Development of a Student Lab Experiment: 1H NMR Characterization and Synthesis of Substituted 2,2’-Bipyridines

This paper describes an undergraduate research project focused on the creation of a laboratory experiment that crosses the fields of green, biomimetic, inorganic, organic, and organometallic chemistry. Research involved investigation of the synthesis and NMR characterization of a series of Water oxidation catalysts for providing a rich learning experience for students. A goal of this project was to consider the implementation of a greener student laboratory where learning outcomes across multiple years of undergraduate laboratories could be proposed. The experimental progress and results to date will be presented

Modular Construction of Photoanodes with Covalently Bonded Ru- and Ir-Polypyridyl Visible Light Chromophores

1,10-phenanthroline is grafted to indium tin oxide (ITO) and titanium dioxide nanoparticle (TiO₂) semiconductors by electroreduction of 5-diazo-1,10-phenanthroline in 0.1 M H₂SO₄. The lower and upper potential limits (−0.20 and 0.15 V_SCE, respectively) were set to avoid reduction and oxidation of the 1,10-phenanthroline (phen) covalently grafted at C5 to the semiconductor. The resulting semiconductor-phen ligand (ITO-phen or TiO₂-phen) was air stable, and was bonded to Ru- or Ir- by reaction with <i>cis-</i>[Ru­(bpy)₂(CH₃CN)₂]²⁺ (bpy = 2,2′-bipyridine) or <i>cis</i>-[Ir­(ppy)₂(CH₃CN)₂]⁺ (ppy = <i>ortho</i>-C_phenyl metalated 2-phenylpyridine) in CH₂Cl₂ and THF solvent at 50 °C. Cyclic voltammetry, X-ray photoelectron spectroscopy, solid-state UV–vis, and inductively coupled plasma–mass spectrometry all confirmed that the chromophores SC-[(phen)­Ru­(bpy)₂]²⁺ and SC-[(phen)­Ir­(ppy)₂]⁺ (SC = ITO or TiO₂) formed in near quantitative yields by these reactions. The resulting photoanodes were active and relatively stable to photoelectrochemical oxidation of hydroquinone and triethylamine under neutral and basic conditions