Theoretical Enthalpies of Formation of NH_mCl_n:  Neutral Molecules, Cations, and Anions

Abstract

Ab initio molecular orbital calculations are reported for all neutrals, anions, and cations of the formula NH m (m = 1−3) and for their chlorinated analogues NH m Cl n (m + n = 1, 2, or 3). Structures were optimized using gradient techniques at HF/6-31++G(d,p) and at MP2(full)/6-311++G(d,p). Single-point calculations are reported at MP4SDTQ(fc)/6-311++G(2df,p) and at QCISD(T)(full)/6-311++G(2df,p) levels using geometries optimized at MP2. Standard enthalpies of formation have been calculated at MP4SDTQ(fc)/6-311++G(2df,p) and at QCISD(T)(full)/6-311++G(2df,p) and, where possible, are compared to experimental and previous theoretical results. These same two levels of theory give adiabatic ionization energies that are within ±0.12 eV of experimental values and proton affinities for neutrals and anions that are within at least 3 kcal mol-1 of experimental values. Electron affinities, anchored on the experimental value of NH, are reported at MP4 and QCI for NCl, NH2, NHCl, and NCl2.

Franck–Condon simulation of the photoelectron spectrum of AsCl2 and the photodetachment spectrum of AsCl employing UCCSD(T)‐F12a potential energy functions: IE and EA of AsCl2

“…36 However, these available computed AIE and/or EA values of PnCl 2 were obtained at different levels of theory and also at significantly lower levels than the best estimates for AsCl 2 benchmarked in this study. To compare computed AIE and EA values for the PnCl 2 (Pn 5 N, P, As, and Sb) series on the same footing, we have performed G4 calculations 42 on NCl 2 , PCl 2 , and AsCl 2 and their cations and anions, using GAUSSIAN09, 43 and further RCCSD(T) calculations (see footnotes e, f, and g of Table 6 for details) on SbCl 2 and its cation and anion using …”

Chlorofluoroamines: Ab Initio and DFT Studies on Their Structure, Enthalpies of Formation, and Unimolecular Reaction Pathways

“…For HNCl, there is no experimental determination available. Milburn et al 16 have reported singlepoint MP4 and QCISD(T) calculations with MP2 optimized geometry for all NH m Cl n species with the same large basis set, 6-311++G**. Their results are in very good agreement with the G2 values reported here for HNCl 2 , HNCl, NCl 2 , NH, and …”

“…For HNF 2 and HNCl 2 , our results exactly agree with the ab initio results previously reported at the same levels. 16,17 For HNF 2 , the N-H distances calculated by MP2 and DFT methods are within 0.003 Å from the experimental value, 28 accurately determined from its rotational spectrum(1.026 Å). The same is true for the N-F distance calculated by DFT method but the deviation is 0.009 Å for the MP2/6-311++G** level calculation.…”

“…Milburn et al have reported theoretical enthalpies of formation for chloroamines (NH m Cl n ). 16 Mack et al have reported ab initio studies on the structural aspects of fluoroamines (NH m F n ). 17 On the other hand, studies on the analogous halomethanes are aplenty.…”

Nitrenium Ions and Problem of Direct Electrophilic Amination of Aromatic Compounds

“…Up to now, quantum-chemical calculations were performed for a wide variety of nitrenium ions: NH 2 + [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40], MeNH + [22,24,25,30,36,41], Me 2 N + [22,24,25,30,41], MeAcN + [22], (CH 2 ) 2 N + [42], (CH 2 ) 4 N + , (CH 2 ) 5 N + [22,24,25], (XCH=CH)MeN + (X = H, Cl) [25], (CH) 2 N + , CHN 2 + [43], (CH) 6 N + [44], XN 3 + (X = O, S, Se, Te) [45], XNH + (X = NH 2 , PH 2 , OR, SH, Cl, F, Br, I, CN, NC 2 ) [23,27,28,32,34,36,40,46], X(CHO)N + [X = N, NH 2 , PH 2 , OR, SH, Ph(CH 2 ) n O] …”