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(η 5 ‐Cyclopentadienyl)(η 4 ‐tetrasila‐ and η 4 ‐trisilagermacyclobutadiene)cobalt: Sandwich Complexes Featuring Heavy Cyclobutadiene Ligands (Eur. J. Inorg. Chem. 35/2007)
Author(s) -
Takanashi Kazunori,
Lee Vladimir Ya.,
Ichinohe Masaaki,
Sekiguchi Akira
Publication year - 2007
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/ejic.200790092
Subject(s) - cyclobutadiene , chemistry , cyclopentadienyl complex , ligand (biochemistry) , cobalt , ring (chemistry) , derivative (finance) , stereochemistry , crystallography , carbon group , medicinal chemistry , group (periodic table) , molecule , inorganic chemistry , organic chemistry , catalysis , biochemistry , receptor , financial economics , economics
The cover picture shows two spotlights illuminating the structure of the first sandwich complex featuring an all‐heavy group 14 element‐consisting Si 4 ‐cyclic ligand, namely, a derivative of (? 5 ‐cyclopentadienyl)(η 4 ‐tetrasilacyclobutadiene)cobalt [(η 4 ‐R 4 Si 4 )CoCp] (R = SiMe t Bu 2 ). The Me and t Bu groups on the Si substituents, as well as the H atoms on the Cp ring, are removed for simplicity. The title compound was smoothly prepared by a ligand exchange reaction between the tetrasilacyclobutadiene dianion salt K + 2 ·[R 4 Si 4 ] 2 and [CpCoI 2 (PPh 3 )]. Systematic comparison of the complex [(η 4 ‐R 4 Si 4 )CoCp] and its carbon analogue [η 4 ‐(Me 3 Si) 4 C 4 ]CoCp revealed important structural distinctions between the two complexes that result from the different ring sizes of the cyclobutadiene ligands η 4 ‐R 4 E 4 (R = SiMe t Bu 2 , E = Si vs. R = SiMe 3 , E = C). Details of the synthesis of the novel Co complex, as well as of its structural and electronic peculiarities, are discussed in the Short Communication by A. Sekiguchi et al. on p. 5471 ff.