Experimental realization of catalytic CH_4 hydroxylation predicted for an iridium NNC pincer complex, demonstrating thermal, protic, and oxidant stability

A discrete, air, protic, and thermally stable (NNC)Ir(III) pincer complex was synthesized that catalytically activates the CH bond of methane in trifluoroacetic acid; functionalization using NaIO_4 and KIO_3 gives the oxy-ester

Benzene C−H Bond Activation in Carboxylic Acids Catalyzed by O-Donor Iridium(III) Complexes: An Experimental and Density Functional Study

The mechanism of benzene C−H bond activation by [Ir(μ-acac-O,O,C^3)(acac-O,O)(OAc)]_2 (4) and [Ir(μ-acac-O,O,C^3)(acac-O,O)(TFA)]_2 (5) complexes (acac = acetylacetonato, OAc = acetate, and TFA = trifluoroacetate) was studied experimentally and theoretically. Hydrogen−deuterium (H/D) exchange between benzene and CD_(3)COOD solvent catalyzed by 4 (ΔH^‡ = 28.3 ± 1.1 kcal/mol, ΔS^‡ = 3.9 ± 3.0 cal K^(−1) mol^(−1)) results in a monotonic increase of all benzene isotopologues, suggesting that once benzene coordinates to the iridium center, there are multiple H/D exchange events prior to benzene dissociation. B3LYP density functional theory (DFT) calculations reveal that this benzene isotopologue pattern is due to a rate-determining step that involves acetate ligand dissociation and benzene coordination, which is then followed by heterolytic C−H bond cleavage to generate an iridium-phenyl intermediate. A synthesized iridium-phenyl intermediate was also shown to be competent for H/D exchange, giving similar rates to the proposed catalytic systems. This mechanism nicely explains why hydroarylation between benzene and alkenes is suppressed in the presence of acetic acid when catalyzed by [Ir(μ-acac-O,O,C^3)(acac-O,O)(acac-C^3)]_2 (3) (Matsumoto et al. J. Am. Chem. Soc. 2000, 122, 7414). Benzene H/D exchange in CF_(3)COOD solvent catalyzed by 5 (ΔH^‡ = 15.3 ± 3.5 kcal/mol, ΔS^‡ = −30.0 ± 5.1 cal K^(−1) mol^(−1)) results in significantly elevated H/D exchange rates and the formation of only a single benzene isotopologue, (C_(6)H_(5)D). DFT calculations show that this is due to a change in the rate-determining step. Now equilibrium between coordinated and uncoordinated benzene precedes a single rate-determining heterolytic C−H bond cleavage step

Hybrid Performance of Sorghum Parental Lines Developed by Mass Selection and S1 Yield Testing

Experiments were conducted co obtain information on the effects of two methods of developing parental lines from a random-mating population of sorghum (Sorghum bicolor L. Moench) on hybrid performance. Gridded mass selection for threshed panicle weight was used in developing IAP1R(M)C3: and a sister population, IAP4R(S1)C3, was advanced each cycle on the basis of grain yield of S1 families in replicated yield trials. Hybrids with male parents developed by mass selection did not differ significantly for grain yield and panicles/plant from those with parents chosen on the basis of S1 yield tests. The S1-selection hybrids were significantly (P ≤0.01 or P ≤0.05) shorter and later to bloom, had smaller seed and more seeds/panicle, but the differences usually were small and of little practical consequence. Estimates of generic variance, heritability, and expected gain from selection among hybrids developed with mass or S1 selected male parents were similar for grain yield and most other characters. Collectively, the results of our experiments indicated that developing sorghum parental lines by using mass selection for panicle weight or replicated S1 yield tests should be equally effective

Dao, harmony and personhood: towards a Confucian ethics of technology

A closer look at the theories and questions in philosophy of technology and ethics of technology shows the absence and marginality of non-Western philosophical traditions in the discussions. Although, increasingly, some philosophers have sought to introduce non-Western philosophical traditions into the debates, there are few systematic attempts to construct and articulate general accounts of ethics and technology based on other philosophical traditions. This situation is understandable, for the questions of modern sciences and technologies appear to be originated from the West; at the same time, the situation is undesirable. The overall aim of this paper, therefore, is to introduce an alternative account of ethics of technology based on the Confucian tradition. In doing so, it is hoped that the current paper can initiate a relatively uncharted field in philosophy of technology and ethics of technology

Using online blogs to explore positive outcomes after burn injuries

This study uses blog analysis, a new and novel technique, to explore the positive outcomes experienced by burn survivors. This study examined 10 burn survivor blogs to offer a unique, longitudinal insight into burn survivor recovery. Using thematic analysis, three themes emerged: shift in self-perception, enhanced relationships and a change in life outlook. Many of these themes contained stories and experiences unique to a traumatic burn injury, suggesting that standardised trauma scales are not effectively measuring the impact of a burn in this population. Reflections on blog analysis are discussed, along with a recommendation that health researchers utilise the vast amount of data available from online blogs