Syntheses, structural characterization and photophysical properties of 4-(2-pyridyl)-1,2,3-triazole rhenium(i) complexes

Abstract

Novel chelators, i.e., 4-(2-pyridyl)-1,2,3-triazole derivatives, were synthesized by means of Cu(I)-catalyzed 1,3-dipolar cycloaddition and used to prepare luminescent Re(I) complexes [ReCl(CO)(3)(Bn-pyta)], [ReCl(CO)(3)(AcGlc-pyta)] and [ReCl(CO)(3)(Glc-pyta)] (Bn-pyta = 1-benzyl-4-(2-pyridyl)-1,2,3-triazole, AcGlc-pyta = 2-(4-(2-pyridyl)-1,2,3-triazol-1-yl)ethyl 2,3,4,6-tetra-O-acetyl-beta-d-glucopyranoside, Glc-pyta = 2-(4-(2-pyridyl)-1,2,3-triazol-1-yl)ethyl beta-d-glucopyranoside). X-Ray crystallography of Bn-pyta and Glc-pyta indicated an azocompound-like structure while the 1,2,4-triazole isomer has an azine character. [ReCl(CO)(3)(Bn-pyta)] crystallized in the monoclinic system with space group P2(1)/n. Bn-pyta ligand coordinates with the nitrogen atoms of the 2-pyridyl group and the 3-position of 1,2,3-triazole ring, which is a very similar coordinating fashion to that of the 2,2'-bipyridine derivative. The glucoconjugated Re(I) complexes [ReCl(CO)(3)(AcGlc-pyta)] and [ReCl(CO)(3)(Glc-pyta)] hardly crystallized, and were analyzed by applying extended X-ray absorption fine structure (EXAFS) analysis. The EXAFS analyses suggested that the glucoconjugation at the 1-position of the 1,2,3-triazole makes no influence to the coordinating fashion of 4-(2-pyridyl)-1,2,3-triazole. [ReCl(CO)(3)(Bn-pyta)] showed a blue-shifted maximum absorption (333 nm, 3.97 x 10(3) M(-1) cm(-1)) compared with [ReCl(CO)(3)(bpy)] (371 nm, 3.35 x 10(3) M(-1) cm(-1)). These absorptions were clearly assigned to be the mixed metal-ligand-to-ligand charge transfer (MLLCT) on the basis of time-dependent density functional theory calculation. The luminescence spectrum of [ReCl(CO)(3)(Bn-pyta)] also showed this blue-shifted feature when compared with that of [ReCl(CO)(3)(bpy)]. The luminescence lifetime of [ReCl(CO)(3)(Bn-pyta)] was determined to be 8.90 mus in 2-methyltetrahydrofuran at 77 K, which is longer than that of [ReCl(CO)(3)(bpy)] (3.17 micros). The blue-shifted electronic absorption and elongated luminescence lifetime of [ReCl(CO)(3)(Bn-pyta)] suggested that 4-(2-pyridyl)-1,2,3-triazole functions as an electron-rich bidentate chelator.

Synthesis, Structure and DFT Study of a Rhenium(I) Pyridylpyrazole Complex as a Potential Photocatalyst for CO2 Reduction

“…In addition, the pyridine plane (N1/C4/C5/C6/C7/C8) and the pyrazole plane (N2/N3/C9/C10/C11) were nearly planar with a minor deviation angle of 3.1(3)º due to the restriction upon coordination with Re I . The bond length of Re-Cl and Re-N of the pyridine and pyrazole groups are similar to the corresponding bond lengths in related structures (Obata et al 2008;Seridi et al 2011). Figure 2 with one water molecule held by intramolecular hydrogen bond between O1W atom of water molecule with H7 atom of the pyrazole moiety FIGURE 2.…”

Re(I) carbonyl complexes: Multimodal platforms for inorganic chemical biology

“…bis(phenanthridinylmethyl)amine (bpm) [22,[43][44][45]. However, other polyazaheterocycles have also been developed, such as 1-R-4-(2-pyridyl)-1,2,3-triazole (pyta) and its derivatives [46][47][48]. More recently, Re(I) tricarbonyl complexes incorporating 5,5'-disubstituted 3,3'-bisisoxazole have also been described [49].…”

“…Interestingly, though, Re(I) tricarbonyl complexes bearing a bis-quinoline ligand could be imaged in cells by fluorescence microscopy with excitation at 488 nm [50,51]. [42] pyta (R = Bn) Cl 355 538 0.33 [46] pyta (R = alkyl) Cl 332 522 0.1 [47] quinta Br N. E.…”

Towards Water Soluble Mitochondria-Targeting Theranostic Osmium(II) Triazole-Based Complexes

“…We, and others, have paid particular attention to the use of copper-catalysed coupling of alkynes and azides to form 1,2,3-triazole-based ligands [7][8][9][10] and have investigated the photophysical properties of their resultant complexes. A significant number of reports have appeared detailing the photophysical and photochemical properties of triazole-based complexes of Re(I), Ru(II) and Ir(III) [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Examples of triazole-containing complexes of osmium(II)…”