3313phate diester anions. The comparisons between our experimental results and the results of both sets of calculations are not as direct as we should like.The theoretical calculations of Collin and of Boyd were carried out with model compounds which are not the same as any in our series but several in each set bear a strong resemblance to ones in our present set. We conclude from our experimental results that Boyd's set of calculations6 is more valid than the other with the regard to the net charge on the phosphoryl oxygen.We are more satisfied that our previous explanation* of the inversion of the values of KL for the methyl-and ethylpiperidinium cations in the case of the oxygen-containing ligands is a correct one in view of the excellent correlation of the values of the ratios KL(Et)/KL(Me) and VPO. Vapor pressures, viscosities, densities, surface tensions, heat of mixing, and molar refractivities of watertetramethylurea mixtures were measured at temperatures from 25 to 85'. The data show that the tri-to pentahydrates are the most stable water-tetramethylurea species formed.

The triruthenium oxo clusters [Ru3(OAc)6O(L)3]+ and [Ru3(OAc)6O(L)2(CO)] possess unique electronic characteristics that vary based on the ligands L. Here we report an investigation of the structural, electrochemical, and optical properties of clusters with imidazole, benzimidazole, and 4‐phenylpyridine ligands. The complexes [Ru3(OAc)6O(L)3]+ [1+: L = imidazole (im); 2+: L = benzimidazole (benzim); 3+: L = 4‐phenylpyridine (4PP)] and [Ru3(OAc)6O(L)2(CO)] (1‐CO and 3‐CO) were synthesized by reaction of either [Ru3(OAc)6O(MeOH)3]+ or [Ru3(OAc)6O(MeOH)2(CO)], respectively, with the corresponding heterocycle. We further discovered that [3]OAc could be reduced to the mixed‐valence neutral state 3 by refluxing the complex under nitrogen in methanol. Single‐crystal X‐ray structure analysis of hexa‐μ2‐acetato‐μ3‐oxido‐tris(1H‐imidazole)triruthenium hexafluorophosphate acetonitrile hemisolvate, [Ru3(C2H3O2)6O(C3H4N2)3]PF6·0.5CH3CN, [1]PF6, hexa‐μ2‐acetato‐carbonylbis(1H‐imidazole)‐μ3‐oxido‐triruthenium methanol monosolvate, [Ru3(C2H3O2)6O(C3H4N2)(CO)]·CH3OH, 1‐CO, hexa‐μ2‐acetato‐μ3‐oxido‐tris(4‐phenylpyridine)triruthenium pentahydrate, [Ru3(C2H3O2)6O(C11H9N)3]·5H2O, 3, and hexa‐μ2‐acetato‐carbonyl‐μ3‐oxido‐bis(4‐phenylpyridine)triruthenium methanol monosolvate, [Ru3(C2H3O2)6O(C11H9N)2(CO)]·CH3OH, 3‐CO, show the expected triruthenium μ3‐oxo core and N‐coordination of the ligands. Cyclic voltammetry revealed quasi‐reversible and irreversible redox couples in [1]PF6, 1‐CO, and [2]PF6, while [3]PF6 and 3‐CO exhibit reversible redox couples. The optical properties of these richly colored species were investigated using UV–Vis spectroscopy.

In 2000, the National Institutes of Health initiated the Protein Structure Initiative as a multi‐center structural biology program with “an initial goal to make the three‐dimensional, atomic‐level structures of most proteins easily obtainable from knowledge of their corresponding DNA sequences.” The third and final phase of this program concluded in 2015 with the publication and distribution of more than 5000 previously uncharacterized proteins.The work described here leverages the availability of high‐quality structures and pre‐cloned expression plasmids to combine forces of undergraduate biochemistry teaching lab courses across a diverse range of participating institutions. This consortium of undergraduate biochemistry faculty and students seeks to identify functional properties of a subset of these uncharacterized proteins, seeking to unify structure□ and □function relationships. Through structural and bioinformatics tools, an number of these proteins were characterized as putative hydrolases due to similarity to known hydrolase enzymes. Some appeared, by sequence homology, to possess features indicative of more specifically identifiable activity, such as halogenases and nucleases. Students in the current biochemistry laboratory class at Hope College have expressed and purified seven of these proteins, finding that structural information can guide, although not predict entirely, functional predictions regarding substrate specificity.Support or Funding InformationThis work was funded in part with support from the National Science Foundation IUSE program.

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