Chiral transmission to crystal photodimerizations of leucine–methionine quasiracemic assemblies

Topochemical polymerization for preparing polymer crystals

“…Kole等 [26] [34] . 同样是化合物7 [35] , 也可以形成矩 [28] (网络版彩图) http://engine.scichina.com/doi/10.1360/N032016-00065 图 3 第2种策略反应原理示意图 [32] [36] . 另外, 关于Zn的配位反 应也有很多 [37,38] .…”

“…开始出现 [75] . Marques等 [76] 在13 GPa、820 K的条件下 C=C双键作为反应活性中心的体系, 应用范围比 较广泛, 既可用于光开关、传感器、发光二极管 [26,48,56] 中, 也可用于手性分子可控合成以及生物化学方面 [28] , 还可用于制备渗透膜实现海水淡化 [19] 等. 例如, 化合 物3的碱金属化合物单晶及其光二聚物单晶都具有蓝 光效应, 其中单体单晶在蓝光区域有尖峰, 而聚合物单 晶在紫光区域有宽峰, 光聚前后两种单晶在470 nm的 发射强度显著降低, 因此利用这种性质, 这个系统可 以用来设计能应用于光记录、光开关及传感器中的 材料 [26] .…”

Chemo- and Stereospecific Solid-State Thermal Dimerization of Sodium trans-2-Butenoate and γ-Ray-Induced Single-Crystal-to-Single-Crystal Dimerization of Hexaaquamagnesium trans-2-Butenoate Dihydrate: Both Give rel-(3S,4R)-1-Hexene-3,4-dicarboxylate but by Different Mechanisms. Stereospecific γ-Ray-Induced Trimerization of Sodium trans-2-Butenoate

“…The dimer occupies a center of symmetry, which results in a 1:1 disorder of the CH 2 =CH− and CH 3 CH 2 − ends of the molecule. The torsion angles C1−C2−C2′−C3′ and C4−C3−C2−C2′ for the major product are 60.5 (11)°and 98.5(14)°, while torsion angles C1− C21−C21′−C31′ and C41−C31−C21−C21′ for the minor product are −54.6(11)°and 175.9(11)°, respectively. While there are only a few structural analogues for the 98.5°and 175.9°t orsion angles, the two different values appear to represent the expected values for each "end" of the disordered product.…”

“…The design and discovery of new classes of materials that undergo solid-state transformations to give products unavailable from solution chemistry and the elucidation of the principles that govern their reactivity remain important challenges in the field. − The use of ionizing radiation as an excitation source provides new synthetic opportunities distinct from thermal or photochemical stimuli. 60 Co γ-rays can initiate radical chain reactions in crystals that lead to products from alkenes very different from those obtained photochemically, such as the cyclobutane derivatives obtained by solid-state [2 + 2] photocycloadditions of cinnamates and other highly conjugated alkenes. − Nonetheless, the distance criterion of the topochemical postulate (C···C contacts ≤4.2 Å), first established by Schmidt and co-workers, , appears to hold well for radical chain reactions in the solid state. − 60 Co γ-ray initiated radical chain solid-state polymerization of solid metal acrylates was first discovered nearly 60 years ago. , Ionizing radiation also effectively initiates single-crystal-to-single-crystal solid-state polymerization of a wide range of diacetylenes and muconate esters. − Although 60 Co γ-ray irradiation of solid metal complexes of acrylates, methacrylates, propynoates, and other unsaturated carboxylates showed widespread reactivity, , the polymeric products were mostly amorphous and atactic, with a unique stereoregular example …”

“…The γ-ray-induced radical chain solid-state dimerization reactions of trans -2-butenoic acid are orthogonal to the better-known solid-state [2 + 2] photocycloadditions of cinnamates and other highly conjugated alkenes. − Cinnamates lack the allylic hydrogen atom needed for initiation of the radical chain upon γ-irradiation. Even with the heavy atom, crystalline ( E )-4-bromocinnamic acid affords the cyclobutane dimer β-truxinic acid in only 24% yield after exposure to a very large 1160 kGy γ-ray dose .…”