N2/plus/ potential energy curves

Molecular nitrogen ion potential energy curve

Hybridization in Fused Strained Rings by Maxim.um Overlap Method. III. Benzocyclobutadiene and Benzocyclobutene-7,8-dimethylene

The hybnidization in benzocyclobutadiene and benzocyclobutene- 7,8-dimethylene is considered using the method of maximum overlap. The results show considerable variations of s-p content of hybrids describing the molecular skeleton. Endocyclic and exocyclic double bond in four-membered rings in these molecules exhibit values of deviation angles and bond overlap integrals differing from those in other examined fused ring molecules1, 2• The calculated J(C-H) spin-spin coupling constants are in very good agreement with the available experimental data

Hybridization in 1,3,5-Cycloheptatriene and Some Related Molecules by the Method of Maximum Overlap

The hybridization in 1,3,5-cycloheptatriene, 1,3,5,7-cyclooctatetraene, 1,3-cyclohexadiene, and 1,4-cyclohexadiene has been calculated by the method of maximum overlap. The results show that if the molecules are assumed to be planar, hybrids describing the molecular skeleton deviate from the line joining the neighbouring carbon atoms and are directed towards the ins.ide of the ring. The deviation angles for the above molecules vary between 1.25° and 7 .5°. For non-planar structures the deviation angles are decreased or are equal to zero. The puckering of the molecular skeleton thus considerably reduces the strain

Hybridization in Several Polycyclic Alkanes by the Method of Maximum Overlap

The hybridization · in spiropentane, nortricyclene, cu bane, tricyclo( l.1.0.02,4)butane, bicyclo(l.1.l)pentane, and tetracyclo(3,3.l 2, 8.04,6) nonane has been determined by the method of maximum overlap. For the atomic functions Clementi Orbitals (ref. 1) have been assumed. A comparison between these results and those, obtained previously, by assuming Slater orbitals indicates the improvements that can be achieved by using more exact wave functions. The overlaps for CC bonds fall into the groups: (1) S 0.64. They are characteristic of highly strained three-membered rings, (6 ~ 20°), of four membered rings, (b ~ 10°), and of normal or very slightly bent bonds, (6 < 5°), respectively

Geometry of Molecules. Part 4. Iterative Maximum Overlap Calculations of lnteratomic 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

Tables of Overlap Integrals

Tables of overlap integrals for bonds between the first row atoms and their hydrides are given. They are based on atomic orbitals suggested by Clementi, which provide a more reliable guide to the description of bonds than do Slater orbitals. The region of interatomic distances is limited so as to cover known bond lengths found in the literature

Tables of Overlap Integrals. II. Bonds between Some First Row and Second Row Atoms

Tables of overlap integrals for some bonds between the first row atoms and the second row atoms are given. They are based on atomic orbitals o,f Clementi and include the basic overlap integrals of the valence shell orbitals only, i. e. overlaps between 2s anu 2p orbitals of the first row atoms with 3s and 3p orbitals of tne second row atoms. The intervals of interatomic distances are lim~ted so as to cover known _variations in bond lengths reported in the, literature

Tables of Overlap Integrals. II. Bonds between Some First Row and Second Row Atoms

Tables of overlap integrals for some bonds between the first row atoms and the second row atoms are given. They are based on atomic orbitals o,f Clementi and include the basic overlap integrals of the valence shell orbitals only, i. e. overlaps between 2s anu 2p orbitals of the first row atoms with 3s and 3p orbitals of tne second row atoms. The intervals of interatomic distances are lim~ted so as to cover known _variations in bond lengths reported in the, literature