We show how to improve the yield of MeX from CH 4 activation catalysts from 12% to 90% through the use of "capping arene" ligands. Four (FP)Rh III (Me)(TFA) 2 {FP = "capping arene" ligands, including 8,8′-(1,2-phenylene)diquinoline (6-FP), 8,8′-(1,2naphthalene)diquinoline (6-NP FP), 1,2-bis(N-7-azaindolyl)benzene (5-FP), and 1,2-bis(N-7-azaindolyl)naphthalene (5-NP FP)} complexes. These complexes and (dpe)Rh III (Me)(TFA) 2 (dpe = 1,2-di-2-pyridylethane) were synthesized and tested for their performance in reductive elimination of MeX (X = TFA or halide). The FP ligands were used with the goal of blocking a coordination site to destabilize the Rh III complexes and facilitate MeX reductive elimination. On the basis of single-crystal X-ray diffraction studies, the 6-FP and 6-NP FP ligated Rh complexes have Rh−arene distances shorter than those of the 5-FP and 5-NP FP Rh complexes; thus, it is expected that the Rh−arene interactions are weaker for the 5-FP complexes than for the 6-FP complexes. Consistent with our hypothesis, the 5-FP and 5-NP FP Rh III complexes demonstrate improved performance (from 12% to ∼60% yield) in the reductive elimination of MeX. The reductive elimination of MeX from (FP)Rh III (Me)(TFA) 2 can be further improved by the use of chemical oxidants. For example, the addition of 2 equiv of AgOTf leads to 87(2)% yield of MeTFA and can be achieved in CD 3 CN at 90 °C using (5-FP)Rh(Me)(TFA) 2 .

We report the dimerization and oligomerization of ethylene using bis(phosphino)boryl supported Ni(II) complexes as catalyst precursors. By using alkylaluminum(III) compounds or other Lewis acid additives, Ni(II) complexes of the type ( R PBP)NiBr (R = tBu or Ph) show activity for the production of butenes and higher olefins. Optimized turnover frequencies of 640 mol ethylene •mol Ni −1 •s −1 for the formation of butenes with 41(1)% selectivity for 1butene using ( Ph PBP)NiBr, and 68 mol ethylene •mol Ni −1 •s −1 for butenes production with 87.2(3)% selectivity for 1-butene using ( tBu PBP)NiBr, have been demonstrated. With methylaluminoxane as a co-catalyst and ( tBu PBP)NiBr as the precatalyst, ethylene oligomerization to form C 4 through C 20 products was achieved, while the use of ( Ph PBP)NiBr as the pre-catalyst retained selectivity for C 4 products. Our studies suggest that the ethylene dimerization is not initiated by Ni hydride or alkyl intermediates. Rather, our studies point to a mechanism that involves a cooperative B/Ni activation of ethylene to form a key 6-membered borametallacycle intermediate. Thus, a cooperative activation of ethylene by the Ni−B unit of the ( R PBP)Ni catalysts is proposed as a key element of the Ni catalysis.

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In this laboratory experiment, students evaluated three silver­(I) complexes as potential additives for dental adhesives based on bacterial growth inhibition, heat stability, water insolubility, and cost-effectiveness. Each student prepared and analyzed a cyanoxime ligand and its corresponding silver­(I) complex. Students characterized the antibacterial activity of the silver complexes against E. coli using a Kirby–Bauer disk-diffusion test. Laboratory data were shared among students to compare observed properties to determine which derivative is the most suitable. This multiweek experiment was used in inorganic chemistry laboratory courses to demonstrate the application of inorganic chemistry to biomedicine. The framework of the experiment was developed by a multi-institutional collaboration, and we highlight how the general procedures of the experiment were adapted to meet the needs of varying courses and contexts.