4,5-Substituted C^C* cyclometalated thiazol-2-ylidene platinum(ii) complexes – synthesis and photophysical properties

Abstract

We report the synthesis of seven novel backbone functionalized N-phenyl-1,3-thiazol-2-ylidene platinum(ii) complexes and their photophysical properties. Electronically diverse N-phenyl-1,3-thiazol-2-thiones were prepared by a reaction of aniline with carbon disulfide and different α-haloketone compounds. Oxidative desulfuration and salt metathesis yielded the desired NHC-precursors with hexafluorophosphate counterions. In addition, a new route for the synthesis of N-phenyl-1,3-benzo[d]thiazole tetrafluoroborate via N-arylation using hypervalent iodine species is presented. All complexes were prepared from the corresponding NHC precursor in a one-pot process using silver(i)oxide, transmetalation to platinum and reaction with the β-diketone acetylacetone under basic conditions. These complexes exhibit strong phosphorescence with quantum yields up to 72% in 2 wt% PMMA films with decay lifetimes of 8.8-12.3 μs. The influence of methyl- and phenyl-groups, and an ester-substituent at the 4- and/or 5-position of the 1,3-thiazole moiety, as well as the N-phenyl-1,3-benzo[d]thiazole-derived motif is discussed. The 4,5-unsubstituted-N-phenyl-1,3-thiazol-2-ylidene platinum(ii) acetylacetonato complex served as a reference in this study to evaluate the electronic effects originating from the backbone substitution. All complexes emit in a narrow range of the bluish-green spectrum of the visible light (510 ± 10 nm).

Retracted Article: Facile preparation of bithiazole-based material for inkjet printed light-emitting electrochemical cell

“…This was on average more than double the uorescence lifetime of the bithiazole starting material. 51 These three samples possess relatively high decay time, as a result of their inhomogeneity. 52 Compound 1c exhibited the longest uorescence lifetime decay s F ¼ 9.54 ns.…”

Synthesis and Photochemical Properties of Re(I) Tricarbonyl Complexes Bound to Thione and Thiazole-2-ylidene Ligands

“…The syntheses of 1 and 2H[PF6] were adapted from previously published works (Scheme 1, see Figures S1-4 for 1 H-NMR and 13 C-NMR spectra). [40][41] The thione complexes Re(1)(CO)3X (X = Cl, Br) were synthesized by reacting the ligand 1 with Re(CO)5X in tetrahydrofuran at reflux under nitrogen and in the dark for 24 h (Scheme 1). The target complexes were isolated by precipitation from dichloromethane solutions with the addition diethyl ether, and obtained in good yields of 76% and 77%, respectively.…”

“…Studies conducted by Strassner et al [40][41] outlined a synthetic pathway to prepare a broad range of N-arylthiazole-2-thiones, which were further reacted to form the corresponding N-arylthiazolium salts. Upon deprotonation, these ligands were bound to Pt(II) in a bidentate fashion, with an acetylacetonato ligand filling the Pt(II) coordination sphere.…”

Synthesis and Photochemical Properties of Re(I) Tricarbonyl Complexes Bound to Thione and Thiazole-2-ylidene Ligands

“…The mechanism of this photochemical transformation was later established by time-resolved IR (TR-IR) studies and computer modelling. [35] The pyridyl-imidazole Re(I) complex was found to react via thermal population of higher lying 3 Studies conducted by Strassner et al [40][41] outlined a synthetic pathway to prepare a broad range of N-arylthiazole-2-thiones, which were further reacted to form the corresponding N-arylthiazolium salts. Upon deprotonation, these ligands were bound to Pt(II) in a bidentate fashion, with an acetylacetonato ligand filling the Pt(II) coordination sphere.…”

“…All the prepared solutions were filtered through a 0.2 μm syringe filter before measurement.Deaerated samples were prepared by the freeze-pump-thaw technique.Experimental uncertainties are estimated to be ±8% for lifetime determinations, ±20% for quantum yields, and ±2 nm and ±5 nm for absorption and emission peaks, respectively. Synthetic Details Ligand 1 was synthesised by a modification of a previously reported procedure Leopold et al[40][41] 2-Aminopyridine (5.0 g, 53.0 mmol) was added to dimethylsulfoxide (20 mL) and the resulting yellow/brown solution stirred for 15 min. Crushed sodium hydroxide (2.0 g, 50.0 mmol) was added, followed by water (5 mL) and the mixture stirred at 50°C for 1 h. The mixture was cooled to 0°C, and carbon disulfide (3.0 mL, 50.0 mmol) was added, forming a blood red solution which was stirred at room temperature for 1 h. The solution was cooled to 0°C and 3-chloro-2-butanone (5.0 mL, 50.0 mmol) was added, the solution turning yellow upon the addition.…”