Anion-induced differential assembly and structural transformation of supramolecular coordination cages

The intimate host-anion interactions will regulate thermodynamics and kinetics in the self-assembly of cationic cages mimicking biological counterparts. Herein, we report construction and transformation of three Pd(II)-based metal-organic cages (MOCs) depending on different anions. Stoichiometric conversions of the lantern-shaped MOC-34 into either octahedral MOC-35 or tricapped trigonal prism MOC-36 are induced by BF4 - or NO3 -, respectively. MOC-36 is kinetically favored and can undergo quantitative conversion to the thermodynamically preferred MOC-35 upon heating, accelerated by excess BF4 - to motivate dissociative dynamics of Pd-vertices and lower activation barrier of cage transformation. The guest encapsulation behaviors of MOC-35 and MOC-36 have also been tested. These results manifest a significance of host-anion dynamics beyond complementary anion template, shedding light on the understanding of intricate anion recognition in nature. (c) 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.