Amber L. Thompson

Feb 192012
 

Dalton Trans. (2012), 41, 1951-1960.    [ doi:10.1039/C1DT11758K ]

Uranium complexes of bis(p-tert-butyl-salicylidene)-1,2-diphenylethylenediamine (1) and bis(salicylidene)-1,2-diphenylethylenediamine (2) have been synthesized and investigated by X-ray single crystal diffraction and MD calculations in Periodic Boundary Conditions. Both compounds form crystals which are densely packed and do not provide voids accessible to solvent molecules. The configurations adopted by 1 and 2 are determined by well defined T-shaped and π-stacking non covalent interactions between phenyl groups of adjacent molecules as well as by a network of hydrogen bonds. These interactions and the relative arrangements of the molecules, explain the packing in the crystal structures. Each uranyl moiety shows a penta-coordination in the equatorial plane perpendicular to the trans oxygens giving rise, in both compounds, to a bypiramidal geometry. As usual for this class of compounds, the 5th position is characterized by the presence of the coordinated solvent. The in silico simulations confirm this hypothesis in very fine details. Moreover, in 1, even the partial occupancy of the solvent molecule determined from the crystal structure refinement, was shown to be due to a constrained freedom of motion of the solvent molecule that can be reproduced by molecular dynamics. This suggests that the reported disorder is not due to a poor quality of the harvested crystals but to a structural feature. In further agreement with the above mentioned results, DFT calculations demonstrated that the molecular orbital configuration and energies suit the described properties of complexes 1 and 2 suggesting a potential enantioselective activity as already shown by molecules belonging to this class of compounds.

Electronic reprints

  • Oxford University Research Archive [direct pdf]

Publisher’s copy

Feb 082012
 

Emma McKinleyEmma completed her Part II in 2011 in Chem. Cryst., but it seems we can’t get rid of her!  Ever cheerful, she brings a spark of life to the lab and has come back for a bit to encourage us to write up the outstanding papers from her thesis, in particular her work chalcones and on the modulated phase of Barluenga’s reagent.  Since her prize winning poetry performance at the BCA, we keep expecting her to start rapping…

Feb 032012
 

Acta Cryst. (2012), E68, o593-o594.    [ doi:10.1107/S1600536812003303 ]

The title compound, C7H13NO3, adopts an approximately planar conformation. The torsion angles in the aliphatic chain between the carbonyl group C atoms range from 172.97 (14) to 179.38 (14)° and the r.m.s. deviation of all non-H atoms is 0.059 Å. The crystal packing is dominated by two strong N-H···O hydrogen bonds involving the amide groups and forming R22(8) rings and C(4) chains. Overall, a two-dimensional network parallel to (100) is formed. A weak intermolecular C-H···O interaction is also present.

Hydrogen bonding in methyl 6-amino-6-oxohexanoate

Hydrogen bonding in methyl 6-amino-6-oxohexanoate

Electronic reprints

  • Oxford University Research Archive [direct pdf]

Publisher’s copy


Acta Cryst. (2012), E68, o595.    [ doi:10.1107/S1600536812003297 ]

In the title compound, C4H10NO2+·Cl, the central ethylene bond of the cation adopts a gauche conformation. The three H atoms of the -NH3+ group are engaged in strong and highly directional intermolecular N-H···Cl hydrogen bonds, which result in a tape-like arrangement along [010] of the respective ion pairs. In addition, weak intermolecular C-H···Cl and C-H···O interactions are present.

Hydrogen bonding in 3-methoxy-3-oxopropanaminium chloride

Hydrogen bonding in 3-methoxy-3-oxopropanaminium chloride

Electronic reprints

  • Oxford University Research Archive [direct pdf]

Publisher’s copy

Jan 012012
 

Presented by: Dr. Andrew D. Schwarz
Research Leader: Prof. Philip Mountford
Published: Chemical Science

Inspired by the development of high-energy, early transition metal-ligand multiply-bonded systems, we targeted the unprecedented classes of bis(imido) and tris(imido) compounds of the group 4 metals (to give the first example of a group 4 metal simultaneously containing two or three multiply-bonded ligands). The product above was prepared by deprotonation with methyl lithium of a mono(imido) bis(amido) sython [Ti(NAr)(NHAr)2(py)2] to form the supposed intermediate “Li2[Ti(NAr)3(py)x]” which undergoes 1,2-N–H addition of ArNH2 across one of the Ti‑NAr linkages. This represents the first bis(imido) complex of a group 4 metal, and indeed the first example of any compound of these metals simultaneously containing two or more metal-ligand multiple bonds to dianionic ligands.

Structure of the Month - January 2012

Structure of the Month - January 2012

Dec 012011
 

Red Kite Crystallographers logo[Update:  Thank-you to all the speakers and attendees who made this a great event; details are available on the main Red Kite web page.  See you all again next year!]

The inaugural meeting of the Red Kite Crystallographers will be held on Thursday 12th January, 2012 in the Inorganic Chemistry Laboratory, Oxford.

Attendance will be free of charge.  The meeting will consist of three sessions, each commencing with a half hour Plenary delivered by a leading academic, followed by a three shorter talks by younger researchers.

 

Programme

9:00 Set up Posters etc.
9:50 Introduction
10:00 Prof. Harry L. Anderson (Oxford) “Porphyrin Nanorings”
10:30 Claire Murray (Reading/Diamond) “Pairwise Assembly of Organopalladium(II) Centres with the Cyanurato(3-) Ligand”
10:45 Nick White (Oxford) “Towards Selective Anion Binding inside Interlocked Molecules”
11:00 Dr. Fraser White (Oxford Diffraction/Agilent) “Copper or Molybdenum? A Comparative Study”
11:15 Tea Break
11:45 Prof. Bill I. F. David (ISIS) “Structure-property Relationships in Lightweight Hydrides – Playing the Odds”
12:15 Stefan Sedlmaier (Oxford) “Synthesis, Identification and Characterisation of novel, condensed Oxonitridophosphates and Phosphorus Oxonitrides”
12:30 Karim Sutton (Oxford/Diamond) “Exploiting the Tunable Wavelength Capabilities of Beamline I19”
12:45 Michael Kelly (Oxford) “Exploring Catalysts for Novel Hydrogen Storage Materials”
1:00 Lunch (Not included)
2:00 Posters
2:30 Dr. Andrew L. Goodwin (Oxford) “Size Matters: The Anomalous Mechanics of Frameworks”
3:00 Dr. Jeppe Christensen (RCaH) “Dynamical Structural Science at RCaH”
3:20 Dr. Matthias Gutmann (ISIS) “A combined neutron, X-ray and Computational Study of Croconic Acid”
3:40 Dr. Robin Owen (Diamond) “Exploiting Fast Detectors and Bright Beamlines for Room Temperature MX at the Synchrotron”
4:00 Close

 

 

 

Those not speaking are encouraged to bring posters and the best will be rewarded.

Lunch is not included, but will be available from either the Chemistry Canteen, the Biochemistry Café or the University Staff Club on the day.  Alternatively you can bring a packed lunch.  Parking is notoriously difficult in Oxford, so please keep that in mind if travelling and we would recommend the train or Park & Ride.

In order to ensure there is enough tea/coffee/cake/poster boards, please let Amber L. Thompson (amber.thompson @ chem.ox.ac.uk) or Richard I. Cooper (richard.cooper @ chem.ox.ac.uk) know BY MONDAY if you are coming and whether you are going to bring a poster.

Nov 052011
 

Our application to secure funds to refurbish our existing DSC and TGA analysis equipment has been successful.  Sample analysis by TGA/DSC allow detection and characterisation of solvent-loss and phase changes and, as such are complementary to solid-state X-ray crystallography.  The equipment was abandoned by a researcher leaving in 2007 and has not been operational since. Reinstallation and refurbishment of the equipment within an existing departmental research facility will make it accessible to all research groups within Chemistry and the Science Area.

DSC and TGA

DSC and TGA

Nov 012011
 

Presented by: Matthew P.Blake
Research Leader: Prof. Philip Mountford
Published: Journal of the American Chemical Society

Metal-metal bonded molecular compounds have been an essential part of development in inorganic chemistry for decades; research has been reenergized by the discovery of the first Cr-Cr quintuple-, Zn-Zn single- and Mg-Mg single bonds. However, within this rich and topical area, there remains very little experimental or theoretical information regarding bonds between alkaline earth elements and transition metals. While bonds between calcium and main group metals (Ga, Sn) have been reported, the bonding of calcium with a transition metal had not been studied. Reaction of calcium amalgam with [CpFe(CO)2]2 (Fp2) gave the alkaline earth compound [CaFp2(THF)3]2containing two direct Ca–Fe (3.0185(6) Å) bonds.

Structure of the Month - November 2011

Structure of the Month - November 2011

Oct 072011
 

Photo of Kirsten ChristensenKirsten’s research is focused on several areas that will establish a fundamental understanding of modulation in molecular materials e.g. their formation and properties. This knowledge can be put to immediate use in Crystal Engineering, and will also affect research in pharmaceuticals, developments in molecular modelling and crystal packing predictions.

See Kirsten’s Departmental web-page for further information.

Sep 282011
 

Mr. Karim J. SuttonFor his Part II year, Karim worked in Chem. Cryst. studying ion binding in rotaxanes (in collaboration with Paul Beer’s research group).  He has now returned to do a D. Phil. spending part of his time at Diamond Light Source.  When he’s not at Diamond he can be found playing darts or cricket for Worcester College.

Karim is a founder member of the Quiztallographers.