Direct amidation of metallaaromatics: access to N-functionalized osmapentalynes via a 1,5-bromoamidated intermediate.

The direct C-H amidation or imidation of metallaaromatics with N-bromoamides or imides has been achieved under mild conditions and leads to the formation of a family of N-functionalized metallapentalyne derivatives. A unique 1,5-bromoamidated species has been identified, and can be viewed as a σH-adduct intermediate in a nucleophilic aromatic substitution. The 1,5-addition of both electrophilic and nucleophilic moieties into the metallaaromatic framework demonstrates a novel pathway in contrast to the typical radical process of arene C-H amidation involving N-haloamide reagents.

[3+2] cycloaddition reaction of metallacyclopropene with nitrosonium ion: isolation of aromatic metallaisoxazole.

The synthesis of metallaisoxazole by the [3+2] cycloaddition reaction of metallacyclopropene with nitrosonium tetra-fluoroborate has been achieved under mild conditions. Nuclear magnetic resonance spectra, X-ray crystallographic analysis, and density functional theory calculations all suggest that the metallaisoxazole exhibits an aromatic character.

Dynamic Polymer Network System Mediated by Radically Exchangeable Covalent Bond and Carbolong Complex.

It is appealing to develop dynamic polymer systems with multifunctionl properties. Herein, we report a polyurethane elastomer with a dynamic covalent polymer network containing a radically exchangeable 2-arylindane-l,3-dione dimer as thermally sensitive and reversible cross-links. In addition, the carbolong complex, an excellent photothermal agent, is incorporated into the dynamic network backbone. With the irradiation of NIR light, the carbolong complex rapidly generates thermal energy, which subsequently triggers the cleavage of the dynamic covalent bond to generate radicals and activate the polyurethane network. In proof-of-concept experiments, we demonstrate that the utility of a combination of radically exchangeable covalent bond and carbolong moiety brings multiple functional characteristics to the polymer network with a capability of spatiotemporal control, including thermochromism, photochromism, rewritability, malleability, and self-healing. This study holds potentials for exploring more tunable dynamics and improved material properties.

Mechanochromism and optical remodeling of multi-network elastomers containing anthracene dimers.

Multi-network elastomers are both stiff and tough by virtue of containing a pre-stretched stiff network that can rupture and dissipate energy under load. However, the rupture of this sacrificial network in all described covalent multi-network elastomers is irreversible. Herein, we describe the first example of multi-network elastomers with a reformable sacrificial network containing mechanochemically sensitive anthracene-dimer cross-links. These cross-links also make our elastomers mechanochromic, with coloration that is both persistent and reversible, because the fluorogenic moiety (anthracene dimer) is regenerated upon irradiation of the material. In proof-of-concept experiments we demonstrate the utility of incorporating anthracene dimers in the backbone of the sacrificial network for monitoring mechanochemical remodeling of multi-network elastomers under cycling mechanical load. Stretching or compressing these elastomers makes them fluorescent and irradiating them eliminates the fluorescence by regenerating anthracene dimers. Reformable mechanochromic cross-links, exemplified by anthracene dimers, hold potential for enabling detailed studies of the molecular origin of the unique mechanical properties of multi-network elastomers.

[Impacts on motor function in the children of cerebral palsy treated with acupuncture and acupoint embedding therapy].

OBJECTIVE: To observe the efficacy difference on the motor function in the children of cerebral palsy between acupuncture combined with acupoint embedding therapy and simple acupuncture. METHODS: One hundred and twenty children of cerebral palsy were randomized into an observation group and a control group, 60 cases in, each one. In the observation group, acupuncture was applied in combination with acupoint embedding therapy. For the acupoint embedding therapy, the main acupoints were Pishu (BL 20), Shenshu (BL 23); the supplementary points were Dazhui (GV 14), Mingmen (GV 4), Yaoyangguan (GV 3), Sanjiaoshu (BL 22), Xinshu (BL 15) and Ganshu (BL 18). The catgut was embedded to the acupoints. Acupuncture was applied to the acupoints on the head and four limbs and the needles were retained for 40 min after qi arrival. In the control group, the simple acupuncture was applied, except for the acupoint embedding therapy. The rest treatment was the same as the observation group. The treatment lasted continuously for 3 months in the two groups. Before and after treatment, the gross motor function measure (GMFM) and the gross motor function classification system (GMFCS) were used for the assessment and the efficacy was analyzed. RESULTS: (1) After treatment, the total score of GMFM was increased in the two groups (both P<0. 01) and the score in the observation group was higher than that in the control group (P<0. 05). (2) The scores in A and B areas of GMFM were all improved in the two groups after treat ment (all P<0. 01) and the scores in the observation group were higher than those in the control group (P<0. 01 P<0. 05). (3) The total effective rate was 76. 7% (46/60) in the observation group, which was better than 55. 0% (33/60) in the control group (P<0. 01). CONCLUSION: The combined therapy of acupuncture and acupoint embedding much better improves the motor function in the children of cerebral palsy as compared with the simple acupuncture.

Change of handedness in cholesteric liquid crystalline phase for N-phthaloylchitosan solutions in organic solvents.

The influence of concentration on the helicoidal change of N-phthaloylchitosan (PhCh) solutions in Me2SO, DMAc and DMF was investigated by means of circular dichroism (CD). The critical concentrations to form liquid crystal phase in these three solvents were 43, 45 and 48 wt.%, respectively as measured with polarized optical microscope. There were two kinds of CD peaks, sharp peaks with absorption maximum at about 330 nm induced by the helical conformation of molecular chain, and very broad peaks covering almost whole visible region induced by the cholesteric helix of mesophase. The later only appeared in concentrated solutions with the concentration higher than the critical concentration. The handedness of both levels of helicoidal structures changed from left- to right-handed with the increase of concentration for PhCh/Me2SO solutions. The chirality transfer occurred between these two chiral levels. For PhCh/DMAc and PhCh/DMF systems, only the handedness of helical conformation reversed, but the cholesteric helix did not change. As a method to measure critical concentration, CD is more sensitive than polarized optical microscopy (POM).