Cinnamal Sensing and Luminescence Color Tuning in a Series of Rare-Earth Metal−Organic Frameworks with Trans-1,4-cyclohexanedicarboxylate

Three isostructural metal–organic frameworks ([Ln2(phen)2(NO3)2(chdc)2]·2DMF (Ln3+ = Y3+ for 1, Eu3+ for 2 or Tb3+ for 3; phen = 1,10-phenanthroline; H2chdc = trans-1,4-cyclohexanedicarboxylic acid) were synthesized and characterized. The compounds are based on a binuclear block {M2(phen)2(NO3)2(OOCR)4} assembled into a two-dime nsional square-grid network containing tetragonal channels with 26% total solvent-accessible volume. Yttrium (1)-, europium (2)- and terbium (3)-based structures emit in the blue, red and green regions, respectively, representing the basic colors of the standard RGB matrix. A doping of Eu3+ and/or Tb3+ centers into the Y3+-based phase led to mixed-metal compositions with tunable emission color and high quantum yields (QY) up to 84%. The bright luminescence of a suspension of microcrystalline 3 in DMF (QY = 78%) is effectively quenched by diluted cinnamaldehyde (cinnamal) solutions at millimolar concentrations, suggesting a convenient and analytically viable sensing method for this important chemical.

Homochiral Metal–Organic Framework [Co(L)(bpe)2(H2O)2]·H2O Used for Separation of Racemates in High-Performance Liquid Chromatography

A homochiral metal–organic framework (MOF) comprising [Co(L)(bpe)2(H2O)2]·H2O was prepared using (1R,2R)-(−)-1,2-cyclohexanedicarboxylic acid (H2L) and 1,2-bis(4-pyridyl)-ethylene as organic ligands. The homochiral MOF [Co(L)(bpe)2(H2O)2]·H2O was explored as chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC) separation of racemates. Nine racemates including naphthol, alcohol, diol, amine, ketone, ether and organic acid were well separated on the homochiral MOF [Co(L)(bpe)2(H2O)2]·H2O column (250 mm long × 4.6 mm i.d.). The relative standard deviation for five replicate separations of 1,1′-bi-2-naphthol is 0.69% for the retention time, indicating that the good reproducibility and stability of the homochiral MOF column for HPLC enantioseparation. The results indicated that the homochiral MOF as CSP is practical, which promotes the application of homochiral MOFs in HPLC.

One-pot crystallization of two 1,4-cyclohexanedicarboxylate-based tetranuclear Cu(ii) compounds and their DNA binding affinities

Two new tetranuclear Cu(ii) compounds have been synthesized using flexible linker 1,4-cyclohexanedicarboxylic acid in an one-pot crystallization which exhibit dissimilar affinities to DNA binding.

Exploration of semiconducting properties of Zn(II) and Cd(II) based coordination polymers with dicarboxylate of chair-type backbone

A new Cd(II)-based two-dimensional coordination polymer (2D CP) [{Cd2(cis-1,4-chdc)2(1,10-phen)2}۰5H2O]n (1) has been synthesized at room temperature by slow diffusion technique using 1,4-cyclohexanedicarboxylic acid (1,4-H2chdc) and 1,10-phenanthroline (1,10-phen) mixed-ligand system. The...

Fluorescent Recognition of Adenosine Triphosphate and Uric Acid by two Eu-Based Metal-Organic Frameworks

Two Eu-based MOF fluorescent sensors, Eu2(CHDA)2(C2O4)(H2O)4 (1) (CHDA = 1,4-cyclohexanedicarboxylic acid, C2O4 = oxalate group) and Eu2(PDA)3(H2O)3 (2) (p-Phenylenediacetic acid = PDA), were prepared for the rapid detection of uric...