新型离域碳负离子键：1,3-双（二氰基亚甲基）番红花盐（CNOK·2HO）的晶体结构
New Bond-Delocalized Dianions: The Crystal Structure of 1,3-Bis(dicyanomethylene) Croconate Salt (CNOK · 2HO).
作者信息
Himes Vicky L, Mighell Alan D, Hubbard Camden R, Fatiadi Alexander J
机构信息
Department of Chemistry, The Catholic University of America, Washington, D.C. 20064 and the National Bureau of Standards.
National Bureau of Standards, Washington, D.C. 20234.
出版信息
J Res Natl Bur Stand (1977). 1980 Mar-Apr;85(2):87-97. doi: 10.6028/jres.085.006.
CNOK · 2HO crystallizes in the triclinic space group with = 8.568(2), = 9.105(4), = 9.818(4)Å, = 103.61(3), = 107.63(3), = 101.58(3)°; = 2, = 1.716, = 1.72(2)g cm (flotation). The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final of 0.074 for 1989 observed reflections. The five-membered ring is planar and pentagonal. The two = C(CN) groups define separate planes which form angles of 3.36 and 6.30° with the plane of the five-membered ring. The dianions form stacks along the a-axis. In a given stack, there is an alternating sequence of perpendicular distances (3.32, 3.42Å) between the planes defined by the ring atoms.
CNOK·2HO以三斜空间群结晶，晶胞参数为：a = 8.568(2)，b = 9.105(4)，c = 9.818(4)Å，α = 103.61(3)，β = 107.63(3)，γ = 101.58(3)°；Z = 2，Dc = 1.716，Dm = 1.72(2)g/cm³（浮选法）。结构通过直接法解析，并采用全矩阵最小二乘法精修，对于1989个观测反射，最终R为0.074。五元环呈平面五边形。两个=C(CN)基团定义了与五元环平面分别成3.36°和6.30°角的不同平面。双阴离子沿a轴形成堆积。在给定的堆积中，由环原子定义的平面之间存在垂直距离交替序列（3.32, 3.42Å）。
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