Synthesis, Crystal Structure, Properties, and Theoretical Study of CdI₂(phen)₂ (phen = 1,10-phenanthroline)

Ligand-driven self-assembly of iodine-based Cd(ii) complexes via dissolution–recrystallization structural transformation

“…The replacement of AS ligands by iodide/polyiodide species causes the rearrangement of the framework of 1 to form various final structures in different solutions. In comparison with the solvothermal synthesis in previous studies, 30,31 it is noted that the pure crystalline phases of iodo–Cd( ii ) complexes with the phen ligand in this work can be obtained at room temperature, which is caused by the lower energy barrier required to activate the DRST process facilitated by the AS ligand as a key ancillary. 12 In the case of complex 8 , substituent coordination did not occur (Fig.…”

“…The crystal structure of 2 was revealed by single-crystal X-ray diffraction (SC-XRD), whereas both crystal structures of 3 and 4 have been reported. 30,31 However, the reported synthesis of 3 and 4 was totally different from this work in that they were formed under solvothermal conditions between CdI 2 salt and the phen ligand. The PXRD patterns of as-synthesized 2–4 are in good agreement with the simulated patterns from SC-XRD, indicating crystalline phase purity (Fig.…”

“…The crystallographic data of 3 and 4 has been reported. 30,31 Supramolecular interactions facilitated by iodide ligands are explained further. The monomeric units of 3 are linked to each other through various hydrogen bonds (I4⋯H8A = 2.93 Å, I4⋯H32A = 2.98 Å, I1⋯H15A = 3.04 Å, and I1⋯H44A = 2.95 Å), contributing to the 3D supramolecular framework as shown in Fig.…”

“…25–28 Iodo–Cd( ii ) complexes have been widely synthesized over the past two decades because of their soft acid and base nature. 7,29–33 Most of them were obtained under solvothermal conditions, which require a high temperature in order to overcome the energy barrier for crystal growth. Therefore, it is challenging to develop facile chemical processes to assemble iodine-based Cd( ii ) complexes.…”

“…Complex 1 was transformed to [Cd(I)(I 3 )(phen) 2 ] ( 2 ) in I 2 -containing MeOH or EtOH solution, whereas the THF and MeCN or acetone (AC) solution of I 2 gave rise to the construction of known Cd( ii ) complexes, namely [Cd(I) 2 (phen) 2 ] ( 3 ) and [Cd(I) 2 (phen)] n ( 4 ), respectively. 30,31 The supramolecular structures of the obtained complexes facilitated by substituted iodo ligands were identified using single-crystal X-ray diffraction analysis. Importantly, the DRST process and the driving force behind the synthesis were elucidated.…”