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A system has been developed which uses an imaging-plate diffraction apparatus to obtain structure factors for protein crystals. The latter is connected to a graphics workstation through an Ethernet. Pixel data from an imaging plate are transferred via the Ethernet to a workstation and processed to give the structure factors. The quality and precision of the diffraction data were examined from the point of view of spatial uniformity, linearity with exposure, decay with time, and reproducibility. X-rays from an 55Fe source and Debye-Scherrer rings from Si powder were used for calibration purposes. Finally, diffraction data were obtained and evaluated for lysozyme and cytochrome c-553 using this system. The results were satisfactory in terms of sensitivity and precision.

Recently some of the above authors determined the structure of an unsolved organic compound employing X-rays from a Synchrotron, an Imaging Plate, and a large radius camera. It would be more desirable if the high quality powder diffaction data could be obtained by a diffractometer or a camera of laboratory use. Therefore a multimode X-ray powder diffractometer which can be used for various experimental geometries such as Bragg-Brentano mode, Guinier mode and parallel beam mode was constructed in order to find the highest resolution geometry. In this paper wc present the results of the measurements employing these three modes.

A new image-plate reader which can read image plates (IPs) having various sizes and shapes has been developed. The machine consists of a rotating laser head to induce luminescence photons from IPs and a porous cylindrical holder made of a composite of cast iron and porous ceramic – so-called `breathnite'. Image plates can be fixed onto the inner surface of the cylindrical holder by evacuating the outer surface through a vacuum chamber with a mechanical pump. Image plates having various shapes and sizes up to 400 × 400 mm can be fixed without covering the open surface on the cylinder. In spite of such flexibility to various applications, the reader produces competitive performances compared with other commercial readers.

An imaging plate Weissenberg camera was installed in the BL04B2 beamline of SPring-8 aiming at automated crystal structure determinations of small molecules. Since this beamline is designed to provide X-rays with the energies higher than 37 keV (λ < 0.33 A), this camera is advantageous in crystal structure analyses of heavily X-ray absorbing materials. The title crystal structure analysis led to precise positional parameters and well-behaved displacement parameters not only for heavy atoms but also for light atoms.

Structure of osladin, a sweet principle of rhizome of Polypodium vulgare, was revised to 26-O-α-L-rhamnopyranosyl-(22R,25S,26R)-22,26-expoxy-6-oxo-5α-cholestan-3β,26-diol-3-o-α-L-rhamnopyrano-syl-(1→2)-β- D-glucopyranoside (1) on the basis of single crystal X-ray diffraction study.

The crystal structure of (DMtTSF)2ReO4 (2 C11H12Se41⁄2+·ReO4−) was determined at room temperature. The structure is monoclinic, space group C2/c, with cell dimensions a=28.518(2), b=7.327(1), c=14.364(1) A β=109.84(1)°, Z=4. The DMtTSF molecules stack along the b axis to form a zigzag column. The interstack contacts between Se atoms are shorter than those in (TMTSF)2X. These contacts indicate that (DMtTSF)2ReO4 has a higher two-dimensional character than (TMTSF)2X.

The structure of oxazolomycin exhibiting antitumor activity has been elucidated.

X-Ray and optical reflection measurements of (DBTTF)2-(Cu2Cl6) single crystals were carried out. The single crystal of the complex consists of stacking columns of the cation molecules DBTTF+. The analysis of the reflection spectra of (DBTTF)2-(Cu2Cl6) single crystals shows that the electronic structure of DBTTF+ cation molecules is typical of the dimer type configuration.

Hexacyanobutadiene(HCBD) forms two kinds of molecular complexes with tetramethyltetrathiafulvalene(TMTTF) one kind with tetramethylthiotetrathiafulvalene(TTMTTF). The crystal structures of these complexes and neutral TTMTTF are determined by X-ray analyses. (TMTTF)2·HCBD is composed of 2:1 donor and acceptor, and TMTTF exists as a dimer cation stacked along the c axis. HCBD anions are included in the cavity of the dimer stack directing their molecular planes parallel to the stacking axis. TMTTF·HCBD is composed of 1:1 donor and acceptor, and has segregated cation and anion stacks with the interplanar spacing of 3.61 A in TMTTF and 3.43 A in HCBD columns. TTMTTF·HCBD is shown to have a regular segregated column with a partial charge transfer. Neutral TTMTTF has a non-planar conformation. The C=C and C–S bond lengths of the donors in free and complexed states are correlated with the degree of the charge transfer in these four complexes, and linear relationships are found between these two quantities.

The molecular structures of tetramethyl[3.3]paracyclophadine(I) and [3.4]paracyclophadiyne(II) have been determined by X-ray analysis. Both crystals are monoclinic, with the space group of P21/c. The crystal data are: a=9.170(4), b=9.208(3), c=18.232(7) A, β=94.0(1)°, Z=4 for (I) and a=10.938(3), b=9.173(2), c=14.988(4) A, β=116.1(1)°, Z=4 for (II). In both molecules, consisting of benzene and diacetylene groups linked by two methylene-bridges, the diacetylene chain is bent into a bow shape. The (I) molecule has Cs symmetry, and the distances (3.019–3.256 A) between the atoms of the diacetylene group and the benzene plane are smaller than those of [3.3]paracyclophadiyne(Aono, Sakabe, Sakabe, Katayama, and Tanaka, 1975). The methylene-bridge of [3.4]paracyclophadiyne has a disordered structure.

The single crystal of (HMTTeF)4(PF6)2 was first prepared by the electrochemical method. The X-ray crystal structure analysis revealed that among four HMTTeF molecules in the unit cell, three are stacked to form trimeric molecular column along the a-axis and the remaining one is located between the HMTTeF columns, having very short intermolecular Te–Te distances with the HMTTeF column.

The single crystal of dimethyldibenzotetrathiafulvalenium tetrafluoroborate (1 : 1) has been prepared by electrocrystallization. The crystal structure has been determined by X-ray crystal analysis. The salt crystallizes in Ibam with a=14.637(3), b=17.625(6), c=13.614(3) A. The radical cations align along the c axis at nearly equal spacing forming eclipsed dimers and the dimeric units are stacked with a staggered mode. The electronic spectra of the radical cation and the dimer have been measured in solution and the assignment has been presented with an aid of the MO calculation by Pariser-Parr-Pople method. A charge transfer (CT) band observed in the dimer has been correlated with the charge resonance of unpaired electron between the HOMOs of the radical cations. Polarized reflection spectra of single crystal have been measured with three different crystal planes and the assignment of both the CT and molecular type bands have been confirmed with polarization measurement. The energy and the intensity of the...

A series of tetrakis(n-alkylthio)tetrathiafulvalene (alkyl-methyl to octadecyl; TTCn-TTF (n = 1-18) has been synthesized. Synthesis, structure, and some physical properties of these uncapped analogues of bis(ethylenedithiolo)tetrathiafulvalene (BEDT-TTF) are described and compared with those of BEDT-TTF. Several charge transfer complexes of TTC1-TTF are presented in terms of their electrical conductivities, ionicity, structures, and intermolecular interactions and compared with those of BEDT-TTF compounds. Molecular conformation, mode of the sulfur-to-sulfur atomic contacts, and requirements for an organic metal are discussed from the viewpoint of the molecular design.

Reduction of B-homocholest-5-en-7a-one, synthesized by a Lewis acid-catalysed ring enlargement of cholest-5-en-7-one, with lithium aluminium hydride, gave B-homocholest-5-en-7aα-ol while reduction with sodium in ethanol afforded a more stable B-homocholest-5-en-7aβ-ol exclusively. The photo-induced reaction of the 7aα-ol in the presence of mercury(II) oxide and iodine gave 5,7aβ-epoxy-B-homo-5α-cholestane as the major product along with 5,7aα-epoxy-6β-iodo-B-homo-5α-cholestane and 5,7aβ-epoxy-6α-iodo-B-homo-5β-cholestane as the minor products. However, the photo-induced reaction of the 7aβ-ol in the presence of mercury(II) oxide and iodine gave 5,7aβ-epoxy-B-homo-5β-cholestane as the major product, with 5,7aβ-epoxy-6α-iodo-B-homo-5β-cholestane as the minor product. All these 5,7-epoxy-B-homocholestanes are formed by intramolecular addition of the oxyl radicals to the 5,6-double bond. The formation of 5,7aβ-epoxy-6α-iodo-B-homo-5β-chplestane from the 7aα-ol occurs via cyclization of a tetrahydropyranyl radical (D) which is formed by intramolecular combination of the allyl radical with carbonyl oxygen. This β-scission of the oxyl radical followed by a new type of radical cyclization was also found in the reaction of the oxyl radical generated from A-homo-cholest-4a-en-3β-ol.

The crystal structures and the electronic properties are investigated on the complex crystals made from the acceptor, hexacyanobutadiene (HCBD) and the donors, tetramethyltetrathiafulvalene (TMTTF) and tetra-methylthiotetrathiafulvalene (TTMTTF). The electrical conductivity, the optical spectra and the magnetic properties of these crystals are discussed in connection with the crystalline structures and the phase transitions.

The solid CT-complex, perylene-HCBD, was found to have 1:1 mixed stacking columns. The degree of CT was evaluated as 0.29 at room temperature from the optical measurements. The structural feature of this complex is discussed comparing with that of the TCNE complexes. Also, the possibility for the occurrence of the neutral-ionic transition is discussed.

The absolute configuration of cycloeudesmol, isolated from the red alga Laurencia nipponica Yamada and Chondria oppositiclada Dawson, is determined by the crystallographic study.

C9H17N~-. C10~ (orange form), Mr = 252.71, monoclinic, P21/a, a=13.671(3), b=14.899(2), c= 6.186(2)/~, fl =97-27(2) °, V= 1249.9(5) A, 3, Z=4, Dx = 1.343 g cm -3, graphite-monochromated Mo Ka radiation, h = 0.71073 A,, /z = 2.606 cm -1, F(000) = 536, T = 140 K, R = 0.045 for 4331 independent data. A slight alternation is found in the bond lengths of the conjugated system of the polymethine cyanine dye [C-C distances 1.376(2), 1.399(2), 1.378(2) and 1.394(2) A at 140 K]. The charge distribution is estimated by the method of Coppens, Guru Row, Leung, Stevens, Becker & Yang [Acta Cryst. (1979), A35, 63-72] and the result is in good agreement with the ab initio MO calculation. In particular, positive charges are found at the methyl groups [except C(11)] and the odd-numbered C atoms in the chain; negative charges are observed at C(4), C(11) and the N atoms.

Two new halo-chamigrane derivatives have been isolated from the title alga and the structure of one of them was determined on the basis of the spectral and chemical evidence. The structure of another compound was established by X-ray diffraction study of its monoacetate epoxide.

We have prepared charge transfer (CT) single crystals comprising TTF derivatives and hexacyanobutadiene (HCBD), which is one of the strongest acceptors. TMTTF gave two crystals in different stoichiometry, one is 2:1 semiconductor and the other is 1:1 insulator. In the 2:1 complex, TMTTF molecules form face-to-face segregated columns with dimerized manner and HCBD lies perpendicular to the donor columns to form side-by-side segregated columns in the cavity produced by donor columns. The ground state of this complex is antiferromagnetic. The 1:1 complex has face-to-face uniform segregated columns and shows some phase transition at around 150K. TTMTTF forms a semi conductive 1:1 complex with uniform face-to-face segregated column.

Isolaurallene (1), a new nonterpenoid C15-bromoallene, was isolated from the red alga Laurencia nipponica Yamada. The structure of this compound was determined by its spectral properties and X-ray diffraction analysis.

The structures of two oxidation products of N-(p-bromobenzoyl)palytoxin were unambiguously determined by means of X-ray crystallographic analysis.

A useful algorithm to find the Bravais lattice on a four-circle diffractometer is developed based on Delaunay's method of classifying the primitive cell. It consists of the evaluation of scalar products between lattice vectors and successive application of transformations to obtain the Bravais lattice. The procedures are found to be satisfactory in practical applications.

Hexacyanobutadiene (HCBD) gives dark red single crystals with equimolar perylene. The crystal structure analysis shows that the complex has mixed regular stacks. The physical properties of the single crystals indicate that the complex is an insulator with neutral ground state and close to neutral-ionic boundary.

The crystal and molecular structure of epoxyisoacoragermacrone, which is an important derivative of acoragermacrone isolated from Acorus calamus L. for the study of the structural organic chemistry and biogenetic reactions, has been determined by the X-ray method. The crystal is orthorhombic, P212121, with lattice parameters a=7.425(2), b=26.604(8), and c=7.150(2) A. The ten-membered ring is in a boat-chair conformation similar to the highly strained cis, trans-germacradiene system. The methyl groups take the axial and syn arrangement, and are on the β-face of the medium ring.

The molecular structure of 7,8-epoxyhalochamigrene, C15H23OBr2Cl, has been confirmed by means of X-ray crystallographic analysis. The crystals are orthorhombic, with sixteen molecules in a unit cell with dimensions of a=10.303, b=71.31, and c=9.061 A; the space group is P212121. 4241 independent intensity data were collected on a four-circle diffractometer with graphite-monochromated Cu Kα radiation. The structure was solved by the Monte Carlo direct method, using 20 reflections as a starting set, and was refined by the block-diagonal least-squares method. The final R value was 0.072. The molecular structure thus obtained corresponds to that proposed by Howard and Fenical on the basis of chemical and spectroscopic evidence. The four crystallographically-independent molecules have almost the same geometries. Of the two spiro-linked six-membered rings, the one having the epoxy group takes a half-chair conformation, while the other adopts a chair conformation. The crystal consists of alternating single and t...

The crystal and molecular structure of γ-metasantonin has been determined by the X-ray method. The crystal is orthorhombic, P212121, with lattice parameters a=10.371(1), b=7.904(1), c=15.975(1) A. The molecule has two independent α,β-unsaturated ketone chromophores which take a chiral configuration. The chromophores show good planarity. A/B ring fusion is cis.

Fukinolidol di-bromoacetate, C19H24O6Br2, is a derivative of the new sesquiterpenoids isolated from the flower stalks of wild butterburs. The crystal of this derivative is monoclinic, with two molecules in a unit cell with dimensions of a=17.13, b=8.21, c=7.59 A, and β=98.8°, and with the space group P21. The structure was elucidated by the heavy-atom method, and the absolute configuration was determined by the application of the anomalous dispersion effect of bromine. The atomic parameters were refined by the least-squares method, using a block-diagonal approximation. The structure thus obtained is the same as that shown by the organic chemical investigation which was carried out parallel with the present X-ray analysis. The molecule has a novel bicyclononane structure with a cis-fused system of a five-membered and a six-membered ring; it also has a spiro γ-lactone ring connected to the former ring. The lactone ring is almost planar, and the other five-membered ring takes a typical envelope conformation,...

The crystal structure of 8,5′-[(allylimino)carbonyloxy]-2-N-dimethylaminomethylene-9-(2′,3′-O-isopropylidene-β-D-ribofuranosyl)guanine (2a) methanol solvate was determined by X-ray analysis. Its base-sugar torsion angle conforms to the CD spectral behavior of the partially deprotected compound 2b in the sense of anti-conformation.

The crystal and molecular structure of a hydroxy derivative of α-ionone, 4-(hydroxy-2,6,6-trimethyl-2-cyclohexenyl)-3-buten-2-one, was studied by means of X-ray analysis. The atoms including the conjugated double bond in the side chain and those around the double bond in the ring form planes orthogonal to each other.

Das aus dem bicyclischen Aldehyd (Ia) uber das Oxim (Ib) dargestellte Hydroxylamin (II) reagiert mit Aldehyden unter Bildung eines Nitrons als Zwi-schenstufe, dessen intramolekulare Cyclisierung zu (III) regiospezifisch verlauft.

The molecular structures of tetramethyl[3.3]paracyclophadine(I) and [3.4]paracyclophadiyne(II) have been determined by X-ray analysis. Both crystals are monoclinic, with the space group of P21/c. The crystal data are: a=9.170(4), b=9.208(3), c=18.232(7) A, β=94.0(1)°, Z=4 for (I) and a=10.938(3), b=9.173(2), c=14.988(4) A, β=116.1(1)°, Z=4 for (II). In both molecules, consisting of benzene and diacetylene groups linked by two methylene-bridges, the diacetylene chain is bent into a bow shape. The (I) molecule has Cs symmetry, and the distances (3.019–3.256 A) between the atoms of the diacetylene group and the benzene plane are smaller than those of [3.3]paracyclophadiyne(Aono, Sakabe, Sakabe, Katayama, and Tanaka, 1975). The methylene-bridge of [3.4]paracyclophadiyne has a disordered structure.

The crystal and the molecular structure of the titled compound was investigated by the X-ray diffraction method. The absolute configuration was determined by the Bijvoet method as 1R4S5R8S.

The major product of photo- and thermally-induced radical rearrangements of hypoiodites of 3α-and 3β-methyl-5-cholesten-3-ols in the presence of iodine with mercury(II) or silver(II) oxide has been established as 3α,5-epoxy-6β-iodo-3β-methyl-A-homo-4-oxa-5α-cholestane by means of X-ray crystal structure analysis.

Crystal and molecular structure of palythene isolated from Palythoa tuberculosa (Coelenterata) was unambiguously determined by X-ray analysis including its absolute configuration. The structure of palythene was defined as an inner salt and then features of delocalization of the positive charge were elucidated.

The crystal and the molecular structure of the titled compound was investigated by the X-ray diffraction method. The absolute configuration was determined by the Bijvoet method as 1R4S5R8S.