C7 H7 Research Articles

Distinct Excitonic Emissions in 2D (C7 H7 N2 )2 PbX4 (X=Cl, Br) under Compression.

Two dimensional (2D) hybrid metal halides (HMHs) usually exhibit free excitonic (FE) emission, and self-trapped excitonic (STE) emission can also be achieved by adopting appropriate halogens and organic cations. Recently, significant efforts have been made to modulate and then clarify the transformation and connection between these two types of excitonic emissions in 2D HMHs. In this study, intriguing pressure-tuned transitions between FE emission and STE emission are observed in 2D (C7 H7 N2 )2 PbCl4 . In contrast, only FE emissions with tunable emission energies are observed in 2D (C7 H7 N2 )2 PbBr4 which possesses a similar structure with (C7 H7 N2 )2 PbCl4 under compression. Such distinct halide-dependent optical responses under pressure are experimentally revealed to arise from the intricate interplay among several factors in these HMHs, including the stiffness of the structure, the Coulomb force between the organic cations and the inorganic octahedra, and the magnitude of inorganic octahedral distortion. These high-pressure optical explorations can unravel the underlying interrelationship between the crystal structure and excitonic emission in 2D HMHs.

Atomically Precise Defective Copper Nanocluster Catalysts for Highly Selective C-C Cross-Coupling Reaction.

Point defects in nanoparticles have long been hypothesized to play an important role in governing the particle's electronic structure and physicochemical properties. However, single point defects in material systems usually exist with other heterogeneities, obscuring the chemical role of the effects. Herein, we report a novel atomically precise, copper hydride nanoclusters (NCs), [Cu28H10(C7H7S)18(TPP)3] (Cu28; TPP: triphenylphosphine; C7H7S: o-thiocresol) with a defined defect in the gram scale via a one-pot reduction method. The Cu28 acts as a highly selective catalyst in for C-C cross-couplings. The work highlights the potential of defective NCs as model systems for investigating individual defects, correlating defects with physiochemical properties, and rationally designing new nanoparticle catalysts.

Discriminating alkylbenzene isomers with tandem mass spectrometry using a dielectric barrier discharge ionization source.

Soft ambient ionization sources generate reactive species that interact with analyte molecules to form intact molecular ions, which allows rapid, sensitive, and direct identification of the molecular mass. We used a dielectric barrier discharge ionization (DBDI) source with nitrogen at atmospheric pressure to detect alkylated aromatic hydrocarbon isomers (C8 H10 or C9 H12 ). Intact molecular ions [M]•+ were detected at 2.4kVpp , but at increased voltage (3.4 kVpp ), [M + N]+ ions were formed, which could be used to differentiate regioisomers by collision-induced dissociation (CID). At 2.4 kVpp , alkylbenzene isomers with different alkyl-substituents could be identified by additional product ions: ethylbenzene and -toluene formed [M-2H]+ , isopropylbenzene formed abundant [M-H]+ , and propylbenzene formed abundant C7 H7 + . At an operating voltage of 3.4 kVpp , fragmentation of [M + N]+ by CID led to neutral loss of HCN and CH3 CN, which corresponded to steric hindrance for excited state N-atoms approaching the aromatic ring (C-H). The ratio of HCN to CH3 N loss (interday relative standard deviation [RSD]< 20%) was distinct for ethylbenzene and ethyltoluene isomers. The greater the number of alkyl-substituents (C-CH3 ) and the more sterically hindered (meta > para > ortho) the aromatic core, the greater the loss of CH3 CN relative to HCN was.

Unconventional Pathway in the Gas-Phase Synthesis of 9H-Fluorene (C13H10) via the Radical - Radical Reaction of Benzyl (C7H7) with Phenyl (C6H5).

The simplest polycyclic aromatic hydrocarbon (PAH) carrying a five-membered ring - 9H-fluorene (C13H10) - is produced isomer-specifically in the gas phase by reacting benzyl (C7H7•) with phenyl (C6H5•) radicals in a pyrolytic reac-tor coupled with single photon ionization mass spectrometry. The unconventional mechanism of reaction is supported by theoretical calculations, which first produces diphenyl-methane and unexpectedly 1-(6-methylenecyclohexa-2,4-dienyl)benzene intermediates (C13H12) accessed via addition of the phenyl radical to the ortho position of the benzyl radical. These findings offer convincing evidence for molecular mass growth processes defying conventional wisdom that radical-radical reactions are initiated through recombination at their radical centers. The structure of 9H-fluorene acts as a molecular building block for complex curved nanostructures like fullerenes and nanobowls providing fundamental insights into the hydrocarbon evolution in high temperature settings.

C-H and Si-H Activation Reactions at Ru/Ga Complexes: A Combined Experimental and Theoretical Case Study on the Ru-Ga Bond.

Treatment of [Ru(COD)(MeAllyl)2 ] and [Ru(COD)(COT)] with GaCp* under hydrogenolytic conditions leads to reactive intermediates which activate Si-H or C-H bonds, respectively. The product complexes [Ru(GaCp*)3 (SiEt3 )H3 ] (1) and [Ru(GaCp*)3 (C7 H7 )H3 ] (2) are formed with HSiEt3 or with toluene as the solvent, respectively. While 1 was isolated and fully characterized by NMR, MS, IR and SC-XRD, 2 was too labile to be isolated and was observed and characterized in situ by using mass spectrometry, including labelling experiments for the unambiguous assignment of the elemental composition. The structural assignment was confirmed by DFT calculations. The relative energies of the four isomers possible upon toluene activation at the ortho-, meta-, para- and CH3 -positions have been determined and point to aromatic C-H activation. The Ru-Ga bond was analyzed by EDA and QTAIM and compared to the Ru-P bond in the analogue phosphine compound. Bonding analyses indicate that the Ru-GaCp* bond is weaker than the Ru-PR3 bond.

Vibrational Strong Coupling between Surface Phonon Polaritons and Organic Molecules via Single Quartz Micropillars.

Vibrational strong coupling (VSC), the strong coupling between optical resonances and the dipolar absorption of molecular vibrations at mid-infrared frequencies, holds the great potential for the development of ultrasensitive infrared spectroscopy, the modification of chemical properties of molecules, and the control of chemical reactions. In the realm of ultracompact VSC, there is a need to scale down the size of mid-infrared optical resonators and to elevate their optical field strength. Herein, by using single quartz micropillars as mid-infrared optical resonators, the strong coupling is demonstrated between surface phonon polariton (SPhP) resonances and molecular vibrations from far-field observation. The single quartz micropillars support sharp SPhP resonances with an ultrasmall mode volume, which strongly couples with the molecular vibrations of 4-nitrobenzyl alcohol (C7 H7 NO3 ) molecules featuring pronounced mode splitting and anticrossing dispersion. The coupling strength depends on the molecular concentration and reaches the strong coupling regime with only 7300 molecules. The findings pave the way for promoting the VSC sensitivity, miniaturing the VSC devices, and will boost the development of ultracompact mid-infrared spectroscopy and chemical reaction control devices.

Crystal structural and in silico studies of Schiff bases derived from 4-aminoantipyrine

Two Schiff bases, 4-[(2-hydroxynaphthalen-1-yl)methylidene]amino}-1,5,-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (APNA) and 4-[(2,3-Dihydroxybenzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (SBAP) derived from 4-aminoantipyrine are reported. The compounds were recrystallized in methanol and characterized using spectroscopic techniques (IR, NMR) and single-crystal X-ray diffraction analysis. The XRD structure shows that APNA and SBAP crystallize respectively in the orthorhombic and monoclinic crystal systems, space groups of Pna2(1) and C2/c, and both has Z = 8 in the unit cells. SBAP has all trans configuration around its central C=N double bond. It is stabilized by C18–H18⋯N2 and C7–H7⋯O3 intramolecular hydrogen bonds. The presence of distinctive bond length of N3–C12 in APNA and C=N (1451 cm−1) stretching vibration in the IR spectrum of SBAP are evidence that the Schiff bases formed. Additional hydroxyl group in SBAP raised the TPSA (146.478 Å2) more than APNA's (83.087 Å2) which had more aromatic ring (increased conjugation) and lesser number of hydroxyl group. The computed molecular descriptors of APNA and SBAP suggest that pyrazolones will have no pharmacokinetic challenge if developed as drug.

Direct Evidence of the Benzylium and Tropylium Cations as the Two Long-Lived Isomers of C7 H7.

Disentangling the isomeric structure of C7 H7 + is a longstanding experimental issue. We report here the full mid-infrared vibrational spectrum of C7 H7 + tagged with Ne obtained with infrared-predissociation spectroscopy at 10 K. Saturation depletion measurements were used to assign the contribution of benzylium and tropylium isomers and demonstrate that no other isomer is involved. Recorded spectral features compare well with density functional theory calculations. This opens perspectives for a better understanding and control of the formation paths leading to either tropylium or benzylium ions.

Dimerization of the Benzyl Radical in a High-Temperature Pyrolysis Reactor Investigated by IR/UV Ion Dip Spectroscopy.

We investigate the self-reaction of benzyl, C7 H7 , in a high-temperature pyrolysis reactor. The work is motivated by the observation that resonance-stabilized benzyl radicals can accumulate in reactive environments and contribute to the formation of polycyclic aromatic hydrocarbons (PAHs) and soot. Reaction products are detected by IR/UV ion dip spectroscopy, using infrared radiation from the free electron laser FELIX, and are identified by comparison with computed spectra. Among the reaction products identified by their IR absorption are several PAHs linked to toluene combustion such as bibenzyl, phenanthrene, diphenylmethane, and fluorene. The identification of 9,10-dihydrophenanthrene provides evidence for a mechanism of phenanthrene formation from bibenzyl that proceeds by initial cyclization rather than an initial hydrogen loss to stilbene.

Characterization of hallucinogenic phenethylamines using high-resolution mass spectrometry for non-targeted screening purposes.

Hallucinogenic phenethylamines such as 2,5-dimethoxyphenethylamines (2C-X) and their N-(2-methoxybenzyl) derivatives (25X-NBOMe) have seen an increase in novel analogues in recent years. These rapidly changing analogues make it difficult for laboratories to rely on traditional targeted screening methods to detect unknown new psychoactive substances (NPS). In this study, twelve 2C-X, six 2,5-dimethoxyamphetamines (DOX), and fourteen 25X-NBOMe derivatives, including two deuterated derivatives (2C-B-d6 and 25I-NBOMe-d9 ), were analyzed using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). Collision-induced dissociation (CID) experiments were performed using collision energies set at 10, 20, and 40eV. For 2C-X and DOX derivatives, common losses were observed including neutral and radical losses such as NH3 (17.0265Da), •CH6 N (32.0500Da), C2 H7 N (45.0578Da) and C2 H9 N (47.0735Da). 2C-X derivatives displayed common product ions at m/z 164.0837 ([C10 H12 O2 ]+• ), 149.0603 ([C9 H9 O2 ]+ ), and 134.0732 ([C9 H10 O]+• ) while DOX derivatives had common product ions at m/z 178.0994 ([C11 H14 O2 ]+• ), 163.0754 ([C10 H11 O2 ]+ ), 147.0804 ([C10 H11 O]+ ), and 135.0810 ([C9 H11 O]+ ). 25X-NBOMe had characteristic product ions at m/z 121.0654 ([C8 H9 O]+ ) and 91.0548 ([C7 H7 ]+ ) with minor common losses corresponding to 2-methylanisole (C8 H10 O, 122.0732Da), 2-methoxybenzylamine (C8 H11 NO, 137.0847Da), and •C9 H14 NO (152.1074Da). Novel analogues of the selected classes can be detected by applying neutral loss filters (NLFs) and extracting the common product ions. Copyright © 2017 John Wiley & Sons, Ltd.

Breaking and Making of Carbon-Carbon Bonds by Lanthanides and Third-Row Transition Metals.

Carbon-atom extrusion from the ipso-position of a halobenzene ring (C6 H5 X; X=F, Cl, Br, I) and its coupling with a methylene ligand to produce acetylene is not confined to [LaCH2 ](+) ; also, the third-row transition-metal complexes [MCH2 ](+) , M=Hf, Ta, W, Re, and Os, bring about this unusual transformation. However, substrates with substituents X=CN, NO2 , OCH3 , and CF3 are either not reactive at all or give rise to different products when reacted with [LaCH2 ](+) . In the thermal gas-phase processes of atomic Ln(+) with C7 H7 Cl substrates, only those lanthanides with a promotion energy small enough to attain a 4f(n) 5d(1) 6s(1) configuration are reactive and form both [LnCl](+) and [LnC5 H5 Cl](+) . Branching ratios and the reaction efficiencies of the various processes seem to correlate with molecular properties, like the bond-dissociation energies of the C-X or M(+) -X bonds or the promotion energies of lanthanides.

Selective Formation of Indene through the Reaction of Benzyl Radicals with Acetylene.

The combustion of fossil fuels forms polycyclic aromatic hydrocarbons (PAHs) composed of five- and six- membered aromatic rings, such as indene (C9 H8 ), which are carcinogenic, mutagenic, and deleterious to the environment. Indene, the simplest PAH with single five- and six-membered rings, has been predicted theoretically to be formed through the reaction of benzyl radicals with acetylene. Benzyl radicals are found in significant concentrations in combustion flames, owing to their highly stable aromatic and resonantly stabilized free-radical character. We provide compelling experimental evidence that indene is synthesized through the reaction of the benzyl radical (C7 H7 ) with acetylene (C2 H2 ) under combustion-like conditions at 600 K. The mechanism involves an initial addition step followed by cyclization and aromatization through atomic hydrogen loss. This reaction was found to form the indene isomer exclusively, which, in conjunction with the high concentrations of benzyl and acetylene in combustion environments, indicates that this pathway is the predominant route to synthesize the prototypical five- and six-membered PAH.

Gas‐Phase Synthesis of the Benzyl Radical (C6H5CH2)

Dicarbon (C2 ), the simplest bare carbon molecule, is ubiquitous in the interstellar medium and in combustion flames. A gas-phase synthesis is presented of the benzyl radical (C6 H5 CH2 ) by the crossed molecular beam reaction of dicarbon, C2 (X(1) Σg (+) , a(3) Πu ), with 2-methyl-1,3-butadiene (isoprene; C5 H8 ; X(1) A') accessing the triplet and singlet C7 H8 potential energy surfaces (PESs) under single collision conditions. The experimental data combined with ab initio and statistical calculations reveal the underlying reaction mechanism and chemical dynamics. On the singlet and triplet surfaces, the reactions involve indirect scattering dynamics and are initiated by the barrierless addition of dicarbon to the carbon-carbon double bond of the 2-methyl-1,3-butadiene molecule. These initial addition complexes rearrange via multiple isomerization steps, leading eventually to the formation of C7 H7 radical species through atomic hydrogen elimination. The benzyl radical (C6 H5 CH2 ), the thermodynamically most stable C7 H7 isomer, is determined as the major product.

Crystal and Molecular Structure of N-[2-(6-Methoxy-2-oxo-2H-Chromen-4-yl-Benzofuran-3-yl]- Benzamide

The crystal structure of the potential active N-[2-(6-Methoxy-2-oxo-2H-chromen-4-yl)-benzofuran-3-yl]-benzamide (C25H17NO5) (I) has been determined from single crystal X-ray diffraction data. The title compound crystallizes in the monoclinic space group P 21/n, with a = 12.0551(11), b = 9.7853(8), c = 16.6517(16) , β = 90.092(4)o, V = 1964.28(3) 3, Dcalc = 1.391 Mg/m3, Z = 4. In the structure, intermolecular H-bonds lead to the formation of a centrosymmetric dimer of the molecule. There is an intramolecular C7—H7…N1 hydrogen bond forming a closed seven membered ring. There are also intramolecular π-π interactions presented between the 3,6-Dihydro-2H-pyran ring of the chromen moiety [Cg2…Cg2 distance = 3.5812(13) ]. The packing structure is stabilized by these C—H…N, N—H…O hydrogen bonds, C—H… π and π…π interactions.

Synthesis, characterization and crystal structures of new bidentate Schiff base ligand and its vanadium(IV) complex: The catalytic activity of vanadyl complex in epoxidation of alkenes

The Schiff base ligand N-salicylidin-2-bromoethylimine ( L) and its vanadium(IV) complex, VOL 2 ( 1), were synthesized and characterized by using X-ray, CHN, 1H NMR and FT-IR methods. X-ray analysis shows the Schiff base ligand L acts as a bidentate (O, N) chelating ligand and coordinates via imine nitrogen and phenolato oxygen atoms to the V(IV) center. The coordination geometry around the V(IV) center in 1 is approximately square pyramidal, as indicated by the unequal metal–ligand bond distances and angles, with the basal plane formed by the N 2O 2 donors of the two bidentate Schiff base ligands, the two phenolato O atoms and the two imine N atoms are in the trans position. The coordination sphere of the V(IV) is completed by one oxygen atom in apical position. In the Schiff base ligand, L, there are some classical intramolecular O1–H1⋯N1 and non-classical intermolecular C9–H9b⋯O1 hydrogen bonds, while in 1, there are two non-classical intermolecular C7–H7⋯O3 and C8–H8b⋯O3 hydrogen bonds. The catalytic activity of 1 in epoxidation of cyclooctene was investigated in different conditions to obtain optimum conditions. The effects of solvent, oxidant, catalyst concentration and alkene/oxidant ratio were studied and the results showed that in CCl 4 in the presence of tert-butylhydroperoxide in 1:3 alkene/oxidant ratio, high epoxide yield was obtained. The epoxidation of alkenes was also carried out in optimized conditions that high catalytic activity and selectivity were obtained.

N-Channel MOSFETs With Embedded Silicon–Carbon Source/Drain Stressors Formed Using Cluster-Carbon Implant and Excimer-Laser-Induced Solid Phase Epitaxy

In this letter, we report the use of a novel cluster-carbon (C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> ) implant and pulsed-excimer-laser-induced solid-phase-epitaxy technique to form embedded silicon-carbon (Si:C) source/drain (S/D) stressors. A substitutional carbon concentration C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sub</sub> of ~ 1.1% was obtained in this letter. N-channel MOSFETs (n-FETs) integrated with embedded silicon-carbon (Si:C) S/D stressors formed using the novel cluster-carbon implant and pulsed-laser-anneal technique demonstrate improvement in current drive of 14% over control n-FETs formed with Si preamorphization implant. I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OFF</sub> I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DSAT</sub> comparison shows a 15% I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DSAT</sub> enhancement for n-FETs with embedded Si:C S/D at an I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OFF</sub> = 1 nA/mum despite a slightly higher series resistance.

Crystal structure of 2-phenylsulfinyl-cyclohexanone,C12H14O2

C12H14O2S, monoclinic, P121/a1 (no. 14), a = 10.787(1) A, b = 10.3955(9) A, c = 10.888(1) A, = 108.928(5)°, V = 1154.9 A, Z = 4, Rgt(F) = 0.047, wRref(F) = 0.142, T = 293 K. Source of material The starting 2-phenylsulfanyl-cyclohexanone was prepared from the reactionof 2-chloro-cyclohexanone and thiophenol [1].A solution of SeO2 (0.2 g, 1.8mmol) and 30%aqueous solution ofH2O2 (0.8 mL, 7.27 mmol) in CH3OH (5 mL) was added dropwise, at 273 K, to a solution of 2-phenylsulfanylcyclohexanone (1.5 g, 7.27 mmol) in CH3OH (10 mL) [2]. The reaction mixture was stirred at 273 K for 3 hours and at room temperature for 2 hours. After completion of the reaction a saturated aqueous NaCl solution (40 mL) was added, the aqueous layer was extracted with CH2Cl2 (60 mL) and the organic solution was dried over anhydrous MgSO4. After solvent evaporation under reduced pressure 1.2 g (5.39 mmol, yield 74 %; m.p. 364-367 K) of the crude 2phenylsulfinyl-cyclohexanonewas obtained (m.p. 377-378K [3]). The oxidation afforded amixture of 2:1 [C(R)S(S)/C(S)S(R)] and [C(R)S(R)/C(S)S(S)] diastereomeric sulfoxides, respectively, (cf. stereogenic centers C2 and S) determined from HNMRspectra of the crude product. From n-hexane/acetone fractional crystallization the pure [C(R)S(S)/C(S)S(R)] diastereomer was obtained as a white solid (m.p. 366-367K). Suitable crystals for X-ray analysis of the referred diastereomer were obtained by vapor diffusion from n-hexane/acetone at 298 K. Elemental analysis – found: C, 64.48 %; H, 6.26 %; calc. for C12H14O2S: C, 64.83 %; H, 6.35 %. Discussion The cyclohexanone ring is in a slightly distorted chair conformation, the Cremer and Pople’s [4] ring-puckering parameters being: q2 = 0.0603(4) A, q3 = 0.530(5) A, 2 = 117(4)°, 2 = 6.5(4)° and Q = 0.533(5) A. The dihedral angle between the phenyl ring and the OSCph moiety amounts of 4.7(3)° and that of 4-t-butyl-2(ptolylsulfinyl)cyclohexanone [5] (CSD ref code HAFCEW) is 0.98°. The S Odistance of 1.497(3)A is in the range found in the CSD [6], mean of 1.4875 A. The molecules are arranged via C–H···O hydrogen bonds in a threedimensional framework. First the molecules form centrosymmetric dimers: d(C3···O1) = 3.387(5) A, C3–H3···O1 = 131°, giving rise to a twelve-membered ring. They are, in turn, related in an helical fashion through: d(C7···O1) = 3.271(4)A, C7–H7···O1 = 163°; d(C11···O2) = 3.586(6) A, C11–H11B···O2 = 152° (symmetry operations: i: 1–x,1–y,–z; ii: x–1⁄2,1⁄2–y,z). Z. Kristallogr. NCS 221 (2006) 311-312 / DOI 10.1524/ncrs.2006.0088 311 © by Oldenbourg Wissenschaftsverlag, Munchen Crystal: colorless irregular plate, size 0.08 × 0.10 × 0.12 mm Wavelength: Mo K radiation (0.71073 A) : 2.58 cm−1 Diffractometer, scan mode: Nonius CAD4, /2 2 max: 50.94° N(hkl)measured, N(hkl)unique: 2251, 2136 Criterion for Iobs, N(hkl)gt: Iobs > 2 (Iobs), 985 N(param)refined: 136 Programs: SIR92 [7], SHELXL-97 [8], PARST [9], PLATON [10], ORTEP-3 [11], WinGX [12] Table 1. Data collection and handling.

Crystal structure of N-methoxy-N-methyl-2-[(4'-nitropheny l)sulfinyl]- propanamide, C11H14N2O5S

C11H14N2O5S, monoclinic, P121/c1 (no. 14), a = 7.4329(9) A, b = 23.631(3) A, c = 7.900(1) A, = 110.723(8)°, V = 1297.9 A, Z = 4, Rgt(F) = 0.045, wRref(F) = 0.114, T = 293 K. Source of material A solution of 2-(4 -nitrophenylthio)propanoyl chloride (3.12 g, 14.53 mmol) in 5 ml CH3CN was added slowly to a solution of N,O-dimethylhydroxylamine hydrochloride (1.42 g, 14,53 mmol) and pyridine (2.52 g, 31.96mmol) in 10ml CH3CN at 273K. The reaction mixture was allowed to reach room temperature and stirred overnight. The crude mixture was concentrated and poured into 0.2 N HCl (10.0 mL) solution, water (10.0 mL) and three times extracted with chloroform. The combined extracts were dried over MgSO4 and rotary-evaporated. The crude material was purified by chromatography on silica gel (chloroform), affording N-methoxy-N-methyl-2-(4 -nitrophenylthio)propanamide as a viscous yellow liquid in 81%yield (2.80 g, 11.76mmol). The 2-(4 -nitrophenylthio)propanoyl chloride was obtained from the reaction of thionyl chloride and 2-(4 -nitrophenylthiophenyl)propionic acid, which in turn was obtained from the reaction of chloropropionic acid and 4-nitrothiophenol in aqueous solution of sodium hydroxide [1]. A solution of oxone (0.60 g, 0.98 mmol) in 4.2 mL of water was added slowly to a solution of N-methoxy-N-methyl-2-[(4 -nitrophenyl)thio]propanamide (0.37 g, 1.37 mmol) and NaHCO3 (0.68 g, 8.14 mmol) in 3.2 mL acetone at 273K.The reactionmixturewas stirred for 30minutes, and then poured into water and extracted with chloroform three times. The combined extracts were dried overMgSO4 and rotaryevaporated. The crude material was purified by chromatography on silica gel (eluent gradient: chloroform/acetone 100:0 to 90:100) giving 0.23 g of N-methoxy-N-methyl-2-[(4 -nitrophenyl)sulfinyl]propanamide (0.80 mmol, 58 % yield) (a pair of diastereomers). The obtained amorphous yellow solid was fractionally recrystallized from chloroform/n-hexane affording initially the C(R)S(S)/C(S)S(R) diastereomer (m.p. 367-370 K, cf. stereogenic centers C7 and S) followed by the C(R)S(R)/C(S)S(S) diastereomer (m.p. 390-392K) in the ratio of 8:2. Suitable crystals of the title compound (C(R)S(R)/C(S)S(S) diastereomer)were obtained by vapor diffusion from chloroform/n-hexane at 278 K. Elemental analysis: found – C, 45.92 %; H, 4.94 %; N, 9.37 %; calc. for C11H14N2O5S – C, 46.15 %; H, 4.93 %; N, 9.78 %. Discussion The S O distance of 1.490(2) A is the shortest distance found in the CSD [2] when searched for 1-(C-sulfinyl)-4-nitrobenzene, albeit the C–S–C angle of 98.0(1)° is the larger. The phenyl ring and the nitro moiety make an angle of 16.0(6)°. The molecules are arranged via C–H···O hydrogen bonds in the threedimensional framework. First, the molecules form centrosymmetric dimers (d(C7···O1S) = 3.381(4) A, C7–H7···O1S = 154°; d(C11···O1S) = 3.401 A, C11–H11C···O1S = 153°) giving rise to three eight membered rings. These are related in an helical fashion through interactions with d(C5···O2N1) = 3.236(5) A, C5–H5···O2N1 = 140° and d(C10···O2) = 3.371(5) A, C10–H10C···O2 = 130°. The helices are connected with d(C6···O1N1) = 3.478(5) A, C6–H6···O1N1 = 142° (symmetry operations i: 2–x,–y,–z; ii: x,1⁄2–y,–1⁄2+z; iii: x,y,z–1). Z. Kristallogr. NCS 221 (2006) 161-162 / DOI 10.1524/ncrs.2006.0021 161 © by Oldenbourg Wissenschaftsverlag, Munchen Crystal: colorless irregular plate, size 0.05 × 0.12 × 0.15 mm Wavelength: Mo K radiation (0.71073 A) : 2.68 cm−1 Diffractometer, scan mode: Nonius CAD4, /2 2 max: 51.16° N(hkl)measured, N(hkl)unique: 2615, 2433 Criterion for Iobs, N(hkl)gt: Iobs > 2 (Iobs), 1349 N(param)refined: 175 Programs: SIR92 [3], SHELXL-97 [4], PARST95 [5], PLATON [6], WinGX [7], ORTEP-3 [8] Table 1. Data collection and handling.

N-(p-Hydroxybenzylidene)phenylamineN-Oxide

The crystal structure of the title compound, C13H11NO2, confirms that it exists as a nitrone. The geometry about the C=N double bond is Z. The torsion angles O8–N8–C7–H7 [174.55 (2)°] and C8–N8–C7–H7 [−0.89 (4)°] indicate the trans and cis positions around the nitrone moiety.