Variable Water Adsorption in Amino Acid Derivative Based Homochiral Metal Organic Frameworks

Six new Cd-containing homochiral metal organic framework materials [{Cd(L1)(C1)}(H2O)](infinity), (1a), [Cd(L1)(Br)](infinity) (1b), [Cd(L2)(Cl)](H2O)](infinity), (2a), [{Cd-2(L2)(2)(Br)(2)}(H2O)(3)](infinity), (2b) [{Cd(L3)(Cl)}(H2O)(2)](infinity) (3a), and [(Cd(L3)(Br)}(H2O)(2)](infinity) (3b) [L1 = 24(PYridin-4-yl)methylamino)-4-methylpentanoic acid], [L2 = 2-(pyridin-4-yl)methylamino)-3-hydroxypropanoic acid], and [L3 = 2((pyridin-4-yl)methylamino)-3-hydroxybutanoic acid] have been synthesized using pyridine functionalized amino acid (L-leucine, L-serine, and L-threonine) homochiral links and Cd(CH3COO)(2)center dot 2H(2)O and characterized via single crystal Xray diffraction (XRD), powder X-ray diffraction (PXRD), variable temperature powder X-ray diffraction (VTPXRD), thermogravimetric analysis and water adsorption experiments. Side chains in different amino acid derivatives and anions (Cl-, Br-) have been identified to play an important role in structural diversity (from porous to nonporous) as well as physical properties. These metal organic frameworks (MOFs) exhibit a distinct water adsorption nature and capacity, e.g., high adsorption at low partial pressure based on architectural diversities.