Prototypal 1,2,3,5-dithia- and -diselenadiazolyl [HCN2E2].bul. (E = sulfur, selenium): molecular and electronic structures of the radicals and their dimers, by theory and experiment

Cordes, A. W.; Bryan, Clinton D.; Davis, W. M.; Laat, R. H. de; Glarum, S. H.; Goddard, John D.; Haddon, Robert C.; Hicks, Robin G.; Kennepohl, Dietmar

doi:10.1021/ja00069a022

Cited by 84 publications

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“…This study predicts the properties and structures of the prototypal 1,2,3,5-ditellura radical l b and cation l a at levels comparable to our earlier study of the sulfur and selenium heterocycles (4). These earlier predictions were in good agreement with available experiments (4).…”

Section: Resultssupporting

confidence: 86%

“…These earlier predictions were in good agreement with available experiments (4). Theoretical studies of the isolated dimers also provide a first step towards understanding the associated dimers in any solid state structure that might be adopted by the ditelluradiazolyl radical.…”

Section: Resultssupporting

confidence: 84%

“…The monomer rings themselves were constrained to be overall planar in all the dimer calculations. The conformations of the dimers and any symmetry restrictions were chosen with reference to the experimentally observed X-ray crystallographic structures of the sulfur and selenium diazolyl dimers (4).…”

Section: 759mentioning

confidence: 99%

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The 1,2,3,5-ditelluradiazolyl [HCN₂Te₂] species. Theoretical characterizations of the cation, radical, and radical dimers

Davis¹,

Goddard²

1996

Can. J. Chem.

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Dithia-and diselena-diazolyl radicals (HCN,E, E = S, Se) and dimers are important building blocks in the design of low-dimensional molecular conductors. Research on the tellurium-based analogues is much rarer. This work reports the molecular and electronic structures of the cation, radical, and radical dimers of 1,2,3,5-ditelluradiazolyl using ab initio theory including electron correlation by Moller-Plesset perturbation theory up to partial fourth order (MP4SDQ). A face-to-face C2v dimer is predicted to be bound with respect to two radicals by approximately 18 kcallmol. A C,, dimer also has been studied and is ca. 2 kcaVmol less stable than the C,, conformer. Relaxing symmetry constraints on the dimers led to more energetically stable structures at the Hartree-Fock level but the C2" structure remains the most stable at a level of theory including electron correlation effects. The results for the Te compounds along with our earlier research on the S and Se analogues provide predictions for the geometries, vibrational frequencies, and ionization potentials for the Te species to assist in future experiments.Key words: tellurium, ab initio, ditelluradiazolyl, dimers, binding.RCsurnC : Les radicaux dithia-et disCltnadiazolyles (HCN2E2, E = S, Se) et leurs dimkres sont des blocs de construction importants dans le dCveloppement de conducteurs moltculaires de faibles dimensions. Des recherches sur des analogues ayant le tellure comme base sont beaucoup plus rares. Dans ce travail, on a calculC les structures moleculaires et electroniques du cation, du radical et des radicaux dimkres du 1,2,3,5-ditelluradiazolyle en utilisant la theorie ab initio, y compris la corrClation d'tlectrons par la thiorie des perturbations de Moiler-Plesser jusqu'au quatrikme ordre partiel (MP4SDQ). I1 est prCvu qu'un dimkre face B face C2v sera lie par environ I8 kcaVmol par rapport aux deux radicaux. On a aussi CtudiC un dimkre C2, et il est moins stable que le conformkre C2, par environ 2 kcallmol. Au niveau de Hartree-Fock, des contraintes de symttrie de relaxation appliquees aux dimkres ont conduit B des structures CnergCtiquement plus stables, mais la structure C2v demeure la plus stable B un niveau de la thCorie qui inclut les effets de correlation d'klectrons. Les rCsultats pour les composCs du Te en relation avec nos Ctudes antkrieures sur les analogues du S et du Se conduisent B des predictions au sujet des gComCtries, aux frCquences vibrationnelles et aux potentiels d'ionisation des espkces du Te qui pourront aider dans des experiences futures.

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Section: Resultssupporting

confidence: 86%

Section: Resultssupporting

confidence: 84%

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The 1,2,3,5-ditelluradiazolyl [HCN₂Te₂] species. Theoretical characterizations of the cation, radical, and radical dimers

Davis¹,

Goddard²

1996

Can. J. Chem.

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“…All reactions and the manipulation of moisture-sensitive products were canied out under an atmosphere of nitrogen by using Schlenk techniques or a Vacuum Atmospheres drybox. Li[4-CH3C6H4C-(NSiMe,),] (7), HCN,(SiMe,), (8), and PhSeN(SiMe,), (9) were prepared by literature methods. LiN(SiMe3), was obtained from Aldrich and recrystallized from hexanesdiethyl ether before use.…”

Section: Methodsmentioning

confidence: 99%

Molecular and electronic structures of the purple chromophore RC(NH₂)(NSePh) (R = H, 4-CH₃C₆H₄)

Chivers¹,

McGregor²,

Parvez³

et al. 1995

Can. J. Chem.

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The reaction of Li[4-CH3C6H4C(NSiMe3)2] with PhECl (E = S, Se) in a 1:1 molar ratio produces the monosubstituted derivatives 4-CH3C6H4C(NEPh)[N(SiMe3)2] (3b, E = Se; 3d, E = S). The thermolysis of 3b at 130 °C produces PhSeN(SiMe3)2 and 4-CH3C6H4CN. Crystals of 3b slowly acquire a purple stain upon prolonged standing at 23 °C owing to the formation of 4-CH3C6H4C(NH2)(NSePh) (4c, λmax = 551 nm). The formamidine derivative HC(NH2)(NSePh) (4a, λmax = 472 nm) was isolated from the reaction of HCN2(SiMe3)3 with PhSeCl (1:3 molar ratio) in dichloromethane. The structure of 4a was shown by X-ray crystallography to involve a syn configuration at the [Formula: see text] bond and hydrogen bonding between amino nitrogen atoms. The crystals of 4a are monoclinic, space group P21 (No. 4), with a = 7.514(1), b = 5.575(1), c = 8.925(1) Å, β = 100.71(1)°, V = 367.40(6) Å3, and Z = 2. The final R and Rw values were 0.055 and 0.060, respectively. The 1H and 77Se NMR spectra indicate that both 4a and 4c exist as a mixture of tautomers in THF solution. DFT calculations for the model tautomers HC(NH2)(NER) and HC(NH)(NHER) (E = S, Se; R = H, Ph) show that the former is more stable in all cases, but the difference in total bonding energy is smaller for selenium than for sulfur (17.5 vs. 29 kJ mol−1). The visible absorption band for 4a is assigned to the HOMO–LUMO transition (ΔE = 2.90 eV, λmax = 427 nm) of the minor tautomer. Keywords: formamidine, tautomer, selenium, purple chromophore.

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“…35 Detailed ab initio studies probed the ‫ء‬ -‫ء‬ dimerization energy and revealed that the energetics were strongly dependent on the basis set employed. 36 Recently DFT studies have been employed to model the spin density distribution in a number of perfluo-rophenyl derivatives. 26 These indicated that there was little spin density population on atoms other than those in the dithiadiazolyl ring.…”

Section: Dft Spin Density Distributionmentioning

confidence: 99%

Spin density studies onp-O2NC6F4CNSSN: A heavyp
Luzón
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et al. 2010
Phys. Rev. B
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A complete picture of the spin density distribution in the organic radical p-O 2 NC 6 F 4 CNSSN has been obtained by a combination of polarized neutron diffraction, electron paramagnetic resonance ͑EPR͒, and electron-nuclear double resonance ͑ENDOR͒ spectroscopies, and ab initio density-functional theory ͑DFT͒ calculations. Polarized neutron diffraction revealed that the spin distribution is predominantly localized on the N and S atoms ͑+0.25 B and +0.28 B , respectively͒ of the heterocyclic ring with a small negative spin density on the heterocyclic C atom ͑−0.06 B ͒. These spin populations are in excellent agreement with both ab initio DFT calculations ͑spin populations on the C, N, and S sites of −0.07, 0.22 and 0.31, respectively͒ and cw-EPR studies which estimated the spin population on the N site as 0.24. The DFT calculated spin density revealed less than 1% spin delocalization onto the perfluoroaryl ring, several orders of magnitude lower than the density on the heterocyclic ring. cw-ENDOR studies at both X-band ͑9 GHz͒ and Q-band ͑34 GHz͒ frequencies probed the spin populations on the two chemically distinct F atoms. These spin populations on the F atoms ortho and meta to the dithiadiazolyl ring are of magnitude 10 −3 and 10 −4 , respectively.

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Prototypal 1,2,3,5-dithia- and -diselenadiazolyl [HCN2E2].bul. (E = sulfur, selenium): molecular and electronic structures of the radicals and their dimers, by theory and experiment

Cited by 84 publications

References 0 publications

The 1,2,3,5-ditelluradiazolyl [HCN₂Te₂] species. Theoretical characterizations of the cation, radical, and radical dimers

The 1,2,3,5-ditelluradiazolyl [HCN₂Te₂] species. Theoretical characterizations of the cation, radical, and radical dimers

Molecular and electronic structures of the purple chromophore RC(NH₂)(NSePh) (R = H, 4-CH₃C₆H₄)

Spin density studies onp-O2NC6F4CNSSN: A heavyp
Luzón
¹
,
Campo
²
,
Palácio
³

et al. 2010
Phys. Rev. B
19
0
9
0
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Prototypal 1,2,3,5-dithia- and -diselenadiazolyl [HCN2E2].bul. (E = sulfur, selenium): molecular and electronic structures of the radicals and their dimers, by theory and experiment

Cited by 84 publications

References 0 publications

The 1,2,3,5-ditelluradiazolyl [HCN2Te2] species. Theoretical characterizations of the cation, radical, and radical dimers

The 1,2,3,5-ditelluradiazolyl [HCN2Te2] species. Theoretical characterizations of the cation, radical, and radical dimers

Molecular and electronic structures of the purple chromophore RC(NH2)(NSePh) (R = H, 4-CH3C6H4)

Spin density studies onp-O2NC6F4CNSSN: A heavypLuzón1, Campo2, Palácio3 et al. 2010Phys. Rev. B19090View full textAdd to dashboardCite

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The 1,2,3,5-ditelluradiazolyl [HCN₂Te₂] species. Theoretical characterizations of the cation, radical, and radical dimers

The 1,2,3,5-ditelluradiazolyl [HCN₂Te₂] species. Theoretical characterizations of the cation, radical, and radical dimers

Molecular and electronic structures of the purple chromophore RC(NH₂)(NSePh) (R = H, 4-CH₃C₆H₄)

Spin density studies onp-O2NC6F4CNSSN: A heavyp
Luzón
¹
,
Campo
²
,
Palácio
³

et al. 2010
Phys. Rev. B
19
0
9
0
View full text Add to dashboard Cite