M. M. Harding

LAUEGEN version 6.0 and INTLDM

LAUEGEN version 6.0 is a significantly developed version of the original LAUEGEN program [Campbell (1995a). J. Appl. Cryst. 28, 228–236]. It is an X-Windows-based program which now carries out the stages of processing Laue diffraction data up to and including the integration of spot intensities. The integration routines have also been incorporated in a stand-alone integration program INTLDM. The programs are distributed as part of the Daresbury Laboratory Laue Software Suite.

Piperazine Silicate (EU 19): the Structure of a Very Small Crystal Determined with Synchrotron Radiation

Single-crystal diffraction data have been recorded for a very small crystal of dimensions 8 x 18 × 175 ~rn 3. From these data the structure of piperazine silicate (EU 19) has been determined and refined to R = 0.094 for 490 observed reflections. Data collection for such a crystal has been made practicable by the high intensity of the Daresbury Synchrotron Radiation Source and the Enraf-Nonius FAST area detector diffractometer. The potential of this synchrotron radiation method for other small crystals including proteins is discussed. Crystal data: 2+ • 2

Structures of [PhCNSSN]2[Pt(mnt)2] and [(p-ClC6H4CNSSN)2Cl][Pt(mnt)2] (mnt = maleonitriledithiolato ligand)

4-Phenyl-1,2-dithia-3,5-diazolium bis(maleonitriledithiolato)platinum(II), [PhCNSSN] 2 [Pt(mnt) 2 ] (1), and bis-[4-(4-chlorophenyl)-1,2-dithia-3,5-diazolium] chloride-bis(maleonitriledithiolato)platinum(III), [p-ClC 6 H 4 CNSSN) 2 Cl][Pt(mnt) 2 ] (2), contain essentially planar [Pt(mnt) 2 ] n- anions [n=2 for complex (1), n=1 for complex (2)], with square-planar coordination of Pt. The Pt-S bonds are slightly, but significantly, shorter for the Pt III complex (2). The cations contain planar CNSSN five-membered rings with an aryl substituent Ar (Ph or p-ClC 6 H 4 ) on C

Determination of dmin and λmin from the Intensity Distributions of Laue Patterns

The parameters d min and λ min , essential for the processing of synchrotron X-ray Laue patterns, can be efficiently estimated by examination of the distribution of measured intensities as a function of d spacing and wavelength, respectively. A procedure that can be carried out automatically as one step in the data processing has been tested with Laue data sets from an organometallic compound and two proteins.

The Laue Data Module (LDM) – a software development for Laue X-ray diffraction data processing

The Laue Data Module (LDM) has been defined and implemented in Fortran as the basis for new developments in the processing of Laue X-ray diffraction data. It provides a program-independent way of handling, storing and accessing the parameters required in the initial stages of Laue data processing. The program-independent Laue Reflection List (LRL) and associated functions have also been developed. The way in which these two developments may be used in application programs and as the basis for developing further program-independent Laue-data processing functions is described.

Structure determination of a complex pentamolybdodisulfate from synchrotron radiation Laue diffraction photographs: derivation and application of a wavelength-dependent absorption correction

Laue diffraction photographs were recorded with the SRS wiggler beam at the SERC Daresbury Laboratory for small electrochemically grown crystals of uncertain composition. Diffraction intensities were obtained from these photographs and the structure successfully solved using direct methods, the cell dimensions and space group having been previously determined from weak diffractometer measurements and Weissenberg photography. The formula of the compound was found to be [Mo 5 S 2 O 23 3]- [N(C 2 H 5 ) 4 ] 4 .C 6 H 5 CN, containing a sulfate analogue of a previously determined pentamolybdodiphosphate ion

Asymmetric induction in the 1,7 ring closure of diene-conjugated diazo-compounds: a route to chiral 1h-2,3-benzodiazepines

Abstract In the cyclisation of the diazo-compound (7) to give the diastereomeric pair of 1H-2,3-benzodiazepines (8) and (9), alkoxy groups, when present as the medium sized group M, show the opposite effect in promoting face selectivity to that of alkyl groups and the alkoxide ion. Thus when MOMe the (8): (9) ratio is 92:8 while in contrast when MO− the ratio is 15:85.

4-Substituted 1-Methyl-1H-2,3-benzodiazepine Compounds

The structures of a series of six 1-methyl-1H-2,3-benzodiazepine compounds, 1(R)-methyl-4-[1(R)-phenylethyl]-1H-2,3-benzodiazepine (C 18 H 18 N 2 ), (1), 1(R)-methyl-4-[1(R),2,2-trimethylpropyl]-1H-2,3-benzodiazepine (C 16 H 22 N 2 ), (2), 1(S)-methyl-4-[1(S)-ethyl-2,2-dimethylpropyl]-1H-2,3-benzodiazepine (C 17 H 24 N 2 ), (3), 1(R)-methyl-4-[1(R)-methoxybenzyl]-1H-2,3-benzodiazepine (C 18 H 18 N 2 O), (4), 1(S)-methyl-4-[1(R)-methoxy-2,2-dimethylpropyl]-1H-2,3-benzodiazepine (C 16 H 22 N 2 O), (5), and 1(R)-methyl-4-[1(R)-benzoyloxy-2,2-dimethylpropyl]-1H-2,3-benzodiazepine (C 22 H 24 N 2 O 2 ), (6), with differing substituents on the 4-position of the seven-membered diazepine ring, have been determined. [The IUPAC name for the ester (6) is 2,2-dimethyl-1-(1-methyl-1H-2,3-benzodiazepin-4-yl)propyl benzoate.]

Rh2I6Cl(CO)2(CH3OH)−.Ph3PNPPh3+. Structure determination of a very small crystal with synchrotron radiation

The crystal and molecular structure of the title compound has been established from synchrotron radiation diffraction data recorded with an area detector for a crystal of dimensions 100 × 50 × 15 lxm. Bis(triphenylphosphoranediyl)ammonium 1,2-dicarbonyl- 1 -chloro-di-/.t-iodo- 1,1,2,2-tetraiodo-2-(methanol)dirhodate(1 -), [N(C 18H ! 5P)2][Rh2CII6(CH40)(CO)2], Mr = 1629-3, monoclinic, P2/a, = 17.528 (10), b = 13.337 (6), c = 21-410 (5) A, /3 = 100.23 (3) °, V = 4925.5 A 3, Z = 4, Dx = 2.197gcm -3, A =0.915(5),~, /z =88.9cm -t, F(000) = 3016, T = 295 K, final R = 0.104 for 1700 reflections. In the anion two square-planar RhI4 groups share two I atoms and are tilted at 23 ° to each other; octahedral coordination around one Rh atom is completed by a C1 atom and a CO group, and about the other by a CH3OH molecule and a CO group (cis to the first).

Asymmetric induction in the electrocyclisations of 1,3 dipolar intermediates: the 1.7 cyclisation of diene-conjugated diazo-compounds to give 1H-2,3-benzodiazepines

In the cyclisation of the diene-conjugated diazo compounds 4 to give the diastereoisomeric pair of 1H-2,3-benzodiazepines 7 and 8, alkyl and silyl ethers when present as the ‘medium’ sized group R3, showed the opposite effect in controlling face selectivity to that of alkyl groups and the alkoxide anion. Thus, for example, when R3= OMe the diastereoisomer ratio (7:8) was 8:92 while in contrast when R3= O– Li+ the ratio was 85:15. The relative configurations of the chiral centres in the products 7 and 8 were determined by X-ray crystallography and their ratio in the cyclisations was measured by 1H NMR spectroscopy and by HPLC. The results are rationalised in terms of a helical transition state for the cyclisation and the steric and polar effects of the substituents.