Å, c = 11.3311(4) Å, β = 109.942(1)°, V = 3143.99(8) Å3, Z = 2). The crystal structure is formed by Na6(C5H8N2)4(C5H7N2)6 molecules. Thermogravimetric studies show that the compound exhibits volatility at elevated temperatures. The compound can be used in chemical gas-phase deposition processes.

Excitation-Wavelength-Dependent Emission and Delayed Fluorescence in a Proton-Transfer System

Manipulating the relaxation pathways of excited states and understanding mechanisms of photochemical reactions present important challenges in chemistry. Here we report a unique zinc(II) complex exhibiting unprecedented interplay between the excitation-wavelength-dependent emission, thermally activated delayed fluorescence (TADF) and excited state intramolecular proton transfer (ESIPT). The ESIPT process in the complex is favoured by a short intramolecular OH⋅⋅⋅N hydrogen bond. Synergy between the excitation-wavelength-dependent emission and ESIPT arises due to heavy zinc atom favouring intersystem crossing (isc). Reverse intersystem crossing (risc) and TADF are favoured by a narrow singlet-triplet gap, ΔEST ≈10 kJ mol-1 . These results provide the first insight into how a proton-transfer system can be modified to show a synergy between the excitation-wavelength-dependent emission, ESIPT and TADF. This strategy offers new perspectives for designing ESIPT and TADF emitters exhibiting tunable excitation-wavelength-dependent luminescence.

CCDC 802635: Experimental Crystal Structure Determination

Related Article: M.B.Bushuev, K.A.Vinogradova, V.P.Krivopalov, E.B.Nikolaenkova, N.V.Pervukhina, D.Yu.Naumov, M.I.Rakhmanova, E.M.Uskov, L.A.Sheludyakova, A.V.Alekseev, S.V.Larionov|2011|Inorg.Chim.Acta|371|88|doi:10.1016/j.ica.2011.03.007