A first anhydrous praseodymium benzoate-benzoic acid adduct, Pr(OBz)3(HOBz)2

Solvent-free rare-earth benzoates appear not to be known. As benzoic acid (HOBz) is thermally sufficiently stable (dec 370 degrees C), the direct oxidation of praseodymium. metal with benzoic acid is an excellent route to secure the solvent-freebenzoate-benzoic acid adduct Pr(OBz)(3)(HOBz)(2).Light green crystals were obtained from praseodymium metal and benzoic acid in a 1:3 molar ratio in a sealed glass ampoule (200 degrees C, 8 days, 100 degrees C, 2.5 days). The coordination polymer Pr(OBz)(3)(HOBz)(2) crystallizes in the orthorhombic space group Pcnn with a=9.755(1), b=24.859(1), c=26.531(1)angstrom,Z=8,R-1 = 0.0588 for I-0 > 2 sigma(I-0). In the crystal structure there are six bidentate-bridging benzoate anions and two unidentate benzoic acid molecules coordinating to Pr3+. The linear chains exhibit a paddle-wheel like structure when viewed down the chain. These are packed in the fashion of a hexagonal densest packing of rods. Pr-O distances range from 2.347(3) to 2.568(3) angstrom with an average of 2.464 angstrom. (C) 2007 Elsevier B.V. All rights reserved.