Crystal and molecular structures of ion radical molecular complexes of cis-bis(trifluoromethylethylene-1,2-dithiolato)nickel with phenothiazine and phenoxazine. Effects of donor-acceptor separation on the molecular properties

1975 ◽  
Vol 14 (2) ◽  
pp. 318-323 ◽  
Author(s):  
Anami. Singhabhandhu ◽  
P. D. Robinson ◽  
J. H. Fang ◽  
W. E. Geiger
Keyword(s):  
Molecular Complexes ◽  
Molecular Structures ◽  
Molecular Properties ◽  
Crystal And Molecular Structures ◽  
Donor Acceptor

Kupfer(I)-Komplexe mit ungesättigten Stickstoffliganden, V / Kupfer(I)-Komplexe mit Diazadienen als Chelate und Brücken: Röntgenstrukturenuntersuchungen an (DAD)Cu(μ-Cl)2Cu(DAD), [(DAD)2Cu]⁺ (CuCl2)-, (DAD)CuCl, [μ-(DAD)2Cu5Cl5]n und [μ-(DAD)Cu(OTf)]n (DAD = Diazadien) / Copper(I) Complexes with Unsaturated Nitrogen Ligands, V Copper(I) Complexes with Chelating and Bridging Diazadienes: X-Ray Diffraction Studies of (DAD)Cu(μ-Cl)2Cu(DAD), [(DAD)2Cu]+ (CuCl2)-, (DAD)CuCl, [μ-(DAD)2Cu5Cl5]n and [μ-(DAD)Cu(OTf)]n (DAD = Diazadiene)

1990 ◽  
Vol 45 (10) ◽  
pp. 1369-1382 ◽  
Author(s):  
Heindirk tom Dieck ◽  
Lutz Stamp
Keyword(s):  
Coordination Polymer ◽  
Molecular Complexes ◽  
Molecular Structures ◽  
Coordination Geometry ◽  
Halide Ions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nitrogen Ligands ◽  
Crystal And Molecular Structures ◽  
Irregular Geometries

Diazadienes RN = CR′-CR′ = NR (DAD) form molecular complexes with copper(I) halides of composition (DAD)CuX, the structures of which vary from [(DAD)2Cu]+(CuCl2)⁻ with a non-tetrahedral bis(chelated) cation, over [(DAD)CuCl]2 with asymmetrically bridging chloro ligands to planar three-coordinate (DAD)CuCl. The composition of the isolated complexes depends on the relative concentrations or on the solvent. The “soft” coordination geometry of copper is underlined by the structure of the coordination polymer of composition (DAD)2Cu5Cl5, in which Cu atoms of coordination number 2, 3 and 4 and very irregular geometries are encountered and where the DAD ligands are exclusively bridging. Halide ions and sp2-nitrogen donors are very competitive. Bridging DAD ligands are also encountered in (DAD)Cu-Y with the less nucleophilic anions trifluoromethane-sulphonate or perchlorate. Crystal and molecular structures are established for all these coordination geometries and the causes are discussed for the coordination flexibility of copper(I)

Donor-Acceptor Complexes between Organoamines and Phosphorus Tribromide

2001 ◽  
Vol 56 (11) ◽  
pp. 1163-1171 ◽  
Author(s):  
Gerhard Müller ◽  
Jörg Brand ◽  
Simone Elisabeth Jetter
Keyword(s):  
Lewis Acid ◽  
Phosphorus Atom ◽  
Chair Conformation ◽  
Molecular Structures ◽  
Ionic Character ◽  
Crystal Data ◽  
Acid Base ◽  
Crystal And Molecular Structures ◽  
Phosphorus Tribromide ◽  
Donor Acceptor

Lewis acid-base adducts between NMe3, tmeda (N ,N ,N′ ,N′-tetramethylethylenediamine), and 1.4-dimethylpiperazine as donors and PBr3 as acceptor have been prepared and structurally characterized. NMe3 and tmeda form 1:1 adducts (Me3N)PBr3 (1) and (tmeda)PBr3 (2), respectively, while 1,4-dimethylpiperazine adds 2 molecules of PBr3 leading to [(1,4-dimethylpiperazine)( PBr3)2] (3). Adduct 2 is found in two modifications 2a and 2b with different crystal and molecular structures. (Crystal data of 1: monoclinic P21/n, a = 5.983(3), b = 10.821(2), c = 13.877(5) Å, ß = 99.70(2)°, Z = 4. 2a: monoclinic P21/c, a = 7.891(1), b = 12.826(1), c = 12.218(2) Å ,ß = 102.162(6)°, Z = 4. 2b: monoclinic P21/n, a = 11.687(2), b = 8.375(1), c = 12.668(1) Å, ß = 102.74(1)°, Z = 4. 3: monoclinic P21/c, a = 6.383(3), b = 16.36(3), c = 8.407(3) Å , ß = 101.49(2)°, Z= 2). The molecular structures of 1 and 2 indicate a partially ionic character with a strongly bonded amine and one (1 ) or two (2 ) weakly bonded bromine atoms. In 2 the donor tmeda is bonded through both nitrogen atoms to one phosphorus atom. In 3 the 1,4-dimethylpiperazine ring is in chair conformation, the methyl and PBr3 substituents being in equatorial and axial positions, respectively. Due to axial-axial repulsion the N-P donor-acceptor bonds are long while the P-Br bonds are rather uniform in length.

A Solvent-Dependent and Electrochemically Controlled Self-Assembling/Disassembling System

2003 ◽  
Vol 68 (9) ◽  
pp. 1647-1662 ◽  
Author(s):  
Valeria Amendola ◽  
Massimo Boiocchi ◽  
Yuri Diaz Fernandez ◽  
Carlo Mangano ◽  
Piersandro Pallavicini
Keyword(s):  
Equilibrium Mixture ◽  
Bidentate Ligand ◽  
Molecular Structures ◽  
The Self ◽  
Molar Ratio ◽  
Crystal And Molecular Structures ◽  
Self Assembling ◽  
Irreversible Oxidation ◽  
Irreversible Reduction ◽  
Metal Ligand

The bis-bidentate ligand R,S-1,2-diphenyl-N,N'-bis(2-quinolinemethylidene)ethane-1,2-diamine (ligand 4), containing two (iminomethyl)quinoline moieties separated by a cis-1,2-diphenylethylene spacer, forms stable complexes with both CuI and CuII. With CuII, the monomeric 1:1 complex [CuII(4)]2+ is obtained both in CH3CN and CH2Cl2. With CuI and overall 1:1 metal/ligand molar ratio, an equilibrium mixture is obtained in CH3CN, consisting of [CuI(4)2]+, [CuI2(4)2]2+ and [CuI2(4)(CH3CN)4]2+. The preponderant species is the two-metal one-ligand "open" complex [CuI2(4)(CH3CN)4]2+, in which each Cu+ cation is coordinated in a tetrahedral fashion by one (iminomethyl)quinoline unit and by two CH3CN molecules. Precipitation from the equilibrium mixture yields only crystals of [CuI2(4)(CH3CN)4](ClO4)2·2CH3CN, whose crystal and molecular structures have been determined. On the other hand, in the poorly coordinating CH2Cl2 solvent, only the dimeric helical [CuI2(4)2]2+ complex is obtained, when the overall metal/ligand 1:1 molar ratio is chosen. Addition of large quantities of acetonitrile to solutions of [CuI2(4)2]2+ in dichlorometane results in the formation of [CuI2(4)(CH3CN)4]2+, i.e. in the solvent-driven disassembling of the CuI helicate. While electrochemistry in CH3CN is poorly defined due to the presence of more than one CuI species, cyclic voltammetry experiments carried out in CH2Cl2 revealed a well defined behavior, with irreversible oxidation of [CuI2(4)2]2+ and irreversible reduction of [CuII(4)]2+ taking place at separate potentials (∆E ≈ 700 mV). Irreversibility and separation of the redox events are due to the self-assembling and disassembling processes following the reduction and oxidation, respectively.

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