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Formation and Reactivity of a Tantalocene Trihydride Containing an Aminoethyl‐Functionalised Ligand
Author(s) -
Poulard Cyril,
Perrey Danièle,
Boni Gilles,
Vigier Estelle,
Blacque Olivier,
Kubicki Marek M.,
Moïse Claude
Publication year - 2003
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200390087
Subject(s) - chemistry , ligand (biochemistry) , cyclopentadienyl complex , medicinal chemistry , trifluoroacetic acid , reactivity (psychology) , adduct , crystal structure , intramolecular force , stereochemistry , cationic polymerization , electrophile , borane , ferrocene , derivative (finance) , crystallography , polymer chemistry , organic chemistry , catalysis , medicine , biochemistry , receptor , alternative medicine , electrode , pathology , financial economics , economics , electrochemistry
The complex [Cp*{C 5 H 4 (CH 2 CH 2 NMe 2 )}TaCl 2 ] ( 1 ) was synthesised by reaction of the lithium salt LiC 5 H 4 (CH 2 CH 2 NMe 2 ) with the tantalum compound [Cp*TaCl 3 (PMe 3 )]. Reduction of 1 with NaAl(H) 2 (OCH 2 CH 2 OMe) 2 leads to the trihydride derivative [Cp*{C 5 H 4 (CH 2 CH 2 NMe 2 )}TaH 3 ] ( 2 ). The oxidation of 2 in THF with ferrocenium ion leads to a cationic dihydride intermediate [Cp*{C 5 H 4 (CH 2 CH 2 NMe 2 )}TaH 2 ]PF 6 ( 3 ) with an intramolecular stabilization by the aminoethyl side‐chain of the cyclopentadienyl ligand. The hemilabile character of the functionalised cyclopentadienyl ligand was checked by treating 3 with electron‐donating ligands (e.g. phosphanes, sulfides, anions); in all cases, no displacement of the amino group was observed. When treated with HBF 4 , 2 undergoes a loss of the hydride and the resulting cation can be isolated as a solvento adduct by carrying out the reaction in dimethyl sulfide. Acidolysis of 2 in the presence of an excess of trifluoroacetic acid affords the compound [Cp*{C 5 H 4 (CH 2 CH 2 NHMe 2 )}TaH(OCOCF 3 ) 2 ](CF 3 COO) ( 5 ). Microanalytical and NMR spectroscopic data for these complexes are given. The X‐ray crystal structures are reported for [Cp*{C 5 H 4 (CH 2 CH 2 NMe 2 )}TaH 2 ]PF 6 ( 3 ) and [Cp*{C 5 H 4 (CH 2 CH 2 NHMe 2 )}TaH(OCOCF 3 ) 2 ](CF 3 COO) ( 5 ). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)