Electronic structure and aromaticity of azaphospholes

Nyulászi, László; Veszprémi, Tamás; Réffy, József; Burkhardt, Bernd; Regitz, Manfred

doi:10.1021/ja00049a046

Cited by 81 publications

(29 citation statements)

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“…Ab initio quantum chemical calculations on the similar azaphospholes (3 and 4) [5][6][7] revealed that only the lH-derivative is planar in accordance with the photoelectron spectroscopic results. Furthermore, the alternation of the MP2/6-31G* bond length in the 12 10 8 IE/eV ring is much smaller in this case [7], and the average double bond character (an aromaticity index introduced to measure the bond length shortening [8]) is considerably larger for 3 than for 4 (0.61 vs. 0.52, respectively; confer with the 0.68 for benzene).…”

Section: Results Discussionsupporting

confidence: 60%

The Aromaticity of Phosphorus Compounds

Nyulászi¹,

Veszprémi²

1996

Phosphorus, Sulfur, and Silicon and the Related Elements

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By using photoelectron spectroscopy and ab initio quantum-chemical methods it has been revealed that phosphorus is capable to build cyclic, stabilized, conjugated systems in any of its oxidation state, including a^,X^-, a^,X^-, a-*,^. ^ w e ]j as a^,X^-P. The conjugative ability of phosphorus -as shown on 7r-ionization energies and stabilization energies in isodesmic reactions -is similar to that of carbon, ;•

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Section: Results Discussionsupporting

confidence: 60%

The Aromaticity of Phosphorus Compounds

Nyulászi¹,

Veszprémi²

1996

Phosphorus, Sulfur, and Silicon and the Related Elements

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“…The large conjugative ability of the ~k2-p=c bond has been proven in the recent literature [1][2][3][4], revising the earlier statement of the "double-bond rule" [5]. Conjugation of the phosphorus lone pair with the r-system, however, is significantly smaller than that of the lone pair of nitrogen, as has been shown in case of the nonaromatic phospholes [6][7][8] and 3H-1,3-azaphospholes [2,3,9,10].…”

Section: Introductionmentioning

confidence: 97%

“…Conjugation of the phosphorus lone pair with the r-system, however, is significantly smaller than that of the lone pair of nitrogen, as has been shown in case of the nonaromatic phospholes [6][7][8] and 3H-1,3-azaphospholes [2,3,9,10]. Other molecules with possible conjugation of phosphorus lone pair are phenylphosphine and vinylphosphine, the analogues of aniline and vinylamine.…”

Section: Introductionmentioning

confidence: 99%

The photoelectron spectrum and conformation of phenylphosphine and phenylarsine

et al. 1995

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He(I) and He(II) photoelectron spectra of phenylphosphine and phenylarsine have been investigated and assigned. The rotational barrier of the phosphino group has been investigated at the MP2/6-31G(d,p)//MP2/6-3 IG(d,p) and HF/6-31G(d,p)//HF/6-3 IG(d,p) levels of theory, and that of the arsino group at the HF/6-3 IG(d,p)//6-31G(d,p) levels of theory. The rotational barrier of the two molecules is nearly the same. The energy difference between the two possible conformers of the molecules is low (1.5 kJ/mol at the MP2/6-31G(d,p) level of theory), allowing nearly free rotation about the P--C bond. The photoelectron spectrum cannot be interpreted by considering the most stable rotamer, but all possible conformers should be taken into account. The present interpretation is consistent with the small np-r interaction concluded from other investigations. The rotational barrier of o-phosphinophenol is significantly larger than for phenylphosphine, and the photoelectron spectrum of this compound can be interpreted by considering a single conformer, and no appreciable interaction between the r-system of the ring and the phosphorus lone pair.

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“…5 Aromatic stability of phosphabenzene was found to be just slightly less, than that of benzene. [6][7][8][9][10][11] Azaphospholes 10-11 and thiaphospholes 12 were found to exhibit aromaticity comparable to the corresponding azoles and thiophenes.…”

Section: Introductionmentioning

confidence: 97%

Nature of Bonding in Cyclic Conjugated Ylides

and

Veszprémi

1996

J. Phys. Chem.

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The conjugative ability of the λ 5 -PdC bond has been compared to its λ 3 -PdC counterpart at the MP2/6-31G*//MP2/6-31G* level of theory, using isodesmic reaction energies. Investigating heterobutadienes, it has been observed that compounds containing a λ 3 -PdC bond show similar delocalization energy as those with CdC units. As for λ 5 -phosphabutadienes, however, stabilization is achieved only in the case of C substitution. This behavior has been rationalized by perturbation theory arguments with the conclusion that while for the λ 3 -PdC and CdC bonds a two-way interaction, for the λ 5 -PdC system a one-way interaction is operational. Comparing cyclic systems containing λ 3 -and λ 5 -PdC bonds, similar structures (bond lengths) and stabilizations (as concluded from bond separation and homodesmic reaction energies) were obtained for six-membered rings including benzene and other rings containing one and three (symmetrically arranged) phosphorus atoms. The four-membered rings (1λ 3 ,3λ 3 -and 1λ 5 ,3λ 5 -diphosphacyclobutadienes), however, show completely different behavior, since the λ 5 -P derivative does not show destabilization upon ring formation and has equal bond lengths, while λ 3 -P rings are clearly antiaromatic. Rationalization has been given in terms of the differences in the one-way and two-way conjugative interactions.

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Electronic structure and aromaticity of azaphospholes

Cited by 81 publications

References 0 publications

The Aromaticity of Phosphorus Compounds

The Aromaticity of Phosphorus Compounds

The photoelectron spectrum and conformation of phenylphosphine and phenylarsine

Nature of Bonding in Cyclic Conjugated Ylides

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