TY - JOUR

T1 - Unusual Reactivity and Photophysical Properties of Platinum(II) Pincer Complexes Containing 6,6'‐Diphenyl‐2,2'‐bipyridine Ligands

AU - Kozina , Daria O.

AU - Shakirova, Julia R.

AU - Galenko, Ekaterina E.

AU - Porsev , Vitaly V.

AU - Gurzhiy, Vladislav V.

AU - Khlebnikov, Alexander F.

AU - Tunik, Sergey P.

N1 - Funding Information: The authors greatly appreciate financial support from the Russian Science Foundarion (grant 19‐73‐20055). The work was carried out using equipment of Centres for Magnetic Resonance, for Chemical Analysis and Materials Research, and The work was carried out using equipment of Magnetic Resonance Research Centre, Centre for Optical and Laser Materials Research, Chemical Analysis and Materials Research Centre, Computer Center SPbU and X‐ray Diffraction Centre (Research Park of St. Petersburg State University).

PY - 2020/10/21

Y1 - 2020/10/21

N2 - A series of novel 6,6'‐diphenyl‐2,2'‐bipyridine ligands modified with the substituents at phenyl and bipyridine moieties have been prepared and used in the synthesis of pincer platinum chloride complexes 1–3, [Pt(NNC–R)Cl], where NNC–R – dimethyl 6,6'‐diphenyl‐[2,2'‐bipyridine]‐5,5'‐dicarboxylate (R = H, (1)), dimethyl 6,6'‐bis(4‐fluorophenyl)‐[2,2'‐bipyridine]‐5,5'‐dicarboxylate (R = F (2)), dimethyl 6,6'‐bis(4‐methoxyphenyl)‐[2,2'‐bipyridine]‐5,5'‐dicarboxylate (R = OMe (3)). Reactions of the obtained compounds with triphenylphosphine proceed through unusual pathway, which gives the [Pt(NNC–R)(PPh3)2Cl] products (1a–3a) containing two phosphine ligands, with the chloride retained in coordination sphere and diphenyl‐bipyridine fragment coordinated in η1‐mode through metalation of a pyridine ring. All complexes have been characterized with mass‐spectrometry and NMR spectroscopy, solid‐state structure of 1–3 and 1a, 3a was revealed by using XRD crystallography. The complexes 1–3 are phosphorescent in dichloromethane solution and in solid state. Their photophysical characteristics were determined and analyzed by DFT calculations, which gave assignment of emissive excited state character with the major contribution from the intraligand charge transfer (3ILCT, Ph→bipyridine) and ligand centered (3LC, bipyridine fragment) transitions.

AB - A series of novel 6,6'‐diphenyl‐2,2'‐bipyridine ligands modified with the substituents at phenyl and bipyridine moieties have been prepared and used in the synthesis of pincer platinum chloride complexes 1–3, [Pt(NNC–R)Cl], where NNC–R – dimethyl 6,6'‐diphenyl‐[2,2'‐bipyridine]‐5,5'‐dicarboxylate (R = H, (1)), dimethyl 6,6'‐bis(4‐fluorophenyl)‐[2,2'‐bipyridine]‐5,5'‐dicarboxylate (R = F (2)), dimethyl 6,6'‐bis(4‐methoxyphenyl)‐[2,2'‐bipyridine]‐5,5'‐dicarboxylate (R = OMe (3)). Reactions of the obtained compounds with triphenylphosphine proceed through unusual pathway, which gives the [Pt(NNC–R)(PPh3)2Cl] products (1a–3a) containing two phosphine ligands, with the chloride retained in coordination sphere and diphenyl‐bipyridine fragment coordinated in η1‐mode through metalation of a pyridine ring. All complexes have been characterized with mass‐spectrometry and NMR spectroscopy, solid‐state structure of 1–3 and 1a, 3a was revealed by using XRD crystallography. The complexes 1–3 are phosphorescent in dichloromethane solution and in solid state. Their photophysical characteristics were determined and analyzed by DFT calculations, which gave assignment of emissive excited state character with the major contribution from the intraligand charge transfer (3ILCT, Ph→bipyridine) and ligand centered (3LC, bipyridine fragment) transitions.

KW - Density functional calculations

KW - Phosphine complexes

KW - Photophysics

KW - Pincer ligands

KW - Platinum

UR - http://www.scopus.com/inward/record.url?scp=85096657557&partnerID=8YFLogxK

U2 - 10.1002/ejic.202000827

DO - 10.1002/ejic.202000827

M3 - Article

JO - Berichte der deutschen chemischen Gesellschaft

JF - Berichte der deutschen chemischen Gesellschaft

SN - 0365-9496

ER -