Apr 082016
 

group16The 2016 British Crystallographic Meeting Spring Meeting took place at the University of Nottingham from 4th – 7th April. Contributions from Chem. Cryst. staff and students were:

Jerome G. P. Wicker, Bill I. F. David & Richard I. Cooper
When will it Crystallise? (Talk in session: From Amorphous to Crystal)

Jo Baker & Richard I. Cooper
Making and Measuring Photoswitchable Materials (Talk in session: Young Crystallographers’ Satellite)

Pascal Parois, Karim J. Sutton & Richard I. Cooper
On the application of leverage analysis to parameter precision using area detector strategies (Poster)

Oliver Robshaw & Richard I. Cooper
The role of molecular similarity in crystal structure packing (Poster)

Katie McInally & Richard I. Cooper
Linking crystallization prediction, theory and experiment using solubility curve determination (Poster)

Richard I. Cooper, Pascal Parois & David J. Watkin
Non-routine single crystal structure analyses using CRYSTALS (Poster)

Alex Mercer & Richard I. Cooper
Fitting Disordered Crystal Structures by Simulated Annealing of an Ensemble Model (Poster)

 

Sep 042012
 

Presented by: Sebastian D. Pike & Dr. Amber L. Thompson
Research Leader: Prof. Andrew S. Weller
Published: Science

Transition metal σ-alkane complexes are key intermediates in catalytic C–H activation processes. We have used a direct crystal to crystal transition, by reaction with H2, to produce an alkane σ-complex directly.  This structure is of an alkane (norbornane, NBA) σ-bound to a d8–Rh(I) metal centre, in which the chelating alkane ligand is coordinated to the pseudo-square planar metal centre through two σ-C–H bonds. Although disordered (inset), the structure was refined without restraints for the coordinated NBA. The complex reacts further over time, so many attempts were required to “catch” the crystal free from both starting material and final product.

Structure of the Month – September 2012

Structure of the Month – September 2012

Mar 192012
 

Acta Cryst.  (2012), C68, o152-o155.    [ doi:10.1107/S0108270112009377 ]

Tetraisohexylammonium bromide [systematic name: tetrakis(4-methylpentyl)azanium bromide], C24H52N+·Br, is a powerful structure II clathrate hydrate crystal-growth inhibitor. The crystal structure, in the space group P3221, contains one ammonium cation and one bromide anion in the asymmetric unit, both on general positions. At 100 K, the ammonium cation exhibits one ordered isohexyl chain and three disordered isohexyl chains. At 250 K, all four isohexyl chains are disordered. In an effort to reduce the disorder in the alkyl chains, the crystal was thermally cycled, but the disorder remained, indicating that it is dynamic in nature.

Tetraisohexylammonium Bromide

Tetraisohexylammonium Bromide

Electronic reprints

  • Oxford University Research Archive [direct pdf]

Publisher’s copy