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Transition structures for the cycloadditions of butadiene, acrolein, nitrosoethylene, and methylenenitrone to 1-butene, silyl vinyl ether, and methyl vinyl ether have been located using ab initio RHF theory with the 3-21G basis set and with density functional theory using the Becke3LYP functional and the 6-31G* basis set. The computational results show that there is a switch in the conformation of the enol ether from syn (COCC ) 0°), which is favored by 2.3 kcal/mol in the reactant, to anti (COCC ) 180°), which is favored by 1.2-6.6 kcal/mol in the various transition structures studied here. The results are consistent with the experimental stereoselectivities in reactions of chiral enol ethers observed by Denmark and Reissig. The preference of the anti conformation in the transition structures is due primarily to electrostatic effects and, to a lesser extent, steric effects. The preference is predicted to be influenced significantly by polar solvents. The magnitude of this preference was calculated theoretically and measured experimentally: the rates of cycloadditions of conformationally fixed enol ethers, 2,3-dihydrofuran and 2-methylenetetrahydrofuran, with 1-nitroso-1-phenylethylene and with C-benzoyl-N-phenylnitrone were studied. Observed relative rates are in good agreement with prediction and confirm that enol ethers adopt the s-trans conformation in transition states of cycloadditions.

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Two compounds, 9,10-bis[2-(quinolyl)vinyl]anthracene (BQVA) and 9,10-bis[2-(naphthalen-2-yl)vinyl]anthracene (BNVA), have been synthesised and investigated. Both of them have aggregation-induced enhanced emission (AIEE) properties. Heteroatom-assisted BQVA shows solvatochromism, reversible chromism properties and self-assembly effects. When increasing the solvent polarities, the green solution of BQVA turns to orange with a redshift of the fluorescence emission wavelengths from λ=527 to 565 nm. Notably, BQVA exhibits reversible chromism properties, including mechano- and thermochromism. The as-prepared BQVA powders show green fluorescence (λem=525 nm) and the colour can turn into orange (λem=573 nm) after grinding. Interestingly, the orange colour can return at high temperature. Based on these reversible chromism properties, a simple and convenient erasable board has been designed. Different from BQVA, non-heteroatom-assisted BNVA has no clear chromic processes. The results obtained from XRD, differential scanning calorimetry, single-crystal analysis and theoretical calculations indicate that the chromic processes depend on the heteroatoms in BQVA. Additionally, BQVA also exhibits excellent self-assembly effects in different solvents. Homogeneous nanospheres are formed in mixtures of tetrahydrofuran and water, which are then doped into silica nanoparticles and treated with 3-aminopropyltriethoxysilane to give amino-functionalised nanoparticles (BQVA-AFNPs). The BQVAAFNPs could be used to stain protein markers in polyacrylamide gel electrophoresis.