Synthesis and X-Ray Structure of a Heterovalent, Cycloaurated Pentafluorophenylgold(I)/Pentafluorophenylgold(III) Complex

2002 ◽  
Vol 55 (4) ◽  
pp. 267 ◽  
Author(s):  
M. A. Bennett ◽  
S. K. Bhargava ◽  
F. Mohr ◽  
L. L. Welling ◽  
A. C. Willis
Keyword(s):  
Chelate Ring ◽  
Gold Atom ◽  
Linear Arrangement ◽  
X Ray ◽  
X Ray Crystallography ◽  
Membered Chelate Ring ◽  
Square Planar

The heterovalent gold(I)/gold(III) complex [(C6F5)AuI(μ-2-Ph2PC6H3-6-Me)AuIII(C6F5){η2-(6-MeC6H3-2-PPh2)}] has been prepared and structurally characterized by X-ray crystallography. It shows square planar stereochemistry at AuIII incorporating a four-membered chelate ring and linear arrangement at AuI. The compound is a rare example of a heterovalent complex containing an aryl ligand on each gold atom.

Boron Chelates and Boron-Metal Chelates, X [1]. 3-(2-Hydroxyphenyl)-2,2-diphenyl-1-oxa-3-azonia-2-borata-naphthalene-methanol (1/1): Synthesis, Spectroscopic Investigations and Crystal Structure

1982 ◽  
Vol 37 (11) ◽  
pp. 1450-1455 ◽  
Author(s):  
Rudolf Allmann ◽  
Eberhard Hohaus ◽  
Stanislaw Olejnik
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Structure Analysis ◽  
Title Compound ◽  
Chelate Ring ◽  
Boron Chelates ◽  
X Ray ◽  
Membered Chelate Ring ◽  
Compound C ◽  
Overall Ratio

The title compound, C25H20BNO2 · CH3OH, was examined by UV, IR, 1H, and 13C NMK spectroscopy as well as by thermogravimetry and X-ray structure analysis (Pbnb, a = 8.815, b = 17.309, c=28.992 Å, R= 5.5%). These investigations show the six-membered chelate ring (chelate A) to exist as formulated in [2] and not as a five-membered chelate ring B. One methanol molecule connects two chelate molecules by hydrogen bonds, resulting in an overall ratio of chelate to methanol of 1 : 1.

Crystal Structure, Spectroscopic and Redox Properties of Copper(II) Bis{2-[(2,6-dimethylphenyl)iminomethyl-3-methoxyphenolate]}

2007 ◽  
Vol 62 (9) ◽  
pp. 1133-1138 ◽  
Author(s):  
Veli T. Kasumov ◽  
Ibrahim Uçar ◽  
Ahmet Bulut ◽  
Fevzi Kösal
Keyword(s):  
Crystal Structure ◽  
Title Complex ◽  
Redox Properties ◽  
Orthorhombic Space Group ◽  
Long Distance ◽  
X Ray ◽  
X Ray Crystallography ◽  
Square Planar ◽  
Planar Molecules ◽  
Exchange Interaction Parameter

The coordination chemistry of N-(2,6-di-methylphenyl)-2-hydroxy-3-methoxybenzaldimine (1) with Cu(II) has been investigated by X-ray crystallography, electronic and EPR spectroscopies, as well as by electro- and magnetochemistry. The title complex 2 crystallizes in the orthorhombic space group P212121 (a = 8.1538, b = 17.7466, c =19.8507 Å). The mononuclear square-planar molecules 2 featuring trans-N2O2 coordination are connected via weak intermolecular C-H· · ·π interactions into infinite chains parallel to the a axis. Although the intermolecular Cu· · ·Cu separations within individual chains and between chains are very long (8.154 and 9.726 Å ), the exchange interaction parameter G = 2.03 < 4, estimated from solid state EPR spectra, suggests the existence of long-distance superexchange pathways between adjacent Cu(II) centers. The electronic and electrochemical features of the compound are also discussed.

Induction of Λ-helicity in a zinc complex with an alanine-appended aminopyridine ligand

2021 ◽  
Vol 77 (8) ◽  
Author(s):  
Berislav Perić ◽  
Zoran Kokan ◽  
Srećko I. Kirin
Keyword(s):  
Zinc Complex ◽  
Chelate Ring ◽  
Ionic Interactions ◽  
Stacking Interactions ◽  
Neutral Ligand ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Third ◽  
Membered Chelate Ring ◽  
The Stability

The crystal structure of tris[dimethyl 5-({1-[(pyridin-2-yl-κN)carbamoyl-κO]ethyl}carbamoyl)benzene-1,3-dicarboxylate]zinc(II) dinitrate acetonitrile trisolvate, [Zn(C19H19N3O6)3](NO3)2·3CH3CN or [Zn(L)3](NO3)2·3CH3CN, (1), has been determined by single-crystal X-ray diffraction. The neutral ligand L coordinates to the Zn2+ cation in a bidentate fashion via the pyridine N atom and an amide O atom, forming a six-membered chelate ring. The Λ-helical chirality of the Zn2+ coordination sphere is induced by pendant L-alanine residues through stacking interactions between the arene groups of two coordinated ligands, assisted by a hydrogen bond between amide groups bonded to the stacked arene rings. The third ligand is coordinated to the Zn2+ cation by the same six-membered chelate ring, but in the opposite direction with respect to the analogous chelate rings of the first two coordinated ligands. Besides ionic interactions between [ZnL 3]2+ complexes and NO3 − anions, several types of hydrogen bonds and intermolecular stacking interactions contribute to the stability of the solid-state phase.

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.

Trifluoromethylaryl-Substituted Quinoxalines: Unusual Ruthenium- Amidininate Complexes and their Suitability for Anellation Reactions

2005 ◽  
Vol 60 (8) ◽  
pp. 843-852 ◽  
Author(s):  
Frank Schramm ◽  
Dirk Walther ◽  
Helmar Görls ◽  
Christian Käpplinger ◽  
Rainer Beckert
Keyword(s):  
Boron Trifluoride ◽  
Chelate Ring ◽  
Ruthenium Complex ◽  
Structural Motif ◽  
X Ray Diffraction ◽  
Quinoxaline Derivative ◽  
Imidazolium Salt ◽  
X Ray ◽  
Membered Chelate Ring ◽  
Complex Fragment

The reaction of the 2,3-dianilino-quinoxaline 1 with an equivalent of triethyl orthoformiate results in a cyclic aminalester 2. An excess of triethyl orthoformate results in the carbene dimer 4. With the help of boron trifluoride, 2 can be transformed into the imidazolium salt 3. Reaction of 1 with KOtC4H9 leads to a quinoxaline derivative 5 under anellation of a benzene ring whereas the related pyrazino-quinoxaline 6 (formed from tetraaminobenzene tetrahydrochloride and bis-(3- trifluoromethylphenyl) oxalimidoyl chloride) does not react under similar conditions. However, 6 can be activated towards anellation by employing the complex fragment [(tbbpy)2Ru]2+, tbbpy: bis(4,4’-di-tert-butyl-2,2’-bipyridine). This generates an unusual ruthenium complex 9 which could be characterised by X-ray diffraction. Complex 9 contains a pentacene derivative and coordinates the ruthenium fragment at the amidinate moiety thus forming a four-membered chelate ring. Isolation of a second ruthenium complex 8 which contains an intact pyrazino-quinoxaline 6 in which the metal is also coordinated to an amidinato group supports the assumption that the anellation reaction occurs only after metal complexation at the amidinate group. In contrast to this, the smaller [(tmeda)2Pd]2+ fragment reacts with the pyrazino-quinoxaline 6 to form the mononuclear Pd complex 10. Its structural motif (X-ray diffraction) shows that the palladium centre coordinates at the 1,4-diamino group of the intact pyrazino-quinoxaline to form a five-membered chelate ring. This suggests that the bulkiness of the complex fragment determines whether or not an anellation reaction can take place.

Preparation and characterization of Tl(1,2-C2H4Cl2)B(OTeF5)4: a metal complex of a least coordinating solvent and a least coordinating anion

1992 ◽  
Vol 70 (3) ◽  
pp. 726-731 ◽  
Author(s):  
Paul K. Hurlburt ◽  
Oren P. Anderson ◽  
Steven H. Strauss
Keyword(s):  
Metal Ion ◽  
Chelate Ring ◽  
Ion Solvation ◽  
Crystalline Compound ◽  
Triclinic Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
Solid Salt ◽  
Solvent Metal

Addition of B(OTeF5)3 to TIOTeF5 in the weakly coordinating solvents dichloromethane, 1,2-dichloroethane, and 1,1,2-trichlorotrifluoroethane produces solutions of M(solv)x+B(OTeF5)4−. When the solvent was 1,2-dichloroethane, the crystalline compound Tl(1,2-C2H4Cl2)B(OTeF5)4 was isolated and studied by X-ray crystallography: triclinic, space group [Formula: see text], a = 9.221 (4), b = 11.396(5), c = 12.538 (4) Å, α = 110.75 (3)°, β = 101.72(3)°, γ = 99.74 (3)°, Z = 2, T = −116 °C. The Tl(1,2-C2H4Cl2)+ cation contains a five-membered chelate ring with Tl—Cl distances of 3.138 (4) and 3.179 (3) Å. The metal ion is weakly bonded to four B(OTeF5)4− counterions, with nine Tl—F interactions that range from 2.950 (5) to 3.981 (8) Å. When the solvent is dichloromethane or 1,1,2-trichlorotrifluoroethane, only the unsolvated solid salt TlB(OTeF5)4 can be isolated by crystallization. This salt is thermally unstable, slowly forming TlOTeF5 and volatile B(OTeF5)3. Keywords: noncoordinating anion, noncoordinating solvent, metal ion solvation.

Coordination chemistry of thioether–pyridazine macrocycles. III. Synthetic, structural, and spectroscopic studies of Cu(II), Cu(II)Cu(I), and Cu(I) complexes of a hexathiapyridazinophane macrocyclic ligand

1993 ◽  
Vol 71 (7) ◽  
pp. 1086-1093 ◽  
Author(s):  
Liqin Chen ◽  
Laurence K. Thompson ◽  
John N. Bridson
Keyword(s):  
Mass Spectrometry ◽  
Macrocyclic Ligand ◽  
Spectroscopic Studies ◽  
Orthorhombic System ◽  
Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
Triclinic System ◽  
Square Planar ◽  
Copper Centre

The preparation and properties of the thioether–pyridazine macrocycle (L4; C16H20S6N4) containing two pyridazine subunits, and its Cu(II), Cu(II)Cu(I), and Cu(I) complexes are described. The ligand is characterized by 1H nuclear magnetic resonance and mass spectrometry, and the complexes by infrared, eleetronic spectra, and magnetism, and in some cases by X-ray crystallography. The complex [Cu2(L4)Cl4]x, (1) crystallized in the triclinic system, space group [Formula: see text] with a = 8.6204(8) Å, b = 9.850(1) Å, c = 8.348(1) Å, α = 111.46(1)°, β = 102.50(1)°, γ = 71.818(9)°, V = 622.6(1) Å3, and Z = 1 (R = 0.043, Rw = 0.042 for 1312 reflections). Two monodentate pyridazine rings in the same ligand bind to one trans square-planar copper centre (CuN2Cl2) with two sulfurs from each ligand binding to another trans square-planar copper centre (CuS2Cl2) to form a polynuclear chain. The complex [Cu(L4)Cl2] (3) crystallized in the triclinic system, space group [Formula: see text] with a = 11.001(1) Å, b = 12.888(2) Å, c = 8.704(1) Å, α = 102.89(1)°, β = 103.36(1)°,γ = 75.84(1)°, V = 1145.8(3) Å3 and Z = 2 (R = 0.056, Rw = 0.044 for 2059 reflections). A trans square-planar structure (CuN2Cl2) exists for 3 with monodentate pyridazines. [Cu(L4)(NO3)2] (4) crystallized in the orthorhombic system, space group P212121, with a = 15.148(2) Å, b = 15.562(3) Å, c = 11.064(1) Å, V = 2608.2(7) Å3 and Z = 4 (R = 0.039, Rw = 0.034 for 1864 reflections). Two monodentate pyridazine rings and two bidentate nitrates bind to a pseudo-octahedral copper(II) centre.

scholarly journals Crystal structure of unsymmetrical α-diimine palladium(II) complex cis-[{ArN=C(Me)–(Et)C=NAr}PdCl2] [Ar = 2,6-(iPr)2C6H3]

2017 ◽  
Vol 73 (8) ◽  
pp. 1148-1150
Author(s):  
Shravan Kumar Ellandula ◽  
Cosmos Opoku Amoako ◽  
Joel T. Mague ◽  
Perumalreddy Chandrasekaran
Keyword(s):  
Molecular Structure ◽  
Palladium Complex ◽  
Crystal And Molecular Structure ◽  
Chelate Ring ◽  
X Ray Diffraction ◽  
X Ray ◽  
Square Planar ◽  
Diimine Ligand ◽  
Coordination Plane ◽  
N Vector

The unsymmetrical α-diimine ligand N-{2-[2,6-bis(propan-2-yl)phenylimino]pentan-3-ylidene}-2,6-bis(propan-2-yl)aniline, [ArN=C(Me)—(Et)C=NAr] [Ar = 2,6-(iPr)2C6H3], (I), and the corresponding palladium complex, cis-(N-{2-[2,6-bis(propan-2-yl)phenylimino]pentan-3-ylidene}-2,6-bis(propan-2-yl)aniline)dichloridopalladium(II) 1,2-dichloroethane monosolvate, [PdCl2(C29H42N2)]·C2H4Cl2 or cis[PdCl2{I}], (II), have been synthesized and characterized. The crystal and molecular structure of the palladium(II) complex have been established by single-crystal X-ray diffraction. The compound crystallized along with a 1,2-dichloroethane solvent of crystallization. The coordination plane of the PdII atom shows a slight tetrahedral distortion from square-planar, as indicated by the dihedral angle between the PdCl2 and PdN2 planes of 4.19 (8)°. The chelate ring is folded along the N...N vector by 7.1 (1)°.

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