Theoretical Probe to the Mechanism of Pt-Catalyzed C-H Acylation Reaction: Possible Pathways for the Acylation Reaction of a Platinacycle.

Density functional theory (DFT) and nudged elastic band (NEB) theory have been used to study the possible pathways for the acylation of cycloplatinated complex A derived from 2-phenoxypyridine, which is conceived as the key step in the platinum-catalyzed acylation of 2-aryloxypyridines. Geometry optimization indicates that the previously proposed intermediate, an arenium ion species as a result of analogous aromatic substitution, is not an energy minimum, but rather cationic Pt-arene η2-complex E is obtained as a stable intermediate. NEB simulations suggest that the minimum energy pathway for the acylation reaction has energy barrier of 33.6 kcal/mol and consists of the following steps: (1) Nucleophilic substitution at acetyl chloride by the platinum of the reactant A forms five-coordinate Pt(IV) acylplatinum complex B with an energy barrier of 21.7 kcal/mol. (2) B undergoes 1,2-acyl migration from the platinum to the cyclometalated carbon through a three-membered platinacycle transition state to give Pt-arene η2-complex E with an energy barrier of 14.0 kcal/mol. (3) E undergoes ligand exchange with chloride to form neutral Pt-arene η2-complex F. (4) F undergoes ligand substitution with acetonitrile to give the product and the energy barrier is small (10.6 kcal/mol). The rate-determining step is the 1,2-acyl migration step. It is interesting to note that intermediate F was not included in the proposed mechanism but was identified by the NEB simulations. Five-coordinate Pt(IV) acylplatinum complex B undergoes barrierless ligand coordination with chloride to form neutral formal oxidative addition acylplatinum complex D; however, D is less stable than reactant A by 2.9 kcal/mol, which also implies that the isolation of an oxidative addition product Pt(IV) complex may be very challenging. The direct reductive elimination of D to form product P has a higher energy barrier (36.6 kcal/mol).

Absence of age effects on spontaneous past and future thinking in daily life.

Previous research on voluntary mental time travel (i.e., deliberately thinking about the past or future) has resulted in negative age effects. In contrast, studies on spontaneous past thoughts (i.e., involuntary autobiographical memories) have reported small or no age effects. The aim of the present research was to investigate the effects of age on the nature and frequency of spontaneous future thoughts in everyday life. In two studies, we examined whether older adults reported spontaneous future thoughts as often as younger adults, and whether these thoughts were predominantly goal-oriented and less dependent on incidental cues than thoughts about the past. In Study 1, young and old participants kept a diary of spontaneous thoughts of upcoming prospective memory tasks and involuntary autobiographical memories for 2 weeks. In Study 2, a 1-day experience sampling method was used to investigate spontaneous and deliberate task-unrelated future and past thoughts, by having young and old participants complete a questionnaire in response to 30 random signals. In both studies, no age effects were found in the frequency of spontaneous future thoughts, which were reported as frequently as thoughts about the past (Study 2) and referred predominantly to upcoming tasks and goals rather than future events or hypothetical events (Study 2). Results concerning the triggers of reported thoughts provide initial support for the idea that representations of future thoughts may be more activated than memories of past events. Taken together, these results have important implications for research on cognitive ageing, mind-wandering, prospective memory and involuntary autobiographical memories.

A nurse-driven system for improving patient quality outcomes.

Improvements in nursing care are dependent on key decision makers receiving ongoing and reliable information about outcomes as well as the support of clinical care providers in making change. This article describes the work of one hospital to develop a reporting tool and provides examples of how timely and appropriate reporting of data, combined with a staff-driven improvement process, has resulted in positive nursing and patient outcomes. Recommendations for future improvements in the system and applications to other hospitals are provided.