Rational design and synthesis of cyano-bridged coordination polymers with precise control of particle size from 20 to 500 nm

We demonstrate that the particle sizes in cyano-bridged coordination polymers consisting of Ni^II-C≡N-Fe^II units are precisely controlled by changing the amount of chelating agent, sodium citrate. With an increase in the amount of chelating agent added, the average size of the particles gradually increases from 20 to 350 nm with retention of a well-defined cubic shape. Furthermore, the use of different Fe sources expands the possible control range up to 500 nm. The particle sizes in cyano-bridged coordination polymers consisting of Ni^II-C≡N-Fe^II units are precisely controlled from 20 to 500 nm by changing the amount of sodium citrate added as a chelating agent and/or by using a different Fe source. Our synthetic concept is widely applicable to other coordination polymers, which would be beneficial to various applications in the future.