Solid state reactivity, molecular

The purpose of the following section is that of providing an overview of reactions that take place within a crystal, i.e. intra-solid reactions. In a way, intra-solid reactions represent an area of chemistry where solid-state and molecular chemical reactivity meet more clearly. 

Garcia-Garibay M (2003) Engineering carbene rearrangements in crystals from molecular information to solid-state reactivity. Acc Chem Res 36 491-498... 

The conclusion of this contribution is rather obvious. All in all, Natura non facit saltus solid-state reactivity and molecular materials engineering obey the same basic rules as those governing polymorphism and solid-to-solid transformations. 

Bloor, D., Ando, D. J., Fisher, D. A., Hubble, C. L. Solid state reactivity of some bis (aromatic sulphonate) diacetylenes. In Molecular metals. Hatfield, W. E. (ed.). New York Plenum Press 1979, pp. 249 253... 

The basis for reactivity in the solid state lies in molecular mobility and molecular complementarity. Grinding is well known to create lattice defects and amorphous phases,and the formation of polymorphic forms of drugs as a result of these stresses is well documented in the pharmaceutical literature. Therefore, the concepts of solid-state reactivity in pharmaceutical materials can be applied to understanding the formation of cocrystals. 

It is with these ideas in mind that we focus here on the design and construction of finite molecular assemblies in the organic solid state. Our intention is to provide an overview of finite assemblies with emphasis on properties that such assemblies may provide solids. We will begin by outlining general criteria for constructing finite molecular assemblies in both the solid state and solution, and then describe assemblies isolated and characterized in the solid state to date. We will then use recent advances in our laboratory to illustrate how finite assemblies can be used to control solid-state reactivity and direct the synthesis of molecules. 

Many solid-state reactions of all types rely on cleavage planes [1]. For example a-cinnamic acid 1 (Fig. 2.1.3) or anthracene 14 (Fig.2.1.13) with slightly inclined planar molecules in double or single layers are reactive in both solid-state photolysis and bromination [16]. The molecular packing of 35 is even more favorable for solid-state reactivity at its varied functionality (Fig. 2.1.21) as the molecules lie flat and as there is additional free space between the aromatic rings. The molecules 35 adopt the zwitterionic form with hydrogen bonds exclusively within the double layers. 

The crystal structure of 69 is 3D-interlocked leaving only rectangular channels that appear too narrow (Fig. 2.1.54) to enable molecular migrations and thus no solid-state reactivity is to be expected for this drug either. While these judgments... 

To show solid-state reactivity the molecular structure must be such as to allow packing of the molecules with close contact between the... 

Yang, L. and Foxman, B.M., Crystal and molecular structure of ammonium trans-2-butenoate, and a preliminary investigation of its solid-state reactivity. Mol. Cryst. Liq. Cryst. 

Choi, T, Peterfy, K., Khan, S. I. and Garcia-Garibay, M. A., Molecular Control of Solid State Reactivity and Biradical Formation in Crystalline Ketones, /. Am. Chem. Soc., 118, 12477, 1996. 

In many respects, the present results resemble the pioneering work of the late G. M. J. Schmidt and his co-workers at the Weizmann Institute of Science, who used crystal structure-solid-state reactivity correlations to elucidate the geometric requirements for intermolecular [2+2]-photocycloaddition. In both his case and ours, distance and angular requirements for reaction were established and the structure and stereochemistry of the products were shown to be simply and directly related to the molecular structure existing in the bulk crystal. 

The diacid-diamine amidation described in reaction 2 in Table 5.4 has been widely studied in the melt, in solution, and in the solid state. When equal amounts of two functional groups are present, both the rate laws and the molecular weight distributions are given by the treatment of the preceding sections. The stoichiometric balance between reactive groups is readily obtained by precipitating the 1 1 ammonium salt from ethanol ... 

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