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A π‐Stacked Organometallic Propeller: Experimental and Theoretical Studies on Reactivity and Bonding in the π‐Arene‐Bridged Nickel Triple‐Decker [{(η 5 ‐Me 4 EtC 5 )Ni} 2 (μ‐η 3 :η 3 ‐decacyclene)]
Author(s) -
Schneider Jörg J.,
Spickermann Dirk,
Bläser Dieter,
Boese Roland,
Rademacher Paul,
Labahn Thomas,
Magull Jörg,
Janiak Christoph,
Seidel Naka,
Jacob Klaus
Publication year - 2001
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 - 10.1002/1099-0682(200105)2001:5<1371::aid-ejic1371>3.0.co;2-k
Subject(s) - chemistry , crystallography , reactivity (psychology) , metallacycle , ferrocene , molecular orbital , stereochemistry , antibonding molecular orbital , heterolysis , ring (chemistry) , molecule , atomic orbital , x ray crystallography , medicine , biochemistry , alternative medicine , physics , catalysis , organic chemistry , electrode , pathology , quantum mechanics , diffraction , optics , electrochemistry , electron
Synthesis, structure, reactivity, and theoretical studies of a new type of Ni triple‐decker complexes are reported. A prominent feature of its molecular structure is the (η 3 :η 3 )‐bis(enyl) coordination of two [(η 5 ‐Me 4 EtC 5 )Ni] fragments to the central arene ring of the polycondensed π‐perimeter decacyclene. The central arene ring of decacyclene displays a distinct chair conformation with significant tilt angles of 25.5 and 26.1°. The three naphthalene units are twisted in a propeller‐like fashion with torsion angles of 16°, 16.6°, and 19°, which is twice the twisting observed for the free decacyclene ligand. According to Extended Hückel Molecular Orbital (EHMO) calculations, a qualitative measure for arene lability in the title compound and a number of related arene‐bridged metal complexes can be attributed to a subsequent filling of metal−arene antibonding orbitals. The experimentally observed reactivities of π‐arene exchange in these complexes are reproduced nicely by the EHMO calculations. The title compound offers access to a number of organonickel chalcogenato complexes under mild conditions by cleavage of the S−S, Se−Se, or Te−Te bonds of diorganyl dichalcogenides R−E−E−R. The title compound is also capable of C sp 2−H activation of azobenzene and [(dimethylamino)methyl]ferrocene resulting in orthometallated complexes containing five‐membered metallacycles. PES and semi‐empirical ZINDO/S calculations were used to study the product of the orthometallation of the title compound with azobenzene. These studies reveal that the HOMO of the metallacycle (IE = 6.45 eV) has dominant Ni−Cp and Ni−C aryl π‐antibonding character.