Premium
Structural Analysis of Zincocenes with Substituted Cyclopentadienyl Rings
Author(s) -
Fernández Rafael,
Grirrane Abdessamad,
Resa Irene,
Rodríguez Amor,
Carmona Ernesto,
Álvarez Eleuterio,
GutiérrezPuebla Enrique,
Monge Ángeles,
López del Amo Juan Miguel,
Limbach HansHeinrich,
Lledós Agustí,
Maseras Feliu,
del Río Diego
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200801917
Subject(s) - cyclopentadienyl complex , chemistry , nuclear magnetic resonance spectroscopy , crystallography , zinc , reagent , ring (chemistry) , ligand (biochemistry) , stereochemistry , spectroscopy , organic chemistry , catalysis , biochemistry , physics , receptor , quantum mechanics
New zincocenes [ZnCp′ 2 ] ( 2 – 5 ) with substituted cyclopentadienyl ligands C 5 Me 4 H, C 5 Me 4 t Bu, C 5 Me 4 SiMe 2 t Bu and C 5 Me 4 SiMe 3 , respectively, have been prepared by the reaction of ZnCl 2 with the appropriate Cp′‐transfer reagent. For a comparative structural study, the known [Zn(C 5 H 4 SiMe 3 ) 2 ] ( 1 ), has also been investigated, along with the mixed‐ring zincocenes [Zn(C 5 Me 5 )(C 5 Me 4 SiMe 3 )] ( 6 ) and [Zn(C 5 Me 5 )(C 5 H 4 SiMe 3 )] ( 7 ), the last two obtained by conproportionation of [Zn(C 5 Me 5 ) 2 ] with 5 or 1 , as appropriate. All new compounds were characterised by NMR spectroscopy, and by X‐ray methods, with the exception of 7 , which yields a side‐product ( C ) upon attempted crystallisation. Compounds 5 and 6 were also investigated by 13 C CPMAS NMR spectroscopy. Zincocenes 1 and 2 have infinite chain structures with bridging Cp′ ligands, while 3 and 4 exhibit slipped‐sandwich geometries. Compounds 5 and 6 have rigid, η 5 /η 1 (σ) structures, in which the monohapto C 5 Me 4 SiMe 3 ligand is bound to zinc through the silyl‐bearing carbon atom, forming a ZnC bond of comparable strength to the ZnMe bond in ZnMe 2 . Zincocene 5 has dynamic behaviour in solution, but a rigid η 5 /η 1 (σ) structure in the solid state, as revealed by 13 C CPMAS NMR studies, whereas for 6 the different nature of the Cp′ ligands and of the ring substituents of the η 1 ‐Cp′ group (Me and SiMe 3 ) have permitted observation for the first time of the rigid η 5 /η 1 solution structure. Iminoacyl compounds of composition [Zn(η 5 ‐C 5 Me 4 R)(η 1 ‐C(NXyl)C 5 Me 4 R)] resulting from the reactions of some of the above zincocenes and CNXyl (Xyl=2,6‐dimethylphenylisocyanide) have also been obtained and characterised.