The increased analgesic efficacy of cold therapy after an unsuccessful analgesic experience is associated with inferior parietal lobule activation.

Prior experiences of successful and failed treatments are known to influence the efficacy of a newly applied treatment. However, whether that carry-over effect applies to non-pharmacological treatments is unknown. This study investigated how a failed treatment history with placebo analgesic cream affected the therapeutic outcomes of cold-pack treatment. The neural correlates underlying those effects were also explored using functional magnetic resonance imaging. The effect of the placebo analgesic cream was induced using placebo conditioning with small (44.5 °C to 43.7 °C, negative experience) and large (44.5 °C to 40.0 °C, positive experience) thermal stimuli changes. After the placebo conditioning, brain responses and self-reported evaluations of the effect of subsequent treatment with a cold-pack were contrasted between the two groups. The negative experience group reported less pain and lower anxiety scores in the cold-pack condition than the positive experience group and exhibited significantly greater activation in the right inferior parietal lobule (IPL), which is known to be involved in pain relief. These findings suggest that an unsatisfying experience with an initial pain-relief treatment could increase the expectations for the complementary treatment outcome and improve the analgesic effect of the subsequent treatment. The IPL could be associated with this expectation-induced pain relief process.

Naphthocrown-strapped calix[4]pyrroles: formation of self-assembled structures by ion-pair recognition.

A new approach to the construction of self-assembled structures is reported that is based on ion-pair recognition. Towards this end, the calix[4]pyrrole naphthocrown-4 hybrid structures 2 and 3 were prepared. These multitopic receptors contain recognition sites for both anions and cations. On the basis of solution-phase (1) H NMR spectroscopic analysis and solid-state single-crystal X-ray diffraction structural studies, it was established that receptors 2 and 3 are able to bind specific ion pairs with high selectivity via different binding modes. In the case of CsF and CsCl, the ion-pair complexes formed from receptors 2 and 3 were found to self-assemble to produce either linear supramolecular polymeric crystalline solids or nanotube-like cyclic hexamers depending on the specific choice of ion pairs and crystallization solvents. Proton NMR studies provided evidence for solution-phase self-association in organic media.

Remarkable solvent, porphyrin ligand, and substrate effects on participation of multiple active oxidants in manganese(III) porphyrin catalyzed oxidation reactions.

The participation of multiple active oxidants generated from the reactions of two manganese(III) porphyrin complexes containing electron-withdrawing and -donating substituents with peroxyphenylacetic acid (PPAA) as a mechanistic probe was studied by carrying out catalytic oxidations of cyclohexene, 1-octene, and ethylbenzene in various solvent systems, namely, toluene, CH(2) Cl(2) , CH(3) CN, and H(2) O/CH(3) CN (1:4). With an increase in the concentration of the easy-to-oxidize substrate cyclohexene in the presence of [(TMP)MnCl] (1a) with electron-donating substituents, the ratio of heterolysis to homolysis increased gradually in all solvent systems, suggesting that [(TMP)Mn-OOC(O)R] species 2a is the major active species. When the substrate was changed from the easy-to-oxidize one (cyclohexene) to difficult-to-oxidize ones (1-octene and ethylbenzene), the ratio of heterolysis to homolysis increased a little or did not change. [(F(20) TPP)Mn-OOC(O)R] species 2b generated from the reaction of [(F(20) TPP)MnCl] (1b) with electron-withdrawing substituents and PPAA also gradually becomes involved in olefin epoxidation (although to a much lesser degree than with [(TMP)Mn-OOR] 2a) depending on the concentration of the easy-to-oxidize substrate cyclohexene in all aprotic solvent systems except for CH(3) CN, whereas Mn(V)=O species is the major active oxidant in the protic solvent system. With difficult-to-oxidize substrates, the ratio of heterolysis to homolysis did not vary except for 1-octene in toluene, indicating that a Mn(V)=O intermediate generated from the heterolytic cleavage of 2b becomes a major reactive species. We also studied the competitive epoxidations of cis-2-octene and trans-2-octene with two manganese(III) porphyrin complexes by meta-chloroperbenzoic acid (MCPBA) in various solvents under catalytic reaction conditions. The ratios of cis- to trans-2-octene oxide formed in the reactions of MCPBA varied depending on the substrate concentration, further supporting the contention that the reactions of manganese porphyrin complexes with peracids generate multiple reactive oxidizing intermediates.

Terminal and internal olefin epoxidation with cobalt(II) as the catalyst: evidence for an active oxidant Co(II)-acylperoxo species.

A simple catalytic system that uses commercially available cobalt(II) perchlorate as the catalyst and 3-chloroperoxybenzoic acid as the oxidant was found to be very effective in the epoxidation of a variety of olefins with high product selectivity under mild experimental conditions. More challenging targets such as terminal aliphatic olefins were also efficiently and selectively oxidized to the corresponding epoxides. This catalytic system features a nearly nonradical-type and highly stereospecific epoxidation of aliphatic olefin, fast conversion, and high yields. Olefin epoxidation by this catalytic system is proposed to involve a new reactive Co(II)-OOC(O)R species, based on evidence from H(2)(18)O-exchange experiments, the use of peroxyphenylacetic acid as a mechanistic probe, reactivity and Hammett studies, EPR, and ESI-mass spectrometric investigation. However, the O-O bond of a Co(II)-acylperoxo intermediate (Co(II)-OOC(O)R) was found to be cleaved both heterolytically and homolytically if there is no substrate.

Amide-based nonheme cobalt(III) olefin epoxidation catalyst: partition of multiple active oxidants Co(V)=O, Co(IV)=O, and Co(III)-OO(O)CR.

A mononuclear nonheme cobalt(III) complex of a tetradentate ligand containing two deprotonated amide moieties, [Co(bpc)Cl(2)][Et(4)N] (1; H(2)bpc = 4,5-dichloro-1,2-bis(2-pyridine-2-carboxamido)benzene), was prepared and then characterized by elemental analysis, IR, UV/Vis, and EPR spectroscopy, and X-ray crystallography. This nonheme Co(III) complex catalyzes olefin epoxidation upon treatment with meta-chloroperbenzoic acid. It is proposed that complex 1 shows partitioning between the heterolytic and homolytic cleavage of an O-O bond to afford Co(V)=O (3) and Co(IV)=O (4) intermediates, proposed to be responsible for the stereospecific olefin epoxidation and radical-type oxidations, respectively. Moreover, under extreme conditions, in which the concentration of an active substrate is very high, the Co-OOC(O)R (2) species is a possible reactive species for epoxidation. Furthermore, partitioning between heterolysis and homolysis of the O-O bond of the intermediate 2 might be very sensitive to the nature of the solvent, and the O-O bond of the Co-OOC(O)R species might proceed predominantly by heterolytic cleavage, even in the presence of small amounts of protic solvent, to produce a discrete Co(V) O intermediate as the dominant reactive species. Evidence for these multiple active oxidants was derived from product analysis, the use of peroxyphenylacetic acid as the peracid, and EPR measurements. The results suggest that a less accessible Co(V)=O moiety can form in a system in which the supporting chelate ligand comprises a mixture of neutral and anionic nitrogen donors.

Dibenzoatobis[3-(pyrrol-1-ylmeth-yl)pyridine]-zinc(II).

In the title compound, [Zn(C(7)H(5)O(2))(2)(C(10)H(10)N(2))(2)], the Zn(II) ion, located on a twofold axis, is coordinated by two N atoms from two 3-(pyrrol-1-ylmeth-yl)pyridine ligands and two O atoms from two benzoate ligands in a distorted tetra-hedral geometry. The pyridine and the pyrrole rings are nearly perpendicular to each other, making a dihedral angle of 84.83 (7)°.