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