CH2NOH Research Articles

Sequestering uranium from seawater: binding strength and modes of uranyl complexes with glutarimidedioxime

Glutarimidedioxime (H(2)A), a cyclic imide dioxime ligand that has implications in sequestering uranium from seawater, forms strong tridentate complexes with UO(2)(2+). The stability constants and the enthalpies of complexation for five U(VI) complexes were measured by potentiometry and microcalorimetry. The crystal structure of the 1 : 2 metal-ligand complex, UO(2)(HA)(2)·H(2)O, was determined. The re-arrangement of the protons of the oxime groups (-CH=N-OH) and the deprotonation of the imide group (-CH-NH-CH-) results in a conjugated system with delocalized electron density on the ligand (-O-N-C-N-C-N-O-) that coordinates to UO(2)(2+)via its equatorial plane.

Complexation of formaldoxime with water. Infrared matrix isolation and theoretical studies

The 1:1, 1:2 and 2:1 formaldoxime-water complexes isolated in the argon matrices have been studied by help of FTIR spectroscopy and MP2/6-311++G(2d,2p) method. The calculations predicted the stability of the three CH 2NOH⋯H 2O isomeric complexes, three CH 2NOH⋯(H 2O) 2 ones and one (CH 2NOH) 2⋯H 2O complex. The analysis of the experimental spectra and their comparison with theoretical ones indicated that both the 1:1 and 1:2 complexes trapped in solid argon have the most stable cyclic structures stabilized by the O–H⋯O and O–H⋯N bonds between the formaldoxime and water molecules. In the 1:2 complex formaldoxime interacts with the water dimer, one H 2O molecule acts as a proton acceptor for the OH group of formaldoxime whereas the second H 2O molecule acts as a proton donor toward the nitrogen atom of the formaldoxime molecule. In the (CH 2NOH) 2⋯H 2O complex the OH group of the water molecule acts as a proton donor toward one of the oxygen atoms of the formaldoxime cyclic dimer.

Molecular structure of ( E)-benzaldehyde oxime from gas-phase electron diffraction, quantum-chemical calculations and microwave spectroscopy

The gas-phase structure of ( E)-benzaldehyde oxime (C 6H 5 CH NOH), has been determined by gas-phase electron diffraction (GED), microwave spectroscopy (MW) and quantum-chemical calculations. Two sets of the data analyses were performed. One was GED + MW data analysis with a small-amplitude vibrational model. A planar conformation for this molecule was adopted in the analysis. Another was GED data analysis of a large-amplitude motion of the C C torsion. The potential minimum was located on the planar conformation of this molecule. Above two sets of the data analyses were led to the one consistent result that showed good agreement between the experimental and calculated molecular intensities.

Microwave spectra, molecular structures, and theoretical calculations of ( E)- sp and ( E)- ac isomers of 2-methylpropanal oxime

The microwave spectra of two conformers of ( E)-2-methylpropanal oxime ((CH 3) 2CH CH NOH) and its deuterated species ((CH 3) 2CH CH NOD) were observed in the frequency range from 8 to 40 GHz. The absorption lines in the ground and excited vibrational states were assigned. The rotational constants of normal species in the ground vibrational state were determined to be A = 7343.5(25), B = 1847.20(2), and C = 1607.29(2) MHz for ( E)- sp isomer and A = 7073.15(84), B = 2006.01(1), and C = 1686.62(1) MHz for ( E)- ac isomer. The planar moments ( P bb = ( I c + I a − I b )/2) of the normal and deuterated species were determined to be 54.829(15) and 54.829(8) uÅ 2 for the ( E)- sp, and 59.578(6) and 59.768(7) uÅ 2 for the ( E)- ac, respectively. The P bb values of the ( E)- sp of normal and deuterated species suggest that the ( E)- sp has C s symmetry. The r s coordinates of the hydrogen atoms of the hydroxyl group were determined for the ( E)- sp and the ( E)- ac. They indicated that their OH bonds took trans positions with respect to the C N double bond. The four and six structural parameters were adjusted by fitting to the rotational constants of the ( E)- sp and ( E)- ac, respectively. The observed rotational constants ( B and C) of the ( E)- sp and the ( E)- ac isomers were in better agreement with those calculated using the MP2/6-31++G( d, p) level than with those calculated using the MP2/6-31G( d, p) level.

Microwave spectra, molecular structures, and theoretical calculations of s- trans-( E)- and s- trans-( Z)-crotonaldehyde oximes

The spectroscopic constants of s- trans-( E)- and s- trans-( Z)-crotonaldehyde oxime ( Fig. 1) of normal, CH 3CH CH–CH NOH, and deuterated, CH 3CH CH–CH NOD, species were observed in the frequency range of 8–40 GHz in the ground vibrational state. The rotational constants of two isomers of normal species were determined to be A=27,093(151), B=1270.656(8), and C=1223.288(8) MHz for s- trans-( E) form and A=12,239(19), B=1587.49(2), and C=1417.80(2) MHz for s- trans-( Z) form. The inertial defects (Δ I= I c− I a− I b) of normal and deuterated species were determined to be −3.25(11) and −3.24(20) uÅ 2 for s- trans-( E) form, and −3.191(73) and −3.180(36) uÅ 2 for s- trans-( Z) form, respectively. From the r s coordinates of the hydroxyl hydrogen atom determined for s- trans-( E) and s- trans-( Z) forms, their OH bonds were concluded to be at the trans position with respect to the C N double bond. For s- trans-( E) form, the C 3–C 4 torsional excited vibrational states were observed up to v=3. The vibrational frequency was found to be 90(40) cm −1 from the relative intensity measurement. The vibrational mode was nearly harmonic. The structural parameters of r(C 4 N), r(C 3–C 4), ∠C 3C 4N and ∠C 4NO for s- trans-( E) and s- trans-( Z) forms were adjusted separately to their rotational constants observed. It was found that the bond angle of ∠C 3C 4N in s- trans-( Z) form are much wider than that in s- trans-( E) form by about 10°. The rotational constants observed for s- trans-( E) and s- trans-( Z) forms were consistent with those calculated using MP2/6-31G(d,p) rather than 6-311++G(d,p) basis sets, and those ( B and C) calculated for s- trans-( E) using MP2/6-31G(d,p) were in excellent agreement with those observed.

Structures of pyrido[1,2a]pyrazinium and pyrido[1,2c][1,4]oxazinium bromides studied by 1H, 13C and 15N NMR, FTIR, X-ray and DFT methods

2-R-Pyridines (R CN, CH NOH and COMe) with phenacyl bromide gave the corresponding quaternary bicyclic ring system containing one ring junction nitrogen and one extra nitrogen or oxygen atom ( 1– 3). Their structures were confirmed by 1H, 13C and 15NMR spectra in DMSO-d 6 solution using 2D NMR techniques (COSY, NEOSY, HETCOR and HMBC). The structure of 1-oxo-3-phenyl-pyrido[1,2a]pyrazinium bromide monohydrate, 1, was unambiguously confirmed by X-ray crystallography. The crystals of 1 are monoclinic, space group P2 1/ n, with a=7.730(2) Å, b=14.094(3) Å, c=12.553(3) Å, β=106.18(3)°, V=1311.3(5) Å 3 and Z=4 (at 110 K). The isolated entities of 1– 3 were analyzed by the B3LYP/6-31G(d,p) level of theory in order to get information on the electrostatic interaction between the oppositely charged groups.

Effects of End Groups on the Tribochemical Reactions of Lubricants at Head-Disk Interface

Mass spectrometry was used to monitor in-situ gaseous species that were generated at the head-disk interface (HDI) in a high vacuum. It was found that the end groups of the lubricants significantly affected the wear durability at the HDI; piperonyl (–CH2-phe = (O)2 = CH2) terminated Fomblin AM3001 lubricant exhibited longer life than hydroxyl (–OH) terminated Fomblin ZDOL lubricant. The continuous removal of the lubricants resulted in a continuously increasing friction coefficient. Further, the characteristics of tribochemical reactions of the lubricants (Fomblin Z series) with different end groups was investigated in details using Time-of-Flight Secondary Ion Mass Spectroscopy (TOF-SIMS) just after the sliding tests. It was found that the decomposition of the end groups was more significant than that of the backbone. The lubricants terminated with the following groups showed the following order of increasing decomposition: –CH2O-CH2-phe = (O)2 = CH2 (AM3001), –CH2OH (ZDOL) < –CH2OCH2CH(OH)CH2OH (Z Tetraol) < –CH2(OCH2CH2)nOH (ZDOL-TX), –COOH (Z Diac). The decomposition of the lubricants appeared to start from the end groups.

Reinvestigation of microwave spectrum, molecular structure, dipole moment, and theoretical calculation of s- trans ( E)- and s- trans ( Z)-acrylaldehyde oxime

The spectroscopic constants of s- trans ( E)-acrylaldehyde oxime of normal, CH 2CHCHNOH, and deuterated, CH 2CHCHNOD, species were refined by adding a-type R-branch transitions observed in the frequency range of 34–40 GHz in the ground vibrational state. For s- trans ( Z) form, the spectroscopic constants of normal species were refined by refitting the reported frequencies with four b-type Q-branch transitions and those of deuterated species were determined by the least-squares fitting of the observed a-type R-branch transitions in the ground vibrational state. The spectroscopic constants of two isomers of normal species were also determined in the vibrationally excited states. The inertial defects (Δ I= I c − I a − I b ) of normal and deuterated species were determined to be −0.042(24) and −0.064(17) u Å 2 for s- trans ( E)-1 form, and −0.0536(8) and −0.063(11) u Å 2 for s- trans ( Z)-1 form, respectively. From the r s coordinates of the hydroxyl hydrogen atom determined for s- trans ( Z)-1 form, its OH bond was concluded to be at the trans position with respect to the CN double bond. The dipole moments of deuterated species of s- trans ( E)-1 form and those of normal and deuterated species of s- trans ( Z)-1 form were determined. The structural parameters of r(C 2C 3), ∠C 1C 2C 3, ∠C 2C 3N, and ∠C 3NO for s- trans ( E)-1 and s- trans ( Z)-1 forms were adjusted separately using to their rotational constants observed. It was found that the bond angle of ∠C 2C 3N in s- trans ( Z)-1 form are much wider than that in s- trans ( E)-1 form by about 10°. The difference between the observed and calculated (using MP2/6-311++G (d,p) level) rotational constants of s- trans ( Z)-1 form was larger than that of s- trans ( E)-1 form.

Potential submillimetre laser emission from interstellar formaldoxime molecules

Formaldoxime is a small molecule of the oxime family. Isomers of this family are among the list of chemical species populating the interstellar medium. Several of these species exhibit a maser or laser action. The observation of numerous strong optical-optical double resonance has shown that there are a considerable number of near coincidences between laser lines of CO 2 and the absorption lines of formaldoxime molecule (CH 2NOH). The submillimetre region of this molecule exhibit several laser lines, two of which are distinctively strong. Synthesis, spectral properties of formaldoxime and the conditions for observation of potential laser transitions from this molecule in the interstellar medium are discussed.

Conformational stability and vibrational spectrum of glyoxilic acid oxime predicted from ab initio study

The conformational stability of glyoxilic acid oxime (HOOC–CH–NOH) (GAO) and its anions has been studied by ab initio calculations at different levels of the theory, HF/6-311G ∗∗, MP2/6-311G ∗∗ and B3LYP/6-311G ∗∗. Geometry optimization was performed for 16 conformations of GAO and five anions in C s symmetry. The interconversion pathways for the four lowest energy conformers as well as the corresponding transition states have been investigated using QST3 and IRC techniques. The minima and the transition states obtained were estimated by calculations of the vibrational frequencies. The energy barriers of three interconversions, ectt–ecct, ectt–ettt and ectt–zccc, have been estimated. Vibrational spectra and IR intensities of the lowest energy conformers, zccc, ectt, ettt and ecct, have been calculated and discussed at HF/6-311G ∗∗ optimized geometries.

Optically active aromatic amino acids. Part VI. Synthesis and properties of (Leu5)-enkephalin analogues containing O-methyl-L-tyrosine1 with ring substitution at position 3'.

Twelve new [Tyr(Me)1, Leu5]-enkephalin analogues with substituents at position 3' of the Tyr ring have been synthesized using traditional solution methods. The substituents were -CO2H, -CONH2, -CO2Me, -(E)-CH=NOH, -(E)-CH=NOMe and CH2OH. The analogues were C-terminated with methyl esters, amides or as free acids. In the in vitro biological assays a remarkable agonist activity to the opiate receptor mu in guinea pig ileum (GPI) relative to Leu-ENK was shown by the following: Leu-ENK, 100; [Tyr(Me)(3'-CO2Me)1, Leu-OMe5]-ENK (I), 8.1; [Tyr(Me)(3'-(E)-CH=NOH)1, Leu-OMe5]-ENK (VI), 26.2; [Tyr(Me)(3'-(E)-CH=NOH)1, Leu-OH5]-ENK (VII), 2.9; [Tyr(Me)(3'-(E)-CH=NOH)1, Leu-NH2(5)]-ENK (VIII), 4.7; and [Tyr(Me)(3'-CH2OH)1, Leu-OMe5]-ENK (X), 5.6. The agonist effect was naltrexone- or naloxone-reversible. The masking of the hydroxyl group in (E)-hydroxyiminomethyl group of analogue (VI) by O-methylation has totally abolished its GPI agonist activity. It seems that the (E)-CH=NOH group shows affinity and plays an analogous role to the phenol group Tyr1 in leucine-enkephalin and in the tyramine group of the opiate alkaloids. The analogues: [Tyr(Me)(3'-CO2Me)1, Leu-OMe5]-ENK (I), [Tyr(Me)(3'-CO2H)1, Leu-OMe5]-ENK (II), [Tyr(Me)(3'-CO2Me)1, Leu-NH2(5)]-ENK (III), [Tyr(Me)(3'-CO2H)1, Leu-NH2(5)]-ENK (IV), [Tyr(Me)(3'-CONH2)1, Leu-NH2(5)]-ENK (V), [Tyr(Me)(3'-(E)-CH=NOH)1, Leu-OMe5]-ENK (VI), [Tyr(Me)(3'-(E)-CH=NOH)1, Leu-OH5]-ENK (VII), [Tyr(Me)(3'-(E)-CH=NOH)1, Leu-NH2(5)]-ENK (VIII), [Tyr(Me)(3'-(E)-CH=NOMe)1, Leu-OMe5]-ENK (IX), [Tyr(Me)(3'-CH2OH)1, Leu-OMe5]-ENK (X), [Tyr(Me)(3'-CH2OH)1, Leu-OH5]-ENK (XI) and [Tyr(Me)(3'-CH2OH)1, Leu-NH2(5)]-ENK (XII) under testing had no significant agonist activity to the enkephalinergic receptor in mouse vas deferens (MVD). All methyl esters of synthesized analogues of [Leu5]-ENK showed higher activity to mu receptors than structurally identical C-terminal amides. It is a surprising result since usually C-terminate amides are stronger agonists than C-terminate esters.

Microwave Spectrum and Molecular Conformation of (E)-Benzaldehyde Oxime

The microwave spectrum of (E)-benzaldehyde oxime, C6H5—CHNOH and C6H5—CHNOD, has been observed in the frequency range from 26.5 to 40.0 GHz. The spectrum of the ground vibrational state was assigned and fitted to the Watson's A-reduced Hamiltonian to obtain these rotational and centrifugal distortion constants: A = 5183.13(29) MHz, B = 895.367(3) MHz, C = 763.819(3) MHz, ΔJ = 0.019(3) kHz, and ΔJK = 0.204(7) kHz for the normal species, and A = 5158.4(23) MHz, B = 869.44(2) MHz, C = 744.34(2) MHz, ΔJ = 0.023(2) kHz, and ΔJK = 0.193(7) kHz for the deuterated species. The values of the ΔI (=Ic − Ia − Ib) obtained for the normal and deuterated species were −0.295(6) and −0.28(5) a.m.u. Å2, respectively. The molecular conformation of this molecule was a planar one in which the values of the dihedral angles, CCNO and CNOH, were almost 180° and 180°, respectively.

Fluorescent PET (photoinduced electron transfer) sensors for alkali cations: optimization of sensor action by variation of structure and solvent

The alkali cation-induced fluorescence enhancement of (1) is maximized to a factor of 45 when XCN (as opposed to CHNOH and H) and the solvent is 2-propanol (as opposed to mixtures with methanol).

High-resolution infrared spectrum of formaldoxime (CH 2NOH) in the 3-μm and OH overtone regions

The infrared spectrum of the simplest oxime, CH 2NOH, was obtained in the gas phase with a resolution of 0.01 cm −1 using the Kitt Peak National Observatory Solar Fourier transform spectrometer. The regions covered were from 1800 to 3700 cm −1, and around 7100 cm −1. The ν 1, ν 2, and ν 3 bands have been analyzed in detail, and a partial analysis of the 2 ν 1 band has been made. In the ν 1, ν 2, and ν 3 bands several hundred transitions were fitted and accurate band origins and rotational constants were determined. All these bands are found to be hybrid bands, ν 1 has a dominant A component, whereas ν 2 and ν 3 have a dominant B component, rather than being predominantly A type as previously assumed. The main results (in cm −1) for the excited states are: Band ν 0 A B C ν 1 3650.291 3 2.2517 6 0.3952 8 0.3359 0 ν 2 3109.720 5 2.2543 9 0.3946 7 0.3356 6 ν 3 2973.168 2 2.2508 8 0.3951 2 0.3355 9 2ν 1 7131.4 Several local perturbations have been observed in ν 2 and ν 3. They are presumably caused by overtones and combinations of the low-lying fundamentals, but it has not been possible to make specific assignments to the perturbing levels.

Fourier transform and diode laser spectroscopy of the 10-μm bands of formaldoxime (CH 2NOH)

High-resolution (0.015 cm −1) Fourier transform and Doppler limited diode laser spectra have been obtained of the ν 10 band of CH 2NOH, and medium-resolution (0.05 cm −1) spectra of the ν 8 and ν 11 bands. The band origins determined for the three fundamentals are ν 10, 952.60 8 cm −1; ν 8, 892.5 6 cm −1; and ν 11, 774.1 4 cm −1. A detailed rotational analysis of the ν 10 band has been carried out. Two hot bands have also been identified.

The electronic structure of CH 2NCH 3, CH 2NNH 2, CH 2NOH and CH 2NF

Ab initio geometry optimisation calculations have been carried out on CH 2NCH 3, CH 2NNH 2, CH 2NOH and CH 2NF using 6-31G and 6-31G** basis sets. Three of the four species possess a plane of symmetry while CH 2NNH 2 prefers a non-planar geometry with the amino N adopting sp 3 hybridisation. The CN bond length remains almost constant at 1.25 Å with an accompanying bond index of 2.2 for all four species. The CNR angle decreases and the related inversion energy at N increases as the R group becomes more electronegative. The charge on nitrogen decreases as the R group changes from CH 3 to F and the energy of protonation at N correspondingly decreases from 230 to 194 kcal mol −1. A slight positive charge is present on the imino carbon atoms and the stabilising energy of hydride ion addition to the imino carbon atom lies between 23.7 kcal mol −1 and 47.4 kcal mol −1.

CH 3NO and CH 2NOH: a green's function study of their ionization spectra

The ionization spectra of nitrosomethane and its isomer formaldoxime are investigated theoretically by many-body Green's function techniques. The failure of the Koopmans' ordering of ionization energies in nitrosomethane is discussed and interpreted on the basis of the existence of a low-lying virtual orbital. The low-lying virtual orbital in both molecules leads to the appearance of satellite lines at relatively low energies. In the inner valence region the breakdown of the orbital model of ionization is observed. The differences in the spectroscopic behaviour of the two molecules are related to their bonding structure.

Infrared—infrared double resonance using an acousto—optic modulator

The use of infrared—infrared double resonance to identify near coincidences between vibration—rotation transitions of CH 2NOH and 13CO 2 laser lines is described. The dipole moments derived from these data show that all the transitions belong to the ν 8 A′ band of formaldoxime.

Photolysis of dimethylnitrosamine in the gas phase

AbstractPhotodecomposition of dimethylnitrosamine in the gas phase ( ∼ 1 Torr) has been investigated following irradiation into the S1 (nπ*) ← S0 (363.5 nm) and S2 (ππ*) ← S0 (248.1 nm) transitions at room temperature. With a quantum yield of unity, excitation into the S1 state yields the fragments (CH3)2N⋅ and NO which then recombine leaving no photoproducts. The addition of O2 results in only one photoproduct, (CH3)2NNO2. Irradiating into the S2 state, the products CH2NCH3, (CH2NCH3)3, CH2NOH, N2O, NO, H2, and N2 were identified by capillary gas chromatography mass spectrometry. In the presence of N2 as a buffer gas the photoproducts are only CH2NCH3, (CH2NCH3)3, N2O, and H2. For both excitation conditions a mechanism is proposed involving cleavage of the N, N‐bond as the main primary photolytic process.

Specific 14c‐labeled surfactants. The addition of hohogeneous polyoxyethylene glycols to p‐(l,l,3,3‐tetramethylbutyl)phenol

AbstractTwo surfactants, one containing a six and the other containing a nine unit polyoxyethylene glycol side chain attached to p‐(1,1,3,3‐tetramethylbutyl) phenol (TOPOH), were prepared with specific 14C‐labeling. The radioactive label was introduced into the first ethylene oxide unit attached to the aryl moiety, TOPOCH2*CH2(OCH2CH2)nOH, by coupling chloroacetic‐14C‐l acid with TOPOH. A 4‐step reaction scheme was utilized in the synthesis, and all reactions gave excellent yields except for the final Williamson coupling reaction. A competing elimination reaction occurred in the final reaction to afford a vinylic by‐product, TOPOCHCHCl, which was identified by spectroscopic methods. The overall yields for TOP(OCH2CH2)6OH and TOP(OCH2CH2)9OH were 42 and 33 per cent, respectively.