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1,1,3,3-Tetracyanopropane, 1, was prepared in low yields by a literature method with 2,2,4,4,6-pentacyanocyclohexenamine, 2, as a major by-product. The products were examined by X-ray crystallography. 1has an orthorhombic space group, Pbcn(No. 60) with cell dimensions, a = 7.158(2), b = 10.510(3), c = 9.733(2) Å and has four formula units in the unit cell. 2has a monoclinic cell, P21/c(No. 14) with cell dimensions a = 14.368(3), b = 6.626(1), c = 12.300(2) Å, β = 115.60(1)° and has 4 formula units in the unit cell. Data were collected with use of MoKα radiation and a Nicolet P3 diffractometer. The crystal structures were determined by standard methods and refined to Rw = 0.037 (1) and Rw = 0.040 (2) on the basis of 782 and 2108 unique reflections. Bond lengths and angles in the two compounds are normal. 2has what has been considered to be the less likely tautomeric structure. Both compounds were examined by 1H, 13C nmr, vibrational spectroscopy, and mass spectroscopy. For 2there was no evidence of the alternative tautomeric structure. New methods were developed for the preparation of both compounds and the mechanism of the original reaction rationalized.

Infrared and Raman spectra (4000–100 cm−1) of solid samples of six different methyl substituted thiazolidine products of D-penicillamine and L-cysteine hydrochloride have been observed and assigned. Infrared spectra in D2O solutions have been obtained for comparison in order to study the amino-acid zwitterion equilibria. Proton and 13C nmr spectra for the compounds have also been measured.

Infrared and Raman spectra (4000–100 cm) of solid samples of seven different 2-phenyl-, N-benzoyl-, and 2-ethyl-2 methyl derivatives of L-cysteine and D-penicillamine have been observed and assigned. Proton and 13C nuclear magnetic resonance spectra for the compounds have also been measured. Amino acid/zwitterion equilibria are discussed with reference to pKvalues and the vibrational spectra. Keywords: amino acid/zwitterion equilibria, thiazolidine carboxylic acids.

The crystal structure of Pt(CH3CN)2Cl2has been determined twice independently. The compound is the cisisomer. It crystallizes in the monoclinic P21/cspace group, a = 6.660(3) [6.668(4)], b = 12.500(7) [12.519(8)], c = 10.277(6) [10.308(5)] Å, β = 105.42(4) [105.41(4)]°, V = 824.7(8) [829.6(9)] Å3. The structure was refined by full-matrix least-squares analysis to a conventional Rfactor of 0.054 [0.058] and Rw = 0.053 [0.057] for 1578 [1226] observed reflections. The coordination is square planar with bond lengths (Pt—N = 1.98(1), 1.98(1) [1.95(2), 1.99(2)] Å and Pt—Cl = 2.264(4), 2.263(3) [2.270(6), 2.277(5)] Å) slightly shorter than normal. The N—C bonds are 1.10(2), 1.11(2) [1. 11(3), 1.16(2)] Å. The C—CH3bonds are shorter than normal single bonds (1.48(2), 1.45(2) [1.49(3), 1.45(3)] Å and the N—C—C framework is almost linear. Infrared (4000–100 cm−1) and Raman (4000–60 cm−1) spectra of the crystalline solid have been measured and assigned; the vibrational spectra confirm the cisstructure. A rough molecular force constant analysis based on a cw-planar C2v. skeleton (ignoring H atoms) was carried out and aided in the vibrational assignments. The v(Pt—Cl) bands occur at 362 and 333 cm−1; the v(Pt—N) bands occur at 463 and 408 cm−1, and show strong coupling with the PtNC deformations.

By synchronizing a rotating magnetic-field gradient with the rotation of a sample undergoing magic-angle spinning (MAS), solid-state 13C NMR imaging has been carried out. Two-dimensional spatial-spatial 13C NMR images have been demonstrated in natural abundance on organic solids and a rigid polymer with and without chemical-shift selectivity. A 2D spatial-spectral solid-state 13C NMR image is also presented with MAS-enhanced spectral resolution in the chemical-shift dimension. It was found that the dependence of the 13C Signal intensity on 1H frequency offsets in 1H decoupling is one of the major technical problems that must be minimized in order to perform useful solid-state 13C NMR imaging.Copyright 1995, 1999 Academic Press, Inc.

The validity of the track formation model proposed by Fleischer, Price and Walker was tested for a sensitive cellulose nitrate track detector using protons, deuterons and alpha particles. Quantitative data are given on the threshold energies and etchable track lengths of these particles. The same data were also calculated for 3H, 3He, 6He and 8He by means of the model of primary radiation damage density presented in the paper. A simple empirical relation was found for the evolution of the etch rate ratio along the particle trajectory.

In solids containing both unpaired electrons and nuclear spins, the dynamic nuclear polarization (DNP) technique can be applied to enhance the NMR signal. DNP requires irradiation at or near the electron Larmor frequency, and in this paper two probes are described to achieve this goal. Two new DNP probes were designed for electromagnets operating at a field of 1.4 T. In one probe, DNP can be combined with CPMAS. Compared to a similar probe reported previously, the main advantage of the new probe is the capability to spin vacuum-sealed samples with an improved filling factor. A second probe is based on an oversize microwave cavity. In this probe, large DNP enhancement factors can be obtained in nonlossy samples, e.g., a 1H enhancement factor of 260 for doped polystyrene.Copyright 1994, 1999 Academic Press, Inc.

We have studied the reaction of both D- and L-penicillamine with pyridoxal hydrochloride and examined the products by single crystal X-ray diffraction. The structure of the title compound, A, formed by the reaction of D-penicillamine and pyridoxal was determined. Crystals are orthorhombic, P212121, with cell dimensions a = 9.507(5), b = 19.185(5), c = 7.766(2) Å and Z = 4. The structure was solved by standard methods and refined to R = 0.088, Rw = 0.079 for 2433 independent reflections. Aexists as a zwitterion, and bond lengths and angles are normal. In the solid state, Aand the corresponding product obtained from L-penicillamine, B, have identical geometrical structure but are of opposite chirality; that is, D-penicillamine produces the 2R,4Sdiastereomer and L-penicillamine produces the 2S,4Rdiastereomer (with no S,Sand R,Rcomponents). In solution, however, NMR spectra show the presence of both pairs of diastereomers (2R,4Sand 2S,4S; 2S,4Rand 2R,4R). In neutral or alkaline solution there appears to be a rapid epimerization at the thiazolidine carbon atom attached to the pyridoxal moiety. Features of the mass, 1H NMR, vibrational, and electronic spectra are also discussed. Keywords: D-penicillamine, vitamin B6, pyridoxal hydrochloride, therapeutic uses, bischemical reactions, structures.

The structure of cis-dichlorodiammine-trans-dihydroxoplatinum(IV), PtCl2(OH)2(NH3)2, has been determined by X-ray diffraction. The tetragonal space group, P42/nhas cell dimensions a = 7.328(4), c = 11.362(5) Å and has four formula units in the cell. Intensities were measured using MoKα radiation and a Syntex P21diffractometer. The crystal structure was determined by standard methods and refined to R1 = 0.0460, R2 = 0.0639 based on 447 independent reflections. The platinum atom has roughly octahedral coordination and Pt—Cl, Pt—N, Pt—O distances (2.306(4), 2.00(1), 2.00(1) Å) are normal. The crystal is held together by hydrogen bonds, and the vibrational spectra have been correlated with observed features of the hydrogen bonding.

1-Methylthyminato-N3-triphenylphosphinegold(I) was prepared by reacting chloro(triphenylphosphine)gold(I) with 1-methylthymine in aqueous methanol at pH 11. The product was examined by X-ray crystallography and was found to have the orthorhombic space group C2221(no. 20) with cell dimensions a = 12.760(7) Å, b = 11.530(2) Å, c = 31.893(5) Å, and eight formula units in the unit cell. Data were collected with use of MoKα radiation and a Syntex P21, diffractometer. The crystal structure was determined by standard methods and refined to R = 0.112 and Rw = 0.076 on the basis of 4760 unique reflections. Bond lengths and bond angles are normal. Packing in the crystal lattice is dominated by the triphenylphosphine rings which arrange roughly as blades of a propellor and are the source of the crystal's chirality. The title and related compounds were also examined by 1H nmr, 13C nmr, and vibrational spectroscopy.

The X-ray crystal structure of bis((S)-5,5-dimethylthiazolidine-4-carboxylic acid) protium chloride hydrate, I, has been determined. Crystals are orthorhombic, P212121, with cell dimensions a = 6.463(2), b = 11.832(3), c = 23.966(6) Å, and Z = 4. The structure was solved by standard methods and refined to R = 0.073, Rw = 0.064 for 2969 independent reflections. Compound Iis composed of two zwitterion molecules bridged through a proton which causes a very short hydrogen bond, O … O′ = 2.450 Å. The proton is located roughly halfway between the two carboxylate oxygen atoms, but is not on a special crystallographic position. Characteristic features of the infrared and Raman spectra, mass spectra, and 1H and 13C nmr spectra are discussed.

Despite the use of gold complexes in modern medicine for over 100 years and the use of gold complexes in the management of rheumatoid disease for more than 60 years, the definitive mechanisms of action for efficacy and for toxicity have not been established.

The preparation and some physical and chemical properties of ReOCl2are described.