Addition of Dihalocarbenes to a 蟺-Bowl: First Structural Study

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• 作者：Cristina Dubceac ; Alexander S. Filatov ; Alexander V. Zabula ; Marina A. Petrukhina
• 刊名：Crystal Growth & Design
• 出版年：2015
• 出版时间：February 4, 2015
• 年：2015
• 卷：15
• 期：2
• 页码：778-785
• 全文大小：454K
• ISSN：1528-7505

文摘

The products of 1,2-cycloaddition of dihalocarbene to the bowl-shaped corannulene (C₂₀H₁₀, 1) have been isolated in the solid state and fully characterized. The first X-ray diffraction analysis of mono- and bis-adducts, C₂₀H₁₀CCl₂ (2) and C₂₀H₁₀(CCl₂)₂ (3), has been accomplished to reveal structural changes of the corannulene framework upon addition of dichlorocarbene groups as well as to show variations in the solid state packing of the functionalized polar bowls. For the monoadduct 2, the C_s symmetric molecular structure with the hub attachment of the CCl₂ group to a bowl was confirmed. In the solid state, the polar C₂₀H₁₀CCl₂ molecules form one-dimensional (1D) columns based on strong concave鈥揷onvex 蟺路路路蟺 interactions (ca. 3.36鈥?.37 脜). The resulting polar 1D stacks in 2 are all oriented in the same direction to form polar crystals. The addition of the second dichlorocarbene group in C₂₀H₁₀(CCl₂)₂ caused the drastic reduction of the dipole moment from 3.7 D in 2 to 2.0 D in 3, which was also accompanied by a change of the solid state packing pattern. For the bis-adduct 3, two different polymorphs were obtained under different crystallization conditions, solution (3a) vs gas-phase deposition (3b). Both crystal structures are based on bimolecular aggregation of C₂₀H₁₀(CCl₂)₂ molecules held by C鈥揌路路路Cl interactions (2.988 脜 for 3a and 2.891 脜 for 3b). The resulting dimers show different packing in the solid state structures of 3a and 3b.