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Synthesis, Structure, and Dynamic Behavior of (μ‐Aldimido)(μ‐η 1 : η 2 ‐alkyne)‐ biszirconocene Cation Complexes That Contain Planar‐Tetracoordinate Carbon
Author(s) -
Aglers Wikfgabg,
Erker Gerhard,
Fröblich Roland,
Peuchert Ulrich
Publication year - 1997
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.19971300808
Subject(s) - tetracoordinate , chemistry , alkyne , propynyl , tetraphenylborate , benzonitrile , yield (engineering) , medicinal chemistry , crystallography , metallacycle , stereochemistry , crystal structure , carbon fibers , stereocenter , x ray crystallography , organic chemistry , planar , enantioselective synthesis , catalysis , ion , materials science , computer graphics (images) , physics , composite number , computer science , diffraction , optics , metallurgy , composite material
The benzonitrile hydrozirconation product Cp 2 ZrCl(NCHPh) 8 was treated with propynyl lithium to yield the (propynyl)(benzaldimido)ZrCp; complex 9 . Subsequent treatment with trityl tetraphenylborate generated [Cp 2 Zr(CCCH 3 ) − BPh − 4 ] that instantaneously added to 9 to eventually form the (μ‐aldimido)(μ‐η 1 :η 2 ‐hexadiyne)ZrCp 2 cation 11 . The X‐ray crystal structure analysis showed that 11 contains a planar‐tetracoordinate carbon atom that is stabilized by forming a three‐center‐two‐electron bond with the two adjacent metal atoms. Similarly, complex 9 reacted with [Cp 2 Zr(CH 3 ) + CH 3 B(C 6 F 5 ) 3 1 to yield the planar‐tetracoordinate carbon containing (μ‐aldimido)(μ‐η 1 :η 2 ‐2‐butyne) Cp; cation 12 . Both complexes 11 and 12 exhibit dynamic NMR spectra due to their rapid reorganization of the dimetallabicyclic frameworks (ΔG * = 10 kcal mol −1 ) in addition to an anchimerically assisted CN bond rotation (ΔG * =15 kcal mol −1 ).