Synthesis, Crystal Structure and Thermal Property of Dimethyl Phenanthrene-9,10-dicarboxylate

The target compound(C;H;O;) was synthesized and structurally determined by single-crystal X-ray diffraction. The crystal is of monoclinic system, space group P2;/n with a = 7.9383（6）, b = 19.5083（13）, c = 9.4189（7） ?, β = 98.981（2）°, C;H;O;, Mr = 294.29, D;= 1.357 g/cm;, V = 1440.75（18） ?;, Z = 4, F（000） = 616, μ（MoKa） = 0.096 mm;, T = 293（2） K, 3320 independent reflections with 1845 observed ones(I > 2σ（I）), R = 0.0529 and wR = 0.1082 with GOF = 1.015（R = 0.1202 and wR = 0.1278 for all data）. The phenanthrene skeleton is coplanar. The overall crystal packing revealed that it has reverse staggered parallel and stratified arrangement. And a one-dimensional interaction model was formed by two kinds of π-π interactions between the two adjacent molecules at upper and lower levels. The decomposition mechanism of compound 3 is complex.