Use of an electron equivalent relationship between bond length and bond order to study chemical bonding. Part II. A study of bond orders, bond lengths and aromaticity in polycyclic aromatic hydrocarbons

2004 ◽  
Vol 671 (1-3) ◽  
pp. 211-219
Author(s):  
József Emri ◽  
Gábor Lente
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Bond Length ◽  
Aromatic Hydrocarbons ◽  
Chemical Bonding ◽  
Bond Order ◽  
Bond Orders ◽  
Bond Lengths ◽  
Polycyclic Aromatic ◽  
Electron Equivalent

Bond order-bond length relationships in conjugated hydrocarbons - the microwave spectrum and structure of 3,4-dimethylenecyclobutene

1983 ◽  
Vol 36 (4) ◽  
pp. 639 ◽  
Author(s):  
RD Brown ◽  
PD Godfry ◽  
BT Hart ◽  
AL Ottrey ◽  
M Onda ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Ab Initio ◽  
Bond Length ◽  
Bond Order ◽  
Microwave Spectrum ◽  
Basis Set ◽  
Molecular Orbital Calculations ◽  
Bond Orders ◽  
Bond Lengths ◽  
Typical Error

The microwave spectrum of the benzene isomer 3,4-dimethylenecyclobutene including spectra of all possible single 13C-substituted and sufficient singly and doubly D-substituted species to give a complete r5 geometry, have been measured and analysed. An estimate of the re geometry has also been derived. The additional precise CC bond lengths obtained for an unsubstituted, conjugated hydrocarbon enable us to examine bond order-bond length relationships more thoroughly than has previously been possible. The CC bond lengths exhibit a noticeably better correlation with SCFMO bond orders than with simple H�ckel bond orders. Further confirmatory measurements of the dipole moment of dimethylenecyclobutene have been made. Ab initio molecular orbital calculations using a 6-31G basis set give an optimized geometry with CC bond lengths within 2 pm of the r5 values. The computed dipole moment agrees almost exactly with experiment but a corresponding calculation on fulvene is discrepant with experiment by 0.16 D, which is probably a more typical error.

The Quantum Research on the Nucleophilic Reaction Activity of Polycyclic Aromatic Hydrocarbons

2014 ◽  
Vol 881-883 ◽  
pp. 173-176
Author(s):  
Jin Ling Zhao ◽  
Qing Zhen Han ◽  
Zhao Tan Jiang ◽  
Hao Wen
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Bond Orders ◽  
Nucleophilic Reaction ◽  
Hartree Fock ◽  
Reactive Carbon ◽  
Benzene Rings ◽  
Polycyclic Aromatic

Using the Hartree Fock (RHF) method, we study the most reactive carbon atoms in the polycyclic aromatic hydrocarbons (PAHs). In order to identify the most reactive carbon atoms, the Mulliken charges and the Mayers bond orders were calculated as the criterion. The results demonstrate that the most reactive carbon atoms appear at the locations of the outer C in the inner benzene rings for cata-condensed PAHs, while for peri-condensed PAHs they are the outer C in the outer benzene rings。

scholarly journals Bond lengths in naphthalene and anthracene

1951 ◽  
Vol 207 (1090) ◽  
pp. 306-320 ◽  
Keyword(s):  
Aromatic Hydrocarbon ◽  
Bond Length ◽  
Configuration Interaction ◽  
Bond Order ◽  
Bond Orders ◽  
Bond Lengths ◽  
Self Consistent ◽  
Hydrocarbon Molecules ◽  
Experimental Values ◽  
Correction Terms

An extremely careful inquiry is made into the possibility of predicting bond lengths in condensed aromatic hydrocarbon molecules. Agreement with the best experimental values, such as those of Robertson, Abrahams, White, Mathieson and Sinclair, is fairly easily obtained to an accuracy of about 0.02Å. This shows that the concept of fractional bond order may quite properly be used to infer bond lengths. Both the molecular-orbital and resonance methods are equally good for this purpose. Predictions to within less than 0.02Å require the introduction of new factors usually neglected. No less than five such factors are discussed: ( а ) electrostatic forces, arising from possible differences in electronegativity of the various carbon atoms, ( b ) changes of bond orders due to electronegativity differences, ( c ) variation of resonance integrals with bond length, ( d ) obtaining a self-consistent set of resonance integrals, ( e ) inclusion of configuration interaction. Correction terms which result from these improvements lie between 0 and 0.015Å, and are not all of the same sign. It is unlikely therefore that this type of analysis will be able to give confident predictions of bond lengths to less than 0.01Å.

Correlations Between Carbonyl Vibrational Properties of Polycyclic Aromatic Aldehydes and Electronic Properties of the Corresponding Hydrocarbons

1981 ◽  
Vol 36 (3) ◽  
pp. 297-300 ◽  
Author(s):  
K. D. Gundermann ◽  
C. Lohberger ◽  
M. Zander
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Electronic Properties ◽  
Aromatic Hydrocarbons ◽  
Bond Order ◽  
Aromatic Aldehydes ◽  
Vibrational Properties ◽  
Polycyclic Aromatic ◽  
Carbonyl Bond

Good correlations exist between both the carbonyl stretching frequency and the carbonyl bond order of the monoaldehydes of polycyclic aromatic hydrocarbons and the HMO atom localisation energies or PMO reactivity numbers of the corresponding hydrocarbons at the carbon centres contiguous to the CHO group. Applications of these correlations are discussed

A Correlation between Bond Length and Ionic Bond Order. Application to the Ylide–Ylene Problem

1975 ◽  
Vol 53 (20) ◽  
pp. 3040-3043 ◽  
Author(s):  
Myung-Hwan Whangbo ◽  
Saul Wolfe ◽  
Fernando Bernardi
Keyword(s):  
Bond Length ◽  
Bond Order ◽  
The Other ◽  
Atomic Charges ◽  
Bond Orders ◽  
Ionic Bond ◽  
Molecular Systems ◽  
Bond Lengths ◽  
Coulombic Repulsion ◽  
Overlap Population

The C—O and C—S bond lengths of the cations, radicals, and anions CH3O, CH3S, CH2OH, and CH2SH have been found not to correlate with the overlap populations of the C—X bonds. On the other hand, very satisfactory linear relations are observed with the ionic bond orders of the C—X bonds. It is suggested that, in certain molecular systems, it may be more meaningful to associate shortening of a bond A—B with greater coulombic attraction (or smaller coulombic repulsion) between the two point charges represented by the net atomic charges on the atoms A and B than with an increase in the overlap population between these atoms. It is noted that such an interpretation can account for the short C—P bond in a phosphonium ylide without resort to (p → d)π conjugation.

THE SULPHUR–OXYGEN BOND IN SULPHURYL AND THIONYL COMPOUNDS: CORRELATION OF STRETCHING FREQUENCIES AND FORCE CONSTANTS WITH BOND LENGTHS, BOND ANGLES, AND BOND ORDERS

1963 ◽  
Vol 41 (8) ◽  
pp. 2074-2085 ◽  
Author(s):  
R. J. Gillespie ◽  
E. A. Robinson
Keyword(s):  
Bond Length ◽  
Linear Relationship ◽  
Force Constant ◽  
Bond Order ◽  
Bond Angle ◽  
Bond Orders ◽  
Bond Angles ◽  
Bond Lengths ◽  
Frequency Relationship ◽  
Oxygen Bond

It is shown that the bond length of an SO bond and the bond angle of an SO2 group may be very satisfactorily correlated with the SO stretching frequency. The bond-length – stretching-frequency relationship is used to predict some bond lengths that have not been measured and the OSO angles in some sulphuryl compounds are also calculated. The problem of defining and measuring the bond order of sulphur–oxygen bonds is discussed. It is shown that there is a linear relationship between the force constant and the bond order and a non-linear relationship between the bond length and the bond order.

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