Planar 2‐Pyridyl‐1,2,3‐triazole Derived Metallo‐ligands: Self‐assembly with PdCl₂ and Photocatalysis

Abstract

Self-assembled metallosupramolecular architectures (MSAs) with built-in functionalities such as light-harvesting metal centers are a promising approach for developing emergent properties within discrete molecular systems. Herein we describe the synthesis of two new but simple "click" ligands featuring a bidentate 2-pyridyl-1,2,3-triazole chelate pocket linked to a monodentate pyridyl (either 3-or 4substituted, L1 and L2) unit. The ligands and the corresponding four Pd II and Pt II metallo-ligands (Pd1, Pd2, Pt1 and Pt2) were synthesized and characterized using nuclear magnetic resonance (NMR) spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and X-ray crystallography. Solid-state characterization of the series of ligands and metallo-ligands revealed that these compounds display a co-planar conformation of all the aryl units. The Pt II containing metallo-ligands (Pt1 and Pt2) were found to assemble into square (Sqr) and triangular (Tri) shaped architectures when combined with neutral PdCl 2 linker units. Additionally, the ability of the Pt II metallo-ligands and Tri to photocatalyze the cycloaddition of singlet oxygen to anthracene was investigated.[a] N.

Heterometallic cages: synthesis and applications

“…111 Heterometallic platinum( ii )–palladium( ii ) MSAs are becoming more common but for the most part the interest has been purely structural. 72,130,131 This Pd–Pt donut was shown to be catalytically active. By taking a ligand containing a 2-pyridyl-1,2,3-triazole component ( L16 ), a bidentate binding pocket was formed allowing for complexation of one platinum( ii ) cation with two ligands in a head to tail fashion around the square planar metal (Scheme 13).…”

On the Coordination Chemistry of Triazolyl‐substituted Diborane Ligands, Prepared by 1,3‐dipolar Cycloaddition Reactions between Diazido‐diboranes and Alkynes

“…The organic rest in the azide ends up as substituent at the triazolyl ring, allowing the facile introduction of substituents for a fine-tuning of the electronic and steric properties. [15][16][17][18][19][20] Moreover, reactions between 2-ethynylpyridine and organic di-or oligo-azides lead to polydentate ligands, in which an organic bridge connects two or more 2-pyridyl-1,2,3-triazolyl groups. [21] Other related multidentate 1,2,3-triazole-containing chelating ligands were synthesized from (functionalized) dialkynes and organic azides.…”

“…Following the established protocols, 2‐pyridyl‐1,2,3‐triazolyl ligands are generally synthesized by CuAAC “click“ reaction between 2‐ethynylpyridine and an organic azide, often prepared in situ e. g. from the organic halide and sodium azide. The organic rest in the azide ends up as substituent at the triazolyl ring, allowing the facile introduction of substituents for a fine‐tuning of the electronic and steric properties [15–20] . Moreover, reactions between 2‐ethynylpyridine and organic di‐ or oligo‐azides lead to polydentate ligands, in which an organic bridge connects two or more 2‐pyridyl‐1,2,3‐triazolyl groups [21] .…”

Fluorinated click-derived tripodal ligands drive spin crossover in both iron(ii) and cobalt(ii) complexes

“…[22][23][24][25][26][27] The tuning of electronic and steric properties of the ligands becomes reasonably straightforward with this modular synthesis. The resulting substituted 1,2,3-triazoles have been extensively used in coordination chemistry as ligands, and the resulting metal complexes have been investigated towards their biological activity [28][29][30][31][32][33][34] as well as for their photochemical, [35][36][37][38] catalytic 36,[39][40][41][42][43][44][45] and electrochemical properties. 35,37,46 The click-derived tripodal ligand tbta (tris[(1-benzyl-1H-1,2,3-triazol-4yl)methyl]amine) (Fig.…”