Theoretical studies of the low-lying electronic states of the nitrenium ion (NH+2 and methylene

Chu, Shaoping; Siu, Albert K. Q.; Hayes, Edward F.

doi:10.1021/ja00764a012

Cited by 33 publications

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“…They obtained angular and NH symmetric stretch curves and considered distortions involving asymmetric conformations. They determined the bond angles (in degrees) and relative energies at a fixed NH distance of 1.940 775 au: They also determined the barrier to linearity for the ground state to be 330 cm -1 , in close agreement with prior theoretical studies …”

Section: Introductionsupporting

confidence: 73%

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X̃ ³B₁, ã ¹A₁, b̃ ¹B₁, and c̃ ¹ Electronic States of

et al. 1998

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Ab initio molecular electronic structure theory has been employed in order to investigate systematically the X̃ 3B1, ã 1A1, b̃ 1B1, and c̃ 1 states of N , with emphasis placed on the b̃ 1B1 and c̃ 1 states. The self-consistent-field (SCF), configuration interaction with single and double excitations (CISD), complete active space (CAS) SCF, and CASSCF second-order configuration interaction (SOCI) wave functions with nine basis sets, the largest being a triple-ζ basis set with three sets of polarization functions and two additional sets of higher angular momentum and diffuse functions [TZ3P(2f,2d)+2diff], were used to determine equilibrium geometries, harmonic vibrational frequencies, infrared (IR) intensities, and dipole moments. The ground, first, and second excited states are confirmed to be bent, while the third excited state is predicted to be linear. The bond angles of N are shown to be larger than those of the corresponding isoelectronic CH2 molecule. At the highest level of theory, TZ3P(2f,2d)+2diff CASSCF-SOCI, the triplet−singlet splitting is predicted to be 29.4 kcal/mol (1.28 eV, 10 300 cm-1), which is in good agreement with the experimental observation of 30.1 kcal/mol (1.305 eV, 10 530 cm-1). With the same method, the second excited state (b̃ 1B1) lies 43.7 kcal/mol (1.89 eV, 15 300 cm-1) above the ground state, which is significantly lower than the experimentally proposed value of 2.54 eV. The third excited state (c̃ 1 ) is predicted to lie 77.0 kcal/mol (3.34 eV, 26 900 cm-1) above the ground state. The equilibrium geometry of this c̃ 1 state is determined to be r e = 1.030 Å at the TCSCF-CISD level with the largest basis set. Since the IR intensities of all active vibrational modes are predicted to be substantial, IR spectroscopic studies of the four states are feasible. However, of the six fundamentals experimentally assigned to date, two appear to be incorrect. The energy separations among the four lowest-lying states of N are found to be larger than the corresponding states of CH2.

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Section: Introductionsupporting

confidence: 73%

“…In 1971, Chu, Siu, and Hayes calculated the four lowest electronic states of N with a double-ζ basis set (DZ) and truncated configuration interaction (CI) methods …”

Section: Introductionmentioning

confidence: 99%

X̃ ³B₁, ã ¹A₁, b̃ ¹B₁, and c̃ ¹ Electronic States of

et al. 1998

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“…Therefore, its electronic structure has received much attention.2™7 The properties of CH2 in low-lying electronic states as well as the difference in reactivity in these states were of particular interest. 4…”

Section: Introductionmentioning

confidence: 99%

Ab initio calculation of the reaction path for the addition of singlet (1A1) methylene to ethylene

Zurawski¹,

Kutzelnigg²

1978

J. Am. Chem. Soc.

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“…In dieser Konfiguration ist der Triplett-Zustand etwa 27 kcaVmo1 energiearmer als der Singulett-Zustand [29]. Diese Resultate stimmen qualitativ mit Berechnungen am Nitrenium-Ion (NHP) selbst uberein [30]. (Schema I 4j2').…”

Section: Charakteristika In Denunclassified

“…Analytische Gas-Chromatogramme (GC.) an einem C. Erba-Gerat GI (FID) mit Glaskapillarkolonne nach Grob [47] 6b 6c 6d (3, 6e (3, 6f (3,5, 256 (3,04), 261 (3,09), 267 (3,27), 273 (3,27), 279 (3,42), 304 (3,70) 256 (3,03), 261 (3,05), 267 (3,16), 273 (3,13), 279 (3,28), 314 (3,88) 256 (2,95), 267 (3,00), 279 (3,15), 317 (3,81) 258 (2,97), 269 (3,06), 281 (3,15), 318 (3,75) 257 (2,96), 268 (3,10), 281 (3,26), 316 (3,80) 260 (3,13), 271 (3,20), 283 (3,30), 320 (3,89) 1. Herstellung der 2,l-Benzisoxazole (Anthranile).…”

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Zur Photochemie von 2, 1‐Benzisoxazolen (Anthranilen) und thermischen und photochemischen Umsetzungen von 2‐Azido‐acylbenzolen in stark saurer Lösung

Doppler

Schmid

Hansen

1979

Helvetica Chimica Acta

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Gilt als 58.Mitteilung iiber Photoreaktionen; 57.Mitt. siehe [l]. 3,Autor ftur Korrespondenz. Photolysen der Anthranile und Zersetzungen der 2-Azido-acylbenzole inSchwefelsaure. -Im Gegensatz zu 2H-Indazolen 2, deren konjugierte Sauren pK,-Werte von 2-3 aufweisen [3 b], stellen Anthranile relativ schwache Basen dar. Fur die konjugierten Sauren von Anthranil (6a), seinem 3-Methyl-und 3,4-Dimethylderivat 6 b bzw. 6c werden pK,-Werte von -2,22f0,03, -1,24+0,05 bzw. -1,22 ?r 0,06 angegeben 191. Um eine vollstandige Protonierung der Anthranile zu erreichen, sind also relativ hohe Saurekonzentrationen erforderlich. Die Bestrahlungen wurden deshalb in 96proz. Schwefelsaure (Ho-Wert -10,O [ 101 [ ll]) ausgefuhrt. Die Anthranilkonzentrationen lagen bei (2-5) . mol/l. Die entsprechenden 2-Azido-acylbenzole zersetzten sich beim Eintragen in 96proz. Schwefelsaure (-0'; ca. 1 mmol Azid auf 30 ml der Saure) spontan unter Stickstoffentwicklung. In Figur I sind die UV.-Absorptionsspektren von 3-Methylanthranil (6b) in Athanol, in 96proz. Schwefelsaure sowie in 1,2-Dichlorathan in Gegenwart von 10 Mol-Aquiv. Triathyloxonium-tetrafluoroborat wiedergegeben. Das Auftreten einer starken Absorptionsbande bei etwa 260 nm beim protonierten bzw. alkylierten 6 b und die von der Form her gute Ubereinstimmung mit den Absorptionsspektren von Indazoliumionen [l] [3 b] und 1,2-Benzisoxazoliumionen [ 121 [ 131 lassen den Schluss zu, dass Protonierung bzw. Alkylierung von 6 b am Stickstoffatom erfolgt5) und sich dabei wie bei 2-Alkylindazolen 2 (vgl. Schema 1 ) die 4, Vor uns, doch ohne unsere Kenntnis und von anderen Zielsetzungen geleitet (vgl. [5a]), war die photolytische Ringoffnung von 3-substituierten Anthranilen in wasseriger 66proz. Schwefelsaure bzw. konz. Salzslure unter Bildung von 5-substituierten 2-Amino-acylbenzolen schon von Giovannini el d. [5] (vgl. [6]) beobachtet worden. 1,2-Benzisoxazol wird durch Triathyloxonium-tetrafluoroborat ebenfalls am Stickstoffatom athyliert [I31 [14] (vgl. auch [15]). 5,

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Theoretical studies of the low-lying electronic states of the nitrenium ion (NH+2 and methylene

Cited by 33 publications

References 0 publications

X̃ ³B₁, ã ¹A₁, b̃ ¹B₁, and c̃ ¹ Electronic States of

X̃ ³B₁, ã ¹A₁, b̃ ¹B₁, and c̃ ¹ Electronic States of

Ab initio calculation of the reaction path for the addition of singlet (1A1) methylene to ethylene

Zur Photochemie von 2, 1‐Benzisoxazolen (Anthranilen) und thermischen und photochemischen Umsetzungen von 2‐Azido‐acylbenzolen in stark saurer Lösung

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Theoretical studies of the low-lying electronic states of the nitrenium ion (NH+2 and methylene

Cited by 33 publications

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X̃ 3B1, ã 1A1, b̃ 1B1, and c̃ 1 Electronic States of

X̃ 3B1, ã 1A1, b̃ 1B1, and c̃ 1 Electronic States of

Ab initio calculation of the reaction path for the addition of singlet (1A1) methylene to ethylene

Zur Photochemie von 2, 1‐Benzisoxazolen (Anthranilen) und thermischen und photochemischen Umsetzungen von 2‐Azido‐acylbenzolen in stark saurer Lösung

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X̃ ³B₁, ã ¹A₁, b̃ ¹B₁, and c̃ ¹ Electronic States of

X̃ ³B₁, ã ¹A₁, b̃ ¹B₁, and c̃ ¹ Electronic States of