Ethynylferrocene Compounds of 1,3,5-Tribromobenzene

Abstract

The new compounds 1,3-dibromo-5-(ferrocenylethynyl)benzene (1), 1-bromo-3,5-bis(ferrocenylethynyl)benzene (2), and 1,3,5-tris(ferrocenylethynyl)benzene (3) have been synthesized by palladium-catalyzed cross-coupling reactions and characterized, and the crystal structures of 1 and 3 have been determined; electrochemical studies show chemically reversible oxidations with single-step one-electron, two-electron, and three-electron processes per molecule, respectively, indicating that in 2 and 3 the iron(II) centers do not electronically communicate with each other.

Metallodendrimers in three oxidation states with electronically interacting metals and stabilization of size-selected gold nanoparticles

“…The redox-rich iron centres in the chosen system are Cp à Fe II (dppe)-alkynyl units (Cp à ¼ Z 5 -C 5 Me 5 , dppe ¼ 1,2-bis(diphenylphosphino) ethane) 24 that are isolobal to ferrocene and linked in meta position of an aryl bridge. In 1,3,5-trimetallaalkynylbenzene derivatives [24][25][26][27] , and in such Cp à Fe II (dppe) derivatives in particular 25,26 , it has been shown by density functional theory calculation and electrochemistry that, unlike in the 1,3,5-triferrocenylalkynylbenzene derivatives 28 , the three metals are electronically communicating. We synthesize the dendrons with only two iron-ethynyl groups in 1,3 position, leaving the third ethynyl position free for binding to the dendritic core either by Sonogashira coupling 29,30 or copper-catalysed azide-alkyne cycloaddition (CuAAC, 'click') reactions [31][32][33] with appropriately functionalized dendritic core termini.…”

Polymerization of 4-(ferrocenylethynyl)phenylacetylene with transition metal catalysts

“…By comparison, the same catalyst if applied in polymerization of FcA provides about 14% yield of insoluble polymer and 60% yield of oligomers, mainly cyclotrimers 25) . Thus, also in 4 Sn is well soluble in THF. However, its solubility is rapidly deteriorating during storage in the solid state (under argon): the sample has become only partly soluble in THF (ca.…”

“…Polymerization induced with WOCl 4 /2Me 4 Sn catalyst was performed by using the standard vacuum break-seal technique at room temperature. Benzene solution of WOCl 4 (0,7 mL, 10 mmol/L) was mixed with benzene solution of Me 4 Sn (0,3 mL, 47 mmol/L) and the mixture allowed ripening for 15 min.…”

“…Both steric and electronic effects come into consideration as a rational lying behind this phenomenon: (i) phenylene is a less bulky group than ferrocenyl, and (ii) acetylenes with electron-donating substituents linked to C3CH are not readily polymerized with Rh-diene complexes 30) . The polymerization of FcEPA induced by WOCl 4 / 2Me 4 Sn catalyst leads to a red PFcEPA (yield of 60%) soluble in the reaction mixture. This polymer sample is almost free of oligomers (about 1% of oligomers were detected in the supernatant from the polymer isolation), but it contains about 4% (according to the SEC record area) of high-MW fraction (weight-average molecular weight, M 3 were found.…”

“…However, we found that TaCl 5 catalyst exclusively provides FcA cyclotrimers, 1,2,4-and 1,3,5-triferrocenylbenzenes (the solid state structure of 1,3,5-isomer has been established) 25) . The solid state structure of the related compound 1,3,5-tris-(ferrocenylethynyl)benzene has, recently, also been established 4) . In this contribution we report the polymerization of another ferrocenyl-containing monomer, 4-(ferrocenylethynyl)phenylacetylene (Scheme 1), induced by the metathesis catalyst WOCl 4 /2Me 4 Sn and the [Rh(nbd)-(OCH 3 )] 2 catalyst (where nbd is norbornadiene) operating in the Ziegler-Natta mode.…”