II. “Spectroscopic Investigation of Charge Transfer Complexes of Osazone Intermediates Prepared From certain monosaccharides”

Monosaccharide osazones are utilized in the spectrophotometric determination of their parent compounds through charge transfer complexes (CTC) formation with three-electron acceptor reagents. These acceptors indlude iodine (as -π-acceptor) and chloranil (tetrachloro P-benzoquinone) & TCNE (tetracyano ethylene) as π-acceptors. The presence of two phenylhydrazone moieties in the osazone molecule imparts electron-donating properties toward electron-accepting reagents, yielding spectrophotometrically measurable complexes. However, the reaction of osazone intermediates with TCNE reagent gave tricyanovinyl derivative rather than CTC formation. The above complexes together with their corresponding intermediates were subjected to structure elucidation studies to confirm the results and conclusions obtained. These studies include IR, Raman spectra, H¹, C¹³-NMR, MS, ESR (electron spin resonance spectra) and microanalysis.     

Spectroscopic Investigation of the Antazoune-p-chloranilic Acid Reaction Product

Spectroscopic studies on the reaction of p-chloranilic acid with antazoline base are reported. These include UV/VIS and IR spectrophotoraetry, electron spin resonance (ESR) and nuclear magnetic resonances (¹H-NMR & ¹³C-NMR). The results reveal that the antazoline-p-chloranilic acid product is an ion pair salt rather than a charge-transfer complex.     

13C-NMR Spectra of Some π-(Arene)-Tricarbonylchromium(O) Complexes

Many ¹³C-NMR studies dedicated to the π-(Arene)-tri-carbonylchromium(o) complexes are concerned with the origin of the large upfield shifts of the aromatic carbons on the coordination to the chromiumtricarbonyl group. This effect is not yet completely understood and various hypotheses have been formulated to justify it (1)(2)(3) (4).     

蓝宝石(α-Al_2O_3:Fe~(3+))体系基态分裂与局域晶格畸变的研究

2002年Scholz和Buzaré对蓝宝石晶体中Fe3+离子的基态分裂重新进行了EPR实验测量和研究,他们的初步分析表明在蓝宝石晶体中Fe3+离子的6A1基态分裂有可能同时与两个方向的畸变角(θ和φ)有关.本文采用对角化d5组态在C3点群对称下的252×252完全能量矩阵的方法,对蓝宝石晶体中Fe3+离子的光谱和EPR谱进行了系统的研究.计算结果表明蓝宝石体系中Fe3+离子的6A1基态分裂确实将明显依赖于两个方向的畸变角θ和φ,这一理论结果与Scholz和Buzaré等的实验相符合.同时,通过拟合Fe3+离子在蓝宝石体系中的实验光谱和EPR参量,确定了蓝宝石晶体中(FeO6)9团簇局域晶格畸变角θi的范围.     

STUDIES ON SOME THIAZOLYLAZO COMPOUNDS AND THEIR COBALT,NICKEL, AND COPPER COMPLEXES

ABSTRACT

The thiazolylazo compounds and their Co^(II), Ni^(II) and Cu^(II) complexes of barbituric acid, uracil, thiouracil, citrazinic acid, chromotropic acid, gallic acid, pyrogallol and salicylic acid were prepared and characterized by ¹H NMR, IR and the effect of pH on the electronic absorption spectra. The mode of ionization, the electronic transitions and the dissociation constants were discussed. The stoichiometries of the complexes were of 1:1, 2:1 and 3:2 (M:L). The copper complexes are of isotropic ESR spectra (except that of gallic acid which showed a complicated one) and are of magnetically diluted behaviour with orbital contribution. Detailed DTA data were obtained and discussed.     

Can an IR Diode Laser Spectrometer be Used for the Determination of Natural Isotope Ratios in Biological Samples?

Abstract

An IR diode laser spectrometer can detect the enrichment of stable isotopes (¹³C [1] and ¹⁵N[2]) in tracer studies. However our system cannot detect differences of the natural abundances of these isotopes. This problem is not a principal limitation of the IR diode laser spectroscopy, but is inherent to our standard system. A new isotope ratio IR diode laser spectrometer has an accuracy high enough for most biological applications. Some advantages like flexibility in measuring different isotopes, insensitivity against other gases in the sample and price are correlated to this system.     

Vibrational Assignment of N-Phenylphthalimide and 15N-Phenylphthalimide

Abstract

The i.r. spectra of N-phenylphthalimide and ¹⁵N-phenylphthalimide have been measured in 4000–100 cm^?1 frequency range as KBr and polyethylene pellets and as chloroform solutions. The Raman spectra (4000–50) cm^?1 of microcrystalline powder of the of the same compounds have also been investigated.

A detailed assignment of most of the observed frequencies has been proposed on the basis of the group vibrational concept, isotopic shift data and analogies with the spectra of related molecules. Some literature data have been discussed and some frequencies are reassigned.     

Spectral Characteristics of the Reaction Products of 5-Phenyl-2,3,4-furantrione with o-Diamines

The ¹H and ¹³C NMR and mass spectra of 2-(2-amino-4,5-dimethylphenylcarbamoyl)-3-(hydroxyphenylmethyl)-6,7-dimethylqinoxaline (2), 3-(hydroxyphenylmethyl)-6,7-dimethylquinoxalin-2-carboxylic-γ-lactone (5), 3-(hydroxyphenylmethyl)-6,7-dimethylquinoxalin-2-carboxylic acid phenylhydrazide (6), 3-[2-hydroxy-2-phenyl-1-(phenylhydrazono)ethyl]-6,7-dimethyl-2(1H)-quinoxalinone (7), 2,3-dihydro-6,7-dimethyl-3-phenylhydrazono-2-phenylfuro[2,3-b]auinoxaline (8), 3-(hydroxyphenylmethyl)-6,7-dimethyl-1-phenylflavazole (9), and 3-(acetoxyphenylmethyl)-6,7-dimethyl-1-phenylflavazole (10) have been studied.     

Azetidin‐2‐one Versus Chroman‐2‐one: Application of 1H‐13C COSY NMR and Mass Spectroscopy in Structure Elucidation–Class of Compounds

Azetidin‐2‐ones, commonly known as β‐lactams, constitute a biologically important class of compound. Treatment of azetidin‐2‐ones with alkali is known to form diverse types of compounds depending on the stability of the ring. In many cases, the ring is retained in the product at the cost of transformation of substituents. Spectroscopy is the most important tool to characterize the organic compounds. However, in some cases the structures of the products are so closely related that simple IR, ¹H NMR, and ¹³C NMR spectra do not lead to unambiguous structure elucidation. This article reports a novel application of ¹H‐¹³C COSY NMR and mass spectroscopy in determining unequivocally an azetidin‐2‐one ring structure instead of a chroman‐2‐one ring structure for the product obtained by treatment of 1‐benzhydryl‐3,3‐bis(4‐methylphenyl)‐4‐[2‐(o‐dip‐tolylacyl)hydroxyphenyl]‐2‐azetidinone with ethanolic sodium hydroxide at room temperature.     

Spectral Properties and Molecular Structure of 4-Aryl-3-cyano-1,1-diphenyl-2-azabutadienes

A detailed UV-VIS, IR, ¹H and ¹³C NMR spectroscopic study of (Z)-and (E)-isomers of a series of the title compounds afforded a number of spectral criteria, which could be reliably used for configurational assignment of other compounds of similar type.     

Raman and Infrared Spectra of Cd(15NH3)2Cl2 and Local Symmetry Force Field

The infrared and Raman spectra of Cd(¹⁵NH₃)₂Cl₂ are reported and a comparison is made between the normal and ²H isotope substituted compounds. A further refinement of the Local Symmetry Force Constants was carried out.     

Interaction between 1-[p-(dimethylamino) benzoyl]-4′-phenyl-semicarbazide and Cu

A new compound, 1-[p-(dimethylamino)benzoyl]-4′-phenyl-semicarbazide (1) was synthesized and showed highly selective response to Cu²⁺ over other metal ions such as Pb²⁺, Mg²⁺, Fe²⁺, Co²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Ni²⁺, Ca²⁺, Ag⁺, Na⁺, K⁺, and Li⁺. The control compound, 1-[p-(dimethylamino)benzoyl]-4-phenyl-thiosemicarbazide (2), showed different fluorescence spectral response to Cu²⁺. A 1:1 complex between Cu²⁺ and 1 was formed while 1:1 and 1:2 complexes between Cu²⁺ and 2 were formed. The binding model between the receptor (1 or 2) and Cu²⁺ was supported by IR spectra, mass spectra, and computation model. 1 possessed higher selectivity towards Cu²⁺ compared with 2 owing to the difference of complexation ability between urea and thiourea groups.     

The (p,π−) reaction and Δ++ components of nuclei

The use of the (p, π^?) reaction as a probe to determine Δ⁺⁺(1232) components of nuclear wave functions is examined within the framework of a model which treats baryon resonances on the same footing as nucleons. Nuclear structure properties which affect the Δ -probability are discussed. Estimates of cross sections, at several energies, are made for the Δ⁺⁺ transfer contribution as well as for the competing processes: proton charge exchange (p, n) followed by an (n, π^?) reaction; emission of a π⁰ followed by pion charge exchange (π^?, π⁰) . Even with Δ-probabilities as small as 0.0001 the Δ-transfer process can compete with ordinary background charge-exchange reactions.     

Molecular structure of alkali metal 4‐nitrobenzoates

The influence of lithium, sodium, potassium, rubidium, and cesium on the electronic system of the 4‐nitrobenzoic acid molecule was studied. The vibrational (FT‐IR, FT‐Raman) and NMR (¹H and ¹³C) spectra for 4‐nitrobenzoic acid salts of alkali metals were recorded. The assignment of vibrational spectra was done. Characteristic shifts of band wavenumbers and change in band intensities along the metal series were observed. Good correlation between the wavenumbers of the vibrational bands in the IR and Raman spectra for 4‐nitrobenzoates and ionic potential, electronegativity, atomic mass, and affinity of metals were found. The chemical shifts of protons and carbons (¹H, ¹³C NMR) in the series of studied alkali metal 4‐nitrobenzoates were observed too. Optimized geometrical structures of studied compounds were calculated by HF, B3PW91, B3LYP methods using 6‐311++G** basis set. The theoretical IR, Raman, and NMR spectra were obtained. The theoretical vibrational spectra were interpreted by means of potential energy distributions (PEDs) using VEDA 3 program. The calculated parameters were compared to experimental characteristic of studied compounds. Copyright © 2007 John Wiley & Sons, Ltd.     

Rotational analysis of bands in the high-resolution infrared spectra of the three species of butadiene-1,4-d2; refinement of the assignments of the vibrational fundamentals

Samples of trans,trans and cis,cis forms of butadiene-1,4-d₂ have been synthesized and found to contain useful amounts of the cis,trans species as a contaminant. Assignments of fundamental frequencies for the three isotopomers of butadiene-1,4-d₂ have been extended and improved from investigations of their Raman spectra as well as their infrared (IR) spectra. High-resolution IR spectra have been recorded for the three isotopomers, and a rotational analysis has been completed for strong bands of each species. Ground state and some upper state rotational constants have been fit. Corresponding ground state moments of inertia compare favorably with equilibrium moments of inertia obtained from B3LYP/6-311++G** theory. Two ¹³C isotopomers are being prepared, and an improved structural analysis of butadiene will soon be available to assess how π-electron delocalization affects its structure.     

1H- and 13C-NMR Study of Some 6,7-Dihaloquinolone Nucleosides and Their Derivatives

The ¹H- and ¹³C-NMR spectra of 6,7-dihalo-1,4-dihydro-4-oxo-1-(2,3,5-tri-0-benzoyl-pβ-D-ribofuranosyl)quinoline-3-carboxylic acids (3), (4), the ester (3a), 6-chloro-1-(2-deoxy-3,5-di-O-tolouyl-α- and β-D-erythropentofuranosyl)-7-fluoro-1,4-dihydro-4-oxo-quinoline-3-carboxylic acid (5), and its free a-nucleoside (5a) have been investigated. Resonance signals were assigned by homo- and heteronuclear two dimensional NMR methods (DQF-COSY, HMQC, and HMBC) for (3), (4), (5), and (5a). Ribosylation sites and anomeric configurations were identified from ROESY spectra.     

Experimental Correlations of JNC With S-Character

Some quaternary ammonium salts and isonitriles are examined by ¹³C NMR. A Fermi-Contact type of correlation is suggested as a basis for estimation of the effect of lone pairs, alkyl substitution and π-bonding on ^JNC     

Vibrational spectra of (NH4)3ZnCl5

IR and Raman spectra of (NH₄)₃ZnCl₅ have been recorded. The observed spectra have been analysed on the basis of the vibrations of ZnCl ₄ ²⁻ and NH ₄ ⁺ ions. The appearance of multiple Raman bands indicates the presence of two different types of ammonium ions. The effect of anisotropic crystalline field over the ZnCl₄ and NH₄ tetrahedra is also discussed. The assignment of internal modes has been verified by the potential energy distribution calculations.     

High-resolution infrared spectra of OOO ozone isotopomer in the range 900-5000 cm: line positions

Continuing the systematic study of ozone high-resolution infrared spectra, we present in this paper the measurements and analyses of line positions for the ¹⁸O¹⁶O¹⁸O isotopomer. In the range 900-5000 cm⁻¹, corresponding to the observed spectra, 15 bands are analysed: ν₁, ν₃, ν₂+ν₃, ν₁+ν₂, 2ν₃, ν₁+ν₃, 2ν₁, ν₂+2ν₃, ν₁+ν₂+ν₃, 3ν₃, 2ν₁+ν₃, ν₂+3ν₃, ν₁+3ν₃, ν₁+ν₂+3ν₃, and 5ν₃. As in the case of ¹⁶O₃, ¹⁸O₃, and ¹⁶O¹⁸O¹⁶O, the analysis of these bands is performed using effective rovibrational Hamiltonians for nine polyads of interacting upper vibrational states. To correctly reproduce all observed transitions, we have to account for resonance perturbations due to 13 “Dark” states: (0 3 0), (0 4 0), (2 1 0), (0 3 1), (1 0 2), (0 4 1), (1 1 2), (3 1 0), (0 3 2), (0 0 4), (3 2 0), (0 1 4), and (0 4 2). We present the range of observed transitions, the results for spectroscopic parameters (vibrational energy levels, rotational and centrifugal distortion constants, and resonance coupling parameters), as well as the statistics for rovibrational energy levels, calculations and measurements. A comparison of observed band centres with those predicted from an isotopically invariant potential function is discussed. The RMS deviation between predicted and directly observed band centres is ≈0.03 cm⁻¹ up to 3000 and ≈0.25 cm⁻¹ for all 16 bands up to 5000 cm⁻¹.     

Observation of high spin levels in131Cs from131Ba decay

The γ- and conversion electron spectra following¹³¹Ba ε-decay are investigated, using HPGe detector and mini-orange electron spectrometer. Attention is particularly focussed on identifying weak transitions associated with low energy high spin levels in¹³¹Cs level scheme earlier inferred in reaction studies but not yet observed in¹³¹Ba decay. Our experiment identifies 15 new gammas and 6 new conversion lines in this decay. Internal conversion coefficients and multipolarities of several transitions are determined. Five new levels (3 with I^π = 7/2⁺ and one each with I^π 9/2⁺ and 11/2⁻) are introduced in the¹³¹Cs level scheme based on our observations taken together with the results from reaction studies. Spin-parity assignments to a few other levels are also suggested