Search results for "Ferrocene"
showing 10 items of 306 documents
Palladium-catalyzed formation of secondary and tertiary amines from aryl dihalides with air-stable ferrocenyl tri- and diphosphines: Synthesis and X-…
2014
Abstract Robust, air-stable tridentate and bidentate ferrocenylphosphines 1,2-bis(diphenylphosphino)-1′-(diisopropylphosphino)-4-tert-butylferrocene, L5, and 1,1′-bis(diisopropylphosphino)-3,3′-bis(tert-butyl)ferrocene, L9, combined with 1 mol% of [PdCl(η3-C3H5)]2 led to two new catalytic systems which allow the coupling of aniline derivatives with mono- and dihaloarenes to form functionalized diarylamines and triarylamines. The excellent selectivity of the reactions avoids the deleterious dehalogenation of the substrates and products. The X-ray structure characterization of the related complex [PdCl2(L9)] is reported in which ligand L9 in its meso form is significantly distorted.
Diastereoselective Synthesis of Dialkylated Bis(phosphino)ferrocenes: Their Use in Promoting Silver-Mediated Nucleophilic Fluorination of Chloroquino…
2017
International audience; The diastereoselective synthesis of dialkylated ferrocenyl bis(phosphane)s bearing aryl, alkyl, and hetero- or polycyclic substituents on the phosphino groups is reported, together with their characterization in the solid state by X-ray structure analysis and in solution by multinuclear NMR spectroscopy. Introduction of various alkyl groups on the ferrocene backbone, namely, tert-butyl, isopropyl, and trimethylsilyl, has a significant influence on the stereoselectivity of the ensuing lithiation/phosphination reactions. Only the introduction of the tert-butyl groups ensures both a high yield and perfect diastereoselectivity, which leads to the exclusive formation of t…
Palladium-catalyzed heteroaryl thioethers synthesis overcoming palladium dithiolate resting states inertness: Practical road to sulfones and NH-sulfo…
2018
International audience; We provide efficient synthetic access to heteroaryl sulfones in two-steps using a simple palladium-1,1'-bis [(diphenyl)phosphanyl]ferrocene catalyst to form in high yields variously functionalized heteroaromatic thioethers. Pyridinyl-containing substrates can be subsequently selectively oxidized into sulfones and NH-sulfoximines by using very mild oxidation conditions with a high functional group tolerance. In the palladium catalyzed C-S coupling of heteroaromatic thiols, reactivity limitation is attached with electron-deficient thiols. We show that this limitation can be resolved by the successful use of 2-bromoheteroarenes in the C-S coupling. We established herein…
Nickel-catalyzed carboxylation of aryl zinc reagent with CO2: A theoretical and experimental study
2019
Abstract Two Ni-complexes with 1,1′-bis(diphenylphosphino)ferrocene (dppf) and tricyclohexylphosphine (PCy3) ligands were tested for the Ni-catalyzed cross-coupling of aryl zinc reagent with CO2 to form aryl carboxylic acid. Theoretical study with the aid of density functional theory (DFT) was carried out to understand the detailed reaction mechanism. The reasonable reaction pathway was deduced. The simulation results suggested that the free energy barrier of the rate-limiting step with (dppf)Ni is only 1.64 kcal mol−1 higher than the barrier with (PCy3)2Ni. However, our experiment provided an unexpectedly low yield by using (dppf)Ni complex as the catalyst. Further theoretical study ascrib…
Palladium-Catalyzed Hydroxycarbonylation of Aryl and Vinyl Bromides by Mixed Acetic Formic Anhydride
2006
The palladium-catalyzed hydroxycarbonylation of aryl and vinyl bromides in the presence of acetic anhydride and lithium formate as a carbon monoxide source has been developed. The combination of palladium(II) acetate with 1,1'-bis(diphenylphosphino)ferrocene (dppf) is an efficient catalytic system when the reaction is carried out at 120 °C.
On the mechanism of imine elimination from Fischer tungsten carbene complexes
2016
(Aminoferrocenyl)(ferrocenyl)carbene(pentacarbonyl)tungsten(0) (CO)5W=C(NHFc)Fc (W(CO)5(E-2)) is synthesized by nucleophilic substitution of the ethoxy group of (CO)5W=C(OEt)Fc (M(CO)5(1Et)) by ferrocenyl amide Fc-NH– (Fc = ferrocenyl). W(CO)5(E-2) thermally and photochemically eliminates bulky E-1,2-diferrocenylimine (E-3) via a formal 1,2-H shift from the N to the carbene C atom. Kinetic and mechanistic studies to the formation of imine E-3 are performed by NMR, IR and UV–vis spectroscopy and liquid injection field desorption ionization (LIFDI) mass spectrometry as well as by trapping experiments for low-coordinate tungsten complexes with triphenylphosphane. W(CO)5(E-2) decays thermally i…
New potentially cytotoxic thiolatogold(I) complexes of 1,1′-bis(diphenylphosphino)ferrocene
1996
Abstract 1,1′-Bis[chlorogold(I) diphenylphosphino] ferrocene (1) was chosen as the starting material to synthesize new thiolato gold(I) complexes. This has been achieved by substituting the chlorine atoms by monofunctional and bifunctional thiolates affording ‘open’ thiolatogold complexes and trimetallic ferrocenophane-type structures, respectively. The new 1,1′-bis(2,6-dithia-1-phosphanyl)ferrocene (7) containing directly linked P and S atoms was also prepared but no gold complex was obtained. Compound 2 crystallizes in the monoclinic space group P21/n with a=10.2632), b=21.064(4), c=16.259(3) A , β=97.06(2)° and V=3.488(1) A 3 . The distance between the two gold atoms (3.06 A) indicates a…
Ferrocene compounds: methyl 1′-aminoferrocene-1-carboxylate
2010
The title compund, [Fe(C(5)H(6)N)(C(7)H(7)O(2))], features one strong intermolecular hydrogen bond of the type N-H...O=C [N...O = 3.028 (2) A] between the amine group and the carbonyl group of a neighbouring molecule, and vice versa, to form a centrosymmetric dimer. Furthermore, the carbonyl group acts as a double H-atom acceptor in the formation of a second, weaker, hydrogen bond of the type C-H...O=C [C...O = 3.283 (2) A] with the methyl group of the ester group of a second neighbouring molecule at (x, -y - 1/2, z - 1/2). The methyl group also acts as a weak hydrogen-bond donor, symmetry-related to the latter described C-H...O=C interaction, to a third molecule at (x, -y - 1/2, z + 1/2) t…
Spin crossover in iron(II) complexes with ferrocene-bearing triazole-pyridine ligands.
2015
In the search for new multifunctional spin crossover molecular materials, here we describe the synthesis, crystal structures and magnetic and photomagnetic properties of the complexes trans-[Fe(Fctzpy)2(NCX)2]·CHCl3 where Fc-tzpy is the ferrocene-appended ligand 4-(2-pyridyl)-1H-1,2,3-triazol- 1-ylferrocene, X = S (1) and X = Se (2). Both complexes display thermal- and light-induced (LIESST) spin crossover properties characterised by T1/2 = 85 and 168 K, ΔS = 55 and 66 J K−1 mol−1 , ΔH = 4.7 and 11.1 kJ mol−1 and TLIESST = 47 K and 39 K for 1 and 2 respectively. The crystal structure of 1 and 2 measured at 275 K is consistent with the iron(II) ion in the high-spin state while the crystal st…