Mono‐, Bis‐ and Tris(cyclopentadienyl) Compounds ‐ Syntheses of New Polydentate Ligands and their Molybdenum and Tungsten Complexes

Condensation reactions of cyclopentadienyl‐substituted chlorosilanes CpSiMe 2 Cl (Cp = C 5 H 5 , C 5 HMe 4 ) with a number of phenols [C 6 H 5 OH, 1,3‐C 6 H 4 (OH) 2 , 1,4‐C 6 H 4 (OH) 2 , 1,3,5‐C 6 H 3 (OH) 3 ] in the presence of excess base led to six novel molecules containing up to three cyclopentadienyl groups {e.g. 1,3,5‐C 6 H 3 [OSiMe 2 (C 5 Me 4 H)] 3 ). The dynamic behavior of 1,4‐C 6 H 4 [OSiMe 2 (C 5 H 5 )] 2 ( 2 ) was investigated by temperature‐variable 1 H NMR and the reaction rate of the degenerate 1,2‐silicon shift determined. C 6 H 5 OSiMe 2 (C 5 H 5 ) ( 1 ) and ( 2 ) were treated with NaH, (MeCN) 3 M(CO) 3 (M = Mo, W), and Mel to give the η 5 ‐complexes C 6 H 6 OSiMe 2 —(C 5 H 4 )M(CO) 3 Me ( 8 : M = Mo, 9 : M = W) and 1,4‐C 6 H 4 [OSiMe 2 ‐(C 5 H 4 )M(CO) 3 Me] 2 ( 10 : M = Mo, 11 : M = W) in good yields. The X‐ray crystal structure of 11 was determined.