engleski

Geometry of Molecules. Part 4. Iterative Maximum Overlap Calculations of Interatomic Distances, Bond Angles and Strain Energies in Some Rotanes and Related Spiro-Compounds

The iterative maximum overlap approximation (IMOA) is applied to a series of [n]-rotanes and some related spiro-compounds of unusual topology. The properties of these molecules were discussed in terms of the local hybrid orbitals and extent of their overlapping. Necessity of a clear distinction between bond length and interatomic distance in strained systems is pointed out. Considerableshortening of the C-C interatomic distance of the central carbocycles in [n]-rotanes was established. It was rationalized by the bent bond concept. The delocalization of the pseudo-pi electrons around the central ring in [n]-rotanes is briefly discussed. Angular strain energy and its distribution over the molecular fragments was quantitatively considered in the studied compounds. The strain and heat of formation of spiro (3.3) heptane are favourably compared with available ab initio results.

rotanes ; spiro-compounds ; IMOA method

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