Search results for "Phosphines"
showing 10 items of 59 documents
Stereoselective Synthesis of P-Chirogenic Dibenzophosphole-Boranes via Aryne Intermediates
2012
A new aryne-mediated tandem cross-coupling/P-cyclization sequence starting from tertiary phosphine-boranes and 1,2-dibromobenzenes is reported. P-chirogenic dibenzophospholes become accessible in a regio-, chemo-, and diastereoselective way.
Cubane-Type Mo3FeS44+,5+ Complexes Containing Outer Diphosphane Ligands: Ligand Substitution Reactions, Spectroscopic Studies, and Electronic Structu…
2012
A general protocol to access Mo(3)FeS(4)(4+) clusters selectively modified at the Fe coordination site is presented starting from the all-chlorine Mo(3)(FeCl)S(4)(dmpe)(3)Cl(3) (1) [dmpe = 1,2-bis(dimethylphosphane-ethane)] cluster and tetrabutylammonium salts (n-Bu(4)NX) (X = CN(-), N(3)(-), and PhS(-)). Clusters Mo(3)(FeX)S(4)(dmpe)(3)Cl(3) [X = CN(-) (2), N(3)(-) (3), and PhS(-) (4)] are prepared in high yield, and comparison of geometric and redox features upon modification of the coordination environment at the Fe site at parity of ligands at the Mo sites is also presented. The existence of the cubane-type Mo(3)FeS(4)(4+,5+) redox couple is demonstrated by cyclic voltammetry and for co…
Ligand-Stabilized Au13Cux (x = 2, 4, 8) Bimetallic Nanoclusters: Ligand Engineering to Control the Exposure of Metal Sites
2013
Three novel bimetallic Au-Cu nanoclusters stabilized by a mixed layer of thiolate and phosphine ligands bearing pyridyl groups are synthesized and fully characterized by X-ray single crystal analysis and density functional theory computations. The three clusters have an icosahedral Au13 core face-capped by two, four, and eight Cu atoms, respectively. All face-capping Cu atoms in the clusters are triply coordinated by thiolate or pyridyl groups. The surface ligands control the exposure of Au sites in the clusters. In the case of the Au13Cu8 cluster, the presence of 12 2-pyridylthiolate ligands still leaves open space for catalysis. All the 3 clusters are 8-electron superatoms displaying opti…
Organometallic Oligomers Based on Bis(arylacetylide)bis(P-chirogenic phosphine)platinum(II) Complexes: Synthesis and Photonic Properties
2013
A series of P-chirogenic oligomers of the type (-C≡C-aryl-C≡C-PtL2-)n [L = (R)- and (S)-P(Ph)(iPr)(C17H35); aryl = 1,4-benzene, 2,1,3-benzothiadiazole] along the corresponding achiral analogues (L = PBu3) and model complexes PhC≡CPtL2C≡CPh were prepared from the ephedrine strategy and were fully characterized [(1)H, (31)P NMR; IR; small-angle X-ray scattering (SAXS); gel permeation chromatography (GPC); thermal gravimetric analysis (TGA); circular dichroism, UV-vis, and luminescence spectroscopy; photophysics, and degree of anisotropy measurements]. From the CD measurements, the chiral environment of the phosphine ligands is modestly felt by the aryl moieties. Concurrently, the TGA shows th…
Characterization of Iron−Carbonyl-Protected Gold Clusters
2009
Ligand-stabilized nanometer-sized gold particles are interesting building blocks for molecular electronics, precursors for catalysts, optical labels for biomolecules and diagnosis, and potential nontoxic carriers for therapeutics. In this work we characterize for the first time, by means of near-infrared and Raman spectroscopy and time-dependent density functional calculations, gold clusters protected with iron-carbonyl ligands, such as {Au(22)[Fe(CO)(4)](12)}(6-) shown in the figure. Surprisingly, our results show that these novel compounds bear many analogues to another, well-studied, class of gold clusters, namely those of thiolate-monolayer-protected gold clusters. Our work adds a new d…
Ferrocenyl (P,N)-diphosphines incorporating pyrrolyl, imidazolyl or benzazaphospholyl moieties: Synthesis, coordination to group 10 metals and perfor…
2013
Abstract Three novel symmetrical ferrocenyl diphosphines with tertiary phosphorus atoms holding respectively nitrogen-containing heterocyclic derivatives of pyrrole, imidazole and benzazaphosphole were synthesized and characterized. Up to now, integration of heteroaromatic fragments, or more generally hetero-cycles, as substituents on the tertiary phosphines of symmetrical ferrocenyl diphosphines has been limited to the furyl motif. Their coordination to palladium and platinum group 10 transition metals was exemplified, and analyzed using single crystal X-ray diffraction. The performances obtained in palladium-catalyzed copper-free Sonogashira and Suzuki cross-coupling reactions using bromo…
New heteronuclear gold(I)-platinum(II) complexes with cytotoxic properties: are two metals better than one?
2014
A series of mono- and heterodinuclear gold(I) and platinum(II) complexes with a new bipyridylamine-phosphine ligand have been synthesized and characterized. The X-ray structures of the ligand precursor 4-iodo-N,N-di(pyridin-2-yl)benzamide, and of one gold derivative are reported. All the complexes display antiproliferative properties in vitro in human cancer cells in the range of cisplatin or higher, which appear to correlate with compounds' uptake. Interestingly, studies of the interactions of the compounds with models of DNA indicate different mechanisms of actions with respect to cisplatin. The biological activity study of these complexes provides useful information about the interest of…
Chiral diphosphine derivatives of alkylidyne tricobalt carbonyl clusters – A comparative study of different cobalt carbonyl (pre)catalysts for (asymm…
2016
Reaction of the tricobalt carbyne cluster [Co-3(mu(3)-CH)(CO)(9)] with chiral diphosphines of the Josiphos and Walphos families affords the new clusters [Co-3(mu(3)-CH)(CO)(7)(P-P*)] in good yield (P-P* = J004 (1), J005 (2), J007 (3), W001 (4), W003 (5)). The new alkylidyne tricobalt clusters, and the previously known [Co-3(mu(3)-CH)(CO)(7)(mu-J003)], have been tested as catalysts/catalyst precursors for intermolecular Pauson-Khand cyclization, using norbornene and phenylacetylene as substrate. The diphosphine-substituted tricobalt carbonyl clusters proved to be viable catalysts/catalyst precursors that gave products in moderate to good yields, but the enantiomeric excesses were low. When t…
Synthesis of ortho-fonctionnalized arylphosphines and their applications
2020
This thesis reports with the synthesis of ortho-functionnalized phosphines bearing phosphonium and 1,2,3-triazole moieties.The synthesis of phosphines-phosphoniums, using as key-step Phospha-Fries rearrangement and Appel reaction is described. Eight new phosphines- phosphoniums, bearing aryl, alkyl or ferrocenyl fragments on the phosphonium part, have been prepared with overall yields reaching 48%. These phosphines- phosphoniums have been used in the preparation of gold (I) complexes which have been characterized using spectroscopic methods and X ray diffraction. Both gold (I) complexes and phosphines-phosphoniums have been studied in biology and these compounds turned out to be cytotoxic i…
Highly Photoluminescent Blue Ionic Platinum-Based Emitters
2019
New cycloplatinated N-heterocyclic carbene (NHC) compounds with chelate diphosphines (P^P) as ancillary ligands: [Pt(R-C^C*)(P^P)]PF6 (R = H, P^P = dppm (1A), dppe (2A), dppbz (3A); R = CN, P^P = dppm (1B), dppe (2B), dppbz (3B)) have been prepared from the corresponding starting material [{Pt(R-C^C*)(μ-Cl)}2] (R = H, A, R = CN, B) and fully characterized. The new compound A has been prepared by a stepwise protocol. The photophysical properties of 1A–3A and 1B–3B have been widely studied and supported by the time-dependent-density functional theory. These compounds show an efficient blue (dppe, dppbz) or cyan (dppm) emission in PMMA films (5 wt %), with photoluminescence quantum yield (PLQY…