Temperature Induced Interpenetration Suppression of a Couple of Azo‐based Isomers with a Flexible Second Ligand

Two new azo‐based coordination compounds with a flexible second ligand, crystal 1 (composed with Zn(adc)(eda)]_n‐1) and crystal 2 (composed with {Zn(adc)]_0.9568(eda)}_n‐1′ and {Zn(adc)]_0.0414}_n) have been synthesized as a couple of isomers with different reaction temperature. Adc^2? and eda represent azobenzene‐4,4′‐dicarboxylic ion and 1,2‐ethanediamine, respectively. Single crystal X‐ray diffraction measurement indicates the interpenetration of the above crystals could be suppressed by simply tuning the reaction temperature, that is, the 5‐fold interpenetration which leads to no free volume left in lower temperature synthesized compound Zn(adc)(eda)]_n‐1 could be reduced to a 4‐fold interpenetration in higher temperature synthesized {Zn(adc)]_0.9568(eda)}_n‐1′ which results in free volume accounting for 3.6% (31.6 ų per unit cell volume) in crystal 2 . The synthesis, crystal structure and fluorescence spectra of crystals 1 and 2 have been discussed, together with the data of elemental analysis and X‐ray powder diffraction.