王英，学者凯发k8国际首页主页-凯发网

two novel two-dimensional(2d)supramolecular organic frameworks were fabricated in water based on the encapsulation-enhanced donor-acceptor interaction between the methyl viologen(mv)units,methoxy naphthyl(mn)units,and cb[8].the tetraphenylethylene(tpe)derivatives 1 with four mv units were employed as rigid building blocks and the two mn units modified oligoethylene glycol derivatives 2 and 3 served as flexible edges,respectively.the obtained two sofs have obvious sheet-like structures and exhibit fluorescence emission at 350-500 nm.in addition,these two sofs were employed for the luminescent detection of cr(vi)and mn(vii)in aqueous solutions,and the detection limits of cro_(4)^(2-),cr_(2)_(o)7%^(2-),and mno_(4)were calculated in a very low concentration range,indicating that these two sofs can serve as a potential sensor for cr(vi)and mn(vii)detection in water.this work constructs two sofs in an aqueous solution through a facile method and further enriches the applications of sofs.

suffrutines a (1) and b (2), a pair of novel photochemical z/e isomeric indolizidine alkaloids, with a unique and highly conjugated c-20 skeleton, were isolated from the roots of flueggea suffruticosa. the structures were elucidated by extensive analysis of nmr spectra and single-crystal x-ray diffraction. the light-induced isomerization and hypothetical biogenetic pathway to 1 and 2, as well as their activity for regulating the morphology of neuro-2a cells are also discussed.

a synthetic strategy based on biogenetic building blocks for the collective and divergent biomimetic synthesis of cleistoperlones a-f, a cinnamoylphloroglucinol collection discovered from cleistocalyx operculatus, has been developed. these syntheses proceeded successfully in only six to seven steps starting from commercially available 1,3,5-benzenetriol and involving oxidative activation of stable biogenetic building blocks as a crucial step. key features of the syntheses include a unique michael addition/ketalization/1,6-addition/enol-keto tautomerism cascade reaction for the construction of the dihydropyrano[3,2-d]xanthene tetracyclic core of cleistoperlones a and b, and a rare inverse-electron-demand hetero-diels-alder cycloaddition for the establishment of benzopyran ring in cleistoperlones d-f. moreover, cleistoperlone a exhibited significant antiviral activity against acyclovir-resistant strains of herpes simplex virus type 1 (hsv-1/blue and hsv-1/153).

single -crystal x-ray diffraction (scxrd) analysis is the most definitive structure determination method, yet it hinges upon the success of crystal growth and that can sometimes be challenging for volatile or complicated molecules. here, we report a highly fluorinated cyclic trinuclear ag(i) pyrazolate complex (ag 3 pz 3 ) with strong p -acidity as a crystalline mate for structural elucidation of those having difficulty crystallizing on their own. dozens of oxygenated organic molecules were smoothly co -crystallized with ag 3 pz 3 , regardless of their sizes and shapes. their chemical structures were unambiguously determined by subsequent scxrd analysis. ag 3 pz 3 is highly adaptive and can pack with organic molecules in four different types of binding modes according to their structural and electronic attributes. moreover, ag 3 pz 3 is a robust crystalline mate and can be directly employed for the co -crystallization of mixtures without tedious separation, as exemplified by the successful identification of individual components in mixtures and even the crude extract of natural medicine.