Calcium L-Lactate Frameworks as Naturally Degradable Carriers for Pesticides.

Two porous, chiral metal-organic frameworks: Ca14(L-lactate)20(Acetate)8(C2H5OH)(H2O), MOF-1201, and Ca6(L-lactate)3(Acetate)9(H2O), MOF-1203, are constructed from Ca(2+) ions and L-lactate [CH3CH(OH)COO-] where Ca(2+) is bridged by carboxylate and hydroxyl groups of lactate, and carboxylate of acetate to give a three-dimensional arrangement of Ca(-COO, -OH) polyhedra supporting one-dimensional pores of apertures and internal diameters of 7.8 and 9.6 Å (MOF-1201), and 4.6 and 5.6 Å (MOF-1203), respectively. These MOFs represent the first examples of extended porous structures based on Ca(2+) and lactate. They show permanent porosity of 430 (MOF-1201) and 160 m(2) g(-1) (MOF-1203), and can encapsulate an agriculturally important fumigant, cis-1,3-dichloropropene. MOF-1201 shows a 100 times slower release rate compared with liquid cis-1,3-dichloropropene under the same test conditions (25 °C, air flow rate of 1 cm(3) min(-1)). The hydrolysis of MOF-1201 in water allows it to be the first example of degradable porous solid carrier for such fumigants.