Calcium L-Lactate Frameworks as Naturally Degradable Carriers for Pesticides

Two porous, chiral metal-organic frameworks (MOFs), Ca-14(L-lactate)(20)(acetate)(8)(C2H5OH)-(H2O) (MOP-1201) and Ca-6(L-lactate)(3)(acetate)(9)(H2O) (MOF-1203), are constructed from Ca2+ ions and L-lactate [CH3CH(OH)COO-], where Ca2+ ions are bridged by the carboxylate and hydroxyl groups of lactate and the carboxylate group of acetate to give a three-dimensional arrangement of Ca(-COO,-OH) polyhedra supporting one-dimensional pores with apertures and internal diameters of 7.8 and 9.6 angstrom (MOF-1201) and 4.6 and 5.6 angstrom (MOF-1203), respectively. These MOFs represent the first examples of extended porous structures based on Ca2+ and lactate. They show permanent porosity of 430 and 160 m(2) g(-1), respectively, and can encapsulate an agriculturally important fumigant, cis-1,3-dichloropropene. MOF-1201 shows a 100 times lower release rate compared with liquid cis-1,3-dichloropropene under the same test conditions (25 degrees C, air flow rate of 1 cm(3) min(-1)). The hydrolysis of MOF-1201 in water makes it the first example of,a degradable porous solid carrier for such fumigants.