Synthesis and Structure of 1-Zirconacyclopent-3-yne Complexes without Substituents Adjacent to the Triple Bond

Abstract

Five-membered metallacyclic alkynes that have no substituents adjacent to the triple bond have been synthesized, isolated, and structurally characterized. Zirconocene dichlorides, Cp'2ZrCl2 (Cp' = C5H5, C5H4-t-Bu), reacted with 1,4-dichlorobut-2-yne in the presence of magnesium to give 1-zirconacyclopent-3-yne compounds (5 (a) Cp' = C5H5, (b) Cp' = C5H4-t-Bu) that have a -CH2CCCH2- moiety in good yields. They are stable enough to be isolated in a pure form, despite the absence of substituents. 5a reacted with an equimolar amount of Cp2Zr(but-1-ene)(PMe3) to produce a bimetallic complex in which the zirconacyclopentyne coordinates to the other zirconocene moiety as an alkyne.

Synthesis and structure of 1-metallacyclopent-3-yne complexes of group 4 metals

“…This is the first example of a structurally characterized 1-titanacyclopent-3-yne. Its structure is similar in principle to that of the corresponding zirconium complex 1c [13,14]. The four carbons of butatriene and Ti metal are coplanar, and the butatriene moiety is bent to form a strained five-membered metallacycle.…”

“…(1)) [12]. We also reported a simple and versatile preparative method for ''non-substituted'' 1-zirconacyclopent-3-ynes (1c-d: R = H) and showed their reactivity [13][14][15][16]. Five-membered metallacyclocumulenes reported by Rosenthal and coworkers showed similar structure and reactivity to metallacyclopentynes [17][18][19][20].…”

Can Acetylenedithiolate Act as a Tetradentate Bridging Ligand?

“…The rather paradoxical idea of having an acetylenedithiolate chelate ligand without coordination at the triple bond is realized in structure A. This type of linkage isomerism A/E has actually been established in corresponding carbon-based ligand systems by isolation of unusual zirconacyclopent-3-ynes B, [9] zirconacyclocumulenes C, [10] and the titana [3]radialene D. [11] In conclusion, we present here a facile access to h 2 -C,C'-acetylenedithiolate complexes and a full characterization of the first heterobimetallic complex containing acetylenedithiolate as an h 2 -C,C'-h 2 -S,S'-bridging ligand. Further investigations are necessary to verify the general applicability of alkyne complexes with acetylenedithiolate as dithiolate chelate ligands.…”

Metallacyclische Fünfring‐Allenoide: Synthese und Struktur stabiler stark verzerrter cyclischer Allen‐Derivate

“…14-18 kcal mol À1 (2). [1,4,5] Wegen der bekannten Tendenz der Gruppe-4-Metallocene, gewinkelte Cumulene 3 [6] und sogar nichtlineare Alkine 4 [7] in metallacyclischen Ringstrukturen erheblich zu stabilisieren, erschien der Versuch naheliegend, auch die entsprechenden metallacyclischen Fünfring-Allene 5 zu synthetisieren (Schema 1 2.340 (3) ). [11] Die C4-C3-Bindung ist kurz (1.276 (4) ).…”