STRUCTURE OF CRYSTALLINE TETRAPHENYLPORPHINE . STEREOCHEMICAL NATURE OF PORPHINE SKELETON
STRUCTURE OF CRYSTALLINE TETRAPHENYLPORPHINE . STEREOCHEMICAL NATURE OF PORPHINE SKELETON
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DOI：
10.1021/ja01064a008
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发表时间：
1964-01-01
影响因子：
15
通讯作者：
HAMOR, TA
中科院分区：
文献类型：
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作者：
HAMOR, MJ;HOARD, JL;HAMOR, TA
对四苯基卟啉四方单晶的 Cu Ka 辐射可照相记录的所有三维 X 射线衍射数据的分析提供了原子排列的明确描述。空间群是I42d，所需的分子对称性是Si-4，并且通过傅里叶差分合成清楚地解析了与氮相连的氢的“半原子”峰；堆叠无序不会严重影响准确性的暗示也得到其他证据的支持，例如，可观察到的反射的高产量，大约。理论值的 91%。卟啉骨架获得的键长被认为是迄今为止报道的最准确的值。简单的理论表明，在足够低的温度下，无约束的卟啉骨架的平衡构型有些褶皱，但通过平均平面反射构型的能量势垒非常低，以至于在常温下骨架是准平面的并且容易变形。因此，在结晶四苯基卟啉中观察到的卟啉骨架的褶皱（图1）与在结晶酞菁中观察到的准平面分子的平行堆叠实现了相互调节。
Analysis of all three-dimensional X-ray diffractiondata photographically recordable with Cu Ka radiation from tetragonal single crystals of tetraphenylporphine provides a definitive description of the atomic arrange-ment. The space group is I42d, the required molecular symmetry is Si-4, and “half-atom” peaks for hydrogen attached to nitrogen are clearly resolved by Fourier difference synthesis; the implication that stacking disorder does not seriously affect accuracy is supported also by other evidence, eg, the high yield of observable re-flections, ca. 91% of theoretical. Bond lengths obtained for the porphine skeleton are thought to be the most accurate values thus far reported. Simple theory suggests that at sufficiently low temperature the equilibrium configuration of the unconstrained porphine skeleton is somewhat ruffled, but theenergy barrier to reflection of configuration through the mean plane is so low that at ordinary temperatures the skeleton is quasi-planar and easily deformable. Thus a mutual accommodation of the observed ruffling of the porphine skeleton (Fig. 1) in crystalline tetraphenylporphine with the observed parallel stacking of quasi-planar molecules in the crystalline phthalocyanines is achieved.