31989-57-8Relevant academic research and scientific papers
Combining organometallic and Werner-type coordination sites in highly preorganized heterobimetallic systems
R?der, Jens C,Meyer, Franc,Winter, Rainer F,Kaifer, Elisabeth
, p. 113 - 120 (2002)
A first example of a novel class of preorganized bimetallic complexes is reported, in which both an organometallic CpMn(CO)2 fragment and a classical Werner-type coordination site are arranged in close proximity by means of a bridging pyrazolat
Novel heterobimetallic compounds with metal-metal bonds: The use of quinolyl-substituted metallocenes as tridentate ligands
Enders, Markus,Kohl, Gerald,Pritzkow, Hans
, p. 1111 - 1117 (2002)
1,1′-Bis(quinolyl)ferrocene (1) and 1,1′-bis(quinolyl)ruthenocene (2) were prepared by palladium-catalyzed cross-coupling of zincated metallocenes ((C6H4ZnCl)2M; M = Fe, Ru) with 8-bromoquinoline. Both complexes can serve as tridentate ligands toward d10 metal ions. Their reactions with anhydrous zinc chloride or with tetrakis(acetonitrile)copper(I) tetrafluoroborate lead to the bimetallic complexes 3-6, in which the zinc or copper ion is coordinated in a tridentate manner by the metallocene derivative 1 or 2, respectively. Two different coordination modes of the ligands 1 and 2 were observed, both with a metal-metal bond as proved by X-ray analysis. The bond distances Fe - Zn in 3 and Ru - Zn in 4 are practically identical (2.56 A); the Ru - Cu bond in 6 is somewhat longer (2.63 ?). Whereas the zinc adducts 3 and 4 contain the metallocene ligand in a Cs-symmetric arrangement with a 4-fold-coordinated Zn atom, the Ru-Cu compound 6 has a C2 symmetry with a 3-fold-coordinated Cu atom. The heterobimetallic compounds 3 and 4 are the first structurally characterized ferrocene and ruthenocene derivatives containing a metal to zinc bond. The complexes 5 and 6 are, to the best of our knowledge, the first examples of adducts of ferrocene and ruthenocene derivatives with copper.
New donor-functionalized Cp ligands: Synthesis and complexation behaviour of quinoxalyl and benzothiadiazolyl systems
Schuhen, Katrin,Sieb, David,Wadepohl, Hubert,Enders, Markus
, p. 1560 - 1567 (2009)
Sodium cyclopentadienide reacts as nucleophile with 4,7-dibromo-2,1,3- benzothiadiazole (BTZ) and leads to the new donorfunctionalized ligand Cp BTZ. Related quinoxalyl Cp systems have been prepared using Pd-catalyzed coupling with zincated Cp-
Synthesis and coordination behaviour of the new (8-quinolyl)cyclopentadienyl ligand
Enders, Markus,Kohl, Gerald,Pritzkow, Hans
, p. 66 - 73 (2001)
8-Bromoquinoline reacts with zincated cyclopentadienyl derivatives of Fe, Mn, and Re in the presence of bis(triphenylphosphine)palladium(0) to yield the corresponding 8-quinolylcyclopentadienyl metal complexes. Tricarbonyl[η5-(8-quinolyl)cyclop
Diaryltriazenido Palladium(II) complexes derived from 1-(2-bromo-4-ethoxycarbonylphenyl)-3-phenyltriazenes
Preusser, Silvio,Sch?nherr, Paul R.W.,G?rls, Helmar,Imhof, Wolfgang,Krieck, Sven,Westerhausen, Matthias
, (2019/08/07)
1-(2-Bromo-4-ethoxycarbonylphenyl)-3-phenyltriazene (1) can easily be deprotonated yielding the corresponding triazenides of lithium, silver, or triethylammonium. The equimolar metathesis reaction of [(Ph3P)2PdCl2] with th
A Combined Experimental/Computational Study of the Mechanism of a Palladium-Catalyzed Bora-Negishi Reaction
Campos, Jesús,Nova, Ainara,Kolychev, Eugene L.,Aldridge, Simon
, p. 12655 - 12667 (2017/09/18)
Experimental and computational efforts are reported which illuminate the mechanism of a novel boron version of the widespread Negishi coupling reaction that offers a new protocol for the formation of aryl/acyl C?B bonds using a bulky boryl fragment. The role of nucleophilic borylzinc reagents in the reduction of the PdII pre-catalysts to Pd0 active species has been demonstrated. The non-innocent behavior of the PPh3 ligands of the [Pd(PPh3)2Cl2] pre-catalyst under activation conditions has been probed both experimentally and computationally, revealing the formation of a trimetallic Pd species bearing bridging phosphide (PPh2?) ligands. Our studies also reveal the monoligated formulation of the Pd0 active species, which led us to synthesize related (η3-indenyl)Pd-monophosphine catalysts which show improved catalytic performances under mild conditions. A complete mechanistic proposal to aid future catalyst developments is provided.
Pd(η3-1-PhC3H4)(η5- C5H5), an unusually effective catalyst precursor for heck-mizoroki and sonogashira cross-coupling reactions catalyzed by bis-phosphine palladium(0) compounds
Fraser, Andrew W.,Jaksic, Bryan E.,Batcup, Rhys,Sarsons, Christopher D.,Woolman, Michael,Baird, Michael C.
supporting information, p. 9 - 11 (2013/03/13)
The compound Pd(η3-1-PhC3H4) (η5-C5H5) reacts essentially quantitatively with a variety of phosphines L to form cross-coupling catalysts of the type PdL2 and has recently been shown to be a much more effective catalyst precursor for Suzuki-Miyaura cross-coupling reactions in comparison to more commonly utilized precursors such as Pd(PPh3)4, Pd 2(dba)3, and Pd(OAc)2, which do not effectively generate two-coordinate species PdL2. This advantage is expected to apply also to e.g. Heck-Mizoroki and Sonogashira cross-coupling reactions, both of which are generally believed to be catalyzed by species of the type PdL 2. Therefore, comparisons of the efficacies of catalyst systems based on Pd(η3-1-PhC3H4)(η5- C5H5), Pd(PPh3)4, Pd 2(dba)3, and Pd(OAc)2 are made utilizing the conventional coupling reactions of aryl halides with methyl acrylate and styrene for Heck-Mizoroki coupling and with phenylacetylene for Sonogashira coupling. As anticipated, catalyst systems based on Pd(η3-1-PhC 3H4)(η5-C5H5) are found to be significantly more active.
Activation and transformation of white phosphorus by palladium(ii) complexes
Kagirov,Voloshin,Rizvanov, I. Kh.,Sinyashin,Yakhvarov
, p. 1116 - 1118 (2011/02/16)
A reaction of bis(triphenylphosphine)palladium dibromide with white phosphorus in the presence of NaBPh4 selectively gives phosphorous acid H3PO3. The mechanism of the formation involves coordination of a white phosphorus molecule, ligand exchange, and hydrolysis of the coordinated P4 molecule in the coordination sphere of palladium.
Reactivity of 2-Silyl- and 2-stannyl-substituted phosphirenes
Panichakul, Duanghathai,Lim, Yi Wee,Mathey, Francois
, p. 1985 - 1987 (2010/06/18)
Two methodologies have been tested for the functionalization of phosphirenes. In the first one, the C-Si bond of a 2-silylphosphirene is activated by a substoichiometric quantity of fluoride ion (TBAF) in THF at -78 °C. Using this technique, it is possible to perform a protodesilylation or a functionalization by benzaldehyde. However, at room temperature with a stoichiometry of fluoride, a nucleophilic attack takes place at P, leading to a ring-opened fluorophosphine. Stille cross-coupling with a 2-stannylphosphirene in the presence of [PdL2] as a catalyst leads to an alkynylphosphine by [1,3] migration of tin from C to P.
Influence of the dba substitution on the reactivity of palladium(0) complexes generated from Pd02(dba-n,n′ -Z) 3 or Pd0(dba-n,n′-Z)2 and PPha 3 in oxidative addition with iodobenzene
Mace, Yohan,Kapdi, Anant R.,Fairlamb, Ian J. S.,Jutand, Anny
, p. 1795 - 1800 (2008/10/09)
The reactivity of Pd(0) complexes generated by addition of PPh3 (PPh3/Pd = 2, 4) to either Pd02(dban,n′- Z)3 (n,n′-Z = 4,4′-F, 4,4′-H, 4,4′-MeO, 3,3′,4,4′,5,5′-OMe) or Pd0(dba-n,n′-Z) 2 (n,n′-Z = 4,4′-Br, 4,4′-Cl, 4,4′-H, 4,4′-CH3, 3,3′,5,5′-OMe) in DMF is affected by the electron-donating or -accepting properties of the groups Z substituted on the aromatic rings of dba. Whatever the nature of Z, the unreactive major complexes Pd0(η2-dba-n,n′-Z)(PPh3)2 are formed, which are in equilibrium with the common reactive complex Pd 0(PPh3)2 and dba-n,n′-Z. The latter controls the concentration of the reactive Pd0(PPh3) 2 and, consequently, also controls the rate of the overall oxidative addition with phenyl iodide. The more electron donating the Z group, the lower the affinity of dba-4,4′-Z for Pd0(PPh3) 2. As a result, the overall rate of the oxidative addition with Phi is faster when Z is an electron-donating group. For a given Z, the overall oxidative addition is faster when using Pd02(dba-n,n′-Z) 3 instead of Pd0(dba-n,n′-Z)2. Therefore, the rate of the oxidative addition can be modulated by changing the electronic properties of the dba ligands determined by substituents on its phenyl groups and by changing the structure of the precursors: P02 (dba-n,n′-Z)3 versus Pd0(dba-n,n′-Z) 2.
