Solid with intermolecular compound formation

Solid-Liquid Equilibria with Intermolecular Compound Formation in the Solid State... 

J. R. Goates, J. B. Ott, and D. E. Oyler, Intermolecular Compound Formation in Solutions of N,N-Dimethylformamide with Carbon Tetrachloride and Several Related Substances. A Solid Phase Transition in N,N-Dimethylformamide, Trans. Faraday Soc., 62, 1511-1518 (1966). 

Numerous examples of different variants of this cyclization/cleavage protocol have been reported. Diketopiperazine formation (Section 15.22.1), an unwanted side reaction in solid-phase peptide synthesis, is also an example of this type of compound release. Because intramolecular processes generally take place more readily than the corresponding intermolecular reactions, cyclization/cleavage can occur with alkyl... 

The spacer-bridged ditin compound MeCl2Sn(CH2)3SnCl2Me239 was reported to contain, in the solid state, hexacoordinated tin atoms as a result of strongly unsymmetrical intermolecular Sn—Cl—Sn bridges with Sn—Cl distances in the range of 2.381(1)—3.484(1) A, giving rise to the formation of a sheet-like polymer. 

The determination of the asymmetry parameters and the direction cosines, together with x-ray investigations of the crystal structure, will shed some light on the crystal field effect in solids. NQR powder spectra can only permit very rough and qualitative conclusions on the intermolecular forces. The results on the Mentschukin complexes with AsCl3 show that the metal-chlorine bond is virtually unaffected by the formation of molecular compounds. From singlecrystal NQR spectroscopy, particularly on the As nucleus, some geometrical information about the molecular compounds can be expected. 

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