Synthesis,Crystal Structure,and Characterization of a Novel Metallo‐Organically‐Templated Pentaborate with Mixed Ligands

A novel metallo‐organically templated pentaborate with layered framework, [Cd(TETA)(C₂H₃O₂)][B₅O₆(OH)₄] ( 1 ) (TETA = triethylenetramine), was synthesized under mild solvothermal conditions. The structure was determined by single‐crystal X‐ray diffraction and further characterized by FT‐IR spectroscopy, elemental analysis, thermogravimetric analysis, and photoluminescence spectroscopy. The structure consists of an isolated polyborate anion [B₅O₆(OH)₄]^– and the cadmium complex cation of [Cd(TETA)(C₂H₃O₂)]⁺, which contains both organic amine and organic acid ligands. The [B₅O₆(OH)₄]^– units are connected together by hydrogen bonds, and a 2D sheet‐like framework with rectangle‐like 12‐membered boron rings are formed. The [Cd(TETA)(C₂H₃O₂)]⁺ complex cations are located in the free space between the layers and connect the adjacent borate layers through hydrogen bonds to form a three‐dimensional supramolecular network. The luminescent properties of the compound were studied for the first time in the series of metallo‐organically‐templated pentaborates, and a blue luminescence occurs with an emission maximum at 468 nm upon excitation at 397 nm.     

Modification of proteins with cyclodextrins prevents aggregation and surface adsorption and increases thermal stability

This work describes a general approach for preventing protein aggregation and surface adsorption by modifying proteins with β-cyclodextrins (βCD) via an efficient water-driven ligation. As compared to native unmodified proteins, the cyclodextrin-modified proteins (lysozyme and RNase A) exhibit significant reduction in aggregation, surface adsorption and increase in thermal stability. These results reveal a new chemistry for preventing protein aggregation and surface adsorption that is likely of different mechanisms than that by modifying proteins with poly(ethylene glycol).     

Wettability conversion from superoleophobic to superhydrophilic on titania/single-walled carbon nanotube composite coatings

Superoleophobic surfaces were demonstrated on perfluorosilane-rendered titania (TiO(2))/single-walled carbon nanotube (SWNT) composite coatings. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations revealed that SWNTs play a key role in the formation of overhanging structures and the nanoscale roughness on the coating surface, which compose the two critical morphologic factors for a superoleophobic surface. The wettability conversion from superoleophobic to superhydrophilic of the composite coatings was realized by the gradual decomposition of 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS) on the coating surface using UV irradiation. Contact angle measurement on both smooth TiO(2) surface and rough composite coating surface under different UV irradiation time revealed that the wetting behavior of the liquids on the composite coating surface passes from the Cassie to the Wenzel and finally to the inversed-Cassie regime. Different liquids show different irradiation time for the wetting state change. By controlling the UV irradiation dose, liquids with surface tension difference smaller than 5 mN/m can exist in completely converse wetting states on the same coating surface, that is, superphobic for one liquid while superphilic for another with lower surface tension. Mixed organic liquids with different surface tension can be completely separated through a coated grid using this wettability tuning technique.     

Hydrothermal synthesis of cubic boron nitride microcrystals

In this paper, combining the hydrothermal method and halide species-inducing effect, we reported cubic-phase BN microcrystals synthesized in hydrothermal condition with N(CH₃)₃ as nitrogen source. These polyhedral microcrystals presented nearly regular octahedral shapes of 0.5?C1.5 ??m in average size.     

The molecular mechanism studies of chirality effect of PHA-739358 on Aurora kinase A by molecular dynamics simulation and free energy calculations

Aurora kinase family is one of the emerging targets in oncology drug discovery and several small molecules targeting aurora kinases have been discovered and evaluated under early phase I/II trials. Among them, PHA-739358 (compound 1r) is a 3-aminopyrazole derivative with strong activity against Aurora A under early phase II trial. Inhibitory potency of compound 1r (the benzylic substituent at the pro-R position) is 30 times over that of compound 1s (the benzylic substituent at the pro-S position). In present study, the mechanism of how different configurations influence the binding affinity was investigated using molecular dynamics (MD) simulations, free energy calculations and free energy decomposition analysis. The predicted binding free energies of these two complexes are consistent with the experimental data. The analysis of the individual energy terms indicates that although the van der Waals contribution is important for distinguishing the binding affinities of these two inhibitors, the electrostatic contribution plays a more crucial role in that. Moreover, it is observed that different configurations of the benzylic substituent could form different binding patterns with protein, thus leading to variant inhibitory potency of compounds 1r and 1s. The combination of different molecular modeling techniques is an efficient way to interpret the chirality effects of inhibitors and our work gives valuable information for the chiral drug design in the near future.     

Side effect reduction of encapsulated hydrocortisone crystals by insulin/alginate shells

Insulin/alginate (ALG) microcapsules for controllable release and side effect reduction of a glucocorticoid have been fabricated via the layer-by-layer (LbL) assembly technique. Insulin and ALG are deposited alternately onto hydrocortisone (HC) crystals to form a core-shell structure. This insulin/ALG microcapsule can prolong the release of HC under physical conditions and control the HC release rate by adjusting the number of insulin/ALG bilayers adsorbed onto HC crystals. The release of insulin from the capsule wall exhibits a little lag, compared with that of the HC. It is a great advantage for this system because hyperglycemia caused by HC usually arises a few hours after its administration, which could be inhibited by the delayed release of insulin from the shell of the microcapsule. This synergy effect might enable a new way of using one carrier to deliver two kinds of drugs and reduce their side effects at the same time.     

Tetra-β-(2-(diethylamino)ethoxy) nickel phthalocyanine: synthesis and inclusion in MCM-41

In order to include phthalocyanine macromolecule in MCM-41 molecular sieve, a inclusion-suitable phthalocyanine derivative tetra-β-(2-(diethylamino)ethoxy) nickel phthalocyanine was synthesized, in two steps, from 4-nitrophthalonitrile and 2-(diethylamino)ethanol, and characterized by mass spectra, ¹H nuclear magnetic resonance spectroscopy, ultraviolet visible spectroscopy, infrared spectroscopy and elemental analysis, which confirmed the proposed molecular structure. The inclusion of synthesized phthalocyanine compound in MCM-41 was carried out by the in situ synthesis method using cetyltrimethyl ammonium bromide as structure template and tetraethyl orthosilicate as silica source in presence of this phthalocyanine compound. The inclusion material was studied by means of X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy, nitrogen adsorption isotherm measurements, etc. Results showed that the macromolecular compound was successfully included into MCM-41, the obtained inclusion material displayed mainly prisms and globes, and the material was a kind of mesoporous materials with regularly hexagonal honeycomb array of uniform cylindrical pores and high surface area.     

Raman spectroscopic characteristics of octa-substituted bis(phthalocyaninato) rare earth complexes peripherally substituted with (4-methoxy)phenoxy derivatives

The Raman spectroscopic data in the range 500-1800 cm⁻¹ for a series of 15 rare earth double-deckers with tervalent rare earths M^III[Pc(MeOPhO)₈]₂ (M = Y, La, …, Lu, except Ce, Pr and Pm), reduced state HPr[Pc(MeOPhO)₈]₂ and intermediate-valent cerium Ce[Pc(MeOPhO)₈]₂ have been collected using laser excitation source emitting at 632.8 nm. With excitation at 632.8 nm, which is in close resonance with the main Q absorption band of the phthalocyanine ligand, typical Raman marker bands of the monoanion radical [Pc(MeOPhO)₈]⁻ were observed at 1500-1528 cm⁻¹ as very strong bands resulting from the coupling of pyrrole CC and aza CN stretchings. For Ce[Pc(MeOPhO)₈]₂ and HPr[Pc(MeOPhO)₈]₂, a very strong band at 1499 cm⁻¹ with contributions from both pyrrole CC and aza CN stretchings and also isoindole stretching was the marker Raman band of [Pc(MeOPhO)₈]²⁻. In addition, the influence of ionic radius of the rare earth metal and substituent species on the Raman scatting characteristics of sandwich-type compounds has also been tentatively studied.     

Syntheses,Structures, and Luminescent Properties of Two Novel Coordination Polymers with Dipicolinate and Diimidazole Ligands

Two novel coordination polymers, [Zn(dpc)(bmix)_0.5]_n ( 1 ), [Pb(dpc)(bmix)_0.5]_n ( 2 ), [dpc = dipicolinate, bmix = 1,4‐bis(2‐methylimidazole‐1‐ylmethyl)benzene], were hydrothermally synthesized and characterized by elemental analyses, IR spectroscopy, TGA, and X‐ray single crystal diffraction. In both complexes, the dipicolinate and bmix ligands act as spacers to link metal ions to give a 2D corrugated (6,3) network of 1 and a 3D microporous framework of 2 , respectively. The difference in the architectures is due to a diverging coordination mode of the carboxylate function. Furthermore, solid state fluorescence properties of the two complexes were investigated at room temperature.     

Study of the Binding of Herbacetin to Bovine Serum Albumin by Fluorescence Spectroscopy

In this paper, the interaction between herbacetin and BSA was investigated by fluorescence and three-dimensional fluorescence spectroscopy under simulated physiological conditions. It was proved that the fluorescence quenching of BSA by herbacetin was mainly the result of the formation of a herbacetin–BSA complex. The modified Stern–Volmer quenching constant and the corresponding thermodynamic parameters ΔH ⁰, ΔG ⁰ and ΔS ⁰ were calculated at different temperatures. The results indicated that electrostatic interactions were the predominant intermolecular forces in stabilizing the complex. The distance r=3.23 nm between the donor (BSA) and acceptor (herbacetin) was obtained according to Förster’s nonradioactive energy transfer theory. The synchronous fluorescence and three-dimensional fluorescence spectra results showed that the hydrophobity of amino acid residues increased in the presence of herbacetin. These results revealed that the microenvironment and conformation of BSA changed during the binding reaction.