Structure nonplanar nature

The nonplanar nature of 11 hinders intermoleeular contacts between the metal dithiolene complexes. Thus, there are few intermoleeular interactions between the anions within [Et4N][ll], although short C-H -S contacts of 2.906 A are observed between the pendent thiophenes of neighboring anions (Figure 13A). In contrast, the more planar structure of 12 allows significant jt stacking of the complexes to form columns with a face-to-face distance of 3.7 A (Figure 13B). ... 

The term zeppelene (Figure 10) has been coined to describe the discrete molecules formed by closing single cylinders at both ends (or alternatively by elongating a fullerene). The nonplanar nature of all these materials has opened a debate on the relative stabilities of carbon structures on the microscopic and macroscopic scale, and has consequences for the generally accepted planar 2D description of graphite. ... 

Single crystals of 34a were grown from 96% ethanol. The structure reveals the very nonplanar nature of this particular heterocalixarene analogue (Figure 31). It also established that a hydrogen-bonding array (not shown) is formed between the macrocycle and four water molecules (also omitted from Figure 31). ... 

Structural studies show allene to be nonplanar As Figure 10 7 illustrates the plane of one HCH unit is perpendicular to the plane of the other Figure 10 7 also portrays the reason for the molecular geometry of allene The 2p orbital of each of the terminal car bons overlaps with a different 2p orbital of the central carbon Because the 2p orbitals of the central carbon are perpendicular to each other the perpendicular nature of the two HCH units follows naturally... 

The aim of the present article is to understand nature s preference for nonplanar porphyrin systems at the active site of several biomolecules. Schiedt and Lee in their article on Recent Advances in the Stereochemistry of Metal-lotetrapyrroles have attempted some structure-function correlations based on the crystal structure analysis [10]. However, the present article is not an extension of it. Here, we have mainly concentrated on the need for the nonplanar conformations of porphyrins in biosystems and critically analysed the... 

The structures solved for various highly sterically crowded porphyrins are found to be nonplanar and the degree of nonplanarity depends on the nature of steric... 

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