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AbstractThe 4,5-diamine-2,6-dimercaptopyrimidine (DAD) molecule contains an aromatic N-heterocyclic center with two amino and two thiol groups, providing an attractive multifunctional ligand to be explored in coordination chemistry and molecular recognition studies. It reacts with [Ru(bipy)2Cl2] in the presence of air, yielding a [Ru(bipy)2DAD]2+ complex, which converts into the corresponding Ru(II)-diimine form, leaving the pyrimidine N-atoms and thiol groups available for participating in intermolecular association through selective hydrogen bonding. This expectation has been confirmed by resonance Raman spectroscopy in solution and the solid state through the detailed analysis of the vibrational peaks of the Ru(II)-bipy and Ru(II)-DAD chromophores under resonance Raman condition. Accordingly, it was observed that the DAD vibrational profiles are sensitive to molecular interactions in the solid state and the presence of species, such as creatinine, thus expressing a typical molecular recognition behavior. [ABSTRACT FROM AUTHOR]

Nanoporous gold electrodes are of great interest in electroanalytical chemistry, because of their unusual activity and large surface area. The electrochemical activity can be further improved by coating with molecular catalysts such as the tetraruthenated cobalt‐tetrapyridylporphyrazines investigated in this work. The plasmonic enhancement of the scattered light at the nanoholes and borders modifies the electrode's optical characteristics, improving the transmission through the surface‐enhanced Raman scattering (SERS) effect. When monitored by hyperspectral dark‐field and confocal Raman microscopy, this effect allows probing of the porphyrazine species at the plasmonic nanholes, improving the understanding of the chemically modified gold electrodes. [ABSTRACT FROM AUTHOR]