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Structures, Dynamics, and Reactivity of Tripodal Amido Ligands Coordinated to Ti IV Centres
Author(s) -
Friedrich Stefan,
Gade Lutz H.,
Edwards Andrew J.,
McPartlin Mary
Publication year - 1993
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19931260807
Subject(s) - chemistry , molecule , crystallography , crystal structure , stereochemistry , reactivity (psychology) , nuclear magnetic resonance spectroscopy , ligand (biochemistry) , nmr spectra database , halide , two dimensional nuclear magnetic resonance spectroscopy , amide , spectral line , inorganic chemistry , biochemistry , receptor , organic chemistry , pathology , astronomy , medicine , physics , alternative medicine
A new class of amido titanium(IV) halides containing tripodal ligands H 3 CC(CH 2 NR) 3 TiX (R = Me, X = Cl: 1 ; R = Me 3 Si, X = Cl: 2a , Br: 2b ; R = SiMe 2 t Bu, X = Cl: 3a , Br: 3b ) has been synthesised. Compound 1 has been structurally characterised by X‐ray crystallography and found to be dimeric in the crystal displaying an idealised C 2 symmetry with bridging amido functions linking the two halves of the molecule. The dimeric structure is retained in solution as has been shown by 1 H‐ and 13 C‐NMR spectroscopy which has also revealed a high degree of ligand dynamics, effecting the interconversion of the two enantiomeric forms of the molecule. This process has been investigated by variable temperature NMR studies and phase‐sensitive 1 H‐NOESY/EXSY spectra. The dimeric μ‐imido complexes [H 3 CC(CH 2 NSiMe 3 ) 2 (H)CH 2 NTiX] 2 (X = Cl: 4a , Br: 4b ) have been isolated as a byproduct in the synthesis of 2a/b , and a single‐crystal X‐ray structure analysis of 4a has established its molecular structure.