TY - JOUR

T1 - Pd(II)- and Pt(II)-Assisted P-C Activation/Cyclization Reactions with a Luminescent α-Aminophosphine

AU - Afonin, Mikhail Yu

AU - Martynenko, Pavel A.

AU - Kolybalov, Dmitry S.

AU - Khisamov, Radmir M.

AU - Konchenko, Sergey N.

AU - Sukhikh, Taisiya S.

N1 - This research was funded by the Russian Science Foundation (project no. 21-73-10096), https://rscf.ru/project/21-73-10096/.

PY - 2024/1/8

Y1 - 2024/1/8

N2 - There is unceasing interest toward transformations of phosphine derivatives, which are facilitated by transition metals. We report a facile Pd(II)- and Pt(II)-assisted P-C bond cleavage in a luminescent 2-phenylbezothiazole-based α-methylaminophosphine (PCN, 1). Specifically, reactions between 1 and [M(COD)Cl2] (M = Pd, Pt; COD = cycloocta-1,5-diene) in different solvents (methylene chloride, acetonitrile, pyridine, toluene) resulted in the formation of PPh2-, captured either as a bridging ligand in binuclear complexes with a {M2(PPh2)2} moiety or as an adduct to COD in [Pt2(PPh2COD)2Cl2]. The heterocyclic part transforms to annulated c-CN+ species with a 1,2-dihydroquinazoline cycle formed. In the presence of pyridine as a base, annulated form c-CN+ destabilizes and undergoes reverse cyclization transforming to deprotonated CN form. Quantum-chemical density functional theory (DFT) calculations predict that a crucial step in the reactions involves proton transfer from the N atom of the amino group of PCN to a neighboring molecule. A combination of high photophysical sensitivity of c-CN+ toward its immediate environment and rich structural capabilities in assembling (c-CN)22+ pairs in different crystal packings in a family of phases with the general formula (c-CN)2[M2(PPh2)2Cl4] allows one to fine-tune the luminescence properties of the latter. The results were rationalized as a variation of π-π intercationic spacings, which tunes the degree of excited-state charge transfer between c-CN+ cations. As a result, compounds with relatively short interplanar π-π-separation between the cations show a stronger charge-transfer-mediated bathochromic shift.

AB - There is unceasing interest toward transformations of phosphine derivatives, which are facilitated by transition metals. We report a facile Pd(II)- and Pt(II)-assisted P-C bond cleavage in a luminescent 2-phenylbezothiazole-based α-methylaminophosphine (PCN, 1). Specifically, reactions between 1 and [M(COD)Cl2] (M = Pd, Pt; COD = cycloocta-1,5-diene) in different solvents (methylene chloride, acetonitrile, pyridine, toluene) resulted in the formation of PPh2-, captured either as a bridging ligand in binuclear complexes with a {M2(PPh2)2} moiety or as an adduct to COD in [Pt2(PPh2COD)2Cl2]. The heterocyclic part transforms to annulated c-CN+ species with a 1,2-dihydroquinazoline cycle formed. In the presence of pyridine as a base, annulated form c-CN+ destabilizes and undergoes reverse cyclization transforming to deprotonated CN form. Quantum-chemical density functional theory (DFT) calculations predict that a crucial step in the reactions involves proton transfer from the N atom of the amino group of PCN to a neighboring molecule. A combination of high photophysical sensitivity of c-CN+ toward its immediate environment and rich structural capabilities in assembling (c-CN)22+ pairs in different crystal packings in a family of phases with the general formula (c-CN)2[M2(PPh2)2Cl4] allows one to fine-tune the luminescence properties of the latter. The results were rationalized as a variation of π-π intercationic spacings, which tunes the degree of excited-state charge transfer between c-CN+ cations. As a result, compounds with relatively short interplanar π-π-separation between the cations show a stronger charge-transfer-mediated bathochromic shift.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85178569455&origin=inward&txGid=bc78a9ae4ee0f1450ba17131e688bcb6

UR - https://www.mendeley.com/catalogue/fb9b2be0-ae61-32e2-a3e4-189c739c6180/

U2 - 10.1021/acs.inorgchem.3c03271

DO - 10.1021/acs.inorgchem.3c03271

M3 - Article

C2 - 37988741

VL - 63

SP - 369

EP - 380

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 1

ER -