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首页> 外文期刊>Acta Crystallographica Section E: Crystallographic Communications >Crystal structures of ethyl 6-(4-methyl-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate and ethyl 6-(4-fluoro-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate
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Crystal structures of ethyl 6-(4-methyl-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate and ethyl 6-(4-fluoro-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate

机译：6-（4-甲基-苯基-基）-4-氧代-4H-色烯-2-羧酸乙酯和6-（4-氟-苯基-基）-4-氧代-4H-色烯乙酯的晶体结构-2-羧酸盐

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The crystal structures of two chromone derivatives, viz. ethyl 6-(4-methyl-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate, C19H16O4, (1), and ethyl 6-(4-fluoro-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate C18H13FO4, (2), have been determined: (1) crystallizes with two mol-ecules in the asymmetric unit. A comparison of the dihedral angles beween the mean planes of the central chromone core with those of the substituents, an ethyl ester moiety at the 2-position and a para-substituted phenyl ring at the 6-position shows that each mol-ecule differs significantly from the others, even the two independent mol-ecules (a and b) of (1). In all three mol-ecules, the carbonyl groups of the chromone and the carboxyl-ate are trans-related. The supra-molecular structure of (1) involves only weak C—H?π inter-actions between H atoms of the substituent phenyl group and the phenyl group, which link mol-ecules into a chain of alternating mol-ecules a and b, and weak π–π stacking inter-actions between the chromone units. The packing in (2) involves C—H?O inter-actions, which form a network of two inter-secting ladders involving the carbonyl atom of the carboxyl-ate group as the acceptor for H atoms at the 7-position of the chromone ring and from an ortho-H atom of the exocyclic benzene ring. The carbonyl atom of the chromone acts as an acceptor from a meta-H atom of the exocyclic benzene ring. π–π inter-actions stack the mol-ecules by unit translation along the a axis.
机译：两种色酮衍生物的晶体结构。 6-（4-甲基-苯基-基）-4-氧代乙酯4H-亚甲基-2-羧酸酯，C19H16O4，（1）和6-（4-氟-苯基-基）-4-氧代乙酯已确定-4H-亚甲基-2-羧基-C18H13FO4，（2）：（1）在不对称单元中以两个分子孔结晶。中心色酮核心的平均平面与取代基的平均平面之间的二面角，在2位的乙酯部分和在6位的对位取代的苯环之间的二面角比较表明，每个分子-分子都有显着不同（1）的两个独立分子（a和b）。在所有三个分子胞中，色酮和羧酸酯的羰基是反式相关的。 （1）的超分子结构仅涉及取代基苯基和苯基的H原子之间的弱CH-π相互作用，其将分子连接成交替的分子a和b的链，色酮单元之间的弱π-π堆积相互作用。 （2）中的堆积涉及CHH相互作用，它形成两个相交的梯形网络，其中涉及色氨酸7位的H原子为羧基的羧基基团的羰基原子作为受体环和来自环外苯环的邻氢原子。色酮的羰基原子充当来自环外苯环的间-H原子的受体。 π–π相互作用通过沿a轴的单位平移堆叠分子。

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