Inclusion compound based approach to arrays of artificial dipolar molecular rotors. A surface inclusion.
We describe an approach to regular triangular arrays of dipolar molecular rotors based on insertion of dipolar rotator carrying shafts as guests into channels of a host, tris(o-phenylenedioxy)cyclotriphosphazene (TPP). The rotor guests can either enter the bulk of the host or stay at or near the surface, if a suitable stopper is installed at the end of the shaft. Differential scanning calorimetry, solid-state NMR, and powder X-ray diffraction were used to examine the insertion of a dipolar rotor synthesized for the purpose, 1-n-hexadecyl-12-(2,3-dichlorophenyl)-p-dicarba-closo-dodecaborane, and it was found that it forms a surface inclusion compound. Rotational barriers from 1.2 to 9 kcal/mol were found by dielectric spectroscopy and were attributed to rotors inserted into the surface to different degrees, some rubbing the surface as they turn.
Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA.
Lukáš
L
Kobr
Ke
K
Zhao
Yongqiang
Y
Shen
Angiolina
A
Comotti
Silvia
S
Bracco
Richard K
RK
Shoemaker
Piero
P
Sozzani
Noel A
NA
Clark
John C
JC
Price
Charles T
CT
Rogers
Josef
J
Michl