An Unusual Cleavage and Macrocyclization in the Zinc-Aqueous Acid Reduction of [2-Methyl-2-Nitro-N,N'-Bis(Pyridin-2-Ylmethyl)-Propane-1,3-Diamine]Coppe R(II) Cation - Crystal-Structure of the (6,13-Dimethyl-1,4,8,11-Tetraazacyclotetradecane-6,13-Diamine)Copper(II) Perchlorate Product

1986 ◽  
Vol 39 (7) ◽  
pp. 1101 ◽  
Author(s):  
GA Lawrance ◽  
BW Skelton ◽  
AH White ◽  
P Comba
Keyword(s):  
Catalytic Reduction ◽  
Electronic Spectroscopy ◽  
Major Product ◽  
Planar Geometry ◽  
X Ray ◽  
Aqueous Acid ◽  
Square Planar ◽  
Spin Resonance ◽  
Unusual Cleavage ◽  
Acid Reduction

Reduction of [2-methyl-2-nitro-N,N?-bis(pyridin-2-ylmethyl)propane- 1,3-diamine]copper(II) with zinc in aqueous hydrochloric acid and subsequent recomplexation yields the macromonocyclic complex (6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diamine)copper(II) perchlorate as the major product, apparently by cleavage of both pyridine rings from the precursor ligand and direct recombination of two saturated residues. Catalytic reduction of the nitro group in the precursor compound can be achieved cleanly over palladium-carbon with hydrogen. The macrocyclic complex crystallized in the space group P21/c, a 8.031(4), b 17.45(1), c 8.436(5) Ǻ, β 117.87(4)°, Z 2; for a single-crystal X-ray structure determination R was 0.078 for 1378 'observed' reflections. The complex is centrosymmetric, the macrocycle having pendant amines on opposite sides of the macrocyclic plane, while perchlorate oxygen atoms occupy the axial sites with Cu-O at 2.59 Ǻ. Observed Cu-N distances of 2.022(6) and 1.996(7) Ǻ are longer than usual for copper(II) amines. Electron spin resonance and electronic spectroscopy define an essentially square-planar geometry in solution, with only weak axial interactions.

Preparation, and complexes with nickel(II) and copper(II), of a diazepane amine alcohol. The structure of [4,4-dimethyl-7-(5,5,7-trimethyl-1,4-diazepan-1-yl)-5-azaheptan-2-ol]nickel(II) perchlorate

1983 ◽  
Vol 36 (7) ◽  
pp. 1341 ◽  
Author(s):  
KR Morgan ◽  
GJ Gainsford ◽  
NF Curtis
Keyword(s):  
Ground State ◽  
Coordination Compounds ◽  
Major Product ◽  
Boat Conformation ◽  
Singlet Ground State ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxygen Donor ◽  
Square Planar ◽  
Coordination Plane

Reduction of 4,4,12,12-tetramethyl-5,8,11-triazapentadecane-2,14-dione diperchlorate by sodium borohydride yields as the major product one isomer of 4,4-dimethyl-7-(5,5,7-trimethyl-1,2-diazepam 1-yl)-5-azaheptan-2-ol, pyaz. The coordination compounds [M(pyaz)] (ClO4), and [Ni(pyaz)(NCS)] CNS (M = NiII, CuII) were prepared, the latter being assigned five-coordinate structures. The structure of singlet ground state [Ni(pyaz)] (ClO4)2 was determined by X-ray diffraction [space group P212121, Z 4, a 1450.8(2), b 1522.2(1), c 1048.5(1) pm, R 0.0675, Rw 0.0768 for 2461 reflections]. The compound has a square-planar coordination arrangement, with the three nitrogen and the oxygen donor atoms of the pyaz ligand approximately coplanar [Ni-O 190.0(6) pm; Ni-N 192.8(6), 189.2(6), 189.2(6) pm in sequence N(5) of chain, N(l), N(4) of diazepane]. The diazepane ring adopts a boat conformation. One side of the nickel(II) coordination plane is sterically crowded by the presence of two axial methyl substituents. The ligand has two non-equivalent chiral centres (C(14) of the diazepane ring and C(2) of the amine alcohol chain), both present in the R configuration in the crystal studied. The three nitrogen atoms, which became chiral centres upon coordination, are present in the S configuration for two diazepane nitrogen atoms and in the R configuration for the 5-aza chain nitrogen.

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.

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.

scholarly journals Synthesis and Characterization of Catecholato Copper(II) Complexes with Sterically Hindered Neutral and Anionic N3 Type Ligands: Tris(3,5-diisopropyl-1-pyrazolyl)methane and Hydrotris(3,5-diisopropyl-1-pyrazolyl)borate

Inorganics ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 37 ◽  
Author(s):  
Kiyoshi Fujisawa ◽  
Tetsuya Ono ◽  
Moemi Okamura
Keyword(s):  
Planar Geometry ◽  
X Ray ◽  
Pyramidal Geometry ◽  
Square Planar ◽  
Ct Transitions ◽  
Sterically Hindered ◽  
Protonated Ligand ◽  
Square Pyramidal Geometry ◽  
Oxidation State Of Copper

Three catecholato copper(II) complexes, [Cu(catCl4)(L1′)], [Cu(catBr4)(L1′)], and [Cu(catCl4)(L1H)], supported by sterically hindered neutral and anionic N3 type ligands: tris(3,5-diisopropyl-1-pyrazolyl)methane (referred to as L1′) and hydrotris(3,5-diisopropyl-1-pyrazolyl)borate (referred to as L1−), are synthesized and characterized in detail. Their X-ray structures reveal that both [Cu(catCl4)(L1′)] and [Cu(catBr4)(L1′)] complexes have a five-coordinate square-pyramidal geometry and [Cu(catCl4)(L1H)] complex has a four-coordinate square-planar geometry. The L1H is unusual protonated ligand that controls its overall charge. For the three catecholato copper(II) complexes, the oxidation state of copper is divalent, and catechol exists in catecholate as two minus anion. This difference in coordination geometry affects their d-d and CT transitions energy and ESR parameters.

Darstellung von 1,3,5-Trimethyl-4,6-dioxo-1,3,5,2λ3-triazaphosphinanen; Einkristall-Röntgenstrukturanalyse eines Platin(II)-Komplexes/Preparation of 1,3,5-Trimethyl-4,6-dioxo-1,3,5,2λ3-triazaphosphinanes; Single Crystal X-Ray Diffraction Study of a Platinum(II)-Complex

1992 ◽  
Vol 47 (4) ◽  
pp. 517-525 ◽  
Author(s):  
Thomas G. Meyer ◽  
Peter G. Jones ◽  
Reinhard Schmutzler
Keyword(s):  
Crown Ether ◽  
Single Crystal ◽  
Diffraction Study ◽  
Planar Geometry ◽  
Boat Conformation ◽  
Staudinger Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
New Synthesis ◽  
Square Planar

A new synthesis for 2-chloro-1,3,5-trimethyl-4,6-dioxo-1,3,5,2λ3-triazaphosphinane (1) is described. Chlorine-fluorine exchange in 1 by means of sodium fluoride in acetonitrile in the presence of catalytic amounts of a crown ether furnished 2-fluoro-1,3,5-trimethyl-4,6-dioxo-1,3,5,2λ3-triazaphosphinane (2). The synthesis of the bromine and iodine analogues, 3 and 4, by metathesis of 1 with the appropriate trimethylsilyl halides, Me3SiBr and Me3SiI, respectively, is also described. The syntheses of an iron(0)tetracarbonyl complex (5) and of a dichloroplatinum( II) complex (6) are reported. A single crystal X-ray diffraction study was conducted on 6. [P21/c, a = 1161.3(3), b = 1423.2(3), c = 1247.7(3) pm, β = 109.42(2)°, R = 0.028], There are deviations from ideal square planar geometry at platinum. The heterocycles display a flattened boat conformation. A Staudinger reaction of 1 with Me3SiN3 led to the formation of a substituted cyclotriphosphazene.

An X-Ray Structure Determination of the Twinned Crystals of Dinitrato-2,2′-dipyridylsilver(II)

1972 ◽  
Vol 50 (3) ◽  
pp. 315-323 ◽  
Author(s):  
G. W. Bushnell ◽  
M. A. Khan
Keyword(s):  
Silver Atom ◽  
Unit Cell ◽  
Planar Geometry ◽  
X Ray ◽  
Square Planar ◽  
Distorted Octahedral ◽  
Cell Dimensions ◽  
The Mean ◽  
Unit Cell Dimensions

The crystal structure of dinitrato-2,2′-dipyridylsilver(II) has been solved and refined to an R-value of 0.070. Four circle diffractometer measurements were obtained from the twinned triclinic crystals. The unit cell dimensions at 22 °C are: a = 697.5 ± 0.2 pm, b = 999.4 ± 0.2 pm, c = 1032.2 ± 0.2 pm, α = 113.46 ± 0.02°, β = 100.71 ± 0.02°, γ = 95.28 ± 0.02°. The space group is [Formula: see text] (No. 2) with two molecules per unit cell. The density is 2.06 ± 0.04 g cm−3 (measured), 2.02 g cm−3 (calculated). The four shortest bond lengths to silver are: Ag—O(1), 214.8 ± 1.5 pm; Ag—O(4), 213.6 ± 1.5 pm; Ag—N(1), 212.4 ± 1.6 pm; Ag—N(2), 220.7 ± 1.6 pm. These four bonds are distorted from square planar geometry with the silver atom lying 19.90 ± 0.17 pm out of the mean plane of the other four atoms. There are also long bonds to the nitrato groups of neighboring molecules: Ag—O(1′), 275.3 ± 1.3 pm; Ag—O(2″), 276.3 ± 1.6 pm. Inclusion of these bonds gives a distorted octahedral silver coordination. Though predominantly unidentate, there is a slight tendency toward bidentate bonding in both nitrato ligands: Ag—O(2), 305.8 ± 1.4 pm; Ag—O(5), 295.0 ± 1.7 pm. O(2) and O(5) approach the convex side of the distorted square planar coordination. The deviation from planarity of the closely bonded square, and angular distortions in the above mentioned octahedral coordination can be rationalized by considering the silver as eight coordinate. The bonds to silver may be grouped 4:2:2 by length or 4:3:1 by angular disposition.

Bimetallomesogens: Synthesis and Mesomorphic Properties of Coppercomplexes of 3,3'-(2-hydroxypropane-1,3-diyl)bis(azan-1- yl-1-ylidene)bis(2-(4-alkoxyphenyl)prop-1-en-1-ol)

2010 ◽  
Vol 428-429 ◽  
pp. 140-143
Author(s):  
Chung Jung Chen ◽  
Chung K. Lai
Keyword(s):  
Copper Complexes ◽  
Crystallographic Analysis ◽  
Planar Geometry ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Square Planar ◽  
New Type ◽  
Optical Textures ◽  
Mesomorphic Properties

A new type of 3,3'-(2-hydroxypropane-1,3-diyl) bis(azan-1-yl-1-ylidene)bis(2-(4-alkoxy phenyl)prop-1-en-1-ol) and their copper complexes were prepared and mesomorphic properties characterized. The mesomorphic properties of these copper complexes were studied by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and powder X-ray diffraction. X-ray structural crystallographic analysis showed that these bimetallic compounds have two copper centers coordinated with central square planar geometry. These molecules all have total two 1a or five alkoxy sidechains 1b appended around the central core. The mesomorphic behavior exhibited was found to be dependent on the sidechain density. All compounds in 1a exhibited smectic mesophases, however, compounds in 1b exhibited hexagonal columnar phases (Colh), which were characterized by optical textures and confirmed by powder x-ray diffraction.

In-house and synchrotron X-ray diffraction studies of 2-phenyl-1,10-phenanthroline, protonated salts, complexes with gold(III) and copper(II), and an orthometallation product with palladium(II)

2014 ◽  
Vol 70 (3) ◽  
pp. 260-266 ◽  
Author(s):  
Jeanette A. Krause ◽  
Daoli Zhao ◽  
Sayandev Chatterjee ◽  
Roland Falcon ◽  
Kristen Stoltz ◽  
...  
Keyword(s):  
Planar Geometry ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Compound I ◽  
Complex Iv ◽  
X Ray ◽  
Lattice Water ◽  
Square Planar ◽  
Salt Complex ◽  
Monodentate Complex

Different salts of the 2-phenyl-1,10-phenanthrolin-1-ium cation, (pnpH)+, are obtained by reacting 2-phenyl-1,10-phenanthroline (pnp), C18H12N2, (I), with a variety of anions, such as hexafluoridophosphate, C18H13N2+·PF6−, (II), trifluoromethanesulfonate, C18H13N2+·CF3SO3−, (III), tetrachloridoaurate, (C18H13N2)[AuCl4], (IV), and bromide (as the dihydrate), C18H13N2+·Br−·2H2O, (V). Compound (I) crystallizes withZ′ = 2, with both independent molecules adopting a coplanar conformation. In (II)–(IV), a hydrogen bond exists between the cation and anion, while one of the lattice water molecules serves as a hydrogen-bonded bridge between the cation and anion in (V). Reaction of (I) with HAuCl4gives the salt complex (IV); however, reaction with KAuCl4produces the monodentate complex trichlorido(2-phenyl-1,10-phenanthroline-κN10)gold(III), [AuCl3(C18H12N2)], (VI). Dichlorido(2-phenyl-1,10-phenanthroline-κ2N,N′)copper(II), [CuCl2(C18H12N2)], (VII), results from the reaction of CuCl2·2H2O and (I), in which the CuIIcenter adopts a tetrahedrally distorted square-planar geometry. The pendent phenyl ring twists to a bisecting position relative to the phenanthroline plane. The square-planar PdIIcomplex, bromido[2-(phenanthrolin-2-yl)phenyl-κ3C1,N,N′]palladium(II), [PdBr(C18H11N2)], (VIII), is obtained from the reaction of (I) with [PdCl2(cycloocta-1,5-diene)], followed by addition of bromine. A coplanar geometry for the pendent ring is adopted as a result of the tridentate bonding motif.

Homonuclear PdII and PtII and heteronuclear PdII-AuI and PtII-AuI complexes of a tripod triphosphine ligand: synthesis, characterization and reactions with molecules of biological relevance

2000 ◽  
Vol 53 (8) ◽  
pp. 635 ◽  
Author(s):  
Paloma Sevillano ◽  
Abraha Habtemariam ◽  
M. Inés García Seijo ◽  
Alfonso Castiñeiras ◽  
Simon Parsons ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Partial Oxidation ◽  
Bond Cleavage ◽  
Planar Geometry ◽  
Conductivity Measurements ◽  
Initial Attack ◽  
X Ray ◽  
Square Planar ◽  
Linear Geometry

Complexes of the type Pd(tripod)X2 [tripod = MeC(CH2PPh2)3; X = Cl (1), Br (2), I (3)] and Pt(tripod)X2 [X = Cl (4), Br (5), I (6)] have been synthesized. In these complexes tripod acts as a bidentate chelating ligand. The uncoordinated phosphorus atom can bind to AuI to form the bimetallic complexes PdAu(tripod)X3 [X = Cl (7), Br (8), I (9)] and PtAu(tripod)X3 [X = Cl (10), Br (11), I (12)]. Complexes (1)–(12) have been characterized by microanalysis, f.a.b. mass spectrometry, i.r. spectroscopy, 31P and 195Pt n.m.r. spectroscopies, and conductivity measurements. The structures of complexes (1), (4) and (11), as well as that of the unusual complex Cl2Pt(tripod)AuBr0.5Cl0.5 (13), isolated from reaction of Pt(tripod)Br2 (5), and [Au(thiodiglycol)Cl], have been determined. All complexes show square-planar geometry for PdII or PtII and linear geometry for AuI. The X-ray crystal structure of (1) showed partial oxidation of the dangling phosphorus of the ligand in 50% of the molecule distributed randomly over the lattice. Reactions of complex (4), Pt(tripod)Cl2, with the tripeptide glutathione (GSH) showed the formation of [Pt2(tripod)2(GS-µ–S)2]2+ (15a). No reaction with N-acetyl-L-methionine (AcMet) or guanosine 5´-monophosphate (5´-GMP) was observed. Reactions of [Pt(tripod–O)(ONO2)2] (14) with GSH resulted in the formation of [Pt2(tripod–O)2(GS-µ-S)2]2+ (15b). Displacement of the S-containing molecules by 5´-GMP in the presence of AuI, via Pt–S bond cleavage, was observed for complex (15b). PtAu(tripod)Cl3 (10) reacted with GSH, with initial attack on the AuI centre.

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