Nujol Mull Research Articles

A Rapid Infrared Procedure for Screening Human Renal Stones Using a Latex-Tissue Substrate

The infrared spectra of solid renal stone material have been obtained traditionally by the KBr pellet and mineral oil mull techniques. Both are time-consuming methods for routine work because of the necessity of mixing the solid samples with diluent and forming the pellet or window film. At our laboratory these methods as well as solid film casting from solutions have been used routinely. We have the need for a rapid infrared screening method to route as many as 100 samples/day to other analytical techniques such as x-ray diffractometry, atomic absorption spectrophotometry, polarization microscopy, chemical analysis, etc., based upon the presence of gross chemical species and their approximate concentrations in the sample. Renal stones are typically crystalline phases of calcium phosphates, calcium oxalates, uric acid, and calcium carbonates. The specific phases are apatite, whewellite, weddellite, calcite, struvite, uric acid, and rarely ammonium and sodium urate and cystine. The specimens are always solid and usually inorganic but relatively soft and easily ground to very fine powder. The spectral region of interest is usually 1800 to 650 cm−1 and a rapid scan with little sample preparation is preferred. The KBr pellet was used with very good analytical results for years, but the time involved in sample preparation limited our throughput to 4 samples/h even though the run itself was standardized to a mere 2 min (2000 to 600 cm−1 at 700 cm−1 min−1). The nujol mull technique proved to be much more time efficient with a routine throughput for one operator at 7 to 9/h.

Syntheses and characterization of tetra-gamma-benzyl-L-glutamates.

Monodisperse tetra-gamma-benzyl-L-glutamates are prepared by coupling two kinds of dimers by means of dicyclohexylcarbodiimide and then converting a terminal group into the other. An o-nitrophenylthio group is used for blocking the amino terminal, and a p-nitrophenyl ester or an ethylamide substitutes the carboxyl end. The amino-terminal-deblocked tetramer, HCl,H-[Glu(OBzl)] 4-NHEt, is alos prepared. Infrared spectra in nujol mull indicate that all the tetramers are in the beta-structure of antiparallel chains in the solid state. Circular dichroism spectra show that the amino-terminal deblocked tetramer keeps the beta-conformation in ethylene dichloride, while it has the solvated sigma-conformation in trifluoroethanol and in dioxane.

Vibrational spectra and i.r. dichroism of p-di(β-hydroxy-iso-propyl)benzene

Raman spectrum of p -di(β-hydroxy-iso-propyl)benzene was recorded in the solid phase. Infrared spectra were measured between 4000 and 200 cm −1 in solution, KI pellet and Nujol mull. Oriented polycrystalline layers were grown from the melt and they were investigated in polarized light at liquid nitrogen temperature. An approximate assignment is given for molecular fundamentals. A spiral hydrogen bond structure has been confirmed by i.r. dichroic data.

Infrared absorption spectra of 2,3- and 3,5-dichloroaniline

The infrared absorption spectra of 2,3- and 3,5-dichloroanilines have been recorded in the region 250–4000 cm−1. The spectra of the latter are recorded in solid phase (KBr and Nujol mull) and in CS2/CCl4 and CHCl3 solutions while that of the former in thin film only. The spectra have been analysed assuming C 3 and C2v point group symmetry respectively and a tentative assignment of the observed bands to different fundamental modes has been made.

Raman and infrared spectra of crystalline [UO2(NH2O)2(H2O)2]·H2O

AbstractRaman spectra of a single crystal were recorded at 292 K in addition to spectra at 292 and 17 K of undeuterated and partly deuterated powder. Infrared spectra of these compounds in KBr discs were recorded in the temperature range 17–360 K. Furthermore far infrared spectra of the undeuterated and partly deuterated compound in nujol mulls were recorded at 292 and 85 K. The stretch frequencies of the uranyl group which in this compound appears to be linear and symmetric, were observed at extremly low values, viz. νs at 783 cm−1 (R) and νas at c. 850 cm−1 (i.r.). The spectroscopic evidence confirmed the strong degree of hydrogen bonding which involves the uranyl group and all hydrogen atoms, even those of the hydroxylamino group. A small but complete correlation field splitting was observed especially in the case of the νs (NO) vibration at 919 (B1g), 921 (Ag), 923 (B2g) and 925 cm−1 (B3g) in agreement with the predictions of a factor‐group analysis.

The infrared spectrum of isotopically diluted potassium hydrogen bifluoride. Doubling of the HF stretching and of the v3 + v1 band

Infrared spectra (of mulls in Nujol and Fluorolube and discs in potasium iodide) have been obtained for crystalline KDF2 of higher deuterium content (c. 97.5%) than used by previous workers. This made possible an unambiguous identification of the bands of KHF2 as a solid solute in KDF2. HF stretching (v3) is split into a doublet with separation c. 52 cm-1, and the combination band v3 + v1 has a doublet separation of c. 64 cm-1. For 1.5% KDF2 in KHF2 the splitting of v3 of DF2- is too small to produce two separate bands. The splitting is attributed to the interconversion doubling which Ketelaar erroneously believed to have detected in 1941. Arguments previously put forward against the F-...HF structure are shown not to take into account the increasing tendency of the anionic dipoles to adopt an ordered arrangement as the temperature is lowered. ��� KHF2 and KDF2 have also been examined in solid solution in potassium halides and in water. Narrow v3 bands are obtained in KCl and KBr, but broad ones, as in crystalline KHF2, in KI and in water.

Infrared spectra of BeSO4.4H2O and its deuterated analogue in 4000–1200 cm−1 region

IR spectra of BeSO4.4H2O and its deuterated analogue at ∼300 K and ∼110 K are reported in the region 4000–1200 cm−1 using thin film and nujol mull techniques. The observed bands have been assigned as the internal modes of the water and the overtones and combinations of various modes using the recently revised assignments of SO42− and Be(aq)4 fundamentals in the region 1200–250 cm−1 (Srivastavaet al 1976). The splitting of the internal modes of water has been discussed in the light of the effects of deuteration and cooling and it is shown that all the water molecules in a unit cell are asymmetric but crystallographically equivalent.

The i.r. spectrum of sodium diacetylide

The i.r. spectrum of sodium diacetylide was observed in the range of 4000-200 cm −1 by Nujol mull method. The observed frequencies are assigned satisfactorily on the basis of C ∞υ symmetry of diacetylide anion. The fundamental frequencies of diacetylide anion correspond well to those of the related compound cyanoacetylene. The normal frequency of the stretching vibration of diacetylide anion was calculated on the assumption of a simplified force field and compared with those of cyanoacetylene and diacetylene. The force constants obtained indicate that the resonance structure, HC −CCC:, is of significance in diacetylide anion.

Stereochemical features versus magnetic and spectral data on iron(III) complex with p-dimethylamino-9-anthracyl glyoxal anil

4 new complex of Iron(III) with DIMAGA (p-dimethylamino-9-anthracyl glyoxal anil) with the composition [Fe(C24H20N2O)2(Cl2]Cl has been isolated and its structure is established on the basis of chemical analysis, molecular conductivity, magnetic moment and electronic spectra in nujol mull solvent. Relevant ligand field parameters and infra-red data are also discussed.

The vibrational spectra of N-Cl maleimide

The infrared spectra of N-Cl maleimide as a Nujol mull and dissolved in various solvents were recorded between 4000 and 30 cm −1. Raman spectra of the crystalline solid and saturated solution in CH 3CN were recorded and semiquantitative polarization measurements were made. The fundamental frequencies have been tentatively assigned in terms of C 2V symmetry, based upon Raman polarization data and analogies with the spectra of maleimide and maleic anhydride. A force field was derived by initially transferring force constants from maleimide. After small iterations a satisfactory correspondance was achieved between the observed and calculated in-plane modes whereas larger discrepancies remained for some of the out-of-plane vibrations.

Poly(L-valine). Conformational dependence on the degree of polymerization: infrared studies.

AbstractThe infrared spectra of poly(L‐valine)'s with varying degrees of polymerization have been investigated, as well as copolymers of L‐alanine and L‐valine. The spectra of nujol mulls of various molecular‐weight poly(L‐valine)'s, isolated directly from the polymerization media, as well as spectra of these same samples after treatment with strong acid, are recorded. In the 700–250‐cm−1 region, bands at 543 and 414 cm−1 are found to increase with increasing degree of polymerization in the nujol mulls, but are missing in the acid‐treated samples. These bands are assigned to the L‐valine residues with an β‐helixlike local conformation. It is inferred that the polymerization proceeds initially in the β form, and after a critical degree of polymerization the chains adopt an appreciable amount of an α‐helixlike local conformation.

Properties and Structure of Glasses in the Na<sub>2</sub>O-As<sub>2</sub>O<sub>3</sub> System

As2O3 glass was prepared by heating As2O3 in the evacuated, sealed silica-glass tube under the conditions given in Table 1, followed by quenching in water. Binary Na2O-As2O3 glasses containing less than 50mol% Na2O were prepared by melting the batches composed of As2O3 and NaAsO2 in the evacuated, sealed silica-glass tubes for 15-30min at 700°C with subsequent quenching in water or acetone-dry ice mixture. Density, refractive index, thermal expansion, crystallization behavior and infrared absorption of the glass were measured.The expansion coefficient of As2O3 glass was measured to be 37.3×10-6/deg, which was much larger than that of B2O3 or P2O5 glass having a layer structure, and the infrared absorption peaks of As2O3 glass in a nujol mull were found at the positions entirely identical with those of arsenolite in a KBr pellet. The absorption peak at 600cm-1 found for the KBr pellet was probably due to some mechanochemical changes of arsenolite which is considered to take place during pressing for pelletizing KBr. It was, therefore, inferred that As2O3 glass comprised a majority of As4O6 molecules and a small amount of layer- or chain-like linkage of AsO3/2 pyramids distributed over at random.In the composition region of low Na2O content in the binary glass system, the glass showed rapid decreases in thermal expansion coefficient and molar volume with increase of Na2O, and in its infrared spectrum a shoulder was found at about 830cm-1. Moreover, when the glass was heated, the crystal of claudetite II as a metastable phase of the system was separated out of it. These revealed that the glasses changed the structure from that of As2O3 glass rich in As4O6 molecules into a layer network of AsO3/2 pyramids with one or two nonbridging oxygens per each pyramid. The break of molar refractivity-composition curve at about 15mol% Na2O was presumably due to the disappearance of As4O6 molecule in the network. The experimental facts that the crystal of NaAsO2 was separated out of the glasses containing more than 20mol% Na2O and the infrared spectra of the glasses with 40-50mol% Na2O were similar to that for crystalline NaAsO2, revealed the resemblance of the structure of glasses in the region of high alkali content to that of crystalline NaAsO2.It was assumed that As3+ ion was impossible to have tetrahedral coordination because of electrostatic repulsion between the nonbridging oxygen and the unshared electron pair occupying one of sp3 hybrid orbitals of As. This assumption was supported experimentally by the fact that Tg and Mg of the glasses in the composition region of low alkali content were considerably lower than those of As2O3 glass.

Derivatives of bivalent germanium, tin, and lead. Part XI. The interaction of tin(II) halides and bis(β-ketoenolates) with di-iron enneacarbonyl

Tin(II) halides and bis(β-ketoenolates) react with di-iron enneacarbonyl to give high yields of complexes [(X2Sn)-Fe(CO)4](X = Cl, Br, pd, tbd, bpd, pbd, or dpd). In chloroform solution (osmometry), the pentane-2,4-dionate (pd) is dimeric but the remainder are only partially associated. Nujol mull i.r. spectra of the halide derivatives are consistent with a dimeric structure, but some dissociation is apparent for the β-ketoenolates being essentially complete for the bulky 4-phenylbutane-2,4-and 1,3-diphenylpropane-1,3-dionate ligands. In pyridine solution all the complexes are completely dissociated into pyridine-stabilised monomeric [(X2Sn)Fe(CO)4]˙py species. Varying degrees of dissociation occur in less nucleophilic solvents such as tetrahydrofuran and acetonitrile. lron-57 Mossbauer spectra of all the solid complexes demonstrate complete association into dimers at 77 K, but in frozen pyridine solution rehybridisation at iron to give trigonal-bipyramidal geometry occurs. The very low values of the tin-119 isomer shifts in the base-stabilised monomer complexes indicate substantial synergic tin→iron σ and iron→tin (d→d)π bonding.

Molecular Vibrations and Force Fields of Alkyl Sulfides. VII. Polythiomethylene (PTM) and Polythiomethylene-d2 (PTM-D2), and Their Model Compounds: CH3S(CH2S)nCH3 (n=1–3)

Abstract Infrared spectra of polythiomethylene (PTM) and polythiomethylene-d2 (PTM-D2) observed by a Nujol mull method are reported, and their spectra are assigned. Normal coordinates of bis (methylthio)methane, CH3SCH2SCH3, bis(methylthiomethyl) sulfide, CH3SCH2SCH2SCH3, bis[methylthio(methylthio)]methane, CH3SCH2SCH2SCH2SCH3, PTM, and PTM-D2 have been treated. The force field used in the computation is a modified Urey-Bradley type. The skeletal conformation of these model compounds in the solid state is confirmed to be the [G] form. The relations between the degree of n and their CH2 deformation fundamentals are explained by the concept of the frequency-phase difference. The calculated frequencies are compared with those of experiment. A comparison of the force fields of PTM and polyoxyme hylene (POM) is also briefly made.

A comparison of solution and solid state electronic absorption spectra of pyridinium iodides

Charge-transfer (CT) absorption spectra from CH2C12 solutions and Nujol mulls of a variety of pyridinium iodides have been compared. Factors such as hand grindings vs. mechanical milling, milling time, and support medium were examined with respect to effects on the position of the absorption bands in the solid state. Generally, the position of the low energy CT band appeared at lower wavelengths in mulls between CaF2 plates than in CH2Cl2 solutions. However, it was interesting to discover that the same mulls on filter paper or glass microfiber paper exhibit the CT band at energies higher than those found between CaF2 plates or in CH2Cl2 solution. As might be expected, small changes in structure such as differences in alkyl chain length influence the CT band position significantly more in the solid state than in solution.

Far-infrared spectra of some β-hydroquinone clathrates

Far-infrared spectra (400-30 cm −1) of Nujol mulls of the β-hydroquinone clathrates containing the following guest molecules were investigated: formic acid, formic acid-d 2, methanol, methanol-d 4, acetonitrile, acetonitrile-d 3, sulphur dioxide and also both of methanol and sulphur dioxide. The observed infrared bands of the mulls in the region of 4000-30 cm −1 were classified into those due to the host lattice and those due to the guest molecules. On the basis of the comparison of the spectra, some bands were assigned to the translational or the rotational vibrations of guest molecules. Appearance of those bands suggested that some guest molecules are considerably bound in the cavities of the host lattice. Effect of temperature change on the bands was also measured.

The influence of pressure on the infrared spectrum of the perchlorate-group in 1-aminopyridinium perchlorate

Abstract The i.r. spectrum of 1-aminopyridinium perchlorate as a KBr disc shows evidence of the presence of strongly perturbed perchlorate groups of effective symmetry C 2 v , whereas the nujol mull spectrum is consistent with the presence of T d perchlorate ions. It is suggested that, on application of pressure, a crystal modification involving strong cation-anion interaction is produced.

Synthesis and characterization of some octahedral cobalt(III) complexes with β, β′, β″-(triaminotriethylamine)

The preparation of several new octahedral cobalt(III) complexes of the type [Co(tren) X 2] A (tren = β, β′, β″-triaminotriethylamine; X = NO 2, NCS; N 3; A = anion) is reported, as well as those of several mixed complexes of the type [Co(tren) XY] A( X = NO 2, NCS; Y = F, Cl, Br; X = Cl, Y = Br). The chelating anion C 2O 4 2− forms a complex with the formula [Co(tren)C 2O 4] A. The visible spectra of some of the tren complexes in water, and as Nujol mull indicate that the average ligand field around the cobalt ion can be higher or lower than in the corresponding ethylenediamine complexes, depending upon the nature of the cis anionic ligands. The i.r. spectra of the complexes [Co(tren)BrClO 4]Br.H 2O and [Co(tren) XSO 4].H 2O ( X = Cl, Br) indicates that the perchlorate and sulfate ions are coordinated in the solid state.

KBr-pellet vs Nujol mull IR spectra of some pyrazine N-oxide complexes with transition metal perchlorates

KBr-pellet vs Nujol mull IR spectra of some pyrazine N-oxide complexes with transition metal perchlorates

Ultraviolet and Infrared Spectra of Cupferron and Neocupferron

Abstract N-nitroso-N-phenylhydroxylamine, N-nitroso-α-naphthylhydroxylamine, and their sodium salts have been prepared from the ammonium salt of N-nitroso-N-phenylhydroxylamine (cupferron) and the ammonium salt of N-nitroso-α-naphthylhydroxylamine (neocupferron) respectively. The measurements of the UV spectra in solution and the IR spectra with Nujol mull have been carried out on these compounds, including their ammonium salts. The solvent effect and the deuteration effect on the IR spectra have also been examined for the compounds with a hydroxyl group. The formation of a rather strong hydrogen bonding in these aromatic nitrosohydroxyl-amines has been confirmed from the deuteration effect on the IR spectra and from the solvent effect on the UV and IR spectra. These compounds and their salts have shown the absorption band considered to be a chargetransfer band in the UV spectra, and they have also shown the N=O stretching mode between 1450 and 1468 cm−1 corresponding to those of nitrosamines in the IR spectra with the HCB mull.