Anion‐ and Solvent‐Induced Assembly and Reversible Structural Transformation of d 10 ‐Metal Coordination Architectures Containing N ‐(4‐(4‐Aminophenyloxy)phenyl)isonicotinamide

We set out studies on anion‐ and solvent‐induced assembly based on the ligand N ‐(4‐(4‐aminophenyloxy)phenyl)isonicotinamide (papoa), which is synthesized to show a bent and flexible backbone. Reactions of papoa with ZnX 2 (X=Cl, Br, and I) gave the dinuclear macrocycles ([ZnX 2 (papoa)] 2 ; X=Cl ( 1 a ), Br ( 2 a ), I ( 3 )), the structure of which was determined by X‐ray diffraction. Notably, the less bulky Cl and Br compounds afforded the coordinated imine in acetone (i.e., [ZnX 2 (papoi)] 2 , papoi= N ‐(4‐(4‐(propan‐2‐ylideneamino)phenoxy)phenyl)isonicotinamide; X=Cl ( 1 b ), Br ( 2 b )), whereas the iodine one only gave the coordinated amine compound 3 under the same reaction condition. In fact, the coordinated imine can return to the amine analogue upon exposure to air or in DMSO, which has been monitored by 1 H NMR spectroscopy and powder X‐ray diffraction. Both the dinuclear [Zn(papoa)(NO 3 ) 2 ] 2 ( 4 a ) and the 1D [Zn(papoa) 2 (NO 3 ) 2 ] n ( 4 b ) were formed from the reaction of Zn(NO 3 ) 2 and papoa in mixed solvents with acetone and acetonitrile, respectively. In addition, Cd(ClO 4 ) 2 can react with papoa to give the 1D framework {[Cd(papoa) 2 (CH 3 CN) 2 ](ClO 4 ) 2 } n ( 5 a ) and the 2D framework [Cd(papoa) 2 (ClO 4 ) 2 ] n ( 5 b ), depending on the solvent used, that is, MeOH and CH 3 CN, respectively. Importantly, the 1D framework with axially coordinated CH 3 CN molecules and the 2D framework with axially coordinated ClO 4 − ions can be interconverted by heating and grinding in the presence of CH 3 CN, respectively. Such a reversible structural transformation process was proven by PXRD studies.