500022-57-1Relevant academic research and scientific papers
Synthesis and structural characterization of molybdenum complexes with linked cycloheptatrienyl-phosphane ligands
Tamm, Matthias,Dressel, Bernd,Baum, Kim,Lügger, Thomas,Pape, Tania
, p. 1 - 9 (2003)
The synthesis of P-functionalized cycloheptatrienyl chelate complexes incorporating the linked cycloheptatrienyl-phosphane ligand [2-(diisopropylphosphanyl)phenyl]cycloheptatrienyl, o-iPr2P-C6H4-C7 H6, is described. The ligand precursor [2-(cyclohepta-2,4,6-trienyl)phenyl]diisopropylphosphane (2b) can be obtained by addition of lithiated 2-BrC6H4 PiPr2 (1b) to the tropylium cation C7H7+. On reaction with Mo(CO)6, the P-functionalized cycloheptatriene 2b acts as an eight-electron ligand to afford the cycloheptatriene-phosphane chelate complex [(o-iPr2P-C6H4 -η6-C7H7)Mo(CO)2(P-Mo)] (3b) as a single, chiral regioisomer, which undergoes clean hydride abstraction on treatment with (Ph3C)BF4. The resulting cationic complex 4b reacts with sodium bromide to yield the 'chiral-at-metal' complex [(o-iPr2 P-C6H4-η7-C7 H6)Mo(CO)Br(P - Mo)] (5b). This 18-electron complex can be oxidized with 0.5 equivalent Br2 to give paramagnetic [(o-iPr2P-C6H4 -η7-C7H6)MoBr2 (P-Mo)] (6b). 6b is a versatile starting material for the preparation of various cycloheptatrienyl-molybdenum complexes, which is exemplified by the isolation of the dialkyl complex [(o-iPr2 P-C6H4-;η7-C7 H6)Mo(CH2SiMe3)2(P-Mo)] (7b) upon reaction of 6b with Me3SiCH2MgCl. In addition, the X-ray crystal structures of 3b, 4b, 5b, 6b, and 7b are reported.
