A new two-dimensional homochiral cadmium(II) coordination polymer: synthesis, structure determination, optical properties, and fluorescent sensing

Homochiral Metallohelicates Based on Zinc(II) and Cadmium(II) Clusters with Excellent Thermostability and Remarkable Second-Harmonic Generation

“…A mixture of Zn(OH) 2 (0.05 mmol, 4.9 mg), H 3 L (0.025 mmol, 7.7 mg), and H 2 O (2 mL) was stirred continuously under ambient temperature for 30 min, then was placed in a 25 mL airproof Teflon-lined stainless autoclave, and heated at 110 °C for 96 h. After cooling to ambient temperature at 5 °C h −1 , colorless block crystals were filtrated, washed with distilled water, and dried naturally to obtain 56% yield (based on Zn). Elemental analysis calcd (%) for C 28 and H 2 O (1 mL) was stirred continuously under ambient temperature for 30 min, then was placed in a 25 mL airproof Teflon-lined stainless autoclave, and heated at 120 °C for 72 h. After cooling to ambient temperature gradually, colorless needle crystals were filtrated, washed with distilled water, and dried naturally to obtain 49% yield (based on Cd). Elemental analysis calcd (%) for C 28 H 36 Cd 3 N 2 O 22 (1089.79): C, 30.86; H, 3.33; N, 2.57; found, C, 30.57; H, 3.37; N, 2.59 IR (KBr, cm −1 ): 3408 (s), 1666 (s), 1656 (s), 1609 (s), 1557 (s), 1457 (s), 1380 (s), 1301 (m), 1081 (m), 779 (m), 737 (m), 657 (m).…”

“…Especially, the different side groups of amino acids embedding in those ligands could delicately adjust the structure and performance of the resulting HMOFs. More importantly and intriguingly, the in situ formation of metal cluster subunits with different structural types was found during the assembly of Zn-, Cd-, or Eu-HMOF. − In contrast, metal clusters with specific geometry and more ligation sites may provide more opportunities for the construction of HMOFs with a novel structure and unique properties. − Continuing our work in exploring optical materials of HMOFs, ( S )-5-((2-carboxy-5-oxopyrrolidin-1-yl)­methyl)­isophthalic acid (H 3 L), which had been used by us to construct novel 3D porous helical Ln-HMOFs (Ln = Eu 3+ or Tb 3+ ) with interesting optical properties and excellent thermotolerance, was chosen and synthesized as the enantiopure chiral bridge. In this work, d 10 metal ions Zn 2+ and Cd 2+ were used as metal centers to construct H 3 L-based HMOFs because these metal ions are ideal candidates for fabricating HMOFs due to their flexible coordination number and configuration as well as their complexes’ appealing photoelectric properties. − Additionally, the crystalline samples of Zn 2+ and Cd 2+ metal–organic frameworks usually display high optical transparency and excellent physicochemical stability, which are conducive to greatly improving NLO performance .…”

“…Recently, we deliberately modified the 5-methyl of 5-methylisophthalic acid with various chiral amide acids and synthesized enantiopure chiral aromatic tricarboxylic acid ligands to explore the construction of HMOFs. ,− Our results showed that those enantiopure chiral aromatic tricarboxylic acid ligands could not only adopt flexible bridging modes from μ 3 to μ 7 to connect metal ions (such as Pb 2+ , Zn 2+ , Cd 2+ , Eu 3+ , or Tb 3+ ) to form interesting 2D–3D HMOFs with various structural types and properties but also act as excellent chromophores to improve the optical properties of the materials. Especially, the different side groups of amino acids embedding in those ligands could delicately adjust the structure and performance of the resulting HMOFs.…”