A Host–Guest Electron Transfer Mechanism for Magnetic and Electronic Modifications in a Redox‐Active Metal–Organic Framework
Jun Zhang, Wataru Kosaka, Yasutaka Kitagawa, Hitoshi Miyasaka
Abstract
Abstract Host–guest electron transfer (HGET) in molecular framework systems is a critical trigger for drastic functional changes in both host framework and guest. A reversible magnetic phase transition was achieved via HGET in a layered framework, [{Ru 2 (2,6‐F 2 PhCO 2 ) 4 } 2 (BTDA‐TCNQ)] ( 1 ), where 2,6‐F 2 PhCO 2 − and BTDA‐TCNQ represent 2,6‐difluorobenzoate and bis[1,2,5]dithiazolotetracyanoquinodimethane, respectively. The guest‐free 1 with an antiferromagnetic ground state transformed into a paramagnet, [{Ru 2 (2,6‐F 2 PhCO 2 ) 4 } 2 (BTDA‐TCNQ)]I 3 ( 1‐I 3 ), by adsorbing iodine (I 2 ). The local charge distribution of [{Ru 2 II,III } + ‐(BTDA‐TCNQ) .− ‐{Ru 2 II,II }] in 1 was reversibly modified to [{Ru 2 II,III } + ‐(BTDA‐TCNQ) 0 ‐{Ru 2 II,II }](I 3 − ) in 1‐I 3 through HGET. Theoretical calculations of 1‐I 3 indicated a partial charge delocalization as [{Ru 2 } (1− δ )+ ‐(BTDA‐TCNQ) 0 ‐{Ru 2 } δ + ](I 3 − ) with δ ≈0.2, aided by weak ferromagnetic coupling. 1‐I 3 exhibited a hundred‐fold enhancement in electrical conductivity compared to that of 1 .