Structure, Synthesis, and Properties of Some Persubstituted 1,2-Dintroethanes. In Quest of Nitrocyclopropyl-Anion Derivatives
作者:Yasushi Kai、Paul Knochel、Stefan Kwiatkowski、Jack D. Dunitz、Jean F. M. Oth、Dieter Seebach、Hans-Otto Kalinowski
DOI:10.1002/hlca.19820650114
日期:1982.2.3
reveal striking structural differences between the openchain and the cyclic derivatives (Fig. 4–6): the central C, C-bond is long in 1 (1.575 Å), short in 2 (1.479 Å); the C, N-bonds are long in 1 (1.549 Å), short in 2 (1.488 Å); the orientation of the nitro groups is bisected in 2 and perpendicular in 1. The crystal structure of the nitro-nitroso compound 3 is isomorphous with that of the dinitro compound
尝试使硝基环丙烷去质子化导致溶液显示出强大的ESR。信号(图1),从中分离出1-硝基-1'-亚硝基双环丙基(3)和1,1'-二硝基-双环丙基(2)。围绕中心C,C键2旋转的活化能估计约为12 kcal / mol(图2中的1 H-NMR光谱)。与此相反,烘箱链类似物2,3-二甲基-2,3-二硝基(1)示出了单甲基下降到-70℃的低温透视分析1,2,3,并且还1,1'-二硝基-二环丁基(4)表明所有四个分子均具有gauche构象,但揭示了开链与环状衍生物之间的显着结构差异(图4-6):中心C,C键长1(1.575Å),短2( 1.479Å); C,N键长1(1.549Å),短2(1.488Å); 硝基的方向一分为二,垂直的一分为二。硝基-亚硝基化合物3的晶体结构与二硝基化合物2的晶体结构同构,因此是无序的(图15-16))。讨论了作为π电子受体的硝基对分子构象和键长的影响。通过对2的各向异性