Molecule of the year 2008
Dichlorobis(η5-tert-butylcyclopentadienyl)titanium(IV)
The title compound (1) exists in three polymorphs and undergoes two enantiomorphic phase transitions between them. The low-temperature, non-merohedrally twinned monoclinic phase III (space group P21) undergoes a first order phase transition into an orthorhombic phase II (space group P212121) at 147(1) K. Subsequent heating of the crystal results in a gradual second-order k2 transformation of this phase into the high-temperature orthorhombic phase I (P21212). This phase transition is completed at ~330 K. The phase transitions were monitored by single-crystal X-ray diffraction, differential scanning calorimetry, and powder diffraction; however, the II->I transition did not register on the DSC curve or powder patterns. The molecular conformations and mutual arrangement of molecules in the crystal in the three phases are very similar. The location of the ancillary ligands relative to the Cl—Ti—Cl wedge in the solid state structures of 1 and 32 related Ti(C5H4R)2Cl2 complexes seems to be principally determined by weak C—H…Cl intramolecular interactions between the R substituents and Cl ligands rather than by steric factors. Reference: Ilia A. Guzei, Amitabha Mitra, Håkon Hope (UC-Davis), Lara C. Spencer. Crystal Growth and Design, 2009, accepted.
Molecular Structure Laboratory
University of Wisconsin-Madison
The Crystallography Laboratory provides single crystal X-ray crystallographic facilites and services to members of the Chemistry Department and to other collaborators. The laboratory is a part of the Paul Bender Chemical Instrumentation Laboratories that provide access to major shared resources in NMR, MS, ESR, IR, and X-ray diffraction facilities.
News and Info
The Larry Dahl Symposium, Madison, Wisconsin, May 29-30, 2009.
The 17th Bruker Area Detector Users Group Meeting, Madison, Wisconsin, May 31 - June 2, 2009
Presentations from the 16th Bruker Area Detector Users Group Meeting, Delft, the Netherlands