Evaluation of the 5-ethynyl-1,3,3-trimethyl-3H-indole ligand for molecular materials applications

The modification of conjugated organic compounds with organometallic moieties allows the modulation of the electronic and optoelectronic properties of such compounds and lends them to a variety of material applications. The organometallic complexes [M(Cp′)(L)n] (M = Ru or Fe; Cp′ = cyclopentadiene (Cp) or pentamethylcyclopentadiene (Cp*); (L)n = (PPh3)2 or 1,2-bi(diphenylphosphino)ethane (dppe)) and [M(L)n] (M = Ru; (L)n = (dppe)2 or (P(OEt)3)4; or M = Pt; (L)n = (PEt3)2, (PPh3)2 or tricyclohexylphosphine, (PCy3)2) modified with a 5-ethynyl-1,3,3-trimethyl-3H-indole ligand were prepared and characterised by NMR spectroscopy, IR and single-crystal X-ray diffraction. Cyclic voltammetry and IR spectroelectrochemistry of the ruthenium systems showed a single-electron oxidation localised over the M–C≡C–aryl moiety. The N-heteroatom of the indole ligand showed Lewis base properties and was able to extract a proton from a vinylidene intermediate as well as coordinate to CuI. Examples from the wire-like compounds were also studied by single-molecule break junction experiments but molecular junction formation was not observed. This is most likely attributable to the binding characteristics of the substituted terminal indole groups used here to the gold contacts.</jats:p

Deprotonation of large calixarenes-cation binding and conformations

© 2016 CSIRO. Single crystal X-ray studies of p-t-butylcalix[10]arene·2dmso·7H2O (1) and [NMe4][p-t-butylcalix[9]arene-H]·2dmso·H2O (2), provide new data on these large macrocycles and their conformations, that of 2 being the first where an encapsulated [NMe4]+ cation is present, while 1 contains the neutral ligand. Both were obtained as crystalline products of the reactions of the calixarenes with tetramethylammonium hydroxide after prolonged standing. The structure of [NEt4][calix[4]arene-H], in which the cation approaches inclusion in the shallow cone of the anion, is also defined and compared with various other alkylammonium derivatives of calixarenes as well as that of p-t-butylcalix[9]arene

Highly Fluorous Bidentate Phosphines

The reaction of tetrachlorodiphosphines [Cl2P(CH2)nPCl2; n = 2-4] with fluorous aromatic precursors 4-bromo(perfluorohexyl)benzene and 4-(perfluorohexyl)phenol gave a series of fluorous-tagged diphosphines [(p-C6F13C6H4)2P(CH2)nP(C6H4C6F13-p)2; n = 2-4] and a new diphosphonite [(p-C6F13C6H4O)2P(CH2)3P(OC6H4C6F13-p)2]. The improved synthesis of 1,3-bis(dichlorophosphino)propane (dcpp), involved the facile chlorination of the corresponding primary phosphine with triphosgene. Fluorinated diimines RN=C(CH3)C(CH3)=NR, where R = p-C6H4C6F13 or p-C6H4C8F17 have also been prepared, and were found to be air-stable alternatives to the highly air-sensitive phosphorus-containing ligands. All compounds were characterised by a variety of techniques including NMR, IR, MS and microanalysis. The successful reduction of the phosphine-oxides [(p-C6F13C6H4)2P(O)(CH2)nP(O)(C6H4C6F13-p)2; n = 2,3] with phenylsilane is also presented

Coordinating Tectons 4: Coordination Chemistry of the 4,5-Diazafluoren-9-yl Moiety as a Metallo-Ligand for Allenylidene Complexes

We describe how the 4,5-diazafluoren-9-yl moiety has been utilized in the construction of multinuclear complexes incorporating a ruthenium­(II) allenylidene functionality. The coordination chemistry of diazafluorenyl-terminated allenylidene complexes is limited by the sensitivity (instability) of the allenylidene moiety under a variety of synthetic conditions. In contrast the κ²-N,N′-coordination of the diazafluorenyl propargylic alcohol (alkynol) to a metal center <i>prior</i> to allenylidene formation provides a facile route toward the synthesis of multinuclear allenylidene coordination complexes. Our synthetic attempts and successes are discussed in combination with spectroscopic and electronic characterization of the latter cases

Coordinating Tectons 4: Coordination Chemistry of the 4,5-Diazafluoren-9-yl Moiety as a Metallo-Ligand for Allenylidene Complexes

We describe how the 4,5-diazafluoren-9-yl moiety has been utilized in the construction of multinuclear complexes incorporating a ruthenium­(II) allenylidene functionality. The coordination chemistry of diazafluorenyl-terminated allenylidene complexes is limited by the sensitivity (instability) of the allenylidene moiety under a variety of synthetic conditions. In contrast the κ²-N,N′-coordination of the diazafluorenyl propargylic alcohol (alkynol) to a metal center <i>prior</i> to allenylidene formation provides a facile route toward the synthesis of multinuclear allenylidene coordination complexes. Our synthetic attempts and successes are discussed in combination with spectroscopic and electronic characterization of the latter cases

Competition between cluster fragmentation, C-C bond coupling and C-X bond activation in silver hexynyl cluster cations, [(C4H9CCAg)(n)Ag](+). Size does matter!

Silver hexynyl cluster cations, [(C4H9CCAg)(n)Ag](+), exhibit a rich unimolecular chemistry that is dependant on the cluster size, n (1-5), cluster fragmentation (for all n > 1); C-C bond coupling (n = 3 & 4); C-H bond activation with comcomitant silver hydride formation (n = 1 & 4); C-C bond activation (n = 1 & 4)