Platinum(ii) and palladium(ii) complexes with electron-deficient meso-diethoxyphosphorylporphyrins: synthesis, structure and tuning of photophysical properties by varying peripheral substituents

Marina V Volostnykh; Sergey M Borisov; Mikhail A Konovalov; Anna A Sinelshchikova; Yulia G Gorbunova; Aslan Yu Tsivadze; Michel Meyer; Christine Stern; Alla Bessmertnykh-Lemeune

doi:10.1039/c9dt01577a

Platinum(ii) and palladium(ii) complexes with electron-deficient meso-diethoxyphosphorylporphyrins: synthesis, structure and tuning of photophysical properties by varying peripheral substituents

Dalton Trans. 2019 Jun 28;48(24):8882-8898. doi: 10.1039/c9dt01577a. Epub 2019 May 29.

Authors

Marina V Volostnykh¹, Sergey M Borisov², Mikhail A Konovalov³, Anna A Sinelshchikova¹, Yulia G Gorbunova⁴, Aslan Yu Tsivadze⁴, Michel Meyer⁵, Christine Stern⁵, Alla Bessmertnykh-Lemeune⁵

Affiliations

¹ Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr. 31-4, Moscow, 119071, Russia. yulia@igic.ras.ru.
² Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology, Stremayrgasse 9, A-8010 Graz, Austria.
³ Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr. 31-4, Moscow, 119071, Russia. yulia@igic.ras.ru and Chemistry Department, Lomonosov Moscow State University, Leninskie Gory 1/3, Moscow, 119991, Russia.
⁴ Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr. 31-4, Moscow, 119071, Russia. yulia@igic.ras.ru and Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninsky pr. 31, Moscow, 119991, Russia.
⁵ Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR 6302 CNRS, Université Bourgogne Franche-Comté, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex, France.

PMID: 31140507
DOI: 10.1039/c9dt01577a

Abstract

A series of electron-deficient platinum(ii) and palladium(ii) meso-(diethoxyphosphoryl)porphyrins, namely [10-(diethoxyphosphoryl)-5,15-bis(p-tolyl)porphyrinato]palladium(ii) (PdDTolPP), {10-(diethoxyphosphoryl)-5,15-bis[p-(methoxycarbonyl)phenyl]porphyrinato}palladium(ii) [PdD(CMP)PP], [10-(diethoxyphosphoryl)-5,15-dimesitylporphyrinato]palladium(ii) (PdDMesPP), [5-(diethoxyphosphoryl)-10,15,20-trimesitylporphyrinato]palladium(ii) (PdTMesPP) and the corresponding platinum(ii) compounds, were synthesized and structurally characterized in solution by means of ¹H, ¹³C, ³¹P NMR spectroscopies and in the solid state by single crystal X-ray diffraction [PdDTolPP, PdD(CMP)PP and PtD(CMP)PP]. Their optical and photophysical properties (UV-vis absorption, luminescence and excitation spectra, phosphorescence quantum yields and lifetimes) were also determined. The complexes under investigation emit at room temperature in the near-infrared region (670-770 nm). Phosphorescence quantum yields of the palladium(ii) meso-phosphorylated porphyrins lie in the range of 3.4 to 5.8%, with lifetimes of 633 to 858 μs in deoxygenated toluene solutions at room temperature. The corresponding platinum(ii) complexes exhibit phosphorescence quantum yields in the range of 9.2 to 11%, with luminescence decay times of 56 to 69 μs. Moreover, effective homogeneous oxygen quenching and good sensitivity in toluene (∼155 Pa^-1 s^-1) were observed for the platinum(ii) complexes with phosphorylporphyrins in solution. Investigations of the photostability of porphyrinylposphonates and related complexes lacking a phosphoryl group in DMF under irradiation in air using a 400 W vis-NIR lamp demonstrated that photobleaching is strongly dependent on the substituents at the periphery of the macrocycle. Platinum and palladium trimesitylphosphorylporphyrins PdTMesPP and PtTMesPP exhibit high photostability in DMF solution and seem to be the most potentially interesting derivatives of the series for oxygen sensing in biological samples and the covalent immobilization on solid supports to prepare sensing devices including optic fibers.