Organic Solid-state Systems

Far less effort has been directed at organic solid-state spectra than at organo-metallics and coordination complexes. Much of the work on organic systems was done by Walter Gordy and his students at Duke University in the 1960s and 1970s. We review a couple of these experiments here. More information is available in Gordy s book.30... 

Even starting from achiral molecules it is in some systems possible to achieve crystallization in a chiral structure. Perhaps one of the most striking achievements in organic solid-state chemistry has been the trapping of the chirality of such a crystal as the chirality of the stable product of chemical reactions in the crystal. Such asymmetric synthesis has been reviewed (255), and a recent book (256) also provides a thorough discussion of chirality in crystals. The related and fascinating topic of the chemical consequences of the presence of a polar axis in some organic crystals has also been reviewed (257). 

Curtin and Paul [56] contributed substantially also to the investigation of intra-solid reactions between crystals. In this context. Ref [57] constitutes, together with the other references quoted throughout, a useful entry in the recent literature of organic solid-state reactions, including those activated mechanochemically [57]. An early application to the preparation of charge-transfer systems was reported by Toda and Miyamoto [58]. 

Some successful development of rechargeable solid state systems was achieved by using lithium intercalation cathodes, such as TiS2, which operate in exactly the same manner as in the lithium-organic cells described in Chapter 7. One example of this type of cell is provided by the battery system developed in the 1970s by P. R. Mallory and Co. (now Duracell) based on the following scheme ... 

However, metallic conduction in organic systems had been dreamt of as early as 1911 [1]. Until the mid 1960s the serious researchers of the organic solid state were few Hideo Akamatsu [2], Noel S. Bayliss [3], Melvin Calvin [4], Daniel D. Eley [5], Helmuth Kainer [6], Aleksandr I. Kitaigorodskii [7], Jan Kommandeur [8], Yoshio Matsunaga [9], Harden M. McConnell [10], Albert Szentgyorgyi [11], A.N. Terenin [12] and A.T. Vartanyan [12]. 

In recent years interest in these materials has grown mainly for physical reasons. The layer perovskites are looked at as model compounds for the study of magnetic properties in two-dimensional systems (J2) and as models for the study of structural phase transitions in lipid bilayer-type arrays ( ). The use of layer perovskites as a matrix for organic solid state reactions represents a fairly new research topic. First experiments were carried out studying the photolysis of butadiyne (diacetylene) derivatives (li-ZSl) For a corresponding study of the butadiene derivatives the compounds listed in Table I were synthesized. 

Nonradiative energy transfer with the simultaneous involvement of different mechanisms has been modelled by Rotman for solid state systems. Although his treatment is particularly directed towards inorganic systems it is generally relevant to organic systems also. The complex kinetics of sequential energy processes involving four species each with a dependence of rate coefficients has also been analyzed. ... 

Among the numerous examples of organic solid state photopolymerizations (e.g., 9-12) only two systems have been thoroughly studied with regard to the relationship between crystal and molecular structure. The first is the so called four-center type photopolymerization (Reaction 1) which was investigated by Hasegawa and co-workers (13) this is a straightforward translation of the work of G. M. J. Schmidt (3) and his students on the photodimerization of cinnamic acids in the crystalline state into polymer chemistry. 

One possibility to realize low-threshold organic solid-state lasers is to utilize guest-host systems. In the following this is demonstrated for the example of DCM- and DCM2-doped organic semiconductors. As host materials the electron-transport material Alq3 and the hole-conducting materials NPD and CBP are used. 

We concentrate on jr-electron systems. One can learn most of what is interesting in organic solid-state physics from them and they provide an entry to the physics of other materials. We use the term molecular crystals not only in the narrow sense, but also consider thin layers of oriented molecules which are attracting increasing interest. 

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