X-ray Structures of 1-Ethynyl-2-Nitrobenzene and 1-Ethynyl-4,5-Dimethyl-2-Nitrobenzene: Correlation to the Enhanced Rate of Hydration and Investigation of the C–H···O Alkyne-Nitro Hydrogen Bonding
作者:Eric Bosch、Laura Jeffries
DOI:10.1007/s10870-016-0660-0
日期:2016.7
The single crystal X-ray structures of 2-nitrophenylacetylene, 1, and 4,5-dimethyl-2-nitrophenylacetylene, 2, are presented. In both structures the nitro moiety is essentially coplanar with the benzene ring and interacts with the proximal alkyne which is slightly distorted. The crystal packing of both compounds is dominated by intramolecular alkyne-nitro C–H···O hydrogen bonds that are supplemented by weak arene C–H···O (nitro) hydrogen bonds. Compound 1 crystallizes in the monoclinic space group P21/c with a = 3.7874(5), b = 13.0673(16), c = 13.98174(17) Å, β = 90.587(2) and Z = 4. The molecule is disordered over two sites with occupancy ratio of 88:12. Compound 2 crystallizes in the triclinic space group P-1 with a = 7.6080(5), b = 9.8811(6), c = 12.8240(8) Å, α = 108.1760(10), β = 102.4170, γ = 96.6480(10) and Z = 4. The intermolecular interactions in both structures were dominated by alkyne-nitro and arene-nitro C–H···O hydrogen bonds. The structures of 2-nitrophenylacetylene and 4,5-dimethyl-2-nitrophenylacetylene display a strong nitro-alkyne intramolecular O···C interaction resulting in distortion of the alkyne and terminal alkyne-nitro CH···O intermolecular interactions.
呈现了2-硝基苯乙炔(1)和4,5-二甲基-2-硝基苯乙炔(2)的单晶X射线结构。在这两种结构中,硝基基团基本上与苯环共平面,并与略微扭曲的近端炔烃相互作用。这两种化合物的晶体堆积主要由分子内炔烃-硝基C–H···O氢键主导,同时也有弱的芳香烃C–H···O(硝基)氢键作为补充。化合物1结晶于单斜晶系P21/c空间群,a = 3.7874(5) Å, b = 13.0673(16) Å, c = 13.98174(17) Å,β = 90.587(2)°,Z = 4。该分子在两个位置上无序,占据比例为88:12。化合物2结晶于三斜晶系P-1空间群,a = 7.6080(5) Å, b = 9.8811(6) Å, c = 12.8240(8) Å,α = 108.1760(10)°,β = 102.4170°,γ = 96.6480(10)°,Z = 4。这两种结构中的分子间相互作用主要由炔烃-硝基和芳香烃-硝基C–H···O氢键主导。2-硝基苯乙炔和4,5-二甲基-2-硝基苯乙炔的结构展示了强烈的硝基-炔烃分子内O···C相互作用,导致炔烃的扭曲和末端炔烃-硝基CH···O分子间相互作用。