Synthesis, structural, spectral, and photoswitchable properties of cis- and trans-2,2,2',2'-tetramethyl-1,1'-indanylindanes

As versatile synthetic intermediates for new photoswitchable molecules with a tetramethylindanylindane (stiff-stilbene) core, the cis and trans isomers of 5,16-dibromo-2,2,13',13'-tetramethylindanylindanes 2 were synthesized by the Barton-Kellogg coupling. The bromine atoms of trans-2 could be readily replaced with alkyl (sp3), aryl (sp2), and ethynyl (sp) groups. The cis isomers of the parent tetramethylindanylindane 1 and its bromo derivative 2 were isolated, and their structural and photophysical properties were examined for the first time. Clean and efficient trans-cis and cis-trans photochemical isomerization processes were observed in 1.     

Synthesis, Crystal Structure and Theoretical Calculation of 1,1',5,5'-Tetramethyl-2,2'-diphenyl-4,4'-[i-phenylene-bis(methylidynenitrilo)] di-1H-pyrazol-3(2H)-one

1,1',5,5'-Tetramethy1-2,2'-diphenyl-4,4'-[i-phenylenebis(methylidynenitrilo)]di1H-pyrazol-3(2H)-one was synthesized and characterized by X-ray single-crystal diffraction analysis. The crystal crystallizes in monoclinic, space group P21/c with a = 6.1375(1), b =24.6571(4), c = 17.7487(3)(A), β = 94.781(1)°, V= 2676.62(8)(A)3, C30H28N6O2, Mr= 504.58, Z = 4,Dc = 1.252 g/cm3, F(000) = 1064, μ = 0.081 mm-1, R = 0.0463 and wR = 0.1153 (I ＞ 2σ(Ⅰ)).Theoretical studies of the title compound were carried out by density functional theory (DFT) BLYP method, using ADF program package. It indicates that N(26) and N(41) are active sites of the title compound.     

1,1-Dichloro-2,2,2-trihaloethyl Isocyanates and N-(1-Chloro-2,2,2-trihaloethylidene)urethanes in the Synthesis of 4-Trihalomethyl-2H-1,3-benzoxazin-2-ones

4-Trihalomethyl-2H-1,3-benzoxazin-2-ones have been synthesized by the reaction of 1,1-dichloro-2,2,2-trihaloethyl isocyanates or N-(1-chloro-2,2,2-trihaloethylidene)urethanes with 3-dialkylamino(alkoxy)phenols. The character of the products from the addition of nucleophiles has been shown to depend on the nature of the nucleophile and the trihalomethyl group.     

Highly efficient synthesis of optically pure 5,5',6,6',7,7',8,8'-octahydro-1,1'-bi-2-naphthol and -naphthylamine derivatives by partial hydrogenation of 1,1'-binaphthyls with carbon nanofiber supported ruthenium nanoparticles

Use of Ru/CNF-P, nanoruthenium particles dispersed on a nanocarbon fiber support, realizes highly efficient catalytic partial hydrogenation of 1,1'-bi-2-naphthol and -naphthyl-amine derivatives. The reactions proceed in high turnover numbers without racemization of the axial chirality, offering a practical procedure for the production of optically pure 5,5',6,6',7,7',8,8'-octahydro-1,1'-binaphthyls in good to high yields.     

1,1',3,3',6,6',8,8'-Octachloro-9,9'-bifluorenylidene and perchloro-9,9'-bifluorenylidene,two exceedingly twisted ethylenes

The syntheses of 1,1',3,3',6,6',8,8'-octachloro-9,9'-bifluorenylidene (1), its precursors, and the byproduct 3,3',5,5'-tetrachloro-4-(trichloromethyl)biphenyl (5) are described. Accurate structural X-ray data on 1 and on perchloro-9,9'-bifluorenylidene (2) are reported and discussed. Because of chlorine overcrowding, the dihedral angles between their two identical fluorenylidene moieties are abnormally large, the central-ethylene twist angles being 55 and 66 degrees, respectively. Significant out-of-plane carbon-chlorine bond bending is likewise exhibited. Their ESR spectra and magnetic measurements prove that they are singlet species. The exceptionally large bathochromic displacements of their UV-vis absorption spectrum with respect to that of their parent hydrocarbon are mainly attributed to bond bending and molecular warping.