Thioformaldehyde S-Sulfide, Sulfur Analogue of the Criegee

Subscriber access provided by NEW MEXICO STATE UNIV

Article

Thioformaldehyde S-Sulfide, Sulfur Analog of the Criegee Intermediate: Structures, Energetics, and Rovibrational Analysis Kevin V. Murphy, Whitney James Morgan, Zhi Sun, Henry F. Schaefer, and Jay Agarwal J. Phys. Chem. A, Just Accepted Manuscript • DOI: 10.1021/acs.jpca.6b12473 • Publication Date (Web): 06 Jan 2017 Downloaded from http://pubs.acs.org on January 16, 2017

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

The Journal of Physical Chemistry A is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

The Journal of Physical Chemistry

Thioformaldehyde S-Sulfide, Sulfur Analog of the Criegee Intermediate: Structures, Energetics, and Rovibrational Analysis Kevin V. Murphy, Whitney J. Morgan, Zhi Sun, Henry F. Schaefer III, and Jay Agarwal∗ Center for Computational Quantum Chemistry, University of Georgia, Athens, GA 30602 USA E-mail: [email protected]

Abstract The ephemeral Criegee intermediate, first postulated over 70 years ago, has only recently been isolated in the gas phase. The sulfur analog of this canonical zwitterion, thioformaldehyde S -sulfide, has eluded similar analysis; however, argon matrix isolation has been achieved (Angew. Chem. 2001, 40, 393-396). Here, thioformaldehyde S-sulfide and its valence isomer dithiirane are examined with high-level coupledcluster methods, including the minimum energy pathway for interconversion. Relative enthalpies, calculated from extrapolated energies at the complete basis set limit of the full CCSDTQ method, are reported. Isomerization from thioformaldehyde S-sulfide to the lower-lying dithiirane (-7.2 kcal mol−1 ) is predicted to include a 27.0 kcal mol−1 barrier. Harmonic and anharmonic vibrational frequencies are also predicted using second-order vibrational perturbation theory (VPT2). These results should aid in future gas-phase identification.

1 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Introduction Rudolf Criegee’s proposed mechanism of olefin ozonolysis includes the formation of a zwitterionic, carbonyl O-oxide (CH2 OO), often termed the “Criegee intermediate” (e.g., 1b in Figure 1). 1 For over half a century this transient species evaded gas-phase isolation. 2 Then,

Figure 1: Mechanism of ozonolysis as proposed by Criegee 3 , including formation of the carbonyl O-oxide intermediate, 1b. in 2013, Huang, Witek, and Lee reported its infrared signature by generating CH2 OO from the reaction of O2 and CH2 I – the latter being the photolysis product of CH2 I2 . 4 Early attempts to form this intermediate via the cycloreversion of 1,2,4-trioxolane (1e in Figure 1), which is the ozonolysis product of ethylene (via 1a), were unsuccessful. 5 However, cycloreversion proved a successful strategy for studying the sulfur analog, thioformaldehyde S -sulfide (CH2 SS; 2b in Figure 2). 6 Indeed, Maier and co-workers 7 showed via matrix iso-

Figure 2: Formation of the sulfur analogue of the Criegee intermediate from a sulfur heterocycle precursor. 7 lation that the thermal fragmentation of 1,2,4-trithiolane (2a), a stable substance that is common in nature, 8–10 yields CH2 SS (2b) and the companion product dithiirane (H2 CS2 ; 2c in Figure 2) in a ratio of 1:2.5. Complete conversion to H2 CS2 (2c) was achieved photochemically, through irradiation of the product mixture with visible light (λ > 570 nm). A photoequilibrium (CH2 SS − )− −* − H2 CS2 ) was achieved when ca. 500 nm light was employed. The fate of transient thiosulfines (CR2 SS) and their valence isomers, the dithiiranes (R2 CS2 ), is unclear, but it has been speculated that each isomer yields distinct products when combined with thioformaldehyde (2d) or via self-reaction. As such, there is interest in trapping these intermediates for synthetic purposes. 11 For reference, the lighter congener of dithiirane, dioxirane (1c), can undergo homolytic O–O cleavage to yield dioxymethylene, which subsequently decomposes to furnish simpler downstream molecules such as CO2 . 12 Conversely, the Criegee intermediate (1b) combines with formaldehyde (1d) to generate the canonical product, 1,2,4-trioxolane (1e). 13 Likely, the sulfur analogs exhibit equally rich but unknown chemistry.


Page 2 of 20

Page 3 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


In 2001, argon matrix isolation was utilized by Maier and coworkers 7 to characterize CH2 SS (2b) and H2 CS2 (2c) for the first time; seven fundamental vibrational transitions were identified for both structures using Fourier-transform infrared (IR) spectroscopy. This prior work is pursued in the present research through the characterization of CH2 SS (2b) and H2 CS2 (2c) with high-level electronic structure theory. The similarity between CH2 SS (2b) and CH2 OO (1b) provides the opportunity to study intricate ozonolysis chemistry with a heavy congener that may exhibit a longer lifetime, facilitating experimental interrogation. 14 Notwithstanding this application, the chemistry of CH2 SS (2b) is associated with several other processes — for example, 1,2,4-trithiiolane (2a) has relevance to the sulfur cycle 15–17 and astrochemistry, 18–20 underscoring interest in its cycloreversion. Dithiiranes (CR2 SS) and their valence isomers, the thiosulfines (R2 CS2 ), have also been proposed as intermediates in reaction mechanisms leading to sulfur-rich compounds. 21–24 To date, however, substituted forms of thiosulfine (thiocarbonyl S -sulfides) have received the most attention. 25–29 The current study reports results from high-level theory to augment the limited literature concerned with the unsubstituted forms, as well as to assist the future identification of thioformaldehyde S -sulfide (2b) and dithiirane (2c) in the gas phase. Specifically, relative electronic energies between stationary points on the isomerization pathway are reported at the complete basis set (CBS) limit of coupled-cluster theory with full quadruple excitations (CCSDTQ). Fundamental frequencies are predicted for the first time using coupled-cluster theory [CCSD(T)] and second-order vibrational-perturbation theory (VPT2). Vibrationrotation interaction constants (αrB ) and rotational constants (Be and B0 ) are also reported. 30 Analysis of atomic charges, resonance structures, and chemical bonding is facilitated by Natural Bond Orbital (NBO) methods, 31 and comparisons to prior research are made where possible. 7,11

Theoretical Methods Optimized geometries for minima on the potential energy surface for the CH2 SS − )− −* − H2 CS2 isomerization were obtained using coupled-cluster theory with single, double, and perturbative triple excitations [CCSD(T)]. 32–35 The carbon and hydrogen atoms were described with Dunning’s augmented, correlation-consistent, valence, triple-ζ (aug-cc-pVTZ) basis set. 36,37 Sulfur atoms were described (with added tight d functions) using the aug-cc-pV(T+d)Z basis set, 38,39 because the aug-cc-pVTZ basis sets do not fully capture core polarization and valence-orbital correlation effects in second row atoms. 40 For all computations, a frozen core (FC) approximation was applied, such that inner shell electrons of the carbon and sulfur atoms were not correlated in the post-Hartree-Fock computations. Harmonic vibrational frequencies were obtained at the same level of theory as the geometry optimizations. A restricted Hartree-Fock (RHF) reference was employed throughout, and optimized structures were verified as local minima or transition states by vibrational analyses. The relative enthalpies at 0 K (∆H0K ) were determined for all species with respect to thioformaldehyde S -sulfide (2b) by computing relative electronic energies (∆Ee ) using the focal point approach (FPA) 41,42 and appending zero-point vibrational (ZPVE) 3 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

energy corrections. 43 Specifically, absolute electronic energies were systematically extrapolated to the complete basis set (CBS) limit of coupled-cluster theory with full quadruple excitations (CCSDTQ) using a three-parameter exponential function 44 and a two-parameter power function 45 for the Hartree-Fock and correlation energies, respectively. In addition to the augmented, triple-ζ Dunning basis sets already described, CBS extrapolation was achieved with quadruple- and quintuple-ζ basis sets — i.e., aug-cc-pVXZ (X = Q, 5) on carbon and hydrogen atoms, and aug-cc-pV(X+d)Z on sulfur atoms. The T1 diagnostic was employed as a metric to gauge the multireference character of stationary points, s |t1α |2 + |t1β |2 (1) T1 = Ncorr 46,47 No value above 0.044 for T1 and 0.108 for tab along with the largest tab ij was ij amplitudes. 48 observed. The CASSCF reference coefficients for an active space of 14 electrons distributed in 14 orbitals were also considered. The dominant CI coefficients indicate that 87, 84, and 90% of the reactant, transition state, and product wavefunctions, respectively, can be described by a single-reference determinant, corroborating the validity of the methods employed in the present research. Geometry optimizations, computed at the CCSD(T) level, were performed in CFour 2.0 using the ECC module; 49 higher-order coupled-cluster computations were performed using the NCC module. 50–52 All CCSD(T) computations for the focal point analysis, as well as the CASSCF computations, were performed in Molpro 2010.1. 53 Natural bond orbital (NBO) analyses 54–57 were performed using the NBO 6.0 package, 31,58 as interfaced with Q-Chem 4.4. 59 NBO results include natural resonance theory (NRT) analysis, 60–62 which provide properties from a weighted average of first-order density matrices. The B3LYP functional and cc-pVTZ basis set were used for the NBO computations only.

Results and Discussion In the present research, optimized geometries, relative energies, and anharmonic frequencies for thioformaldehyde S-sulfide (2b, Cs point-group symmetry), dithiirane (2c, C2v ), and the corresponding cyclization transition state (C1 ; see Figure 3) are reported. Optimized structures are compared to the earlier computational study by Fabian and Senning, 11 which included MP2 theory and the 6-31+G** Pople basis-set. For qualitative purposes, comparisons are also made to the predicted geometries of carbonyl O-oxide reported by McCarthy, Stanton, and colleagues. 63

Molecular Structures The structure of thioformaldehyde S-sulfide (CH2 SS, 2b) is predicted, by the results of the present study, to possess a S—S bond length of 1.941 ˚ A (see Figure 3). Upon cyclization to dithiirane (H2 CS2 , 2c), this bond elongates 8% to 2.100 ˚ A; a similar, 13% change in O—O bond distance is observed when the Criegee intermediate (1.349 ˚ A) cyclizes to dioxirane 4 ACS Paragon Plus Environment

Page 4 of 20

Page 5 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Thioformaldehyde S-sulfide (2b)

Transition state

Dithiirane (2c)

Figure 3: Optimized geometric parameters for thioformaldehyde S-sulfide (Cs ), the cyclization transition state (C1 ), and dithiirane (C2v ). Reported distances (˚ A) and angles (◦ ) are from CCSD(T)/aug-cc-pVTZ computations, which include additional tight d functions on sulfur. Also see the Supporting Information. (1.525 ˚ A). 63 The C—S bond length extends 10% from 1.634 ˚ A (CH2 SS, 2b) to 1.801 ˚ A (H2 CS2 , 2c), accompanying a lowering of bond order and the formation of another C—S bond. The C—S bond length is more than 0.35 ˚ A longer than the C—O bond in CH2 OO 63 (1b). In CH2 SS (2b), the C-S-S bond angle is 113.9◦ (see Figure 3). In the transition state, the same bond is approximately a right angle, 84.0◦ . Closing the three-membered ring (i.e., continuing along the reaction path) yields dithiirane, H2 CS2 (2c), which possesses a C-S-S angle of 54.3◦ . Starting from CH2 SS, the dihedral angle between the H-C-H plane involving methylene hydrogen atoms relative to the C-S-S plane is 0◦ . The H-C-H plane rotates to yield a dihedral angle of 90◦ in the product; in the C1 transition state, the same angle is 54.5◦ . The latter value is interesting in light of Hammond’s postulate, which states that in an exothermic reaction the geometry of the transition state may be more reactant-like than product-like. 64 Although the S—S bond of the C1 transition state is 69% reactant-like, the C—S bond is only 35% reactant-like — i.e., closer in length to the product. Perhaps most distinctly, the H-C-S-S dihedral angle is only 39% reactant-like. It would appear that Hammond’s postulate is not appropriate for these evanescent intermediates. Interestingly, an ab initio molecular dynamics study by Kalinowski and colleagues suggests that isomerization of the Criegee intermediate also appears to challenge Hammond’s postulate, 65 though along different coordinates: the C—O bond of the transition state is 96% product-like, but the O—O bond is 79% reactant-like. The H-C-O-O dihedral angle is not reported, therein. For both CH2 SS (2b) and H2 CS2 (2c), the present coupled-cluster theory values for the S—S bond length are shorter than prior predictions with MP2/6-31+G** by 0.035 ˚ A and 11 ˚ 0.004 A respectively. The C—S bond distance of CH2 SS (2b) is predicted by MP2 to be 0.097 ˚ A longer than the current results; in H2 CS2 (2c) this MP2 overestimate is 0.065 ˚ A. 66 While CCSD(T) is generally the superior theory, particularly for thermochemistry, MP2 provides geometries for closed-shell, first- and second-row systems that are reasonably comparable to CCSD(T). 67–69 Likely, the contraction of bonds observed here are attributable to 5 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 6 of 20

the higher quality basis set. 70 In fact, the improvement gained by adding tight d functions has been previously noted to be dramatic for triple-ζ basis sets in sulfur-containing systems. 71

Relative Energies −− To further characterize the Cs , C1 , and C2v stationary points pertaining to the CH2 SS ) −* − H2 CS2 isomerization, the energetic relationships between the three conformers were computed using coupled-cluster theory with up to full quadruple excitations, extrapolated to the complete-basis limit. The focal point extrapolations in Table 1 show good convergence, with respect to the one-particle basis (down) and increasing levels of correlation treatment (across), instilling confidence in the final values (also see Figure 4). The ring closure of CH2 SS (2b) examined in this paper exhibits an enthalpy of activa‡ tion (∆H0K = 27.0 kcal mol−1 ) consistent with the formation of dithiirane under thermal 7 conditions. Even so, this barrier is 8.0 kcal mol−1 greater than the analogous barrier to cyclization of the Criegee intermediate (1b; 19.0 kcal mol−1 ) computed by Bowman, Guo, and colleagues. 72 Additionally, the isomerization product of the Criegee intermediate (dioxirane, 1c) lies considerably lower, at -25.0 kcal mol−1 , than the product of the present system (dithiirane, 2c), which has a relative enthalpy of -7.2 kcal mol−1 . Table 1: Focal point extrapolations of the relative energies (in kcal mol−1 ) to the CBS limit of CCSDTQ. CBS extrapolation was achieved with double-, triple-, quadruple- and quintupleζ basis sets — i.e., aug-cc-pVXZ (X = D, T, Q, 5) on carbon and hydrogen atoms, and aug-cc-pV(X+d)Z on sulfur atoms; these are notated in the table as DZ, TZ, QZ, and 5Z, respectively. Harmonic zero-point vibrational energy corrections (ZPVE) were computed at CCSD(T)/aug-cc-pVTZ, with added tight d functions on sulfur. CH2 SS → TS HF +δMP2 +δCCSD +δCCSD(T) +δCCSDT +δCCSDT(Q) +δCCSDTQ DZ +29.81 −0.19 −2.45 −1.82 +0.38 −0.50 +0.31 TZ +30.69 −0.75 −2.07 −1.82 +0.31 −0.44 [+0.31] QZ +30.94 −0.44 −1.82 −1.82 [+0.31] [−0.44] [+0.31] 5Z +31.06 −0.50 −1.69 −1.76 [+0.31] [−0.44] [+0.31] CBS limit [+31.12] [−0.57] [−1.56] [−1.69] [+0.31] [−0.44] [+0.31] ∆H0 = ∆Ee + ∆ZVPE [CCSD(T)/aug-cc-pVTZ] = +27.48 + (−0.51) = +26.97 kcal mol−1 CH2 SS → H2 CS2 HF +δMP2 +δCCSD +δCCSD(T) +δCCSDT +δCCSDT(Q) +δCCSDTQ DZ −15.06 +4.27 −0.75 +2.51 +0.31 +0.50 −0.13 TZ −14.75 +3.01 −0.94 +2.57 +0.19 +0.69 [−0.13] QZ −14.50 +3.45 −0.88 +2.57 [+0.19] [+0.69] [−0.13] 5Z −14.37 +3.45 −0.82 +2.57 [+0.19] [+0.69] [−0.13] CBS limit [−14.32] [+3.45] [−0.75] [+2.57] [+0.19] [+0.69] [−0.13] ∆H0 = ∆Ee + ∆ZVPE [CCSD(T)/aug-cc-pVTZ] = −8.29 + 1.13 = -7.16 kcal mol−1

Net [+25.54] [+26.23] [+27.05] [+27.30] [+27.48] Net [−8.35] [−9.35] [−8.60] [−8.41] [−8.29]

Vibrational Frequencies The fundamental vibrational frequencies of thioformaldehyde S-sulfide (CH2 SS; 2b) and dithiirane (H2 CS2 ; 2c), reported in Table 2, were computed to aid in the detection and 6 ACS Paragon Plus Environment

Page 7 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 4: Relative enthalpy profile (see Table 1) of the isomerization of thioformaldehyde S-sulfide to dithiirane, and the natural charges (units e = 1.6 × 10−19 coulombs) of each conformer. analysis of these molecules in the gas phase. Fundamental values were obtained by appending anharmonic corrections (δν) determined at CCSD(T)/aug-cc-pVTZ, with added tight d functions on sulfur, to the harmonic frequencies (ω) determined at the same level of theory. Second-order vibrational perturbation theory (VPT2) was employed to yield the anharmonic corrections using analytic second derivatives at displaced geometries along the normal coordinates. 73 The theoretical frequencies correspond well with the argon matrix experiment results of Maier and co-workers. 7 The average absolute deviation is 0.77%, which is consistent with the matrix shifts typically associated with argon (0.65%). 74 To further understand the vibrational modes of CH2 SS (2b), H2 CS2 (2c), and the transition state linking them (see Figure 3), a total energy distribution (TED) analysis was computed as advocated by Pulay and Török 75 and implemented in the INTDER program by Allen. 76 The results for CH2 SS (2b) and H2 CS2 (2c) appear in Table 2; those for the transition state appear in Table 3. The most intense vibrational frequency of thioformaldehyde S-sulfide (CH2 SS, 2b) is ν8 , and consists of the methylene “wag” in and out of the Cs plane. Mode ν6 , the S—S stretch, is predicted to have the second largest IR absorption. The large intensity derives from the change in dipole moment induced not only by the dominant S—S vibration, but also the bending motion of the carbon and two sulfur atoms (B312 ; see Figure 3), a motion that draws the sulfur atoms towards one another and anticipates cyclization. From argon matrix IR spectroscopy, Maier and co-workers 7 also showed this to be an intense band. The C—S stretch, ν4 , is of medium strength. The CH2 rocking, ν5 , is comprised in roughly equal measure of bending of the peripheral atoms around the central carbon (B312 , B412 , B512 ), giving 7 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Table 2: Fundamental vibrational frequencies (cm-1 ) for thioformaldehyde S-sulfide (CH2 SS, Cs ) and dithiirane (H2 CS2 , C2v ). Frequencies are given by ν = ω + δν, where ω is a harmonic frequency and δν is the anharmonic correction. All values were determined with CCSD(T)/aug-cc-pVTZ (with added tight d functions on sulfur). Harmonic intensities are shown in km mol−1 . Total Energy Distributions (TED) show percentage contributions from the indicated coordinates. Third column: str. = stretching, sciss. = scissoring, rock. = rocking, wag. = wagging, twist. = twisting, def. = deformation. Last column: S = stretch, B = bend, T = torsion; subscripts refer to atoms as shown in Figure 3. c Argon matrix IR spectroscopy results from Maier and co-workers. 7 Mode Sym Descriptiona CH2 SS (Cs ) ν1 a0 CH2 str. ν2 a0 CH2 str. ν3 a0 CH2 sciss. ν4 a0 CS str. ν5 a0 CH2 rock. ν6 a0 SS str. ν7 a0 def. ν8 a00 CH2 wag. ν9 a00 CH2 twist. H2 CS2 (C2v ) ν1 a1 CH2 str. ν2 a1 CH2 sciss. ν3 a1 ring str. ν4 a1 SS str. ν5 a2 CH2 twist. ν6 b1 CH2 str. ν8 b1 CH2 rock. ν7 b2 CH2 wag. ν9 b2 ring str.

ω δν ν Int CCSD(T)/aug-cc-pVTZ 3262.0 -146.8 3115.1 (1.9) 3135.0 -129.1 3005.9 (2.1) 1408.3 -53.3 1354.9 (8.4) 984.6 -23.1 961.5 (24.4) 925.0 5.9 930.9 (11.5) 621.1 -6.6 614.5 (36.9) 302.1 -1.8 300.3 (0.8) 754.0 0.0 754.0 (51.3) 557.3 -17.6 539.7 (2.8) CCSD(T)/aug-cc-pVTZ 3127.5 -127.3 3000.2 (7.2) 1467.1 -41.7 1425.4 (1.8) 860.1 -18.4 841.7 (0.7) 501.2 -5.0 496.3 (1.1) 954.6 -20.7 933.7 (- -) 3226.2 -150.0 3076.2 (0.0) 941.7 -4.1 933.9 (2.0) 1067.8 -24.0 1043.8 (1.2) 596.4 -14.3 582.1 (8.8)

ν Int Ar, 10Kc 3126.3 (vw) 3010.4 (w) 1366.4 (m) 970.9 (m) 910.2 (m) 622.8 (s) – – 756.8 (s) – – Ar, 10Kc 2986.7 (m) 1412.0 (w) – – – – – – – – 928.3 (m) 1053.0 (m) 581.0 (s)

TED Coordinateb (%) S14 (50) + S15 (50) S14 (50) + S15 (50) S13 (4) + B412 (43) + B512 (53) S13 (95) − S12 (5) + B412 (11) B312 (23) + B412 (36) + B512 (40) S12 (62) + B312 (37) S12 (45) + B312 (40) + B412 (9) + B512 (6) T4123 (64) + T5123 (36) T4123 (36) + T5123 (64) Coordinateb (%) S14 (50) + S15 (50) B312 (29) + B412 (29) + T4123 (21) + T5123 (21) S12 (52) + S13 (52) B312 (104) B312 (21) + B412 (21) + T4123 (29) + T5123 (29) S14 (50) + S15 (50) B312 (29) + B412 (29) + T4123 (21) + T5123 (21) B312 (21) + B412 (21) + T4123 (30) + T5123 (30) S12 (52) + S13 (52)

rise to a dynamic contraction and relaxation of the polar ends of the molecule, and thereby inducing a moderately strong IR absorption of intensity 11.5 km mol−1 . This appears as a band of medium intensity in the experiments of Maier et al. 7 The vibrational frequencies corresponding to CH2 stretching and scissoring (ν1 , ν2 , ν3 ) bear considerable similarity to the oxygen analog – cf., the NEVPT2/aug-cc-pVDZ computed band of a C—H stretch is 3149 cm−1 in the Criegee intermediate (1b), 4 and 3115 cm-1 in the present system (CH2 SS, 2b). Salient frequency differences involve modes of the chalcogen atoms. Notably, the O—O stretch of CH2 OO (1b) is experimentally shown 4 to be 908 cm−1 , while the predicted gas-phase S—S stretch in CH2 SS (2b) is 615 cm−1 . This disparity is attributable to the differing masses of the chalcogen atoms. 77 The imaginary mode, ν9 , of the transition state (see Figure 3) includes S—S lengthening, the continued bending of carbon and the two sulfurs (B312 , B512 ), and twisting of the hydrogens relative to carbon and sulfur (T4123 , T5123 ). The C—S stretching mode of the transition state, ν4 , also features a large contribution from this twisting motion. Modes ν6 and ν7 describe a deformation of the entire molecule as it isomerizes from planar Cs symmetry toward a structure bearing the methylene oriented at a right angle to the planar three-membered ring. In dithiirane (H2 CS2 , 2c) the CH2 twist is IR inactive. Furthermore, the IR bands 8 ACS Paragon Plus Environment

Page 8 of 20

Page 9 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Table 3: Harmonic frequencies ω (cm-1 ) and intensities (km mol−1 ) for the C1 transition state linking thioformaldehyde S-sulfide (CH2 SS) and dithiirane (H2 CS2 ). Also see Table 2 caption.

Mode ν1 ν2 ν3 ν4 ν5 ν6 ν7 ν8 ν9

Descriptiona CH2 str. CH2 str. CH2 sciss. CS str. CH2 rock. SS str. def. CH2 wag. CH2 twist.

ω Int 3253.8 (1.2) 3121.6 (0.9) 1442.5 (2.6) 971.5 (1.1) 913.8 (1.9) 773.1 (34.3) 595.1 (24.6) 523.3 (5.4) 586.1i (52.3)

TED: Coordinate (%) S14 (68) + S15 (32) S14 (32) + S15 (68) B412 (26) + T4123 (25) + T5123 (44) B412 (26) + T4123 (25) + T5123 (44) S13 (74) + B512 (22) S13 (13) + B312 (23) + B412 (32) + B512 (27) S12 (20) + B312 (14) + B412 (22) + B512 (27) + T4123 (17) S12 (44) + B312 (55) S12 (34) + B312 (35) + B512 (13) + T4123 (8) + T5123 (4)

of H2 CS2 (2c) are generally much less intense than those of CH2 SS (2b), due to the reduced dipole moment, which is matched by experiment. 7 The most intense modes involve a “breathing” motion (ν9 ) formed by the stretching of both symmetrical C—S bonds to induce ring stretching, as well as the methylene C—H symmetric stretches (ν1 ). The S—S stretching mode, ν4 , is coincident with the bending of the SCS angle (B312 ), and less intense. The largest deviation from experiment is the CH2 stretching mode in the C2v structure H2 CS2 (2c), ν1 , wherein the current study’s predictions of gas-phase frequency differ from the published argon matrix IR spectroscopy value by 13.5 cm−1 . This discrepancy is for a high-frequency mode, and the corresponding errors are amplified. Part of this discrepancy could also be a consequence of matrix effects.

Rotational and Vibration-Rotation Interaction Constants Equilibrium rotational constants for the species under study (Ae , Be , Ce ) are reported in Table 4. Zero-point corrected values (A0 , B0 , C0 ) are also provided, and account for the vibrational dependence of B0 along the principal axis b by the expression 78 B0 = Be −

1X B α 2 r r

(2)

where αrB are vibration-rotation interaction constants. These constants, αrB , describe the coupling of rotations about the principal axis corresponding to B with the normal mode r; the computed values appear in Table 5. (Analogous expressions apply to the vibrational dependence of A0 and C0 , which involve rotation about the axes a and c, respectively.) The high accuracy of αrB constants obtained from ab initio theory has been demonstrated previously. 30,79–81 The vibrationally averaged rotational constants A0 , B0 , and C0 are lower than their equilibrium counterparts by 0.3, 0.4, and 0.5%, respectively. Both CH2 SS (2b) and H2 CS2



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 10 of 20

(2c) are asymmetric tops; however, by Ray’s asymmetry parameter κ: 82 2B − A − C −1.0 =⇒ near prolate κ→ κ= +1.0 =⇒ near oblate A−C

(3)

CH2 SS (2b) is near prolate (κ = −0.95) and H2 CS2 (2c) is approximately prolate (κ = −0.74). The rotational constants of CH2 SS (2b) are 62% smaller than those of the Criegee intermediate CH2 OO (1b) computed by Bowman, Guo, and colleagues (A0 = 2.5934, B0 = 0.4158, C0 = 0.3576). 72 This is to be expected, as smaller rotational constants are observed with heavier atoms and longer bond lengths. 77 Table 4: Vibrational contributions to the equilibrium rotational constants and dipole moments were obtained from VPT2 analysis [CCSD(T)/aug-cc-pVTZ, +d functions on sulfur]. Rotational constants are in cm−1 and dipole moments are in Debye. µ is the equilibrium dipole moment, whereas hµi is the vibrationally averaged dipole moment. Parameter Ae Be Ce A0 B0 C0 |Ae − A0 | |Be − B0 | |Ce − C0 | µ hµi

Thioformaldehyde S-sulfide (CH2 SS) 0.9663 0.1604 0.1376 0.9638 0.1598 0.1369 0.0025 0.0006 0.0007 2.89 2.83

Dithiirane (H2 CS2 ) 0.5675 0.2335 0.1712 0.5626 0.2329 0.1702 0.0049 0.0006 0.0010 1.56 1.53

Bonding Analysis Cremer, Schmidt, Gauss, and Radhakarishnan describe the cyclization of the Criegee intermediate as being initiated by donation of an electron from the carbon atom to the neighboring oxygen. 83 The lowest unoccupied molecular orbital (LUMO) of CH2 SS (2b) features a large 3p orbital over the proximal sulfur, which is the electron sink for the highest occupied molecular orbital (HOMO) of the methylene carbon. The HOMO of CH2 SS (2b) is formed from a large 3p orbital on the non-bonding sulfur atom, as well as overlapping p-orbitals on the bonded sulfur and carbon atoms, for which Natural Bond Orbital (NBO) analysis (B3LYP/cc-pVTZ) describe as possessing sp2 and sp3 character, respectively. The overlapping p-orbitals observed in the HOMO are consistent with the double-bond character of the dominant resonance structure in CH2 SS (2b; also see Figure 5). The bond order of the C—S bond (bCS ) in the transition state is reduced from to 1.7 to 1.3, and the p character 10 ACS Paragon Plus Environment

Page 11 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Table 5: Vibration-rotation interaction constants (αrB , in 10−3 cm-1 ) for thioformaldehyde S-sufide (CH2 SS) and dithiirane (H2 CS2 ). Mode (r) 1 2 3 4 5 6 7 8 9

A 1.720 2.087 -2.180 5.352 -4.430 -1.463 -8.811 4.016 8.770

CH2 SS B C 0.072 0.078 0.048 0.077 -0.044 0.090 0.296 0.133 -0.108 0.332 0.637 0.522 0.011 0.207 0.195 -0.041 0.100 0.004

A 0.075 -0.173 0.273 1.464 -6.134 0.101 0.158 6.332 -0.167

H2 CS2 B 0.659 1.614 3.304 -2.313 1.338 0.139 1.309 0.260 3.552

C 0.185 -0.164 0.353 1.391 -0.103 0.233 -0.701 0.359 -0.326

is increased on the bonded sulfur atom. This rearrangement (Figure 3) entails a concerted electrocyclic mechanism, whereby ring closure occurs with the formation of a new sigma bond, concomitant with the reduction of the double bond to a single bond. In H2 CS2 (2c), the molecular orbital of each sulfur donates an electron into the methylene LUMO to furnish the symmetric structure. The bond order of the C—S bond in H2 CS2 (2c) is 1.0, and the sulfur atoms are described by p character. The HOMO-LUMO gap of H2 CS2 (11.5 eV) is larger than that of CH2 SS (9.1 eV), indicative of lesser thermal reactivity. 84 For CH2 SS (2b), natural population analysis yields natural charges for the carbon atom of -0.58 e (where e = 1.6 × 10−19 coulomb), along with the bonded sulfur atom (0.51 e), and the non-bonded sulfur atom (-0.36 e), see Figure 4. The leading resonance structure features a double bond between the carbon and proximal sulfur atoms, a single bond between the two sulfur atoms, and three lone pairs (one contributing to a negative charge) on the terminal sulfur. These features of CH2 SS (2b) match the leading zwitterionic form of carbonyl O-oxide, CH2 OO (1b). 85 The natural bond order analysis reveals, for CH2 SS, an 84% covalent (16% ionic) bond between the carbon and sulfur atoms (bCS = 1.7), and 68% covalent bond between the two sulfur atoms (bSS = 1.2). While this structure describes 58% of the resonance character, an important contributor (22%) is one in which the double bond is located between the two sulfur atoms. A minor contributor is one in which a single bond forms between the terminal sulfur atom and the carbon atom, rendering the primary C—S interaction a single bond; this structure is akin to the transition state. Interestingly, in CH2 OO (1b), this same transition state-like structure, in addition to the dominant C—O double bond resonance form, comprises its sole resonance contributors, notably absent an O—O double bond structure. This is reasonable given that CH2 OO’s smaller interatomic distances foster the formation of a new bond. The dipole moment of CH2 SS (2b) is 2.89 Debye, considerably less than the 4.0 Debye dipole moment of CH2 OO (1b), 86 consistent with the smaller electronegativity of sulfur. The transition state (Figures 4 and 5) displays reduced polarized charges: -0.45 e on the 11 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(2b)

(TS)

(2c)

(1b)

(1c)

Figure 5: Resonance contributions of the equilibrium stationary points: Thioformaldehyde S-sulfide (2b); cyclization transition state (TS); dithiirane (2c); carbonyl O-oxide, the Criegee intermediate (1b); dioxirane (1c).


Page 12 of 20

Page 13 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


carbon atom, and 0.28 and -0.25 e on the proximal and terminal sulfur atoms, respectively. The leading resonance structure from natural bond order analysis (54%) features single bonds between the carbon atom and both sulfur atoms, akin to the product. The bond between the proximal sulfur atom and carbon atom is 82% covalent (bCS = 1.3), while the newly formed bond between the terminal sulfur atom and the carbon atom is just 25% covalent (bCS = 0.6). The covalent character of the S—S bond is increased from its predecessor to 80% (bSS = 1.1). In the second leading resonance structure (26%), which is similar to the reactant, the double bond exists between the carbon and proximal sulfur atom; the bond between the carbon atom and terminal sulfur atom is absent. These relative contributions support the interpretation that Hammond’s postulate may not apply to this system. In dithiirane (2c) both C—S bonds are 88% covalent (bCS = 1.0), whereas the S—S bond is entirely covalent (bSS = 1.0). This nearly exclusive (94%) “resonance” structure features single bonds between all atoms. A similar picture describes the dominant form of CH2 OO (1b). 87 The carbon atom of CH2 SS has a natural charge, -0.68 e, while the other atoms are nearly neutral. The dipole moment is reduced to 1.56 Debye.

Conclusions A high-level ab initio study of the sulfur analog of the Criegee intermediate (thioformaldehyde S-sulfide), its valence isomer (dithiirane), and the transition state linking these molecules is described. The results of a focal point extrapolation and vibrational analysis indicate that dithiirane is 7.2 kcal mol−1 lower in energy than thioformaldehyde S-sulfide, and that there is a 27.0 kcal mol−1 barrier to cyclization. The resonance contributors of the Cs -symmetric thioformaldehyde S-sulfide structure are predominantly characterized by the presence of a double-bond bond between the carbon and proximal sulfur atoms, and a third lone pair on the terminal sulfur atom, lending it a negative charge. The C2v -symmetric structure dithiirane is formed by a ring-closing, electrocycylic mechanism, and features lengthened S—S and C—S bonds relative to the antecedent structure. Dithiirane’s S—S bond is almost exclusively covalent and of single-bond character, while its two C—S bonds are 88% covalent. The geometric parameters of the transition state generally bear more resemblance to the thioformaldehyde S-sulfide reactant than the dithiirane product. The computed fundamental frequencies are in very good agreement with the argon matrix experiments of Maier et al., 7 and our predictions of the currently unknown gas-phase infrared bands should be reliable.

Acknowledgments This research was supported by the U.S. Department of Energy, Office of Basic Energy Science, Computational and Theoretical Chemistry Program, Grant No. DEFG02-97-ER14748.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Supporting Information Cartesian coordinates, computational details, and harmonic vibrational frequencies. This material is available free of charge via the Internet at http://pubs.acs.org/.

References (1) Wang, Z. Comprehensive Organic Name Reactions and Reagents; John Wiley & Sons, Inc., 2010. (2) Hoops, M. D.; Ault, B. S. Matrix Isolation Study of the Early Intermediates in the Ozonolysis of Cyclopentene and Cyclopentadiene: Observation of Two Criegee Intermediates. J. Am. Chem. Soc. 2009, 131, 2853–2863. (3) Criegee, R. Concerning a Crystalised Dekalin Peroxide. Chem. Ber. 1944, 77, 722. (4) Su, Y. T.; Huang, Y. H.; Witek, H. A.; Lee, Y. P. Infrared Absorption Spectrum of the Simplest Criegee Intermediate CH2 OO. Science 2013, 340, 174–177. ¨ (5) Criegee, R. Uber den Verlauf der Ozonspaltung (III. Mitteilung). Eur. J. Org. Chem. 1953, 583, 1–36. (6) Weisheit, T.; Kriltz, A.; Gorls, H.; Mloston, G. .; Imhof, W.; Weigand, W. Reaction of Non-Symmetrical 1,2,4-Trithiolanes with [(phosphane)Pt0(η2-nbe)] Complexes. Chem. Asian J. 2012, 7, 1383–1393. (7) Mlosto´ n, G.; Roma´ nski, J.; Reisenauer, H. P.; Maier, G. Thioformaldehyde S-sulfide (Thiosulfine). Angew. Chem. 2001, 40, 393–396. (8) Tjan, S. B. Of 3,5-Dialkyl-1,2,4-Trithiolanes. J. Agr. Food Chem. 1972, 20, 177–181. (9) Akhmetova, V. R.; Nadyrgulova, G. R.; Khafizova, S. R.; Tyumkina, T. V.; Yakovenko, A. A.; Antipin, M. Y.; Khalilov, L. M.; Kunakova, R. V.; Dzhemileva, U. M. Reactions of Aminophenols with Formaldehyde and Hydrogen Sulfide. Russ. Chem. Bull. 2006, 55, 312–316. (10) Reisenauer, H. P.; Mloston, G.; Romanski, J.; Schreiner, P. R. Thermolysis of 3,3,5,5tetramethyl-1,2,4-trithiolane 1-oxide: First Matrix Isolation of the HOSS Radical. Eur. J. Org. Chem. 2012, 3408–3415. (11) Fabian, J.; Senning, A. The Thiosulfine-Dithiirane-Dithioester Manifold. Sulf. Rep. 1998, 21, 1–42. (12) Womack, C. C.; Martin-Drumel, M. A.; Brown, G. G.; Field, R. W.; McCarthy, M. C. Observation of the Simplest Criegee Intermediate CH2 OO in the Gas-Phase Ozonolysis of Ethylene. Sci. Adv. 2015, 1, 1400105. (13) Ishiguro, K.; Nojima, T.; Sawaki, Y. Novel Aspects of Carbonyl Oxide Chemistry. J. Phys. Org. Chem. 1997, 10, 787–796. 14 ACS Paragon Plus Environment

Page 14 of 20

Page 15 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(14) Jacox, M. E. Electronic Energy Levels of Small Polyatomic Transient Molecules. 1988, 17, 269–511. (15) Brock, N. L.; Citron, C. A.; Zell, C.; Berger, M.; Wagner-Döbler, I.; Petersen, J.; Brinkhoff, T.; Simon, M.; Dickschat, J. S. Isotopically Labeled Sulfur Compounds and Synthetic Selenium and Tellurium Analogues to Study Sulfur Metabolism in Marine Bacteria. Beilstein J. Org. Chem. 2013, 9, 942–950. (16) Rushdi, A., Simoneit, B. R. Abiotic Synthesis of Organic Compounds from Carbon Disulfide Under Hydrothermal Conditions. Astrobio. 2005, 5, 749–769. (17) Glass, R. In Sulfur-Centered Reactive Intermediates in Chemistry and Biology, 1st ed.; Chatgilialoglu, C., Asmus, K., Eds.; Springer US: New York, 1990; Chapter Design, Sy, pp 227–254. (18) Minh, Y.; Irvine, W.; Brewer, M. H2 CS Abundances and Ortho-to-Para Ratios in Interstellar Clouds. Astron. Astrophys. 1991, 244, 181–189. (19) Oppenheimer, M., Dalgarno, A. The Chemistry of Sulfur in Interstellar Clouds. Astrophys. J. 1974, 187, 231. (20) Prasad, S. S.; Huntress, W. T. Sulfur Chemistry in Dense Interstellar Clouds. Astrophys. J. 1982, 260, 590. (21) Senning, A.; Hansen, H.; Abdel-Megeed, M.; Mazurkieqixz, W.; Jensen, B. Studies of Dithiiranes and Thiosulfines as Reactive Intermediates. Tet. 1986, 42, 739–746. (22) Shimada, K.; Kodaki, K. Formation of Kinetically Stabilized Dithiiranes by Treating Thione S-Oxides Bearing a Bulky Substituent with Lawesson’s Reagent. Chem. Lett. 1999, 695–696. (23) Huisgen, R.; Li, X. The Activity Scale of Dipolarophiles versus Thiobenzophenone SMethylide. Tet. Lett. 1983, 24, 4185–4189. (24) Franek, W. New Dithio-Bis-(Diaroylmethanes) and Acetyl Diaroylchloromethyl Disulfides: Attractive Synthons and Precursors for the Liberation of Highly Reactive Dithiiranes or Thiosulfines. Chem. Mon. 1995, 127, 895–907. (25) Fabian, J. A Theoretical Study of some Non-Classical Organic Compounds with DiCoordinated Sulfur. J. Mol. Struc. 1997, 398, 411–416. (26) Huisgen, R.; Rapp, J. Thiocarbonyl S-Sulfides: A New Class of 1,3-Dipoles. J. Am. Chem. Soc. 1987, 109, 902–903. (27) Ishii, A.; Hoshino, M.; Nakayama, J. Recent Advances in Chemistry of Dithiirane and Small Ring Compounds Containing Two Chalcogen Atoms. Pure App. Chem. 1996, 68, 869–874. (28) Ishii, A.; Umezawa, K.; Nakayama, J. Preparation and Properties of a 3,3Dialkyldithiirane. Tet. Lett. 1997, 38, 1431–1434. 15 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(29) Nakayama, J.; Ishii, A. Chemistry of Dithiiranes, 1,2-Dithietanes, and 1,2-Dithietes. Adv. Heterocyc. Chem. 2000, 77, 1055–1078. (30) Clabo Jr., D. A.; Allen, W. D.; Remington, R. B.; Yamaguchi, Y.; Schaefer, H. F. A Systematic Study of Molecular Vibrational Anharmonicity and Vibration-Rotation Interaction by Self-Consistent-Field Higher-Derivative Methods. Chem. Phys. 1988, 123, 187–239. (31) Glendening, E.; Badenhoop, J.; Reed, A.; Carpenter, J.; Bohmann, J.; Morales, C.; Landis, C.; Weinhold, F. NBO v. 6.0. 2013. (32) Bartlett, R. J.; Musial, M. Coupled-Cluster Theory in Quantum Chemistry. Rev. Mod. Phys. 2007, 79, 291–349. (33) Raghavachari, K.; Trucks, G.; Pople, J.; Head-Gordon, M. A Fifth-Order Perturbation Comparison of Electron Correlation Theories. Chem. Phys. Lett. 1989, 157, 479–483. (34) Stanton, J. F.; Lopreore, C. L.; Gauss, J. The Equilibrium Structure and Fundamental Vibrational Frequencies of Dioxirane. J. Chem. Phys. 1998, 108, 7190. (35) Hehre, W.; Radom, L.; Schleyer, P.; Pople, J. Ab Initio Molecular Orbital Theory; Wiley: New York, 1986. (36) Kendall, R.; Dunning, T., Jr.; Harrison, R. Electron Affinities of the First-Row Atoms Revisited. Systematic Basis Sets and Wave Functions. J. Chem. Phys. 1992, 96, 6796– 6806. (37) Dunning, T. H. Gaussian Basis Sets for Use in Correlated Molecular Calculations . I . The Atoms Boron through Neon and Hydrogen. J. Chem. Phys. 1989, 90, 1007–1023. (38) Dunning, T. H.; Peterson, K. A.; Wilson, A. K. Gaussian Basis Sets for Use in Correlated Molecular Calculations . X . The Atoms Aluminum through Argon Revisited. J. Chem. Phys. 2001, 114, 9244–9253. (39) Wilson, A. K.; Dunning, T. H. The HSO-SOH Isomers Revisited: The Effect of Tight d Functions. J. Phys. Chem. A 2004, 108, 3129–3133. (40) Martin, J. M.; Uzan, O. Basis Set Convergence in Second-Row Compounds. The Importance of Core Polarization Functions. Chem. Phys. Lett. 1998, 282, 16–24. (41) Császár, A. G.; Allen, W. D.; Schaefer, H. F. In Pursuit of the Ab Initio Limit for Conformational Energy Prototypes. J. Chem. Phys. 1998, 108, 9751–9764. (42) Allen, W. D.; East, A. L.; Császár, A. G. Structures and Conformations of Non-Rigid Molecules; Kluwer Academic Publishers: Dordrecht, Netherlands, 1993; pp 343–373. (43) Allinger, N. L.; Fermann, J. T.; Allen, W. D.; Schaefer, H. F. The Torsional Conformations of Butane: Definitive Energetics from Ab Initio Methods. J. Chem. Phys. 1997, 106, 5143–5150. 16 ACS Paragon Plus Environment

Page 16 of 20

Page 17 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(44) Feller, D. The Use of Systematic Sequences of Wave Functions for Estimating the Complete Basis Set, Full Configuration Interaction Limit in Water. J. Chem. Phys. 1993, 98, 7059–7071. (45) Helgaker, T.; Klopper, W.; Koch, H.; Noga, J. Basis-Set Convergence of Correlated Calculations on Water. J. Chem. Phys. 1997, 106, 9639–9646. (46) Copan, A. V.; Wiens, A. E.; Nowara, E. M.; Schaefer, H. F.; Agarwal, J. Peroxyacetyl Radical: Electronic Excitation Energies, Fundamental Vibrational Frequencies, and Symmetry Breaking in the First Excited State. J. Chem. Phys. 2015, 142, 054303. (47) Launder, A. M.; Agarwal, J.; Schaefer, H. F. Exploring Mechanisms of a Tropospheric Archetype: CH3 O2 + NO. J. Chem. Phys. 2015, 143, 234302. (48) Lee, T. J.; Taylor, P. R. A Diagnostic for Determining the Quality of Single-Reference Electron Correlation Methods. Int. J. Quant. Chem. 1989, 36, 199–207. (49) CFOUR, a quantum chemical program package by Stanton, J. F.; Gauss, J.; Harding, M. E.; Szalay, P. G. with contributions from Auer, A. A.; Bartlett, R. J.; Benedikt, U.; Berger, C.; Bernholdt, D. E.; Bomble, Y. J.; Cheng, L.; Christiansen, O.; Heckert, M.; Heun, O.; Huber, C.; Jagau, T.-C.; Jonsson, D.; Juslius, J.; Klein, K.; Lauderdale, W. J.; Lipparini, F.; Matthews, D. A.; Metzroth, T.; Mck, L. A.; O’Neill, D. P.; Price, D. R.; Prochnow, E.; Puzzarini,C.; Ruud, K.; Schiffmann, F.; Schwalbach, W.; Simmons, C.; Stopkowicz, S.; Tajti, A.; Vzquez, J.; Wang, F.; Watts, J. D. and the integral packages MOLECULE (Almlf, J. and Taylor, P. R.), PROPS (Taylor, P. R.), ABACUS (Helgaker, T.; Jensen, H. J. Aa.; Jrgensen, P.; and Olsen, J.), and ECP routines by Mitin, A. V. and van Wullen, C. Version 2.0 Beta. (50) Matthews, D. A.; Gauss, J.; Stanton, J. F. Revisitation of Nonorthogonal Spin Adaptation in Coupled Cluster Theory. J. Chem. Theo. Comp. 2013, 1, 1011. (51) Matthews, D. A.; Stanton, J. F. Non-Orthogonal Spin-Adaptation of Coupled Cluster Methods: A New Implementation of Methods Including Quadruple Excitations. J. Chem. Phys. 2015, 142, 64108. (52) Matthews, D. A.; Stanton, J. F. Accelerating the Convergence of Higher-Order Coupled Cluster Methods. J. Chem. Phys. 2015, 143, 204103. (53) Werner, H. J.; Knowles, P. J. MOLPRO ver. 2010.1, a package of ab initio programs. (54) Reed, A.; Weinstock, R.; Weinhold, F. Natural Population Analysis. J. Chem. Phys. 1985, 83, 735–746. (55) Weinhold, F. Chemical Bonding as a Superposition Phenomenon. J. Chem. Ed. 1999, 76, 1141–1146. (56) Weinhold, F.; Landis, C. Natural Bond Orbitals and Extensions of Localized Bonding Concepts. Chem. Educ. Res. Pract. 2001, 2, 91–104.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(57) Turner, W. E.; Agarwal, J.; Schaefer, H. F. Structures, Bonding, and Energetics of Potential Triatomic Circumstellar Molecules Containing Group 15 and 16 Elements. J. Phys. Chem. A. 2015, 119, 11693 – 11700. (58) Glendening, E.; Landis, C.; Weinhold, F. NBO 6.0: Natural Bond Orbital Analysis Program. J. Comp. Chem. 2013, 34, 1429–1437. (59) Advances in Molecular Quantum Chemistry Contained in the Q-Chem 4 Program Package. Mol. Phys. 2015, 113, 184–215. (60) Glendening, E.; Weinhold, F. Natural Resonance Theory. I. General Formulation. J. Comp. Chem. 1998, 19, 593–609. (61) Glendening, E.; Weinhold, F. Natural Resonance Theory. II. Natural Bond Order and Valency. J. Comp. Chem. 1998, 19, 610–627. (62) Glendening, E.; Weinhold, F. Natural Resonance Theory. III. Chemical Applications. J. Comp. Chem. 1998, 19, 628–646. (63) McCarthy, M. C.; Cheng, L.; Crabtree, K. N.; Martinez, O.; Nguyen, T. L.; Womack, C. C.; Stanton, J. F. The Simplest Criegee Intermediate (H2C=O-O): Isotopic Spectroscopy, Equilibrium Structure, and Possible Formation from Atmospheric Lightning. J. Phys. Chem. Lett. 2013, 4, 4133–4139. (64) Bruice, P. Organic Chemistry; Pearson: New York, 2006. (65) Kalinowski, J.; Rasanen, M.; Heinonen, P.; Kilpelainen, I.; Gerber, R. B. Isomerization and Decomposition of a Criegee Intermediate in the Ozonolysis of Alkenes: Dynamics Using a Multireference Potential. Angew. Chem. Int. Ed. 2014, 53, 265–268. (66) Helgaker, T.; Ruden, T. A.; Jorgensen, P.; Olsen, J.; Klopper, W. A Priori Calculation of Molecular Properties to Chemical Accuracy. J. Phys. Org. Chem. 2004, 17, 913–933. (67) Coriani, S.; Marchesan, D.; Gauss, J.; Hättig, C.; Helgaker, T.; Jorgensen, P. The Accuracy of Ab Initio Molecular Geometries for Systems Containing Second-Row Atoms. J. Chem. Phys. 2005, 123, 184107. (68) Helgaker, T.; Gauss, J.; Jorgensen, P.; Olsen, J. The Prediction of Molecular Equilibrium Structures by the Standard Electronic Wave Functions. J. Chem. Phys. 1997, 106, 6430–6440. (69) Cremer, D.; Kraka, E.; He, Y. Exact Geometries from Quantum Chemical Calculations. J. Mol. Struc. 2001, 567, 275–293. (70) Cramer, C. Essentials of Computational Chemistry; Wiley: New York, 2002. (71) Wilson, A. K.; Dunning, T. H. SO2 : Impact of Tight d Augmented Correlation Consistent Basis Sets on Structure and Energetics. J. Chem. Phys. 2003, 119, 11712–11714.


Page 18 of 20

Page 19 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(72) Li, J.; Carter, S.; Bowman, J. M.; Dawes, R.; Xie, D.; Guo, H. High-Level, FirstPrinciples, Full-Dimensional Quantum Calculation of the Ro-vibrational Spectrum of the Simplest Criegee Intermediate. J. Chem. Phys. Letter 2014, 5, 2364–2369. (73) Mills, I. M. In Molecular Spectroscopy: Modern Research; Rao, K. N., Matthews, C., Ed.; Academic Press: New York, 1972; Chapter 3, pp 115–140. (74) Jacox, M. E. The Spectroscopy of Molecular Reaction Intermediates Trapped in the Solid Rare Gases. Chem. Soc. Rev. 2002, 31, 108–115. ¨ (75) Pulay, P.; Török, F. Uber die Parameterdarstellung der Kraftkonstantenmatrix I. Acta Chim. Hung. 1965, 44, 287. (76) INTDER2005, is a general program developed by Wesley D. Allen and co-workers that performs various vibrational analyses and higher-order nonlinear transformations among force field representations. (77) Harris, D. C.; Bertolucci, M. D. Symmetry and Spectroscopy, 1st ed.; Dover: New York, 1989; Chapter Design, Sy. (78) Bak, K. L.; Gauss, J.; Jorgensen, P.; Olsen, J.; Helgaker, T.; Stanton, J. F. The Accurate Deterination of Molecular Equilibrium Structures. J. Chem. Phys. 2001, 114, 6548– 6556. (79) Chang, C.-H.; Agarwal, J.; Allen, W. D.; Nesbitt, D. J. Sub-Doppler Infrared Spectroscopy and Formation Dynamics of Triacetylene in a Slit Supersonic Expansion. J. Chem. Phys. 2016, 144, 074301. (80) Allen, W. D.; Yamaguchi, Y.; Császár, A. G.; Clabo Jr., D. A.; Remington, R. B.; Schaefer, H. F. A Systematic Study of Molecular Vibrational Anharmonicity and VibrationRotation Interaction by Self-Consistent-Field Higher-Derivative Methods. Linear Polyatomic Molecules. Chem. Phys. 1990, 145, 427–466. (81) Watson, J. K. G. In Vibrational Structure and Spectra; Durig, J. R., Ed.; 1977; Vol. 6; p 1. (82) Bernath, P. F. Spectra of Atoms and Molecules, 3rd ed.; Oxford University Press: New York, 2015. (83) Cremer, D.; Schmidt, T.; Gauss, J.; Radhakrishnan, T. Formation of Dioxirane from Carbonyl Oxide. Angew. Chem. Int. Ed. 1989, 27, 427–428. (84) Rao, V. P.; Chandrasekhar, J.; Ramamurthy, V. Thermal and Photochemical Cycloaddition Reactions of Thiocarbonyls: A Qualitative Molecular Orbital Analysis. J. Chem. Soc. Perkin Trans. 1988, 2, 647–659. (85) Samanta, K.; Beames, J. M.; Lester, M. I.; Subotnik, J. E. Quantum Dynamical Investigation of the Simplest Criegee Intermediate CH2OO and its O-O Photodissociation Channels. J. Chem. Phys. 2014, 141, 134303. 19 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(86) Osborn, D. L.; Taatjes, C. A. The Physical Chemistry of Criegee Intermediates in the Gas Phase. Int. Rev. Phys. Chem. 2015, 34, 309–360. (87) Wilke, J. J.; Weinhold, F. Resonance Bonding Patterns of Peroxide Chemistry: Cyclic Three-Center Hyperbonding in “Phosphadioxirane” Intermediates. J. Am. Chem. Soc. 2006, 128, 11850–11859. Table of Contents Graphic:

12/11/2016

drawingB.svg

file:///Users/jayagarwal/Library/Containers/com.apple.mail/Data/Library/Mail%20Downloads/1246273B-ABD5-42D6-8D2E-BC8C5B9E1E19/drawingB.svg

1/1


Page 20 of 20

Thioformaldehyde S-Sulfide, Sulfur Analogue of the Criegee

Recommend Documents