A1 Journal article – refereed
Oligophosphine-thiocyanate Copper(I) and Silver(I) Complexes and Their Borane Derivatives Showing Delayed Fluorescence

List of Authors: Chakkaradhari G., Eskelinen T., Degbe C., Belyaev A., Melnikov A.S., Grachova E.V., Tunik S.P., Hirva P., Koshevoy I.O.
Publication year: 2019
Journal: Inorganic Chemistry
Journal name in source: INORGANIC CHEMISTRY
Journal acronym: INORG CHEM
Volume number: 58
Issue number: 6
Number of pages: 15
ISSN: 0020-1669

The series of chelating phosphine ligands, which contain bidentate P-2 (bis[(2-diphenylphosphino)-phenyl] ether, DPEphos; 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene, Xantphos; 1,2-bis(diphenylphosphino)benzene, dppb), tridentate P-3 (bis(2 diphenylphosphinophenyl)phenylphosphine), and tetradentate P4 (tris(2-diphenylphosphino)phenylphosphine) ligands, was used for the preparation of the corresponding dinuclear [M(mu(2)-SCN)P-2](2) (M = Cu, 1, 3, 5; M = Ag, 2, 4, 6) and mononuclear [CuNCS(P-3/P-4)] (7, 9) and [AgSCN(P-3/P-4)] (8, 10) complexes. The reactions of P4 with silver salts in a 1:2 molar ratio produce tetranuclear clusters [Ag-2(3-SCN)(tSCN)(P-4)](2) (11) and [Ag-2(mu(3)-SCN)(P-4)](2)(2+) (12). Complexes 7-11 bearing terminally coordinated SCN ligands were efficiently converted into derivatives 13-17 with the weakly coordinating-SCN:B(C6F5)(3) isothiocyanatoborate ligand. Compounds 1 and 5-17 exhibit thermally activated delayed fluorescence (TADF) behavior in the solid state. The excited states of thiocyanate species are dominated by the ligand to ligand SCN 2r(phosphine) charge transfer transitions mixed with a variable contribution of MLCT. The boronation of SCN groups changes the nature of both the S1 and T, states to (L + M)LCT d,p(M, P) + ir(phosphine). The localization of the excited states on the aromatic systems of the phosphine ligands determines a wide range of luminescence energies achieved for the title complexes (.1,, varies from 448 nm for 1 to 630 nm for 10c). The emission of compounds 10 and 15, based on the P4 ligand, strongly depends on the solid-state packing (A,, = 50S and 625 nm for two crystalline forms of 15), which affects structural reorganizations accompanying the formation of electronically excited states.

Last updated on 2019-25-04 at 13:05