Two geometrical isomers, exo- and endo-[VO(3-EtOsal-meso-stien)] (H2(3-EtOsal-meso-stien) = N,N′-di-3-ethoxysalicylidene-(R,S)(S,R)-1,2-diphenyl-1,2-ethanediamine), were selectively prepared separately. X-Ray structure analyses were carried out for two different crystals of the endo-isomer: endo-[VO(3-EtOsal-meso-stien)]·3H2O, (A), monoclinic P21/c, a = 10.435(3), b = 9.696(3), c = 30.948(3) Å, β = 94.87(2)°, V = 3120(1) Å3 and Z = 4; endo-[VO(3-EtOsal-meso-stien)]·CH3CN, (B), monoclinic P21/c, a = 15.935(3), b = 9.510(2), c = 20.891(2) Å, β = 100.58(1)°, V = 3112(1) Å3 and Z = 4. Under an argon atmosphere, the endo-isomer in both crystals A and B isomerized to the exo-isomer completely upon heating at 210 °C for 20 h. The X-ray powder diffraction patterns of the heated crystals A′ and B′ were approximately identical with that of exo-[VO(3-EtOsal-meso-stien)]·H2O (C). In the latter the V=O bonds are arranged in crystals to form a fairly weak linear chain structure (V=O···V=O···). The drastic rearrangement of the metal complexes in the solid state accompanied by the isomerization reaction indicates that the thermal reaction proceeds in a non-topochemical fashion.
                                    选择性地分别制备了两种几何异构体:外向异构体和内向异构体[VO(3-EtOsal-meso-stien)](H2(3-EtOsal-meso-stien) = N,N′-二-3-乙氧基
水杨-(R,S)(S,R)-1,2
-二苯基-1,2-
乙二胺)。对内向异构体的两种不同晶体进行了 X 射线结构分析:内向[VO(3-EtOsal-meso-stien)]-3H2O,(A),单斜 P21/c,a = 10.435(3),b = 9.696(3),c = 30.948(3)埃,β = 94.87(2)°,V = 3120(1) Å3,Z = 4;内[VO(3-EtOsal-meso-stien)]-CH3CN,(B),单斜 P21/c,a = 15.935(3),b = 9.510(2),c = 20.891(2) Å,β = 100.58(1)°,V = 3112(1) Å3,Z = 4。在
氩气环境下,晶体 A 和 B 中的内异构体在 210 °C 下加热 20 小时后完全异构成外异构体。在后者中,V=O 键在晶体中排列成相当弱的线性链结构(V=O---V=O---)。
金属络合物在固态下的剧烈重排和异构化反应表明,热反应是以非拓扑
化学方式进行的。