Effect of sunset yellow dye on morphological,optical, dielectric,thermal and mechanical properties of KDP crystal

Herein, we describe the growth and morphology of well-defined dyed crystals of KH₂PO₄ (potassium dihydrogen orthophosphate; KDP) containing organic azo (sunset yellow; SSY) dye in the {1 0 1} & {0 0 1} pyramidal growth sectors. An understanding on selective dye inclusion in various growth sector of host crystal is proposed, which will help in designing novel tailor-made dyed photonic crystals. The structural analysis and the identification of various functional groups present in as grown KDP crystals were carried out using powder XRD, FTIR and Raman studies. Solid state transmittance spectra for dyed KDP crystals displayed three absorption peaks at 230 nm, 311 nm and 477 nm, which were blue shifted for SSY dye in KDP crystal relative to neutral aqueous solution of SSY dye. These blue shifts in the absorption maxima confirm the successful incorporation of sunset yellow dye into the pyramidal growth sectors of dyed KDP crystals. The band around 409 nm in the photoluminescence emission spectrum indicates a violet emission. SSY dye doped KDP crystals showed enhanced dielectric properties and thermal stability as compared to pure KDP crystal. The mechanical strength of the KDP crystals estimated using Vickers microhardness test was found to decrease with the increase in SSY dye doping.     

Organic intercalation material: reversible change in interlayer distances by guest release and insertion in sandwich-type inclusion crystals of cholic acid

Cholic acid (CA) forms inclusion crystals that have a sandwich-type lamellar structure constructed by the alternative stacking of host bilayers and guest layers. Five disubstituted benzenes, o-toluidine, m-fluoroaniline, o-chlorotoluene, o-bromotoluene, and indene, are accommodated in the two-dimensional void space between the host bilayers at 1:2 host-guest stoichiometries. Thermal gravimetric analysis of the inclusion crystals revealed that all the guest molecules, except o-toluidine, are released in two separate steps, indicating the formation of intermediate crystals after the first guest release. Adequate heat treatment of the four inclusion crystals induces release of half or three quarters of the guest molecules. X-ray diffraction patterns of the intermediate crystals revealed that the crystals have a bilayer structure the same as those of the common CA inclusion crystals. They have one-dimensional cavities, in which the guest molecules are included at a 1:1 or 2:1 host-guest stoichiometry. These facts indicate that the host bilayers move 1.6-4.5 A perpendicular to the layer direction by desorption of the guest molecules. Furthermore, a reverse structural change is also achieved by absorption of the guest molecules to regenerate the starting sandwich-type inclusion crystals. This reversible change in the host bilayer by the guest sorption and desorption is a novel example of organic intercalation materials.     

Synthesis and Fluorescence Properties of Pyrimidine‐Based Diboron Complexes with Donor–π–Acceptor Structures

Pyrimidine‐based diboron complexes bearing β‐iminoenolate ligands and phenyl groups as bulky substituents on the boron atoms were synthesized as novel fluorescent dyes, and their fluorescence properties were investigated in solution and in the solid state. The diboron complexes with donor–π–acceptor structures showed positive solvatochromism in the fluorescence spectra. The cyano derivative exhibited the most dramatic redshift of the fluorescence maximum F_max with increasing solvent polarity (from 551 nm in n‐hexane to 710 nm in acetonitrile). The diboron complexes showed solid‐state fluorescence in the range of 578–706 nm with fluorescence quantum yields of 0.06–0.28. Additionally, the trifluoromethyl derivative exhibited solvent‐inclusion solid‐state fluorescence. The trifluoromethyl derivative formed toluene‐inclusion and ethyl acetate‐inclusion crystals. The toluene‐inclusion crystal (F_max=668 nm, Φ_f=0.16) showed a blueshifted F_max and higher Φ_f value compared to the original trifluoromethyl derivative (F_max=694 nm, Φ_f=0.08) in the solid state. On the other hand, the F_max (709 nm) and Φ_f (0.04) values of the ethyl acetate‐inclusion crystal were redshifted and lower, respectively.     

Enantioselective photocyclization of amides to beta-lactam derivatives in inclusion crystals with an optically active host

Irradiation of inclusion crystals of 2-(N-acyl-N-alkylamino)cyclohex-2-enones and N,N-dimethylphenylglyoxylamide with chiral host molecules gave the optically active N-alkyl-1-azaspiro[3.5]-nonane-2,5-diones and 3-hydroxy-1-methyl-3-phenylazetidin-2-one, respectively. The crystal structure of the 1:1 inclusion complex of N,N-dimethylphenylglyoxylamide with (-)-trans-1,4-bis[3-(o-chlorophenyl)-3-hydroxy-3-phenylprop-1-ynyl]-2,3,5,6- tetrachloro-2,5-cyclohexadiene-1,4-diol was analyzed by X-ray diffraction.     

Study on inclusion complex of cyclodextrin with methyl xanthine derivatives by fluorimetry

The inclusion complexes of beta-cyclodextrin (beta-CD) and HP-beta-cyclodextrin (HP-beta-CD) with caffeine, theophylline and theobromine were investigated by fluorimetry. Various factors affecting the formation of inclusion complexes were discussed in detail including forming time, pH effect and temperature. The results indicate that inclusion process was affected seriously by laying time and pH. The forming time of beta-CD inclusion complexes is much longer than that of HP-beta-CD. The optimum pH range is about 7-12 for caffeine, 8-10 for TP, 10.5-12 for TB. The intensities of their fluorescence increase with the decreasing of temperature. Their maximum excitation wavelengths are all in the range of 280-290 nm. The emission wavelength of caffeine and theophylline are both in the range of 340-360 nm, and that of theobromine is about 325 nm. The fluorescence signals are intensified with the increasing concentration of CD. The stoichiometry of the inclusion complexes of CD with these three methyl xanthine derivatives are all 1:1 and the formation constant are all calculated.     

Nd3+:NaLa(WO4)2晶体的生长和光学性质

Nd3+:NaLa(WO4)2 crystals with a dimension up to 7 mm were grown from a high temperature solution using a double-crucible method. Scanning electron microscopy observations of the crystals showed that there were no small cracks on the surface of the crystals although they underwent two phase transitions when cooling down from high temperatures. X-ray diffraction studies indicated that the as-obtained product is pure low- temperature tetragonal Nd3+:NaLa(WO4)2. The absorption and fluorescence spectra for Nd3+:NaLa(WO4)2 were measured at room temperature. The absorption band at 804 nm has a wide full-width half maximum of 23 nm whose origin is discussed. The absorption and emission cross sections were calculated to be 7.24*10-20 cm2 at 804 nm and 6.54*10-20 cm2 at 1057 nm, respectively.     

Resolution of α-aminolactams by inclusion complexation with chiral host compounds

3-Aminopiperidin-2-one and α-amino-ε-caprolactam were efficiently resolved by inclusion complexation with a chiral host compound, (R,R)-(−)-trans-4,5-bis(hydroxydiphenylmethyl)-1,4-dioxaspiro[4.5]decane. The amino substituent on the lactam ring was found to play an important role in efficient chiral recognition in the inclusion crystals.     

Pd nanoparticle aging and its implications in the suzuki cross-coupling reaction

Examination of the catalysts recovered in the N,N-dihexylcarbodiimide-palladium nanoparticle composite catalyzed Suzuki cross-coupling reactions revealed that the metal nanoparticles transformed gradually from spherical-shape to larger needle-shaped crystals. Two types of Ostwald ripening processes were observed. One involves rapid aggregation of the incipient nanoparticle catalyst (2-5 nm) into blackberry-like assemblies (100-200 nm), which is accompanied with the much slower dissolution of small crystals or amorphous nanoparticles and the formation of larger needle-shaped crystals. The observed structural changes provided new insights into the durability of the polymer nanoparticle composite catalyst.     

Resolution of 4-oxoazetidin-2-yl benzoate by inclusion crystallization with an optically active host compound

4-Oxoazetidin-2-yl benzoate was resolved efficiently by an inclusion complexation with a chiral host compound, (R,R)-(−)-trans-4,5-bis(hydroxydiphenylmethyl)-1,4-dioxaspiro[4.5]decane. The phenyl substituent on the β-lactam ring was found to play an important role in an efficient chiral recognition in the inclusion crystals.     

球形主体分子的包结性能及其在制备有机非线性光学材料 中的应用

提出了球形主体分子的设计思想,把具有球形结构的分子柏木醇(1)、马钱子碱(2)、三乙烯二胺(1,4-二氮-二环[2.2.2]辛烷(3)作为主体分子,把酚类化合物,诸如苯酚(4)、邻甲苯酚(5)、间甲苯酚(6)、对甲苯酚(7)、对氯苯酚(8)和对硝基苯酚(11)等作为客体分子,进行了主客体分子相素作用实验,采用粉末X射线衍射、1^HNMR等分析手段确认了包结化合物的形成及主客体分子的摩尔比,摩尔比(H/G)分别为(1)+(4)1:1,(1)+(5)1:1,(1)+(6)1:1,(1)+(7)1:1,(1)+(11)1:2,(2)+(11)1:1,(3)+(4)1:2,(3)+(5)1:3,(3)+(6)1:2,(3)+(7)1:2,(3)+(8)1:2,(3)+(11)1:2,对典型包结化合物的单晶,诸如柏木醇和邻甲苯酚、马钱子碱和对硝基苯酚以及三乙烯二胺和对硝基苯酚,进行了四圆X射线衍射结构分析,结果表明,包结化合物的堆砌结构特征随主体分子的体积大小而改变,从隧道型如(1)+(5)和(2)+(11)转变为夹层型如(3)+(11)。用Nd:YAG激光测试晶体的SHG效应,结果表明,大部分包结物晶体具有非线性光学性质。     

Crystal structure and morphology of poly(16-hexadecalactone) chain-folded lamellar crystals

Solution-grown, chain-folded lamellar crystals of poly(16-hexadecalactone) (PHDL) were crystallized isothermally from 1-hexanol at 70 degrees C. The morphology of lozenge-shaped crystals was studied by TEM and AFM. The lamellae are ca. 10 nm thick and the chains run orthogonal to the lamellar surface with folding along (110) and (110) planes. The crystal structure of PHDL was determined by XRD and election diffraction of single crystals. The chains are in the 2(1) helix conformation close to all-trans and the structure consists of an orthorhombic unit cell with a P2(1)2(1)2(1) space group with the lattice constants a = 0.746 +/- 0.001 nm, b = 0.504 +/- 0.001 nm, and c (chain axis) = 4.116 +/- 0.003 nm. There are two chains per unit cell, which exist in an antiparallel arrangement. Molecular packing structure has been studied in detail, taking into account both diffraction data and energy calculations. The setting angles, with respect to a axis, were +/-40 degrees for the corner and center chains, respectively. By using the electron and XRD data, the best molecular packing model was refined to R-factors of 0.168 and 0.196, respectively. A brief comparison of chain-packing structure is also made with related polymer structures.     

Adsorption of biopolyester depolymerase on silicon wafer and poly[(R)-3-hydroxybutyric acid] single crystal revealed by real-time AFM

The adsorption behavior of PHB depolymerase from R. pickettii T1 on a silicon wafer and on P(3HB) single crystals has been studied by real-time and AFM in air and a buffer solution. First, the morphology of PHB depolymerase adsorbed on a silicon wafer was characterized to show that one molecule of PHB depolymerase has dimensions of 2.2 +/- 0.7 nm height and 16 +/- 5 nm width. The observation of PHB depolymerase adsorbed on a P(3HB) single crystal indicated that the dimensions of enzyme on the crystalline surface in air were 1.2 +/- 0.5 nm high and 28 +/- 7 nm wide, while enzyme molecules with dimensions of 2.1 +/- 0.6 nm height and 16 +/- 7 nm width were detected in a buffer solution. Comparison of the dimensions of PHB depolymerase in air with those in a buffer solution showed that the enzyme was squashed in air, but not in a buffer solution. In addition, the influence of enzymatic adsorption on the molecular state of the P(3HB) crystalline surface was investigated. The AFM images of P(3HB) single crystals after enzymatic adsorption and washing with ethanol indicated that the adhesion of PHB depolymerase changed the molecular state and generated holes on the crystalline surface.     

The fluorescence study of the inclusion coordinated compound of beta-cyclodextrin and p-hydroxyphenolacetamide and its analytical applications

The inclusion coordinated compound fluorescence of p-hydroxyphenolacetamide (PHPA) with beta-cyclodextrin was studied and a high sensitive analytical method to determine the content of PHPA was established based on the increased fluorescence intensity of the coordinated compounds in Britton-Robinson buffer solution (pH 7). The wavelength of the excited emission are 282 and 310 nm, respectively. The enhanced coordinated compounds fluorescence intensity is proportional to the concentration of PHPA in the range 0.030-11.0 mg/l. The relative standard deviation (R.S.D.) were within 0.66-4.2%. Correlation coefficient and inclusion binding constant Kf are obtained within 0.9950-0.9996 and 4.67 x 10(2), respectively. Meanwhile, a linear increase of the resonance light scattering (RLS) with the inclusion coordinated compounds concentration was noticed at a synchronous wavelength of 584 nm. The forming reasons of inclusion coordinated compounds were investigated. The 1:1 molar ratio composition of inclusion compound was measured with DTA and elemental analysis. The method is simple, rapid and has a good reproducibility. The method was used for determination of PHPA in an artificial sample with satisfactory results.     

Synthesis of zeolite nanocrystals at room temperature

Zeolite A nanoparticles were synthesized under room-temperature conditions from a very reactive organic-template-free gel system. The optimization of the syntheses parameters, namely, the composition of the initial system and the careful choice of the reactants, allowed the crystallization to be accomplished within 3 days. At this stage the individual zeolite crystals were in the range of 100-300 nm without well-developed crystal faces. The prolongation of the synthesis time up to 10 days led to formation of larger well-faceted cubic crystals averaging about 400-500 nm in size. The high-resolution transmission electron microscopy (HRTEM) study revealed that a thin layer of amorphous material covers the zeolite particles acting as a binder between individual zeolite crystals. The postsynthesis treatment of the product in NH(3) media under ultrasonic radiation disintegrated the loosely attached zeolite particles and decreased the fraction of zeolite A particles with low colloidal stability. The employed approach, however, did not result in complete disintegration of aggregated crystals. The zeolite crystals obtained under ambient conditions were characterized by XRD, SEM, dynamic light scattering, and N(2) adsorption measurements.     

Synthesis of Nanosized NaY Zeolite by Confined Space Method

Nanosized NaY crystals have been prepared from metakaolin and sodium silicate by confined space synthesis with starch additive. It is found that the product has a narrow crystal size distribution (50-100nm), high Si/Al ratio (Si/Al=4.6-6.1), high surface area (1090m^2/g) and the average diameter of nanosized NaY(75nm) synthesized is 30nm ,it is smaller than that of without starch additive.     

Formation of gold-like metal-lustrous inclusion crystals from 1-phenyl-2,5-bis[5-(tricyanoethenyl)-2-thienyl]pyrrole host and an electron-donating aromatic guest

A novel pi-conjugated organic compound, 1-phenyl-2,5-bis[5-(tricyanoethenyl)-2-thienyl]pyrrole, which bears two powerful electron-withdrawing tricyanoethenyl substitutents, readily yielded gold-like metal-lustrous inclusion crystals with a series of aromatic guest molecules such as toluene, p-xylene, anisole, dimethoxybenzenes and indene. All the inclusion compounds have a common stoichiometric ratio (host/guest) of 2 : 1. X-Ray structural analyses demonstrate that the structural feature for toluene included crystal is similar to those containing p-xylene, anisole, dimethoxybenzenes and indene.     

UV-induced nonlinear absorption in lanthanum calcium borate single crystals

It has been revealed that lanthanum calcium borate (La2CaB10O19) crystals show two-photon absorption (TPA) induced by a UV laser field. UV-induced TPA measurements were performed in the spectral range of 475-1130 nm using as fundamental beam the third harmonics of the 28 ps Nd-YAG pulsed laser as a pumping beam for LiB3O5 optical parametrized generator using Z-scan method. Investigations performed by the Z-scan method were done during illumination by a Xe-F laser (lambda = 217 nm) as a photoinducing (pumping) beam. The pumping laser beam created a thin surface layer (about 80-90 nm) that was the source of the observed photoinduced TPA. The highest values of the TPA beta coefficients were achieved for polarization of the pumping light directed along the second-order crystallographic axis of the investigated crystals. The obtained values of the TPA coefficients were higher than those for the BiB3O6 crystals investigated earlier by us.     

Exclusion of impurity particles during grain growth in charged colloidal crystals

We examine the spatial distribution of fluorescent-labeled charged polystyrene (PS) particles (particle volume fraction ? = 0.0001 and 0.001, diameter d = 183 and 333 nm) added to colloidal crystals of charged silica particles (? = ?(s) = 0.035-0.05, d = 118 nm). At ?(s) = 0.05, the PS particles were almost randomly distributed in the volume-filling polycrystal structures before the grain growth process. Time-resolved confocal laser scanning microscopy observations reveal that the PS particles are swept to the grain boundaries of the colloidal silica crystals owing to grain boundary migration. PS particles with d = 2420 nm are not excluded from the silica crystals. We also examine influences of the impurities on the grain growth laws, such as the power law growth, size distribution, and existence of a time-independent distribution function of the scaled grain size.     

一种新的有机非线性光学晶体——L-精氨酸磷酸盐

近年来,在探索新的有机非线性光学晶体的工作中,对含有给电子或受电子基团的芳香族化合物已有广泛深入的研究,并已研制出像2,4-二硝基苯丙氨酸甲酯(MAP)等具有较大倍频系数的新的非线性光学晶体。但是,由于强的共轭效应使它们大π键各能级间的距离接近而使此类晶体无法应用于紫外区。     

Recovery of host crystals from inclusion crystals of <Emphasis Type="Italic">p-tert-</Emphasis>butylcalix[4]arene and <Emphasis Type="Italic">p-tert</Emphasis>-butylthiacalix[4]arene by the treatment with a solvent and/or supercritical CO<Subscript>2</Subscript>

Upon stirring inclusion crystals of p-tert-butylthiacalix[4]arene (2) in solvents with heating, guest compounds were efficiently desorbed to yield guest-free crystals. More specifically, upon treatment with methanol, the exchange of guest compounds with methanol in the crystals, followed by the desorption of the methanol afforded metastable host crystals 2β, whereas, upon treatment with heptane, the dissolution of the inclusion crystals and simultaneous crystallization of compound 2 afforded stable host crystals 2α. Further, a host crystal of p-tert-butylcalix[4]arene (1) was recovered by the treatment of 2:1 (host/guest) inclusion crystals of compound 1 with supercritical carbon dioxide (scCO₂), and through the combination of the guest exchange of 1:1 inclusion crystals of compound 1 with hexane and scCO₂ treatment of the resulting 2:1 inclusion crystals 1₂·hexane. Although the recovered host crystal of compound 1 contained a small amount of CO₂, it could be reused for the inclusion of organic compounds.