Infrared Spectral Data Research Articles

Synthesis of and physico-chemical studies on poly(4,4′-cyclopentylidene diphenylene toluene-2,4-disulfonate)

Poly(4,4′-cyclopentylidene diphenylene toluene-2,4-disulfonate) (PSBPT) has been synthesized by conventional interfacial polycondensation of 1,1′-bis(4-hydroxyphenyl) cyclopentane (0.005 mol) and toluene-2,4-disulfonyl chloride (0.005 mol) using water (50 ml)-chloroform (12.5 ml) as interphase, alkali (0.015 mol) as acid acceptor and cetyltrimethyl ammonium bromide (0.125 g) as emulsifier. The structure of PSBPT has been supported by infra-red and nuclear magnetic resonance spectral data. A 40 μm thick film has 200.1 kg cm −2 tensile strength and 0.6% elongation at break. A 0.19 mm thick film has static hardness 14.5–16.5 kg mm −2 at different loads (15–60 g). The density (1.353 ± 0.0009 g cm −3) of PSBPT has been determined by the floatation method and compared with calculated values (1.3973 g cm −3). Thermogravimetric (t.g.a.) and differential thermal (d.t.a.) measurements have been made at four different heating rates and 10°C min −1, respectively in N 2 atmosphere. D.t.a. showed the glass transition temperature T g at about 134°C and two exotherms at 337°C and 362°C which might be due to decomposition. PSBPT is stable up to about 355°C in N 2 atmosphere and involves two-step degradation. The average energy of activation, pyrolysis order and frequency factor for step-I are 52.6 kcal mol −1, 2.5 and 9.22 × 10 13 min −1, respectively. PSBPT has excellent hydrolytic stability towards acids and alkalis.

Synthesis and characterization of a new metal chelating polymer and derived Ni(II) and Cu(II) polymer complexes

Abstract 2-Hydroxy-4-acryloyloxybenzaldehyde (2H4ABA) prepared from acryloyl chloride and 2,4-dihydroxybenzaldehyde, was polymerized in 2-butanone at 65°C using benzoyl peroxide as initiator. Polychelates were obtained in N , N -dimethylformamide solution of poly(2H4ABA) with aqueous solution of Cu(II)/Ni(II) ions. The polymers and polychelates were characterized by elemental analysis and spectral studies. The infra-red spectral data of polychelates suggest that the metals are coordinated through the oxygen of the aldehyde group and oxygen of the phenolic-OH group. The electronic spectra, e.p.r. and magnetic moments of polychelates show an octahedral and square planar structure for poly(2H4ABA) Ni(II) and poly(2H4ABA) Cu(II) complexes respectively. X-ray diffraction studies revealed the highly crystalline nature of polychelates. The thermal properties of polymer-metal complexes and their catalytic activity are discussed.

Rapid Analysis of Whole Blood and Blood Serum Using near Infrared Spectroscopy

In the present study we describe the relationship between laboratory values obtained with routinely used laboratory analytical methods and near infrared (NIR) spectral data of 126 whole blood and 228 blood serum samples. Spectra were measured with a SPECTRALYZER 1025 (PMC) computerised research analyser. The relationship among laboratory data and values of the second derivative of the log (1/ R) spectra measured at different wavelengths was determined by multiple linear regression (MLR) using three and four term linear summation equations, principal component regression (PCR) and partial least-squares (PLS) regression methods. Along with examples for qualitative detection of protein and lipid in human sera, as well as distinction of albumin and globulin dissolved in physiological saline solution, we describe mathematical models and evaluate their performance for the determination of protein and beta-lipoprotein (β-LP) content of serum as well as oxygen saturation and carbon dioxide pressure in whole blood. Validation of our results yielded a standard error of performance (SEP) of 2.47 g L−1 for protein content and 0.79 TU for β-LP content in blood serum, whereas SEP values of 5.41% for oxygen saturation and 5.27 mm Hg for carbon dioxide pressure in whole blood were found. Our results presented in this preliminary study indicate that NIR measurements can be related to analytical data of whole blood and serum. NIR spectroscopy is a rapid, accurate, cost effective method for determining quality parameters of whole blood and serum and might be a promising new tool in the field of automated clinical laboratory analysis.

Application of an Artificial Neural Network to the Identification of Amino Acids from near Infrared Spectral Data

An artificial neural network (ANN) was trained to identify a group of amino acids from near infrared (NIR) spectral data. The input, the hidden and the output layers were composed of 701 (for raw spectral data, fixed) or 324 (for second derivative of the spectral data, fixed) units, 1 to 100 (changeable) units and 20 (fixed) units, respectively. Using the raw spectral data, the ANN did not converge to a suitable error level. However, when the second derivative spectra were used, whether original or standardised spectra, the error reduced to a suitable level, because this mathematical treatment made their differences in NIR spectra clearer. The ANN was trained for non-pretreated amino acids and then applied to the other prediction sets. When standardised spectra were used, the ANN could almost correctly identify the amino acids not only for non-pretreated amino acids but also for ground samples or samples from different batches. The results obtained by principal component analysis (PCA) were also compared with those by the ANN.

Synthesis and Physico-Chemical Studies of Some Novel Mixed-Ligand Cyanonitrosyl {CrNO}5and {FeNO}6Chelates Involving Tridentate Schiff Bases Derived from 4-Acyl-3-Methyl-2-Pyrazoline-5-One and 2-(2′-Aminoethyl)Pyridine

Abstract The synthesis and characterization of a series of novel mixed-ligand cyanonitrosyl chelates of chromium(I) and iron(II) of the type [M(NO)(CN)2 (L)](where L = tridentate Schiff bases derived from 2-(2′-aminoethylpyridine) and 4-acetyl-3-methyl-l-phenyl-2-pyrazoline-5-one (a), 4-chloroacetyl-3-methyl-l-phenyl-2-pyrazoline-5-one (b), 4-benzoyl-3-methyl-l-phenyl-2-pyrazoline-5-one (c), or 4-p-nitrobenzoyl-3-methyl-l-phenyl-2-pyrazoline-5-one (d) have been described. Analytical, conductance, magnetic, electron spin resonance and infra-red spectral data show that the resulting chelates are non-electrolytes and have an octahedral geometry.

Theoretical evaluation of three-dimensional elastic constants of native and regenerated celluloses: role of hydrogen bonds

Three-dimensional elastic constants were calculated for cellulose crystalline forms I and II (native and regenerated celluloses, respectively). The calculated Young's modulus E l along the chain axis is 167.5 GPa for form I and 162.1 GPa for form II. The E l of form II has only a slightly lower value than that for form I. This is consistent with the X-ray data ( c. 120–140 GPa for form I and c. 110 GPa for form II) although the absolute values are large. The E l was found not to be affected by intermolecular interactions but by intramolecular hydrogen bonds along the chain axis, especially the bond between the hydroxyl side group and the ether oxygen atom of the glucose ring (type a). A calculation neglecting this hydrogen bond gives the largely reduced E l of c. 70 GPa. Anisotropy of the Young's modulus and linear compressibility in the planes perpendicular to the molecular chain axis were also calculated. In the form I crystal, where the hydrogen-bonded sheet planes are stacked together by non-bonded van der Waals interactions, the modulus is large within the sheet plane and small in the direction perpendicular to the sheet: the anisotropy is similar to that reported for the nylon 6 α and γ forms. In form II the modulus is large but the anisotropy is not so remarkable, which is similar to atactic poly(vinyl alcohol) and poly( m-phenylene isophthalamide). The same tendency is seen also for the linear compressibility. In parallel with the calculation of the elastic constants, the lattice vibrational frequencies were calculated for forms I and II and compared with the observed infra-red and Raman spectral data so as to confirm whether the force fields used were reasonable.

Cobalt (II) Complexes with Tri- and Tetradentate Schiff Bases Derived From 2-Furyl Glyoxal and Some Amines

Coordination compounds of cobalt (II) with four new schiff bases of furyl glyoxal, 2-furyl-methyl-2′-carboxylato ketoanil (2 FMCKA), 2-furyl glyoxal ethyenediimine (2 FGED), 2-furyl giyoxal-2′-sulphonic acid anil (2 FGSAA) and 2-furyl glyoxal-2′-chloro-4-nitro anilimimine (2 FGCNA) were prepared and characterised with the help of elemental analyses, magnetic measurements, infra-red and electonic spectral data. Various ligand field parameters such as 10 Dq, B & C, F2 & F4, f2 & f4, h, B° etc. and transition energies ν1;, ν2 & ν3, were calculated with the help of electronic spectral data. The ν(C=N) bands in the IR spectra of all the ligands are lowered in complexation indicating nitrogen coordination of the ligands. All these studies indicate that cobalt(II) ion is in a distorted octahedral environment.

Organosilicon and Organotin Derivatives of N-Aryl Amidoximes

Abstract Some interesting compounds of N-phenyl benzamidoxime and N-m-tolyl benzamidoxime derived from diorganosilicon(IV), triorganotin(IV) and diorganotin(IV) are reported. The molecular weight, infra-red and proton magnetic resonance spectral data suggest stereochemical variations in the compounds.

Hydrolytically stable fluorocarbon ether bibenzoxazole polymers

AbstractHydrolytically and thermooxidatively stable fluorocarbon ether bibenzoxazole (FEB) polymers were synthesized by the acetic acid‐promoted polycondensation of fluorocarbon ether bis(o‐aminophenol) monomers with novel fluorocarbon ether dithioimidate ester monomers. The dithioimidate esters were derived from hexafluoropropylene oxide (HFPO) or, preferably, from a combination of HFPO and tetrafluoroethylene oxide (TFEO). The latter class of TFEO:HFPO‐derived dithioimidate esters imparted improved hydrolytic stability to the resultant FEB polymers while minimizing undesirable, concomitant increases in polymer glass transition temperatures. The polymers exhibited inherent viscosities in the range of 0.20 to 0.41 dl/g. Polymer structures were verified by elemental and infrared (IR) spectral analyses. Lower glass transition temperatures were obtained with increased fluorocarbon ether content, a minimum value of −48°C being achieved. High thermooxidative stability of the HFPO‐ and TFEO:HFPO‐based FEB polymers was substantiated by thermogravimetric analysis and isothermal aging studies in air. After isothermal aging in air for 200 hr at 288 and 260°C, representative polymers exhibited weight losses of 17 and 7%, respectively. Hydrolytic stability of the polymers was evaluated by exposure to a 95% relative humidity, 93°C environment for prolonged periods of time. Based on comparative glass transition temperature, inherent viscosity, and IR spectral data, the HFPO‐ and TFEO:HFPO‐based FEB polymers exhibited vastly improved hydrolytic stability over analogous TFEO‐based FEB polymers. Optimum hydrolytic stability and low‐temperature viscoelastic properties were achieved by the use of a TFEO:HFPO‐derived dithioimidate ester that did not contain structural isomers that would lead to sites of hydrolytic instability in the polymer backbone.

COMPLEXES OF LANTHANIDE PERCHLORATES WITH N,N,N′N′-TETRAMETHYL PYRIDINE DICARBOXAMIDE

Abstract The synthesis and a study of the physical properties of lanthanide perchlorate complexes with N,N,N′,N′ Tetramethyl pyridine dicarboxamide of the general formula Ln(ClO4)3 (tmpd)3 where Ln=La-Yb and Y and tmpd=N,N,N′,N′ Tetramethyl pyridine dicarboxamide have been made. Conductance and infra-red data show that all the perchlorates are ionic. Infra-red spectral data suggest that the co-ordination of the ligand occurs through the oxygen atoms of the two amide moieties and through the pyridine nitrogen. Proton NMR spectra of the diamagnetic Y and La complexes confirm bonding through the pyridine nitrogen. Electronic spectral data for the Pr, Nd, Ho and Er complexes are also reported. A co-ordination number of nine has been assigned for all the complexes.

Application of computer-assisted learning methods in the teaching of chemical spectroscopy

Spectroscopic data are widely used in the elucidation of chemical structures. Students acquire skill in interpreting spectra generally by applying sets of rules, often empirically, to sample spectra as either tutorial or laboratory exercises. The assistance available from demonstrators or from fellow students is rarely adequate to promote the development of this skill in a systematic manner and, in any case, individual teachers seem to adopt quite different strategies which can be confusing in the early stages of development. The opportunity for the student to develop his own methodology under guidance is highly desirable and the use of CAL techniques in which the student is given individualized instruction makes this possible. The programs to assist in the interpretation of spectra are, of necessity, complex since they must accommodate a variety of strategies, keep a record of the interpretation of individual pieces of information, suggest reasonable alternatives to student hypotheses, and provide hints based on information which the student has acquired. In this paper the application of CAL methods to the interpretation of infrared (IR), nuclear magnetic resonance (NMR) and mass spectra are discussed and extensions into the area of ‘integrated spectroscopy’, in which a student is presented with IR, NMR and mass spectral data on a molecule in order to determine its structure, are outlined.

Backbone torsional potential functions for rotations about N--Calpha and Calpha--C bonds in dipeptide model systems in relation to nuclear magnetic resonance and infra red spectral data.

A comparative study of the conventional three‐fold torsional potential functions (referred to as “Old V”), the potential function having zero φ barrier and a twofold ψ‐barrier, proposed from this laboratory (“Int V”), and those developed recently in this laboratory from the study of dipeptide conformations in protein crystal structures (“New V”) has been carried out by comparing theoretically calculated and experimentally observed NH‐CαH coupling constants from n.m.r. studies and the relative occupancy of hydrogen‐bonded conformations from i.r. studies of dipeptide model systems. It is observed that no fully satisfactory agreement with both n.m.r. and i.r. data is possible in any one of the three functions. For the hydrogen bond‐disrupting solvent DMSO, (NH‐CαH) coupling constant values were predicted equally well in all three. However, only for New V are values of the constants A (= 8.62), B (= ‐2.33), C (= 1.51) as obtained by the least‐squares method in the expression J(θ) = A cos2θ+ B cos θ+ C sin2θ such that J‐values in excess of 10Hz, observed experimentally in some cases, are permissible. However, the same potential function yields unsatisfactory agreement in the case of hydrogen bond‐promoting solvent CCl4. This was interpreted to be because the potential function concerned was obtained from data in solid state where solvent interaction is absent.In view of the lack of satisfactory agreement with the solution data for all three potential functions, it was concluded that solvent effects other than the promotion of intramolecular hydrogen bonding, which were ignored in the present study, must be taken into account for better prediction of experimental data from theoretical potential functions.

The synthesis and characterization of α- and β-1, 1-diiodo-3,4-benzo-1-telluracyclopentane, C 8H 8Tel 2

Elemental Tellurium reacts with α,α′-dichloro- o-xylene and NaI in 2-methoxyethanol to form 1,1-diiodo-3,4-benzo-1-telluracyclopentane in 83% yield. C 8H 8TeI 2 is molecular in acetone, methylene chloride and methyl ethyl ketone, but ionic in DMF. Two crystalline modifications of the compound have been isolated from 2-methoxyethanol. The yellow-orange or α form is monoclinić, space group P2 1/ c; the orange-red or β form is also monoclinic, space group I2/ c. Infrared, optical and mass spectral data, along with solution UV, NMR, molecular weight and conductivity data, suggest that the two crystalline modifications are plymorphs, possibly differing in the degree and type of heavy atom interaction. In 2-methoxyethanol the β form undergoes a solution phase transformation to the stable α form. Both forms are thermochromic.

Infrared and electronic spectral studies of metal halide complexes-I: Preparation and infrared spectra of group (IV) halide complexes with ethylene urea and ethylene thiourea

The coordination complexes of tin(IV) and titanium(IV) halides with ethylene urea and ethylene thiourea have been prepared. Analytical data and the results of non-aquous acid-base titrations indicate their composition to be of the type MX 4. 2 L ( M  Sn, Ti; X  Cl, Br, I; L  ethylene urea, ethylene thiourea). Molecular weight and conductance measurements show them to be true monomeric molecular addition compounds. Infra-red spectral data indicate coordination through carboxyl oxygen in ethylene urea and through imino nitrogen in ethylene thiourea. A study of the relative donor abilities of various oxygen and nitrogen donors has also been made.

Synthesis of Furan Derivatives. LVII. The Reaction of Keto Acetylenic Esters with Carbonyl Reagents

Methyl (ethyl) 5-(2'-furyl) isoxazole-3-carboxylate (3a and 3b) were prepared frommethyl (ethyl) 2-furoylpropiolates with hydroxylamine, respectively. Methyl (ethyl) 5-(2'-furyl) pyrzaole-3-carboxylates (10a and 10b) were formed by the condensation ofmethyl (ethyl) 2-furoylpropiolates with hydrazine hydrate. The corresponding 5'-nitrofuran derivatives (4a and 11b) were obtained in usual manner, and the each position ofnitro group of the furan rings was confirmed by the nuclear magnetic resoance and infraredspectral data.

Re-assignments of the C-H stretching vibrations of some group IV tetramethyl molecules

Abstract A review is given of the currently accepted assignments of the C-H stretching fundamentals of all the group IV tetramethyl molecules. For Sn(CH3)4, Pb(CH3)4 and Ge(CH3)4, I have shown that they are incompatible with the published infra-red and Raman spectral data. I have proposed re-assignments of some of these fundamentals, which are compatible with these data, and with high resolution infra-red studies reported here. I have found the broad band at ~3047 cm−1 in the infra-red spectrum of Sn(CH3)4 to possess fine structure in the form of poorly resolved maxima with a spacing of ~10 cm−1. In terms of the re-assignments proposed here, these maxima are readily interpreted as “Q” branches due to Coriolis coupling of internal rotation with the C-H vibrations. Such coupling should occur in Group IV tetramethyl molecules provided the torsional barriers are low enough; it does occur in a variety of non-rigid molecules including CH3NCS, for example, where the barrier is as high as ~250 cal mole . For Pb(CH3)4 I have reassigned the strongest band in the 3 μ region of the infra-red spectrum as an “overtone” band. For this and for other reasons it would be desirable to make an independent check of these re-assignments. I have outlined one possible way of doing this which is based on the anticipated temperature dependence of the relevant band shapes.

Raman and Infrared Spectral Data for CH2Br2, CHDBr2, and CD2Br2

Raman displacements, relative intensities, and depolarization ratios have been observed for CH2Br2, CD2Br2, and CHDBr2 in the liquid phase, and the wavenumbers and relative intensities for the infrared bands from 400–4000 cm−1 have been obtained for both the liquid and vapor phases. All but five of the 90 bands observed for the liquid phases of these methanes have been assigned to fundamentals, first overtones, and binary combinations. The assignments for the fundamentals of CH2Br2 are in agreement with previous assignments of Plyler, Smith, and Acquista, but the assignment for the b1 fundamental of CD2Br2 at 2313 cm−1 differs from that of Dowling. The assignments for CD2Br2 were made by comparison with those for CH2Br2, and those for CHDBr2 were made with the aid of the Brodersen and Langseth complete isotopic rule. The present assignments are in better agreement with that rule than are the previous assignments.

The chemistry of uranium (IV)—II: Some new compounds with oxygen and nitrogen donor ligands

Some compounds of uranium (IV), several of which are new, have been synthesized and characterized. Preparations are reported for U(OCOCH 3) 4, U(OH)(OCOCH 3) 3, UO(OCOCH 3) 2, U(OCOC 2H 5) 4, U(OH) 2(OCOC 2H 5) 2, UO 1·5(OCOC 2H 5), UCl 4·8NH 3, UCl 4·4NH 3, UCl 4·2NH 3, UCl 3NH 2, UCl 4·4(n-C 4H 9NH 2), UCl 3·(n-C 4H 9NH), UCl 4·2(C 5H 5N), UCl 4·4(C 5H 10NH), UCl 4·4-(NH 2CH 2CH 2NH 2), UCl 4·4[(CH 3) 2SO], UCl 4·3[(C 6H 5) 2SO], and U(C 7H 5O 2) 4 (salicylaldehydo). The compounds with nitrogen-donor ligands are less stable toward both moisture and oxygen than the compounds with oxygen-donor ligands. Some compounds displayed surprising stability for this oxidation state of uranium. Visible and infra-red spectral data are reported, as well as other characterizing data.

Sulphato complexes of palladium (II)

Several new palladium (II) complexes containing co-ordinated sulphato groups are reported. Infra-red spectral data has been applied to the characterization of the compounds. The spectrum of Pd(NH 3)SO 4·H 2O indicates the presence of unidentate sulphato groups, whereas those of [Pd(NH 3) 2SO 4] and PdSO 4 are considered to be consistent with polymeric structures involving bridging sulphato groups. Chemical and infra-red spectral evidence suggest that the complexes [PdphenSO 4], Pdpy 2SO 4·H 2O, [Pd(DMSO) 2SO 4] and PdSO 4·2H 2O involve chelating sulphato groups.

The microwave spectrum of dichlorine oxide. Molecular structure, centrifugal distortion coefficients, and force field

The microwave spectra of the three chlorine isotopic species (35/35, 35/37, 37/37) of dichlorine monoxide have been measured in the region 9–40 Gc./sec. Rotational constants and centrifugal distortion constants have been obtained and used to calculate the structural parameters and the harmonic force constants of the molecule.The structure is highly over-determined. The mean values of the nine ro structures are d= 1·70038 ± 0·00069 A for the bond length, and α= 110·96 ± 0·08° for the bond angle. The mean values of the nine rs structures are d= 1·70038 ± 0·00043 A and α= 110·86 = 0·04°. For 35Cl2O the centrifugal distortion constants could be obtained with sufficient accuracy to allow the determination of all force constants of the general harmonic force field: fd=(2·88 ± 0·08)× 105, fdd=(0·31 ± 0·05)× 105fα/d2=(0·432 ± 0·002)× 105, and fdα/d=(0·17 ± 0·01)× 105(all in dyne/cm.). The force constants are compared with those evaluated by conventional procedures from infrared-spectral data, and it is found that the molecular vibrational frequencies calculated from the force field evaluated solely from microwave data agree well with those observed. The results support the view that centrifugal distortion coefficients for asymmetric rotors provide a useful source of information about molecular force fields. Attention is drawn to the importance of data selection in the evaluation of centrifugal distortion constants.