Surprisingly regular structure–property relationships between C–O bond distances and methoxy group torsional potentials: An ab initio and density functional study

摘要: Abstract The trends in the shape of torsional potential methoxy group a series 4-methoxyheteroarenes and 4-substituted methoxybenzenes were studied systematically with aid large-scale ab initio calculations performed at Moller–Plesset second order level density functional method. Among molecules investigated are 4-methoxy substituted sila-, phospha-, germa-, arsabenzenes as well 4-nitro-, 4-cyano-, 4-amino-, 4-( N , ′dimethyl)amino- 4-fluoro-1-methoxybenzenes. In all these compounds, global minimum corresponds to eclipsed structure which is coplanar aromatic ring. A significant decrease calculated rotational barrier orthogonal by about 1.5 kcal mol −1 accompanied considerable flattening, observed upon going from 4-methoxypyridine 4-methoxyphospha- 4-methoxyarsabenzene. potentials Si Ge containing arenes almost indiscernible significantly flatter than that anisole. wide distribution barriers can also be found for methoxybenzenes. potentials, heights energy differences between conformers discussed correlated selected structural parameters. particularly good correlation two carbon–oxygen distances ether linkage observed.