Block Synthesis of Streptococcus pneumoniae Type 14 Capsular Polysaccharide Structures*

Synthesis of a thioglycoside tetrasaccharide block, β‐D‐Galp‐(1→4)‐β‐DGlcp‐(1→6)‐[β‐D‐Galp‐(1→4)]‐β‐D‐GlcNPhthp‐(1→SEt, corresponding to the repeating unit of Streptococcus pneumoniae serotype 14 CPS is described. Coupling of this block with a spacer followed by removal of an isopropylidene acetal yielded an acceptor, which was elongated with the donor block to give a protected dimer of the repeating unit. Iteration of this methodology yielded the trimer. Deprotection then produced an octa and a dodecasaccharide derivative ready for conjugation to proteins to afford immunoactive glycoconjugates.     

Water-soluble pillar[6]arene stabilized silver nanoparticles: preparation and application in amino acid detection

In the presence of a water-soluble pillar[6]arene WP6 containing 12 imidazolium groups, silver nanoparticles were successfully prepared and investigated in detail by ultraviolet visible spectroscopy, X-ray diffraction, and transmission electron microscopy. Excitingly, these pillar[6]arene stabilized silver nanoparticles were demonstrated to function as a colorimetric sensor to selectively probe glutamic acid in water.     

Cucurbit[7]uril promoting PdCl2-catalyzed cross-coupling reaction of benzyl halides and arylboronic acids in aqueous media

The research provides a novel approach for producing diarylmethane derivatives using CB[7]–NaCl–PdCl₂ catalyzed Suzuki cross-coupling reaction of benzyl chloride derivatives and arylboronic acids in ethanol aqueous solution.     

Self-assembly of a thymine quartet and quadruplex via an organic template

The synthesis of two hydrophobic cavitands bearing four (1) and eight (2) thymidine residues covalently linked with triazole moieties is reported. Spectral evidence indicates the adoption of a hydrogen-bonded T-quartet assembly by 1 in chloroform at low temperature and a π-stacked quadruplex by 2 in DMSO under ambient conditions.     

Synthesis of compounds based on a dimesitylmethane scaffold and representative binding studies showing di- vs monosaccharide preference

Dimesitylmethane-based compounds 9–17, incorporating four groups capable of serving as hydrogen bonding sites, such as pyrazole, pyrimidine, imidazole, indole and aminoalkyl groups, were prepared and their ability to complex selected carbohydrates tested. The tetrasubstituted dimesitylmethane scaffold provides a cavity of a correct shape and size for disaccharide encapsulation and its aromatic units are able to participate in CH-π interactions with the sugar substrate. First binding studies confirmed the expected di- vs monosaccharide binding preference of this type of compounds and their tendency to form strong complexes with maltoside.     

Pseudo-Bonding Interaction between Boron-doped Heterofullerene and Zinc Porphine Predicted by DFT Calculation

Theoretical study on the supramolecular complexes formed between boron-doped het- erofullerene （C59B） and zinc porphine （ZnF）, namely C59B-ZnP and its anion species C59B-ZnP, was performed by density functional theory calculation at wB97XD/6-31G（d） level. Strong interaction between porphyrin and heterofullerene moiety was predicted for these complexes based on geometry and electronic structure analysis. Especially, pseudobonding interaction occurring between the B atom of fullerene and the N atom of porphyrin was predicted to occur in C59B-ZnP complex, but be broken in C59B-ZnP complex. Time-dependent density functional theory calculation manifests the redshift of electron absorption for ZnP upon the interaction with heterofullerene.     

A new 3D supramolecular Zn(II) compound: Crystal structure and important role in treatment of pulpitis

An innovative thermostable 2-D layered Zn(II) compound, chemical terms are written as [Zn(3-pysa)₂(H₂O)₂]_n (1, 3-Hpysa = 3-pyridinesulfonic acid), has been generated from the solvothermal reactions of 3-Hpysa and Zn(NO₃)₂·6H₂O. Its single crystal analysis was implemented via the single crystal X-ray diffraction analysis together with the powder X-ray diffraction, elemental analysis and thermogravimetric analysis. The crystal framework is of monoclinic P2₁/n space group and its crystal cell figures: a = 7.7499(5), b = 10.9923(6), c = 8.3430(5) Å, α = 90, β = 96.924(6), γ = 90°, V = 705.55(7) ų, Z = 4. The 2D layers were finally combined to a 3-D supramolecular conformation through intermolecular H-bonds existing between coordinated H₂O molecules and sulfonate oxygen atoms from adjacent layer. Its practical role in pulpitis treatment was estimated and the relevant mechanism was studied in the meantime.     

Dosimetric gelator probes and their application as sensors

Supramolecular gels formed by the self-assembly of organic molecules are useful in many areas from materials to medicine. Of the different applications, exploitation of gels for the visual detection of analytes is a fairly recent trend in gel chemistry. Most of the gel-based sensors rely on non-covalent interactions between the gelator molecules and the added chemical analytes and therefore, often suffer from less selectivity and long response time. In this context, dosimetric gelator probes are superior to other gel-based sensors with high selectivity and fast response time. Unlike non-covalent binding sites, dosimetric gelators typically contain a reaction centre and undergo a specific chemical reaction selective to an analyte resulting in either formation or rupturing of covalent bonds. In this review, we provide an up-to-date report of various reaction-based gel systems applied for the sensing of analytes. We elaborately discuss the concept, design principles, self-assembly properties, and reaction mechanisms of such gelators. We also highlight the limitations, challenges, and the necessity of further exploration of dosimetric gels in this domain.     

基于豆甾醇衍生物的超分子凝胶的合成与性能

设计合成出两种含有不同结构单元的新型豆甾醇衍生物凝胶因子（化合物1和2）。通过扫描电子显微镜（SEM）、傅里叶变换红外光谱（FT-IR）和紫外-可见光谱（UV-Vis）等技术手段对形成凝胶的结构和性能进行研究。结果表明,两种凝胶因子可分别在二甲基亚砜及甲醇溶剂中形成稳定的凝胶。其中化合物1还可在二甲基亚砜/水混合溶液体积比分别为9∶1、8∶2和7∶3中形成稳定的凝胶。当化合物1和2在DMSO溶剂中以质量浓度均为12 mg/mL形成凝胶时,二者的凝胶-溶胶相转变温度（T_gel）分别为51和46 ℃,表明随着凝胶因子中甾体结构单元的增加,其形成凝胶的热稳定性显著下降。在此基础上,以化合物1制备的凝胶为载体,通过紫外-可见光谱对罗丹明B、亚甲基蓝和阿霉素的包封与释放应用进行了研究。结果表明,制备的凝胶可以作为药物载体,并在240 min时在水中达到的最大释放值为84％。本文为豆甾醇衍生物凝胶的制备,及将其作为药物载体在药物输送领域的应用提供了有益的思路。