Collect. Czech. Chem. Commun. 2001, 66, 382-396

Synthesis of Rhodium Complexes with Novel Perfluoroalkyl Substituted Cyclopentadienyl Ligands

Jan Čermáka,*, Kateřina Auerováa, Huong Thi Thu Nguyena, Vratislav Blechtaa, Pavel Vojtíšekb and Jaroslav Kvíčalac

a Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, Rozvojová 135, CZ-165 02 Prague 6, Czech Republic
b Department of Inorganic Chemistry, Charles University, Hlavova 2030, CZ-128 40 Prague, Czech Republic
c Department of Organic Chemistry, Institute of Chemical Technology, Prague, Technická 5, CZ-166 28 Prague 6, Czech Republic


Mixtures of isomers of (perfluoroalkyl)tetramethylcyclopenta-1,3-dienes (CH3)4C5H(CF2)nCF3 (n = 3, 5, 7, 9) were synthesized as precursors of new cyclopentadienyl ligands for organotransition metal catalysis in fluorous biphase media and characterized by combination of GC-MS and 13C NMR spectroscopy. Rhodium(III) chloro complexes [Rh{(CH3)4C5(CF2)nCF3}Cl2]2 and rhodium(I) carbonyl complexes [Rh{(CH3)4C5(CF2)nCF3}(CO)2] were prepared from the cyclopentadienes and molecular structure of [Rh{(CH3)4C5(CF2)5CF3}Cl2]2 was determined by X-ray diffraction. The ligands are electronically close to the unsubstituted cyclopentadienyl as shown by values of carbonyl stretching frequencies in the carbonyl complexes. Neither carbonyl frequencies nor NMR chemical shifts of the complexes are substantially affected by the length of the perfluoroalkyl chain.

Keywords: Fluorous biphasic catalysis; Carbonyl complexes; Cyclopentadienes; Fluorinated compounds; Rhodium; Sandwich complexes; Fluorophilic ligands.

References: 38 live references.