TY - JOUR

T1 - Luminescent Zn(ii) and Cd(ii) complexes with chiral 2,2′-bipyridine ligands bearing natural monoterpene groups

T2 - synthesis, speciation in solution and photophysics

AU - Kokina, Tatyana E.

AU - Rakhmanova, Marianna I.

AU - Shekhovtsov, Nikita A.

AU - Glinskaya, Ludmila A.

AU - Komarov, Vladislav Y.

AU - Agafontsev, Alexander M.

AU - Baranov, Andrey Y.

AU - Plyusnin, Pavel E.

AU - Sheludyakova, Liliya A.

AU - Tkachev, Alexey V.

AU - Bushuev, Mark B.

PY - 2020/6/14

Y1 - 2020/6/14

N2 - Mononuclear zinc(ii) and cadmium(ii) complexes, ZnLCl2 (1), CdLCl2 (2), ZnL1Cl2·2H2O (3), and CdL1Cl2·2H2O (4), with chiral ligands containing a 2,2'-bipyridine moiety and natural terpene (+)-limonene (L) or (+)-3-carene (L1) moieties were synthesized. In these complexes the L and L1 ligands are shown to coordinate Zn2+ and Cd2+ ions through the 2,2'-bipyridine moiety. The acetamide group of the ligands interacts with M2+ ions by forming NM2+ and C[double bond, length as m-dash]OM2+ contacts and N-HCl hydrogen bonds with coordinated Cl- ions. In solutions the complexes have several conformers differing by the degree of the turn of the acetamide moiety relative to the ligand core and the type of its interaction with the coordination core. The ligands and complexes exhibit luminescence with the quantum yield increasing in the order: ligand < cadmium(ii) complex < zinc(ii) complex. The complexes 3 and 4 demostrate excitation wavelength independent single-channel fluorescence. As opposed to 3 and 4, the complexes 1 and 2 demonstrate excitation wavelength dependent emission with nanosecond and microsecond lifetimes of the excited states. According to our TD-DFT calculations, an interplay of ligand centered and halide to ligand transitions facilitates two deactivation channels in 1 and 2: S1-S0 and T1-S0.

AB - Mononuclear zinc(ii) and cadmium(ii) complexes, ZnLCl2 (1), CdLCl2 (2), ZnL1Cl2·2H2O (3), and CdL1Cl2·2H2O (4), with chiral ligands containing a 2,2'-bipyridine moiety and natural terpene (+)-limonene (L) or (+)-3-carene (L1) moieties were synthesized. In these complexes the L and L1 ligands are shown to coordinate Zn2+ and Cd2+ ions through the 2,2'-bipyridine moiety. The acetamide group of the ligands interacts with M2+ ions by forming NM2+ and C[double bond, length as m-dash]OM2+ contacts and N-HCl hydrogen bonds with coordinated Cl- ions. In solutions the complexes have several conformers differing by the degree of the turn of the acetamide moiety relative to the ligand core and the type of its interaction with the coordination core. The ligands and complexes exhibit luminescence with the quantum yield increasing in the order: ligand < cadmium(ii) complex < zinc(ii) complex. The complexes 3 and 4 demostrate excitation wavelength independent single-channel fluorescence. As opposed to 3 and 4, the complexes 1 and 2 demonstrate excitation wavelength dependent emission with nanosecond and microsecond lifetimes of the excited states. According to our TD-DFT calculations, an interplay of ligand centered and halide to ligand transitions facilitates two deactivation channels in 1 and 2: S1-S0 and T1-S0.

KW - CIRCULARLY-POLARIZED LUMINESCENCE

KW - ROOM-TEMPERATURE PHOSPHORESCENCE

KW - AT-METAL COMPLEXES

KW - COORDINATION POLYMERS

KW - ZINC(II) COMPLEXES

KW - CRYSTAL-STRUCTURE

KW - BUILDING-BLOCKS

KW - BASIS-SETS

KW - DESIGN

KW - PHOTOLUMINESCENCE

UR - http://www.scopus.com/inward/record.url?scp=85086284214&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/997ccee1-3eee-393c-a81e-3ba4713d0dd2/

U2 - 10.1039/d0dt01438a

DO - 10.1039/d0dt01438a

M3 - Article

C2 - 32458904

AN - SCOPUS:85086284214

VL - 49

SP - 7552

EP - 7563

JO - Dalton Transactions

JF - Dalton Transactions

SN - 1477-9226

IS - 22

ER -