Pyridyl functional groups ligands

Heteroaryl groups are present in the 4-pyridyl-ethynyl compounds81,99,100 and their extended variants with C=C-C6H4-C=C-pyr-4 ligands.81,99 These compounds can be quaternized with Mel or coordinated to a metal complex at their terminal pyridyl functions to give species addressed as molecular rods or molecular wires.81,99 Similar reactions were carried out with 3-phenanthrolinyl-ethynyl complexes,62 and special examples are also known with R based on calixarenes.51... 

Nafion was rendered electroactive by cation exchange of a redox centre. Other polymers such as poly-4-vinylpyridine (PVP) may be protonated or quaternized to provide the possibility of introducing a redox anion such as [IrCl6]3- or [Fe(CN)6]3-.50 51 Alternatively, the pendant pyridyl groups on the neutral polymer may function as ligands and species such as [Ru(bipy)J2+ may be polymer bound. 

Work by the group of David Reinhoudt (Twente, Netherlands) has resulted in perhaps the only truly reversible, metal-coordination based dendrimer assembly strategy. Starting with the dendron core 14.4 Reinhoudt s group removed the chloride ligands with AgBp4 and coordinated the pyridyl functionality of... 

Ruthenium phthalocyanine 49 (R = -H, M = Ru(II)) monolayers were obtained by self-assembly on pyridyl-functionalized SiOa or AI2O3 substrates by coordination between Ru and the pyridino group to obtain 63 [155]. The pyridino-functionalized metal oxides were dipped into a solution containing the more soluble benzonitrile derivative of the phthalocyanine RuPc(NC-C6H5)2, and ligand exchange reactions led to 63. Strategies have been described to immobilize a second layer of a Ru-phthalocyanine or a Co tetraphenyl-porphyrin. 

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