Optimization of the geometry of the diphenylamine molecule by semiempirical quantum chemical methods

Journal Article · Sat Mar 01 04:00:00 EST 1986 · J. Struct. Chem. (Engl. Transl.); (United States)

DOI:https://doi.org/10.1007/BF00773277· OSTI ID:6290518

Pankratov, A N; Mushtakova, S P; Gribov, L A

Available data on experimental study of the geometry of the diphenylamine molecule (I) in solution and in the crystal are fragmentary and not always reliable. Previously, they did a conformational analysis of molecule I using the atom-atom potential method. In order to refine the geometric parameters found for molecule I, optimization of its geometry is provided in the paper using the CNDO/2, INDO, MINDO/3 methods with the use of programs for the BESM-6 computer which are part of the VIKING program set. The angles of rotation for the phenyl rings relative to the CNC plane, the bond angles C/sub 2/N/sub 7/C/sub 8/ and C/sub 2/N/sub 7/H/sub 19/, and also the dihedral angle H/sub 19/N/sub 7/C/sub 8/C/sub 9/ were subjected to optimization. For any set of values for the indicated parameters, the bond angle C/sub 8/N/sub 7/H/sub 19/ is determined unambiguously. The results of the calculations are evidence that the MINDO/3 method is not suitable for optimization of the geometry for molecules of the indicated series; in particular, it leads to much too high a value for the CNC angles (135.9/sup 0/). The CNDO/2 method reproduces well the real value of the CNC angle (124.1/sup 0/) and confirms the known pyrimidal character of the nitrogen atom, the sum of the bond angles of which proved to be equal to 353.6/sup 0/. The calculation in the INDO approximation successfully gives the basic characteristics of the molecular geometry of (I); according to this approximation, the CNC angle is equal to 123.2/sup 0/, the CNH angles are equal to 118.0 and 118.8/sup 0/, the sum of the angles for the nitrogen atom is 360.0/sup 0/.

• Research Organization: N.G. Chernyshevskii State Univ., Saratov, USSR
• OSTI ID: 6290518
• Journal Information: J. Struct. Chem. (Engl. Transl.); (United States), Journal Name: J. Struct. Chem. (Engl. Transl.); (United States) Vol. 26:5; ISSN JSTCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
640302 -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
AMINES
ATOMIC MODELS
BOND ANGLE
C CODES
CARBON 13
CARBON ISOTOPES
COMPUTER CODES
COMPUTERIZED SIMULATION
DIPOLE MOMENTS
ELECTRONIC STRUCTURE
EVEN-ODD NUCLEI
I CODES
ISOTOPES
LIGHT NUCLEI
M CODES
MATHEMATICAL MODELS
MECHANICS
MOLECULAR MODELS
MOLECULAR STRUCTURE
MOLECULES
NMR SPECTRA
NUCLEI
OPTIMIZATION
ORGANIC COMPOUNDS
POLYATOMIC MOLECULES
POTENTIALS
QUANTUM MECHANICS
SIMULATION
SPECTRA
STABLE ISOTOPES
SYMMETRY