Structures of 2,6-disubstituted naphthalenes.
Structures of 2,6-disubstituted naphthalenes.
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2,6-二取代萘的结构。
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
Golab
中科院分区：
文献类型：
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作者：
Kaduk;Golab
结合x射线粉末衍射和计算化学技术从头计算了2,6-萘二羧酸（NDA）和2,6-萘二羧酸二甲酯（NDC）的晶体结构。这两种晶体结构，以及2,6-二甲基萘（DMN）的晶体结构，已经通过Rietveld技术得到了改进。DMN在正交空间群Pbca中结晶，a = 7.4544 (4), b = 6.0826 (6), c = 20.0946 （12） Å， V = 911.1 (1) Å(3), Z = 4。结构由平行于a的人字形堆叠构成，形成垂直于c的松散结合层。NDA在三斜空间群P1中结晶；，其中a = 3.7061 (8), b = 7.4688 (14), c = 8.5352 （22） Å， alpha = 86.62 (2), beta = 85.49 (2), gamma = 87.99(2)度，V = 235.00 (6) Å(3), Z = 1。结构由沿[11；1]松散排列的氢键链组成。NDC在单斜空间群P2(1)/c中结晶，在300 K和Z = 2时，a = 13.41931 (14), b = 6.14869 (5), c = 7.15257 (5) Å， beta = 100.400(1)度，V = 580.47 (1) Å(3)。该结构由垂直于a的NDC分子层组成。NDC中的酯基在平均环平面外扭曲了20度。NDA和NDC的羧基构象不同。MP2计算表明，NDC中观察到的扭转对应于构象能增加9 kJ mol（-1）。
The crystal structures of 2,6-naphthalenedicarboxylic acid (NDA) and dimethyl 2,6-naphthalenedicarboxylate (NDC) have been solved ab initio using a combination of X-ray powder diffraction and computational chemistry techniques. These two crystal structures, and that of 2,6-dimethylnaphthalene (DMN), have been refined by the Rietveld technique. DMN crystallizes in the orthorhombic space group Pbca, with a = 7.4544 (4), b = 6.0826 (6), c = 20.0946 (12) Å, V = 911.1 (1) Å(3) and Z = 4. The structure consists of a herringbone stacking parallel to a, resulting in loosely bound layers perpendicular to c. NDA crystallizes in the triclinic space group P1;, with a = 3.7061 (8), b = 7.4688 (14), c = 8.5352 (22) Å, alpha = 86.62 (2), beta = 85.49 (2), gamma = 87.99 (2) degrees, V = 235.00 (6) Å(3) and Z = 1. The structure consists of loosely packed hydrogen-bonded chains along [11;1]. NDC crystallizes in the monoclinic space group P2(1)/c, with a = 13.41931 (14), b = 6.14869 (5), c = 7.15257 (5) Å, beta = 100.400 (1) degrees, V = 580.47 (1) Å(3) at 300 K and Z = 2. The structure consists of layers of NDC molecules perpendicular to a. The ester group is twisted 20 degrees out of the mean ring plane in NDC. The conformations of the carboxyl groups in NDA and NDC differ. MP2 calculations suggest that the observed twist in NDC corresponds to an increase in conformational energy of 9 kJ mol(-1).