Synthesis and Characterisation of Selected Group 4 Metallocene Complexes with 1, 2‐Bis(4′, 4′, 5′, 5′‐tetramethyl[1′, 3′, 2′]dioxaborolan‐2′‐yl)acetylene. Issue 18 (16th May 2013)

• Record Type: Journal Article
• Authors: Altenburger, Kai; Arndt, Perdita; Spannenberg, Anke; Baumann, Wolfgang; Rosenthal, Uwe
• Is Part Of: European journal of inorganic chemistry. Issue 18(2013)
• Page Start: 3200
• Page End: 3205
• Publication Date: 2013-05-16
• Subjects: Metallocenes -- Titanium -- Zirconium -- Diborylalkyne ligands -- Metallacyclo­propenes -- C–C coupling; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201300236
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract: The reactions of the metallocene generators Cp′2 M(L)(η 2 ‐Me3 SiC≡CSiMe3 ) [1a ‐Ti: Cp′ = Cp = η 5 ‐cyclopentadienyl, M = Ti, L = none;1b ‐Ti: Cp′ = Cp* = η 5 ‐pentamethylcyclopentadienyl, M = Ti, L = none;1c ‐Ti: Cp′2 = rac ‐(ebthi) = rac ‐ethylenebistetrahydroindenyl, M = Ti, L = none;1a ‐Zr: Cp′ = Cp, M = Zr, L = pyridine;1b ‐Zr: Cp′ = Cp*, M = Zr, L = none;1c ‐Zr: Cp′2 = rac ‐(ebthi), M = Zr, L = none] with 1, 2‐bis(4′, 4′, 5′, 5′‐tetramethyl[1′, 3′, 2′]dioxaborolan‐2′‐yl)acetylene (bPinBA, 2 ) as a di‐heteroatom‐substituted alkyne were investigated. A slightly special reaction of1a ‐Ti with2 produced no titanacyclopropene or titanacyclopentadiene, but instead complex3 was produced by the coupling of two alkyne units with one of the Cp ligands to form a six‐membered ring annelated to a five‐membered one. The titanocene complexes1b ‐Ti and1c ‐Ti reacted with2 to form the titanacylopropenes4 and5 . The complex1a ‐Zr reacts with2 to the corresponding zirconacyclopropene6 as a byproduct, in which the pyridine ligand remains coordinated. If the pyridine ligand dissociates, a coupling with a second alkyne yields the zirconacyclopentadiene7 as the main product. The reaction of the sterically more demanding zirconocene precursor1c ‐Zr also yielded the zirconacyclopentadiene8, whereas1b ‐Zr did not react with2 . The complex rac ‐(ebthi)Ti(η 2 ‐bPinBA) (5 ) reacts with gaseous dry CO2 directly to form the titanafuranone9 . The molecular structures of complexes5 and6 were characterised by single‐crystal X‐ray crystallography. Abstract : Group 4 metallocenes and bis(tetramethyldioxaborolanyl)acetylene gave different products: "Cp2 Ti" afforded a dihydroindenyl complex. " rac ‐(ebthi)Ti", "Cp*2 Ti" and "Cp2 Zr(py)" led to metallacyclopropenes, whereas "Cp2 Zr" and " rac ‐(ebthi)Zr" yielded metallacyclopentadienes. One of the titanacyclopropenes reacts with CO2 to a titanacyclofuranone.