Steric hindrances and the conformation of molecules

peri Interaction in Naphthalene Derivatives

“…As a result, the conformation of the molecule is very similar to that of 1,4,5,8-tetrachloronaphthalene determined by crystal-structure methods (156,157,228). In 1,8-bis (methylthio) naphthalene, the methylthio groups are forced 40°o ut-of-plane so that the sulfur atoms are separated by about 3.7 A.…”

“…Interest in these compounds stems from the fact that their halogens can be readily located through X-ray diffraction and that, at least in some cases, the steric effects can be discerned more clearly with substituents at least the size of the halogens (226). The compounds studied include 1,4,5,8-tetrachloronaphthalene (155)(156)(157)228), l,5-dichloro-4,8-dibromonaphthalene (157), l,5-dibromo-4,8-diiodonaphthalene (157), octachloronaphthalene ( 229), 5,6-dichloroacenaphthene (27)(28)(29), and 5-chloro-6-bromoacenaphthene (29,31). A few derivatives of naphthacenes which are formally related to pen-substituted naphthalenes have also been studied (8,30,32).…”

“…The structure of 1,4,5,8-tetrachloronaphthalene (VI) has been independently investigated by two groups, one in Russia (155)(156)(157) and the other in South Africa (228). Their experimental findings are in general agreement with each other.…”

Crystal and molecular structures of overcrowded halogenated compounds. VIII. Two overcrowded naphthalenes – octachloronaphthalene and tetrabenznaphthalene (dibenzo[g,p]chrysene)

“…In 4,5-dichloro-1,3,6,8-tetrafluoro-2,7-naphthyridine (van den Ham & van Hummel, 1977) the F atoms are all essentially coplanar with the undistorted part of the naphthyridine skeleton, while the peri CI atoms are displaced up and down (by 0.16 and -0.13 ,~ respectively), together with their associated C atoms, very much as in 1,4,5,8-tetrachloronaphthalene (Gafner & Herbstein, 1962;Davydova & Struchkov, 1962). Octafluoronaphthalene is not significantly non-planar in its molecular complex with naphthalene (Potenza & Mastropaolo, 1975); C10F 8 itself is disordered (Mandel & Donohue, 1972;Ahmed, 1973).…”