Quantum chemical study of butane isomerization on clusters of aluminum and cobalt chlorides. Mixed complexes

Unusual coordination state of cobalt ions in zeolites modified by aluminum chloride

“…It is likely that new compounds similar to cobalt halide-aluminum chloride complexes identified in the gas phase and observed at low temperatures are produced. According to our calculation for such bimetallic systems 58,59 , the transition metal cation that interacts with alkanes forming alkyl-metal derivatives plays the key role in alkane activation via metal alkyl intermediates. These results provide the new important information for rational design of more efficient and selective catalysts based on metal modified zeolites for hydrocarbon conversions.…”

“…15,16 It was proposed that alkane reforming catalyzed by Al-Co-ZSM-5 may take place on these sites 5 or on cluster structures containing cobalt-cobalt links formed from nearby Co-Cl-Al fragments. According to DFT calculations 58,59 bimetallic alkyl clusters containing Co-Co dimeric bonds are key intermediates leading to the formation of both isomerization products and products of alkane metathesis. The sequence of mutual rearrangement of the polynuclear complexes involving metalcarbon bond formation provides a possibility for cleavage and formation of C-C bonds in alkanes.…”