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Neue Wege zu Bis[(cyclopentadienyl)cobalt]‐μ‐(η 5 ‐2,3‐dihydro‐1,3‐diborolyl)‐Tripeldeckerkomplexen über Wasserstoff‐Verschiebungsreaktionen in Derivaten des 4,5‐Diisopropyliden‐1,3‐diborolans, des 2,4,5‐Triisopropyliden‐1,3‐diborolans und des Benzo‐1,3‐diborafulvens
Author(s) -
Enders Markus,
Gangnus Bernd,
Hettrich Ralph,
MagosMartin Zsuzsanna,
Stephan Martin,
Pritzkow Hans,
Siebert Walter,
Zenneck Ulrich
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.19931261006
Subject(s) - chemistry , cobalt , triple bond , cyclopentadienyl complex , stereochemistry , yield (engineering) , metal , medicinal chemistry , nuclear magnetic resonance spectroscopy , hydrogen , catalysis , polymer chemistry , double bond , inorganic chemistry , organic chemistry , materials science , metallurgy
New Routes to Bis[(cyclopentadienyl)cobalt]‐μ‐(η 5 ‐2,3‐dihydro‐1,3‐diborolyl) Triple‐Decker Complexes by Hydrogen Shift Reactions in Derivatives of 4,5‐Diisopropylidene‐1,3‐diborolane, 2,4,5‐Triisopropylidene‐1,3‐diborolane, and Benzo‐1,3‐diborafulvene The 31 VE dicobalt triple‐decker complexes 6, 7a, 7b, c, 8a, b , and 9a, b with bridging 2,3‐dihydro‐1,3‐diborolyl ligands are prepared. The reaction of the 1,3‐diborole 1 with [(C 5 Me 5 )‐Co(C 2 H 4 ) 2 ] leads to the sandwich complex 5 , which is treated with [(C 5 H 5 )Co(C 2 H 4 ) 2 ] to yield unsymmetrical 6 . The 4,5‐diisopropylidenetrimethyl‐1,3‐diborolane 3 undergoes a metal‐induced 1,5‐hydrogen shift and reacts with [(C 5 H 5 )Co(C 2 H 4 ) 2 ] to form the triple‐decker 7a . The reaction of the 2,4,5‐triisopropylidene‐1,3‐diborolane 4 with [(C 5 H 5 )Co(C 2 H 4 ) 2 ] leads to a mixture of the triple‐deckers 7b/c , formed by intermolecular hydrogen shift. The benzo‐1,3‐diborafulvene derivatives 2b and 2c also react with [(C 5 H 5 )Co(C 2 H 4 ) 2 ] to give the triple‐decker 8b and a mixture of 9a, b . In addition, the trinuclear complex 8c is obtained in low yield. The new paramagnetic triple‐decker complexes have been analyzed by NMR and ESR spectroscopic measurements as well as by electochemistry. The constitutions of 7b/c, 8b, 8c , and 9a/b have been confirmed by X‐ray structure analyses. The complexes are iso‐structural, the Co—Co distances range from 3.277(1) ( 7b / c ) to 3.316(1) Å for 8c .