Triaxially Woven Hydrogen-Bonded Chicken Wires of a Tetrakis(carboxybiphenyl)ethene

Interpenetration of low-dimensional networked structural motifs crucially affects porosity, stability, and properties of the whole reticular framework. However, varying and controlling the manner of interpenetration is still challenging. Herein, a porous hydrogen-bonded organic framework (HOF) with wvm -like weave constructed by triaxially woven chicken wires of X-shaped tetra-armed tetrakis(carboxybiphenyl)ethene CBPE , formally 4′,4′′′,4′′′′′,4′′′′′′′-(ethene-1,1,2,2-tetrayl)tetrakis(1,1′-biphenyl-4-carboxylic acid), is reported. The structure is a contrast to a non-interpenetrated layered framework composed of tetrakis(4-carboxyphenyl)ethene CPE . This exotic framework of CBPE is due to the disproportionate conformation of the outer four phenylene rings in the peripheral biphenyl arms. The activated framework CBPE-1a exhibits thermal stability up to 220 °C and a BET surface area of 555 m² g⁻¹. Additionally, the HOF shows mechanochromic behavior in terms of fluorescence color and quantum efficiency. The achievement of the present HOFs can provide insight into constructing a new type of functional porous organic materials with interwoven network structures.     

四-(4-氨基苯)乙烯的合成及溶剂/pH双重响应聚集发光行为

以二苯甲酮为原料,经McMurry、硝化、还原反应合成了化合物3,总收率为59%,其化学结构经¹H NMR和¹³C NMR确证。进一步采用紫外可见吸收光谱和荧光光谱对3在溶液中的聚集发光行为进行研究,结果表明：化合物3具有可逆的溶剂/pH双重响应聚集诱导发光(AIE)特性,主要是由于其在溶液中的聚集状态发生变化。      

Blue Tetrakis(diisopropylamino)-cyclo-tetraborane and Yellow Tetrakis(tetramethylpiperidino)tetrabora-tetrahedrane

The colored boranes closo- 1 and cyclo- 2 are obtained upon dehalogenation of sterically hindered diaminodichlorodiborane(4) 3 . The TMP groups of 1 cause the formation of a tetrahedrane, whereas in 2 the diisopropylamino substituents stabilize the bent four-membered ring. TMP=2,2,6,6-tetramethylpiperidino.     

Bis- and tetrakis(organosilyl) decatungstosilicate,

The high propensity of organosilanes towards polycondensation and reaction with nucleophilic moieties has facilitated the formation of new organic-inorganic hybrids based on the lacunary divacant heteropolyanion [gamma-SiW10O36]8-. Depending on the experimental conditions two different types of derivatives were obtained with the general formula [gamma-SiW10O36(RSi)2O]4- (1) (>90% yield) and [gamma-SiW10O36(RSiO)4]4- (2) (>85% yield) (R = H (1a, 2a), vinyl (1b), -C3H6OC(O)C-(Me)=CH2 (1c, 2c), phenyl (1d, 2d)). The structures of the hybrid anions have been inferred from spectroscopic data, in particular from multinuclear (29Si and 183W) NMR solution studies and from MALDI-TOF mass spectrometry. Both species correspond to the grafting of an oxo-bridged siloxane unit onto the surface of the lacunary polyoxoanion.     

Tetrakis(trimethylsilyl)tetrahedrane

Tetrakis(trimethylsilyl)tetrahedrane 3 has been synthesized upon irradiation of tetrakis(trimethylsilyl)cyclobutadiene 8, which can be prepared either by thermal nitrogen elimination from trimethylsilyl[1,2,3-tris(trimethylsilyl)-2-cycloprop-1-enyl]diazomethane 7 or by mild oxidation of cyclobutadiene dianion 9 with 1,2-dibromoethane. The structural characterization of tetrahedrane 3 has been achieved by X-ray crystallography. The surprising thermal stability of 3 - which is stable up to 300 degrees C - is discussed.     

Tetrakis(2-hydroxyphenyl)ethene and derivatives. A structurally preorganized tetradentate ligand system for polymetallic coordination chemistry and catalysis

A topologically unique, conformationally constrained tetradentate ligand system for polymetallic coordination chemistry has been developed: tetrakis(2-hydroxyphenyl)ethene (1a) and substituted derivatives. The design exploits the planarity of the tetraphenylethylene core to impart rigidity to the roughly square oxygen binding array, while maintaining a degree of conformational mobility associated with rotation about the aryl-ethylene carbon-carbon bonds. Tetrakis(2-hydroxyphenyl)ethene derivatives are designed to promote multiple metal bridging over chelating coordination modes. The ligand is synthesized from anisole or 4-tert-butylanisole in four steps via the 2,2'-dimethoxybenzophenone hydrazones 4a,b. The sterically hindered ortho-substituted tetraphenylethylene core is produced in high yield by acid-catalyzed decomposition of the corresponding diaryl diazomethane prepared in situ by oxidation of the hydrazone using nickel peroxide. Deprotection of the methyl ethers using boron tribromide gives tetrakis(2-hydroxyphenyl)ethene (1a), characterized by X-ray crystallography, and tetrakis(5-tert-butyl-2-hydroxyphenyl)ethene (1b). Sterically isolating substituents in the 3-position can be installed via Claisen rearrangement/hydrogenation, providing tetrakis(3-n-propyl-2-hydroxyphenyl)ethene (6) efficiently. To illustrate potential applications of this unprecedented ligand class, two coordination complexes are reported, including tetrakis(2-diethylaluminoxyphenyl)ethene (8), a structurally robust eight-membered-ring aluminum/oxygen crown complex characterized both in solution and in the solid state.