Theoretical Study on the Topochemical Nature in the Initiation Process of the Solid-State Thermal Isomerization Reaction of Methyl 4-(Dimethylamino)benzenesulfonate

Abstract

The initiation process of the thermal isomerization reaction from methyl 4-(dimethylamino)benzenesulfonate (MDBS) to N,N,N-trimethylbenzenaminium-4-sulfonate (TBS) in the crystalline state has been studied by theoretical calculations: Structural optimization of possible ionic intermediates and the transition-state structure has been carried out by ab initio MO calculations. The comparison of the obtained transition-state structure with the molecular arrangement in the MDBS crystal indicates that cooperative rotation of molecules around their molecular long axes coupled with structural deformation of the methoxy group in an MDBS molecule is necessary for the topochemical initiation reaction for the thermal isomerization in the crystal.

Kinetics and mechanism of structural transformations of 2-(5-ethoxycarbonylmethyl-4-oxothiazolidin-2-ylidene)-N-(2-phenylethyl)-ethanamide during heating

“…These methods are based on the Coats-Redfern approxima tion [21]: (8) Combining Eqs. (5) and (8) we get the KAS method in form the expression:…”

“…For resolution of this problem Flynn and Wall [24] and Ozawa [25] independently use Doyle's approxi mation of p(x) [26] in the form: (10) Using Eqs. (5) and (10) we obtain FWO method in form the expression: (11) The left parts of the Eqs. (9) and (11) are linear with respect to the inverse temperature 1/T α , and the apparent activation energy can be evaluated using a linear regression method for every value of α.…”

“…Many new and different reactions, concerning isomerization, dimerization and polymerization, acti vated thermally and photochemically, which modify the state of the molecules in the crystalline media have been the focus of recent research efforts [1][2][3][4][5] to a point where one can say that solid state reactions have now entered into the mainstream of organic chemistry. The push pull alkenes represent an excellent model for investigation of the effects of weak non covalent inter actions on relationships between structure and reactiv ity in solution and in the solid state [6][7][8].…”

Hexagonal Mesoporous Titanium Tetrasulfonates with Large Conjugated Hybrid Framework for Photoelectric Conversion

“…Electron injection into the conduction band (CB) of TiO 4 occurred from the first excited singlet state (S 1 ) of CuPcS 4 instead of from the first excited triplet state (T 1 ), which is a usual mechanism in dye sensitization of TiO 2 with phthalocyanines (44), shown in Figure S5 (Supporting Information). The large conjugated system of CuPcS 4 molecules could be elongated probably through the participation of sulfur d-orbit into the π system of the connected benzene (45), which acted as both bridging and binding moieties. Generally, this one-pot strategy of condensing TiCl 4 with CuPcS 4 would lead to the molecular-level penetration of large π-aromatic groups into the semiconductor network with limited polymerization degree (TiO 4 oligomers), and the high contact and utilization of organic dyes and the semiconductors in the hybrid materials would contribute to improve the photoelectric conversion efficiency.…”

S-[4-(Trimethylammonio)phenyl]thiosulfate, an aromatic organic thiosulfate

“…The compound that is most closely comparable to (I) is zwitterionic 4-(trimethylammonio)benzenesulfonate, (II) (Even et al, 1999), which is obtained from the thermally induced rearrangement of methyl 4-(dimethylamino)benzenesulfonate (Kusto et al, 1999). The rearrangement has been investigated theoretically (Oda & Sato, 1998) and the driving force has been attributed to the large electric dipolar interactions among the zwitterions in the resulting product (Oda & Sato, 1997). Compound (II) exhibits three phases, viz.…”