Hemilabile imino-phosphine palladium(II) complexes: synthesis, molecular structure, and evaluation in Heck reactions

2014 ◽  
Vol 68 (7) ◽  
Author(s):  
William Motswainyana ◽  
Martin Onani ◽  
Roger Lalancette ◽  
Paul Tarus
Keyword(s):  
Molecular Structure ◽  
Planar Geometry ◽  
Coordination Geometry ◽  
Coupling Reactions ◽  
Heck Coupling ◽  
Heck Reactions ◽  
Reaction Conditions ◽  
X Ray ◽  
X Ray Crystallography ◽  
Square Planar

AbstractThe ligands 2-(diphenylphosphino)benzyl-(2-thiophene)methylimine (V) and 2-(diphenylphosphino) benzyl-(2-thiophene)ethylimine (VI) were prepared from 2-(diphenylphosphino)benzaldehyde and thiophene amines with very good yields. An equimolar reaction of V and VI with either PdCl2(cod) (cod = cyclooctadiene) or PdClMe(cod) afforded palladium(II) complexes I–IV. The molecular structure of II was confirmed by X-ray crystallography. The coordination geometry around the palladium atom exhibited distorted square planar geometry at the palladium centre. Complexes I, II, and IV were evaluated as catalysts for Heck coupling reactions of iodobenzene with methyl acrylate under mild reaction conditions; 0.1 mole % catalyst, Et3N base, MeCN reflux for 8 h, 80°C; isolated yield on a 10 mmol scale with catalyst I (64 %), II (68 %), and IV (58 %). They all exhibited significant activities.

scholarly journals Reaction with Proteins of a Five-Coordinate Platinum(II) Compound

2019 ◽  
Vol 20 (3) ◽  
pp. 520 ◽  
Author(s):  
Giarita Ferraro ◽  
Tiziano Marzo ◽  
Maria Cucciolito ◽  
Francesco Ruffo ◽  
Luigi Messori ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Platinum Complexes ◽  
Rnase A ◽  
Side Chain ◽  
Planar Geometry ◽  
Ionization Mass ◽  
X Ray ◽  
X Ray Crystallography ◽  
Egg White Lysozyme ◽  
Square Planar

Stable five-coordinate Pt(II) complexes have been highlighted as a promising and original platform for the development of new cytotoxic drugs. Their interaction with proteins has been scarcely studied. Here, the reactivity of the five-coordinate Pt(II) compound [Pt(I)(Me) (dmphen)(olefin)] (Me = methyl, dmphen = 2,9-dimethyl-1,10-phenanthroline, olefin = dimethylfumarate) with the model proteins hen egg white lysozyme (HEWL) and bovine pancreatic ribonuclease (RNase A) has been investigated by X-ray crystallography and electrospray ionization mass spectrometry. The X-ray structures of the adducts of RNase A and HEWL with [Pt(I)(Me)(dmphen)(olefin)] are not of very high quality, but overall data indicate that, upon reaction with RNase A, the compound coordinates the side chain of His105 upon releasing the iodide ligand, but retains the pentacoordination. On the contrary, upon reaction with HEWL, the trigonal bi-pyramidal Pt geometry is lost, the iodide and the olefin ligands are released, and the metal center coordinates the side chain of His15 probably adopting a nearly square-planar geometry. This work underlines the importance of the combined use of crystallographic and mass spectrometry techniques to characterize, in detail, the protein–metallodrug recognition process. Our findings also suggest that five-coordinate Pt(II) complexes can act either retaining their uncommon structure or functioning as prodrugs, i.e., releasing square-planar platinum complexes as bioactive species.

scholarly journals Metal Complexes of π-Expanded Ligand (7): Syntheses, Structures and Properties of Pt(II) Complexes Containing the Isomeric 1- and 2-Alkyliminomethyl Pyrene Ligands

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 476 ◽  
Author(s):  
Xuan-Dien Luong ◽  
Xuan-Truong Nguyen
Keyword(s):  
Molecular Structure ◽  
Planar Geometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pt Complex ◽  
Physico Chemical ◽  
Clear Explanation ◽  
Square Planar ◽  
Structures And Properties ◽  
The Relationship

A [O,N] bidentate π-expanded ligand system, (E)-1-(n-octylimino)methylpyren-2-ol (2), was newly synthesized via a six-step synthesis from pyrene. The ligand 2 reacts with [PtCl2(PhCN)2] in chlorobenzene and the presence of a base at reflux for 2 h under the formation of (2(Pt)) complex with a yield of 70%. The molecular structure of (2(Pt)), studied by common spectroscopic methods and X-ray diffraction, shows a square planar geometry with a trans-configuration of the ligands. The molecular structure, absorption spectra, electrochemical properties, and phosphorescence characteristics of the (2(Pt)) complex are discussed, emphasizing the comparison with those of the previously reported Pt complex (1(Pt)) containing the isomeric ligands of 2, (E)-2-(n-octylimino)methylpyren-1-ol. The DFT calculations of the two Pt complexes are carried out and exhibit a clear explanation of the relationship between their physico-chemical characteristics.

scholarly journals Übergangsmetall-Carben-Komplexe, CXXXIV [1]. Synthese neuer Mono- und Biscarben-Komplexe der VI. Nebengruppe; Röntgenstruktur des ersten Bis[amino(alkoxy)carben]-Komplexes / Transition Metal Carbene Complexes, CXXXIV [1]. Synthesis of New Mono- and Bis-Carbene Complexes of Group VIb Elements; Structure of the First Bis[amino(alkoxy)carbene]-Complex

1984 ◽  
Vol 39 (5) ◽  
pp. 668-674 ◽  
Author(s):  
Ernst Otto Fischer ◽  
Rudolf Reitmeier ◽  
Klaus Ackermann
Keyword(s):  
Molecular Structure ◽  
Transition Metal ◽  
Spectroscopic Data ◽  
The Novel ◽  
Nucleophilic Agent ◽  
Reaction Conditions ◽  
Carbene Complexes ◽  
X Ray ◽  
X Ray Crystallography ◽  
New Compounds

The hexacarbonyl compounds of chromium, molybdenum and tungsten react with the highly nucleophilic agent Li NiPr2 and in a subsequent alkylation with (Et3O)BF4 to give the carbene complexes (CO)5M[C(N′Pr2)OEt] (1, 3, 4). In case of W(CO)6 and Mo(CO)6 the novel biscarbene complexes cis(CO)4M[C(NiPr2)OEt]2 (2, 5) are additionally obtained. Reaction conditions, properties and spectroscopic data of the new compounds are reported. The molecular structure of cis(CO)4W[C(NiPr2)OEt]2 (4) was determined by X-ray crystallography

Influence of metal ions on the formation of new metal complexes constructed from tetrachlorophthalic acid

2015 ◽  
Vol 70 (10) ◽  
pp. 711-718
Author(s):  
An-Qi Dai ◽  
Qi Yan ◽  
Jing Zhong ◽  
Sheng-Chun Chen ◽  
Ming-Yang He ◽  
...  
Keyword(s):  
Metal Ions ◽  
Significant Contribution ◽  
Transition Metal Ions ◽  
Planar Geometry ◽  
X Ray ◽  
X Ray Crystallography ◽  
Transitional Metal ◽  
Square Planar ◽  
Structural Differences ◽  
Metal Effect

AbstractReaction of 3,4,5,6-tetrachloro-1,2-benzenedicarboxylyic acid (1,2-H2BDC-Cl4) with transitional metal salts at room temperature in mixed DMF/H2O solvent affords three complexes formulated as [Cu(1,2-HBDC-Cl4)2(DMF)2] (1), {[Cd(1,2-HBDC-Cl4)2(H2O)4]·2DMF} (2), and {[Ni(1,2-BDC-Cl4)(H2O)5]·DMF·H2O} (3) (DMF = N,N-dimethylformamide). All these complexes have been characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and single-crystal X-ray crystallography. In 1, the CuII ion is four-coordinated with a square-planar geometry formed by two 1,2-HBDC-Cl4 anions and two DMF ligands; in 2, the CdII ion takes an octahedral geometry coordinated by two 1,2-HBDC-Cl4 anions and four aqua ligands; while in 3, the NiII ion is octahedrally coordinated by one 1,2-BDC-Cl4 dianion and five aqua ligands. Intermolecular O–H···O hydrogen bonds and Cl···Cl (or C–H···Cl) interactions provide a significant contribution to stabilizing the three mononuclear structures in the solid state. The results suggest that structural differences among them are attributed to the influence of transition metal ions. The fluorescence of the complexes and of 1,2-H2BDC-Cl4 has been investigated. No significant metal effect has been observed.

3-Deoxy-D-erythro-hexos-2-ulose bis(thiosemicarbazone) copper(II) chelate. Studies in solution and in the solid state

1999 ◽  
Vol 77 (9) ◽  
pp. 1492-1497 ◽  
Author(s):  
Sandra Signorella ◽  
Claudia Palopoli ◽  
Alejandro Frutos ◽  
Graciela Escandar ◽  
Tomoaki Tanase ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Structure Stability ◽  
Planar Geometry ◽  
Powdered Sample ◽  
Coordination Geometry ◽  
Spectra Analysis ◽  
X Ray ◽  
Local Coordination ◽  
Square Planar ◽  
X Ray Absorption

The 3-deoxy-D-erythro-hexos-2-ulose bis(thiosemicarbazone) (LH2) acts as a tetradentate ligand with S2N2 donor sites to form a copper(II) chelate (Cu(II)L). The Cu K-edge X-ray absorption spectra analysis of a powdered sample revealed a square-planar S2N2 local coordination geometry with average Cu—N and Cu—S distances of 1.92 and 2.33 Å. The EXAFS and XANES spectra and the structural parameters of a DMF solution sample indicate the retention of the square-planar local structure of the Cu(II)S2N2 chromophore upon dissolution. Semiempirical PM3 calculations indicate that the structure of Cu(II)L with the copper(II) ion bound to the S2N2 donor set disposed in a square-planar geometry is the most favorable one (with the highest |ΔHf |). The formation constant (log Kf = 20.65 ± 0.06) of the neutral [CuL] species was calculated in 30% v/v dioxane-water and the protonation and deprotonation constants determined.Key words: bis(thiosemicarbazone), copper(II), chelate, structure, stability constant.

The crystal and molecular structure of cis-dichloro(2,2′-o-phenylenebisbenzothiazole)copper(II)

1979 ◽  
Vol 57 (11) ◽  
pp. 1368-1371 ◽  
Author(s):  
Richard G. Ball ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Coordination Geometry ◽  
Full Matrix ◽  
X Ray ◽  
Square Planar ◽  
The Mean ◽  
Final Agreement ◽  
Cl Atoms ◽  
Least Squares Techniques

The molecular structure of cis-dichloro(2,2′-o-phenylenebisbenzothiazole)copper(II) has been determined by single crystal X-ray diffractometry. The crystal is monoclinic, P21/n, a = 8.408(1), b = 15.819(1), c = 14.229(2) Å, β = 93.19(1)°, and Z = 4. The structure has been refined by full-matrix least-squares techniques on F, using 3316 unique reflections for which F2 > 3σ(F2), to a final agreement factor of 0.028. The complex adopts an approximately square planar coordination geometry with the Cu bound to two cis Cl atoms and the N atoms of the chelating benzothiazole ligand. The mean Cu—N and Cu—Cl distances are 2.016(6) and 2.217(6) Å, respectively.

Bis(di-tert-butylphosphino)ethan-nickel(0)-Komplexe / Bis(di-tert-butylphosphino)ethane-nickel(0) Complexes

1993 ◽  
Vol 48 (5) ◽  
pp. 608-626 ◽  
Author(s):  
Klaus-Richard Pörschke ◽  
Christian Pluta ◽  
Bernd Proft ◽  
Frank Lutz ◽  
Carl Krüger
Keyword(s):  
Molecular Structure ◽  
Nmr Spectroscopy ◽  
Coordination Geometry ◽  
Screw Axis ◽  
Open Chain ◽  
X Ray ◽  
X Ray Crystallography ◽  
Rapid Exchange ◽  
Displacement Reactions ◽  
Diene Ligands

Ni(cdt) reacts with tBu2Bu2PC2H4P4P'Bu2 in pentane at 20°C to yield brownish crystals of (tBu2Bu2PC2H4P4P'Bu2)Ni(η2-C12H18) (1). The molecular structure of 1, as established by X-ray crystallography, exhibits a trigonal-planar coordination geometry of the nickel center with a η2bonded cdt ligand. In the crystal 1 exists as two enantiomers, which are determined by the leftor right-handed screw axis of the cdt ligand. The cdt ligand in 1 resists most typical displacement reactions but 1 reacts with CO at – 78°C to afford the colorless 18e complex (tBu2Bu2PC2H4P4P'Bu2)Ni(CO)2 (2). From the reaction of Ni(cod)2 with tBu2Bu2PC2H4P4P'Bu2 yellow needles of (tBu2Bu2PC2H4P4P'Bu2)Ni(η2-cod) (3) are obtained. Low temperature NMR spectroscopy established that only one diene C=C bond is coordinated to nickel(0). At higher temperatures a rapid exchange of the coordinated and unbound C=C bonds is induced. When solutions of 3 are kept at 20°C for several days the dinuclear, almost insoluble yellow complex {(tBu2PC2H4P4P'Bu2)Ni}2(μ-η2,η2-cod) (4) precipitates. The reaction of Ni(C2H4)3 and tBu2Bu2PC2H4P4P'Bu2 affords orange (tBu2Bu2PC2H4P4P'Bu2)Ni(C2H4) (5). From Ni(1,5-hexadiene)2 and tBu2Bu2PC2H4P4P'Bu2 in 1,5-hexadiene the yellow-greenish complex (tBu2Bu2PC2H4P4P'Bu2)Ni(η2-C6H10) (6) is obtained. As for 3, only one diene C=C bond is coordinated to nickel(0), but the structure is fluxional with exchange of the coordinated and unbound C=C bonds (NMR at 20°C). From a solution of 6 in pentane the dinuclear, diastereomeric compounds rac/meso-{(tBu2PC2H4P4P'Bu2)Ni}2(μ-η2,η2-C6H10) (7a,b) separate in large yellow crystals. In similar reactions the 1,6-heptadiene complexes (tBu2Bu2PC2H4PtBu2)Ni(η2-C7H12) (8) and rac/meso-{(tBu2Bu2PC2H4PtBu2)Ni}2(µ-η2μ-η2,η2-C7H12) (9a,b) are also obtained. In 6, 7a,b, 8, and 9a,b the open-chain diene ligands can easily be displaced, e.g., by ethene to afford 5. Thus, complexes 6, 7a,b, 8, 9a, b are the most reactive. These complexes react readily (the ethene derivative 5 also reacts but very slowly) with butadiene to yield large yellow cubes of (tBu2Bu2PC2H4P4P'Bu2)Ni(η72-C4H6) (10), which is also fluxional. The alkene complexes 5, 6, 7a, b, 8, 9a,b, 10 react with ethyne to yield yellow-brownish crystalline (tBu2tBu2PC2H4P4P'Bu2)Ni(C2H2) (11).

Applications of molybdenum-95 N.M.R. spectroscopy. VI. 95Mo and 13C N.M.R. of certain cis-dioxomolybdenum(VI) compounds and related species. The crystal and molecular structure of Bis(N,N-diethylhydroxylamido(l -)-O,N)- disulfidomolybdenum(VI) hemibenzene

1982 ◽  
Vol 35 (11) ◽  
pp. 2183 ◽  
Author(s):  
SF Gheller ◽  
TW Hambley ◽  
PR Traill ◽  
RTC Brownlee ◽  
MJ O'Conner ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Related Species ◽  
Crystal And Molecular Structure ◽  
Coordination Geometry ◽  
Crystal Data ◽  
X Ray ◽  
X Ray Crystallography ◽  
Sulfide Ligands

The 95MO n.m.r. spectra of a series of compounds containing the fac-[MoVIO3] and cis-[ MoVIO2] units are reported, together with those for the series [MoX2(R2NO)2] (X = O or S; R = Et, PhCH2). Trends in the data are discussed. The stereochemistry in solution of certain of the cis-dioxo species is assigned by means of 13C n.m.r. spectroscopy. The crystal and molecular structure of [MoS2(Et2NO)2],0.5C6H6 has been determined by X-ray crystallography. The steric and electronic requirements of the terminal sulfide ligands significantly affect the detailed coordination geometry relative to that observed for the dioxo analogue [MoO2(Et2NO)2]. Crystal data: a 10.162(2), b 11.836(2), c 14.437(2) �, β 106.12(2)� P21/a; Z 4.

trans-Bis[1,3-bis(2,4,6-trimethylphenyl)imidazolidin-2-ylidene]dichloronickel(II): Synthesis and Structure

2007 ◽  
Vol 72 (5-6) ◽  
pp. 609-617 ◽  
Author(s):  
Andrzej Kozioł ◽  
Stanisław Pasynkiewicz ◽  
Antoni Pietrzykowski ◽  
Lucjan B. Jerzykiewicz
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Nickel Atom ◽  
Planar Geometry ◽  
Monoclinic Crystal System ◽  
X Ray Diffraction ◽  
Monoclinic Crystal ◽  
One Pot ◽  
X Ray ◽  
Square Planar

trans-Bis[1,3-bis(2,4,6-trimethylphenyl)imidazolidin-2-ylidene]dichloronickel(II), [NiCl2(SIMes)2], was synthesized in a one-pot reaction of fluorenyllithium with nickel(II) bromide followed by the addition of 1,3-bis(2,4,6-trimethylphenyl)imidazolidinium chloride. Labile difluorenyl- nickel, formed in the course of the reaction, behaves differently than nickelocene and indenocene in analogous reactions. It exchanges both fluorenyl ligands giving the title compound. The crystal and molecular structure of this compound have been determined by single-crystal X-ray diffraction. The compound crystallizes in the monoclinic crystal system with square-planar geometry around the central nickel atom.

The crystal and molecular structure of the binuclear complex [(μ-S)-α,α'-{(2-Mercapto-4-methylbenzene-1,3-diyl)di(methylidyne)di(azino)}bis(cyclohexanemethanol)ato(3 - )]-(μ-1-propylimidazolato-C(4),N(3))-dipalladium(II)-ethanol (1/0.75)

1984 ◽  
Vol 37 (7) ◽  
pp. 1395 ◽  
Author(s):  
BF Hoskins ◽  
IAS Mcdonald
Keyword(s):  
Molecular Structure ◽  
Binuclear Complex ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
Fourier Methods ◽  
X Ray ◽  
X Ray Crystallography ◽  
Square Planar ◽  
Planar Geometries ◽  
Significant Structure

The crystal and molecular structure of the 1-propylimidazolate bridged binuclear complex, LPd2(primid) has been determined by single-crystal X-ray diffraction techniques at 20�C; disordered ethanol molecules are also present in the lattice. The quinquedentate ligand L3- is formally the trianion α,α'-{(2-mercapto-4-methylbenzene-1,3-diyl)di(methylidyne)di(azino)bis(cyclohexane-methanol)ato(3 -). Crystals of LPd2 (primid) are triclinic, P1, with a 7.078(2), b l3.615(3), c 17365(3) �, α 78.52(2), β 80.21(2) and γ 83.83(2)�. The structure was solved by conventional Fourier methods and refined by full-matrix least-squares procedures to convergence with R and Rw 0.053 obtained for the 4133 statistically significant structure amplitudes. The ligand sidearms are essentially equivalent with both palladium centres displaying similar distorted square-planar geometries, the separation being 3.605 �. The propylimidazolate bridging group is comfortably accommodated within the binuclear framework and displays a geometry typical of metal complexes of imidazole and its derivatives. Coordination to the palladium centres occurs through C4 and N3, a bridging mode not previously characterized by X-ray crystallography, and one which illustrates the remarkable stability and flexibility of the binuclear LPd2+ core.

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