The dendritic macrocyclic polyarylmethyl polyradical with S = 10 was designed as an organic spin cluster. The precursor to the polyradical (24-polyether) was prepared by an efficient modular synthesis.

According to Monte Carlo conformation search (MM2^*, MacroModel), the 24-radical had elongated shapes, with overall dimensions of 4x3x2 nm.

With this result, we set out to do more to determine the shape of the the dendritic-macrocyclic polyradical.

Small Angle Neutron Scattering (SANS) experiment, a powerful method for determination of size and shape of macromolecules, was the method we considered. With initial consultation with Dr. Paul Butler of the NIST Center for Neutron Research (Gaithersburg, Maryland), we planed for the experiment and requesting the beam time. This experiment involved a complex setup for handling samples that had to be kept at low temperature and under inert atmosphere at all time, requiring special sample preparation and experimental design. With the help from staff at the NIST Center for Neutron Research, we drew up the plan and a platform for insertion of the frozen sample into the SANS cryostat. (The platform, which would be assembled around the cryostat, was constructed at the UNL Physics/chemistry Instrument Shop).

In our lab, the polyradical samples were prepared in a glass reaction vessel, equipped with a quartz cylindrical cell. The quartz cell containing the polyradical sample was flame sealed and stored in liquid nitrogen at all time. The samples were transported to the NIST by car, which took about 18 hrs [road trip map].

Before the neutron time, a cryostat was setup and ready to be installed at the NG3 instrument. The platform was assembled around the cryostat, to accommodate the glove bag and the sample handling [some pictures].