2,2′,6,6′‐Tetraisopropylbenzidine‐Based Sterically Encumbered Ditopic C 2 ‐Symmetric Ligand Systems and Supramolecular Building Blocks

Starting from 2,2′,6,6′‐tetra‐isopropylbenzidine (TBZ), a family of sterically encumbered pseudo ‐C 2 ‐symmetric based ligand systems and supramolecular building blocks have been synthesized. Schiff base scaffolds ( i Pr) 4 (C 6 H 2 ) 2 (NAr′) 2 ( 1‐9 ) (Ar′=‐CH(C 6 H 4 )(OH) ( 1 ); ‐CH(C 6 H 2 )(Me) 2 (OH) ( 2 ); ‐CH(C 6 H 2 )( t Bu) 2 (OH) ( 3 ); ‐CH(C 6 H 2 )( t Bu)(Br)(OH) ( 4 ); ‐CH(C 6 H 3 )(OMe)(OH) ( 5 ); ‐CH(C 6 H 4 )(4‐OH) ( 6 ); ‐CH(2‐Py) ( 7 ); ‐CH(3‐Py) ( 8 ); ‐CH(4‐Py) ( 9 )), ( i Pr) 4 (C 6 H 2 ) 2 (NH(C)(CH)(CO)Me 2 ) 2 ( 10 ), (NH 2 ( i Pr) 4 (C 6 H 2 ) 2 ) 2 (N(C)(CH)(C)N)Me 2 ( 11 ), (NH 2 ( i Pr) 4 (C 6 H 2 ) 2 N(CO)(C 6 H 4 )(CH 2 ) ( 12 ) and ( i Pr) 4 (C 6 H 2 ) 2 (N(CO)(C 6 H 4 )(CH 2 )) 2 ( 13 ) have been assembled through condensation of TBZ with the corresponding formyl compounds. TBZ was also further employed to synthesize two carboxylic acid derivatives, (( i Pr) 4 (C 6 H 2 ) 2 (N(CH 2 COOH) 2 ) 2 ) ( 14 ) and (( i Pr) 4 (C 6 H 2 ) 2 (COOH) 2 ) ( 16 ), both potential connector ligands for MOFs. To explore main group chemistry aspects of TBZ, bis‐ and tetra‐trimethylsilyl derivatives ( i Pr) 4 (C 6 H 2 ) 2 (R) 2 (R=(‐NH(SiMe 3 )) 2 ( 17 ) and (‐N(SiMe 3 ) 2 ) 2 ( 18 )) have been synthesized. The bis‐dichlorophosphine derivative (( i Pr) 4 (C 6 H 2 ) 2 (N(PCl 2 ) 2 ) 2 ) ( 19 ), a compound with promising chemistry for P‐based covalent organic frameworks, has been synthesized by a solvent‐free reaction of TBZ with excess PCl 3 .