Small Molecule Crystallography
First and foremost, 12.2.1 specializes as a premier small-molecule single crystal X-ray facility. We are dedicated to solving the structure of crystalline materials which are too small for home laboratory diffractometers under a variety of experimental conditions. We currently posses the capability to probe a temperature range of 90 - 500 K with a helium system being installed in the near future which will allow us to reach down to 11 K. There are over 1000 papers associated with the Chemical Crystallography program at the ALS (11.3.1 [old home] and 12.2.1 [new home}) and below are some example structures which have been determined. See the publication section for a more comprehensive profile.
In addition to the above examples, Beamline 11.3.1 has had a history of collecting small molecule complexes of several Actinides in collaboration with the Seaborg Lab.
Under Development. The acquisition of a Merill-Basset Diamond Anvil Cell (DAC), which has been developed to sit on the current goniometer set-up of 11.3.1, has resulted in recent success in the probing of high-pressure ( ~10 GPa) single crystal structures. This program is currently being developed; however, pertinent samples are being accepted for use during the development period. Currently only ambient temperature data can be taken.
Bl 11.3.1 currently has two Merill-Basset type DACs fitted with Bohler-Almax diamonds with culets of 600 microns. Below are a few examples of recent systems that have been studied using the DAC on 11.3.1.
The above structure is a alkylbisphosphonate based framework material named Zinc Alkyl Gate-4 or ZAG-4. Recent publication in JACS presents the reversible nature of the compression over a range of 10 GPa applied pressure as well as the existence of changing linear compressibility from positive to negative and back to positive again.
The above structure shows a mechochromic gold complex, [(C6F5Au)2(μ-1,4-diisocyanobenzene)], which exhibits negative linear compressibility over a range up to ~3.5 GPa applied pressure. The full paper was recently published in Angewandte Chemie.
Under Development. In collaboration with Professor Paul Raithby at the University of Bath, BL 11.3.1 has developed a photodiode array which allows for in-situ irradiation of crystals at variable temperatures (90 - 500 K). The details of this can be found in the article found in J. Applied Crstallography. With the future addition of the helium system being installed on the beamline, these irradiation experiments can be further extended to be conducted at temperatures as low as 11 K.
The above examples are from Prof. Raithby's group showing the single-crystal trapping of the excited state M-ONO bonding of two metastable nitrito complexes. The left palladium complex can be found in the Chemical Sciences paper and the right nickle complex can be found in Dalton Transactions.
Environment Cell for Non-Ambient Crystallography
Under Development. Now in phase-II of development, the environment cell has been designed to allow for vacuum controlled desolvation of single crystal samples followed by exposure to a variety of reactive and non reactive gasses. The system is also capable of being subjected to varying temperature from ~90 - 500 K with error due to the thermal gradient in the sample chamber. The sample chamber is designed to be user friendly with minimal divergence from standard sample loading. This system is currently being developed; however, pertinent samples are being accepted for use during the development period. There have been a few successes so far with the system during phase-I and are highlighted below.
Coming Soon: Gas Cell Publications!