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N–H Group Transfer and Oxidative Addition Chemistry Promoted by Isolable Bis(cyclopentadienyl)titanium Sandwich Complexes
Author(s) -
Hanna Tamara E.,
Lobkovsky Emil,
Chirik Paul J.
Publication year - 2007
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.200601134
Subject(s) - chemistry , cyclopentadienyl complex , hydrogenolysis , deprotonation , medicinal chemistry , substituent , hydride , oxidative addition , trimethylsilyl , metallocene , titanium , reductive elimination , metal , isopropyl , stereochemistry , organic chemistry , catalysis , ion , polymer , polymerization
Addition of propylenimine (2‐methylaziridine) to the bis(cyclopentadienyl)titanium sandwich complexes, (η 5 ‐C 5 Me 4 R) 2 Ti (R = i Pr, SiMe 3 ), resulted in rapid [NH] group transfer followed by C–H activation of a cyclopentadienyl methyl group to yield the corresponding cyclometalated titanocene amido compounds. Exposure of these molecules to 4 atm of H 2 at 55 °C resulted in hydrogenolysis of the metal–carbon bond to form the titanium amido hydride compounds, (η 5 ‐C 5 Me 4 R) 2 Ti(NH 2 )H. Deuteriolysis with DCl gas confirmed exclusive cyclometalation from the positions adjacent to the isopropyl and trimethylsilyl substituent. Oxidative addition of the N–H bonds of amines has also been observed. Addition of NH 3 to either (η 5 ‐C 5 Me 4 SiMe 3 ) 2 Ti or (η 5 ‐C 5 Me 4 i Pr) 2 Ti yielded the corresponding titanocene amido hydrides along with the titanocene(III) amides, (η 5 ‐C 5 Me 4 R) 2 TiNH 2 , arising from formal deprotonation by unreacted sandwich from the putativetitanocene ammonia complex.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)