Schmidt s criteria

To summarize, three different situations occur for crystals with two crystallographically independent molecules (A and B) (1) The independent molecules may react with their symmetry-related partners and undergo bimolecular may react with their symmetry-related partners with high dimer yield of 75% (2) it could happen that there is no photoreaction, even when molecules A and B are properly oriented, satisfying Schmidt s criteria and (3) only one of the molecules (either A or B) undergoes reaction with its symmetry-related partner, but not the second one, as it is not favorably oriented with its symmetry-related partner. It is... 

It is now clear from the above scheme (Fig. 3) that critical values for d, d, a, and will depend on both looseness of crystal packing and inherent rates of various elementary processes in addition to crystal structure. In this context, violation of Schmidt s criteria for solid-state photodimerization of alkenes (20) is not surprising. 

Recently another photoactive metal complex, [Ag2(Cl-spy)4(C103)2] (5) (where Cl-spy = /rans-l-(4-Cl-3-pyildyl)-2-(phenyl)ethylene), was s)uithesized with Ag(I) in tetrahedral coordination geometry and coordinated by N of two Cl-spy, O atoms of two CIO3 anions [28], The solid-state structure analysis showed that only 50% of Cl-spy are aligned parallel between the dinuclear complexes and are separated by 3.73 A as shown in Fig. 4. The other 50% are arranged beyond Schmidt s criteria (5.93 and 6.29 A), and the two rings in the Cl-spy are twisted from coplanarity by 20.6°. As expected, on UV irradiation of this compound showed photo-reactivity of this compound in an SCSC manner and resulted in the formation of ID CP. 

Apart from the usual ladder structures formed by a pair of polymeric strands bridged by various anions as well as spacer ligands, one can also visualize three polymer strands to assemble to form an unusual ladder structure. This ladder can be considered as an intermediate in the self-assembly of 2D sheets. Such triple-stranded ladders are of interests to investigate the photo-reactivity, if C=C bonds in the three spacer ligands are aligned perfectly parallel within Schmidt s criteria. 

The local Reynolds number Re = 2rU/v used in the studies of EPRs varies between 100 and 2 000, so that one often takes n = 1/3, m = 1/2, and C = 0.6. The Prandtl and Schmidt criteria express the properties of interacting substances. For the systems heat in air and water vapour in air , they are Pr = (vp1cp)/A 0.7 and Sc = v/D 0.6 [60], Having transformed these basic empirical relations, Berman [60] suggested a relation for spraying systems aE = 3 U/2r, provided the local velocity U is taken in m/s and the droplet diameter 2r in m. The latter was used in the following performance ofSCSs. 

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