Visible Light-induced Photoluminescence of a Zinc(Ⅱ) Complex of N-methyl-4,4-bipyridinium Cation

Compounds with visible-light-induced photoluminescence are particularly attractive in acting as the emitting components of light-emitting diodes and fluorescent probes for biological applications. A new complex [Zn(NCS)_3(MQ)](MQ^+ = N-methyl-4,4?-bipyridinium) with an isolated molecular structure has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy and solid-state photoluminescent determination. Crystal data: C_(14)H_(11)N_5S_3Zn, M_r = 410.83, monoclinic, space group P2_1/c, a = 8.809(5), b = 13.138(7), c = 15.580(9) ?, b = 104.433(10)°, V = 1746.2(17) ?~3, Z = 4, D–c = 1.563 g×cm^3, μ = 1.769 mm^(–1), F(000) = 832, the final R = 0.0376 and wR = 0.1243 for 2850 observed reflections with I > 2s(I). In the crystal structure, the zinc atom is tetrahedrally coordinated by one MQ+ ligand and three NCS– groups to yield a tetrahedral configuration. The bond length of Zn–NMQ is clearly shorter than those found in reported Zn(Ⅱ) complexes of 4,4?-bipy. The isolated units are joined by C–H···S interactions to generate a 2D hydrogen-bonding network. This compound displays visible light-induced photoluminescence, which originates from both intraligand charge-transfer of the MQ+ ligand and NCS~–→MQ^+ charge-transfer according to a density of states(DOS) calculation. Moreover, its emission band shows a clear blue shift compared with those of halide compounds.

Framework-solvent interactional mechanism and effect of NMP/DMF on solvothermal synthesis of [Zn_4O(BDC)_3]_8

In order to explore the effect mechanism of solvent on the synthesis of the metal organic framework materials, the microscopic interaction between solvent and framework and the effects of N,N-dimethyl-formamide(DMF) or N-methyl- 2-pyrrolidone(NMP) on solvothermal synthesis of [Zn4O(BDC)3]8 were investigated through a combined DFT and experimental study. XRD and SEM showed that the absorbability of NMP in the pore of [Zn4O(BDC)3]8 was weaker than that of DMF. The thermal decomposition temperature of [Zn4O(BDC)3]8 synthesized in DMF was higher than that in NMP according to TG and FT-IR. In addition, the nitrogen sorption isotherms indicated that NMP improved gas sorption property of [Zn4O(BDC)3]8. The COSMO optimized calculations indicated that the total energy of Zn4O(BDC)3 in NMP was higher than that in DMF, and compared with non-solvent system, the charge of zinc atoms decreased and the charge value was the smallest in NMP. Furthermore, the interaction of DMF, NMP or DEF in [Zn4O(BDC)3]8 crystal model was calculated by DFT method. The results suggested that NMP should be easier to be removed from pore of materials than DMF from the point of view of energy state. It can be concluded that NMP was a favorable solvent to synthesize [Zn4O(BDC)3]8 and the microscopic mechanism was that the binding force between Zn4O(BDC)3 and NMP molecule was weaker than DMF.

Syntheses of 3－Methyl－1－propyl－4－piperidoneand1－Methyl－3，7－dipropyl－3，7－diazabicyclo［3，3，1］nonan－9－one

Ｓｙｎｔｈｅｓｅｓｏｆ３－Ｍｅｔｈｙｌ－１－ｐｒｏｐｙｌ－４－ｐｉｐｅｒｉｄｏｎｅａｎｄ１－Ｍｅｔｈｙｌ－３，７－ｄｉｐｒｏｐｙｌ－３，７－ｄｉａｚａｂｉｃｙｃｌｏ［３，３，１］ｎｏｎａｎ－９－ｏｎｅＷＡＮＧＹｕ－ｈｕａｎ，ＷＡＮＧＧｕｏ－ｊｉａ，Ｚ...

N-（Substituted benzyl）-3,5-bis（benzylidene）-4-piperidones： Synthesis and Preliminary Anti-leukemia Activity （I）

A series of novel N-（substituted benzyl）-3,5-bis（benzylidene）-4-piperidones 5a--50 were synthesized with substituted benzylamines as raw materials via a series of Michael addition, Dieckmann condensation, hydrolysis decarboxylation and aldol condensation. The structures were confirmed by 1↑H NMR, IR, MS techniques and elemental analysis. Assay-based antiproliferative activity study using leukemic cell lines K562 revealed that most of the title compounds have high effectiveness in inhibiting leukemia K562 cells proliferation, among which the compounds 5g （IC50=7.81 μg·mL^-1）, 5k （IC50=6.35μg·mL^-1）, 51 （IC50=7.20 μg·mL^-1）, and 50 （IC50=5.79 μg·mL^-1） have better inhibition activities than standard 5-fluorouracil （IC50=8.56 μg·mL^-1）.

Cross double Mannich reaction catalyzed by I_2:Synthesis of highly substituted 4-piperidones

Cross double Mannich reaction and tandem cyclization were achieved under iodine catalyzed conditions,yielding a series of highly substituted 4-piperidones.Among the possible diastereomers,only one diastereomer was isolated,which could be ascribed to the chair-like transition state in six-membered ring,in which all of the hindered groups are located in the pseudoequatorial orientation.

Synthsis of 4-Piperidones via Multicomponent Double Mannich Reaction Catalyzed by I2

A multicomponent double Mannich reaction of amines, aldehydes and ketones was efficiently catalyzed by molecular iodine, producing a series of 4-piperidones in a stereoselective way. A variety of amines, aldehydes and ketones were tolerated in this tandem process, including those with labile functinal groups. Further investigation of the reaction between alkyl-imines and ketones showed that imines from amines and ketones were formed in situ and isomerized to enamine in the presence of molecular iodine to accelerate the corresponding Mannich addition.

A novel and concise synthetic access to chiral 2-substituted-4-piperidone

A novel and concise synthetic access to enantiopure chiral 2-aryl/alkyl substituted 4-piperidone has been demonstrated.This new route features two key steps:the highly diastereoselective conjugate addition of homochiral lithium amides to trans-β-substituted-α,β-unsaturated methyl esters guaranteed the enantiopurity at 2 position(de>19:1)and the intramolecular attacking of carbanions to methyl esters led to the formation of the piperidone ring.A wide range of substrates,including chiral2-aryl and 2-alkyl-4-piperidones,were successfully synthesized with modest to high yield.Moreover,some non-chiral3-substituted-4-piperidones were also synthesized with enhanced ring-formation yield,implicating the versatility of this method in construction of various piperidine rings.