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Secondary Interactions in Phosphane‐Functionalized Group 4 Cycloheptatrienyl–Cyclopentadienyl Sandwich Complexes
Author(s) -
Büschel Susanne,
Jungton AnnKatrin,
Bannenberg Thomas,
Randoll Sören,
Hrib Cristian G.,
Jones Peter G.,
Tamm Matthias
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.200802518
Subject(s) - chemistry , cyclopentadienyl complex , intramolecular force , crystallography , denticity , metal , non covalent interactions , stereochemistry , density functional theory , medicinal chemistry , crystal structure , hydrogen bond , molecule , computational chemistry , catalysis , organic chemistry
Twice as reactive : The coordination chemistry of phosphane‐functionalized Zr and Hf cycloheptatrienyl–cyclopentadienyl complexes gives rise to unusual secondary interactions associated with the presence of Lewis acidic 16‐electron sandwich moieties. These structures can develop weak dative bonds as exemplified by the noncovalent Pd→Zr interaction in the heterobimetallic {Zr 2 Pd} complex (see picture).Phosphane‐functionalized cycloheptatrienyl–cyclopentadienyl Group 4 metal complexes of the type [(η 7 ‐C 7 H 7 )M(η 5 ‐C 5 H 4 PR 2 )] (M=Ti ( 9 ); M=Zr ( 10 ); M=Hf ( 11 ); R=Ph ( a ); R= i Pr ( b )) have been prepared by the reduction of [(η 5 ‐C 5 H 4 PR 2 )TiCl 3 ] or [(η 5 ‐C 5 H 4 PR 2 ) 2 MCl 2 ] (M=Zr, Hf) with magnesium in the presence of cycloheptatriene (C 7 H 8 ). In the solid state, the Ti complex 9 a and the complex 11 b are monomeric, whereas 10 a , 10 b , and 11 a form dimers, in which the sandwich units are linked by long ZrP or HfP bonds. Density‐functional theory (DFT) calculations indicate that the metal–phosphane interaction is weak, and accordingly, both the Ti complex 9 b and the Zr complex 10 b act as monodentate phosphane ligands upon reaction with [{(cod)RhCl} 2 ] (cod=η 4 ‐1,5‐cyclooctadiene). The X‐ray crystal structures of [(cod)Rh( 9 b )Cl] ( 12 ) and [(cod)Rh( 10 b )Cl] ( 13 ) reveal that only the latter exhibits a secondary intramolecular Cl–metal interaction. The complex [( 10 b ) 2 Pd] ( 14 ) was obtained by reaction of [(η 5 ‐C 5 H 5 )Pd(η 3 ‐C 3 H 5 )] with two equivalents of 10 b . The solid‐state structure of 14 reveals a T‐shaped Pd 0 center with a long PdZr bond of 2.9709(3) Å, which can be interpreted as a weak noncovalent Pd 0 →Zr +IV bond, as indicated by the calculated relaxed force constant of 5.68 N m −1 .