Tuning the Structural and Photophysical Properties of Cationic Pt(II) Complexes Bearing Neutral Bis(triazolyl)pyridine Ligands

Abstract

The emission properties of a series of cationic Pt(II) complexes bearing neutral tridentate 2,6-bis-(1H-1,2,3-triazol-5-yl)pyridine and monoanionic ancillary ligands (Cl(-) or CN(-)) are described. By varying the substitution pattern on the 1,2,3-triazole moieties of the tridentate luminophore and the nature of the ancillary ligand, we were able to tune the intermolecular interactions between the complexes and therefore the electronic interactions between the metal centers. Indeed, all the compounds possessing Cl(-) as ancillary ligand are nonluminescent at room temperature, while the complexes containing CN(-) are luminescent. Interestingly, the π-accepting nature of this ancillary ligand induces Pt(II)-Pt(II) interactions irrespectively of bulky substitution patterns on the tridentate ligand.

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

“…Complex 1 was prepared by reaction of two equivalents of the ligand btzpy [37,38] with [OsCl6][NH4]2 in refluxing ethylene glycol (Scheme 1). After being left to cool, the complex was isolated as an orange powder, its hexafluorophosphate salt, through treatment with NH4PF6.…”

“…The ligand btzpy [37] and complex 2 [52] were prepared by literature procedures. NMR spectra were recorded on a Bruker Ascend 400 MHz spectrometer (Billerica, MA, USA), with all chemical shifts being quoted in ppm referenced relative to the residual solvent signal (MeCN, 1 H: δ = 1.94, 13 C: 1.32, 118.26; DMSO, 1 H: δ = 2.50, 13 C: 39.52 ).…”

Recent Advances in Phosphorescent Pt(II) Complexes Featuring Metallophilic Interactions: Properties and Applications

“…A series of cationic Pt(II) complexes bearing monoanionic ancillary ligands (either Cl ¹ or CN ¹ ) has been reported by De Cola and co-workers and are displayed in Figure 9. 61 They found that in such derivatives variation of the substitution pattern on either tridentate 1,2,3-triazole moieties and ancillary ligand affects the intermolecular interactions between neighbor complexes and, therefore, the degree of electronic overlap between the platinum centers. Interestingly, all the compounds possessing Cl ¹ as the ancillary ligand were not photoluminescent at room temperature and did not display any self-assembly property; while, the presence of more π-accepting ancillary ligand, such as CN ¹ , induces assembly upon establishment of Pt(II)£Pt(II) interactions and led to emissive Pt aggregates when bulky adamantyl groups were replaced with more planar phenyl moieties ( Figure 9).…”

Control over the Self‐Assembly Modes of PtII Complexes by Alkyl Chain Variation: From Slipped to Parallel π‐Stacks

“…[21][22][23][24][25][26][27][28][29][30] These systems have a strong propensity to aggregate in solution and in the solid state via Pt•••Pt and/or other secondary forces, as recently shown for various classes of complexes in a comprehensive review by Yam and co-workers. 31 Among them, the self-assembly features of hydrophobic Pt(II) complexes with acetylide, [32][33][34][35][36] bidentate, [37][38][39] tridentate N-donor, [40][41][42] and cyclometalating ligands [43][44][45] are relatively well understood. 31 In contrast, their hydrophobic counterparts featuring non-chelating ligands and, in particular, bis(pyridyl) Pt(II) complexes have been limited to liquid crystalline materials [46][47][48] and hydrogen-bonded metallogelators.…”