An additional objective is to provide molecular structures with high rotational flexibility between the silicon atoms and the planar configurations of {HEAD ~ the aromatic moieties} to permit {TAIL ~ tight bonding} of the molecule to the substrate 
to permit
An additional objective is to provide molecular structures with high rotational flexibility between the silicon atoms and the planar configurations of { HEAD ~ the aromatic moieties } to permit { TAIL ~ tight bonding } of the molecule to the substrate
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH