Stabilizing radical cation and dication of a tetrathiafulvalene derivative by a weakly coordinating anion.

After the chemical oxidation of the neutral tetrakis(methylthio)tetrathiafulvalene (TMT-TTF, 1) by specific oxidation agents with weakly coordinating anion, [Al(ORF)4](-) [ORF = OC(CF3)3], the radical cation TMT-TTF(•+) (1(•+)) and dication TMT-TTF(2+) (1(2+)) were successfully stabilized and isolated. All the compounds are well-soluble in some solvents and have been systematically investigated by absorption spectra, (1)H NMR, electron paramagnetic resonance (EPR) measurements. Their crystal structures and electronic properties have been studied in conjunction with theoretical calculation. The synthetic approach for chemical oxidation by specific salts of weakly coordinating anions is useful for stable radical cations of tetrathiafulvalene (TTF) and its derivatives in both solution and solid state, which will extend the further research, including structure-property relations on stable radicals for TTF derivatives and new functional materials based on them.

[Effect of abscisic acid on physiological characteristics in Lonicera macranthoides seedlings under salt stress].

OBJECTIVE: To improve salt resistance of Lonicera macranthoides seedlings and provide reference for its cultivation of salt tolerance. METHODS: Pretreatment of seedlings with abscisic acid (ABA) of different concentrations were used to study the effect of ABA on their physiological and biochemical characteristics under 200 mmol/L NaCl for 7 days. RESULTS: Exogenous ABA significantly decreased the content of malondialdehyde (MDA), increased the contents of chlorophyll, soluble sugar, soluble protein and activities of protected enzymes such as peroxidase (POD), catalase (CAT) and superoxide dismutase (SOD). CONCLUSION: It is proposed that exogenous ABA as chemical activator can induce salt resistance and decrease alleviate damage degree of salt stress of Lonicera macranthoides seedlings in a dose-dependent manner.

Iminoxyl Radical-Promoted Oxycyanation and Aminocyanation of Unactivated Alkenes: Synthesis of Cyano-Featured Isoxazolines and Cyclic Nitrones.

A novel and facile approach to vicinal oxycyanation and aminocyanation of internal unactivated alkenes is developed. This method utilizes the dichotomous reactivity of iminoxyl radical derived from the initiation of ß,γ- and γ,δ-unsaturated ketoximes to provide the general difunctionalization of internal alkenes using tert-butyl hydroperoxide (TBHP) as the environmentally friendly oxidant, CuCN as the commercially available cyanating reagent, and pentamethyldiethylenetriamine (PMDETA) as the ligand. By using this protocol, a series of useful cyano-featured isoxazolines and cyclic nitrones were efficiently prepared.

Enhanced hydroxylation of imidacloprid by Stenotrophomonas maltophilia upon addition of sucrose.

Sucrose's ability to promote the hydroxylation of imidacloprid (IMI) by bacterium Stenotrophomonas maltophilia strain CGMCC 1.1788 was examined. Both growing culture and resting cells could transform IMI into 5-hydroxy IMI. Adding 2% sucrose to the growing culture transformation broth and 5% sucrose to the resting cell transformation broth resulted in biotransformation yields, respectively, 2.5 and 9 times greater than without sucrose. In the growing culture transformation, sucrose increased biomass, which led to enhance hydroxylation of IMI. In the resting cell transformation, sucrose was used not as a carbon source but as an energy source for cofactor regeneration for hydroxylation of IMI. The hydroxylation activity of IMI was promoted eightfold by adding reduced nicotinamide adenine dinucleotide (NADH) to the cell-free extract. The hydroxylation of IMI was significantly inhibited by P450 inhibitor piperonyl butoxide. It seems that the hydroxylation of IMI by S. maltophilia CGMCC 1.1788 might proceed through a system by cooperating with P450 enzyme.