abstract
New lamellar materials intercalated with molybdenum(II) complexes with potential catalytic properties were prepared by a stepwise procedure. The lamellar material was first calcined at 823 K for four hours to eliminate all the carbonate ions; the layered structure was reconstructed after treatment with a solution of either pycH (pyridine-2-carboxylic acid) or pydcH(2) (pyridine-2,6-dicarboxylic acid) in a KOH solution of dint at 343 K. Impregnation with a solution of the organometallic precursor [Mo(CO)(3)I-2(NCCH3)(2)] led to substitution of the nitrile groups by two pyridine ligands. All the materials were characterized by powder X-ray diffraction, FTIR, and C-13 CP MAS and Al-27 MAS solid-state NMR spectroscopy. Similar Mo-II complexes were also prepared by using pycH or pydcH(2) and characterized by elemental analysis as well as FTIR and H-1 and C-13 solution NMR spectroscopy. These new materials and the complexes of pyc or pydc ligands containing 4.54 wt.-% and 6.33 wt.-% of Mo respectively, catalyze the ring-opening-metathesis polymerization of norbornene and the polymerization of styrene at 333 K, their performance increasing upon the addition of methylalumoxane (MAO) as cocatalyst. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).
keywords
LAYERED DOUBLE HYDROXIDES; RAY CRYSTAL-STRUCTURE; 7-COORDINATE MOLYBDENUM(II); METATHESIS POLYMERIZATION; INTERCALATION COMPOUNDS; STYRENE POLYMERIZATION; TUNGSTEN(II); NORBORNADIENE; ANIONS; IMMOBILIZATION
subject category
Chemistry
authors
Vasconcellos-Dias, M; Nunes, CD; Vaz, PD; Ferreira, P; Calhorda, MJ
our authors
