Koordination von Rhodium(III), Iridium(III) und Kupfer(II) mit dem potentiell vierzähnigen Akzeptorliganden Bis(1‐methylimidazol‐2‐yl)glyoxal (big)

Coordination of Rhodium(III), Iridium(III), and Copper(II) with the Potentially Tetradentate Acceptor Ligand Bis(1‐methylimidazol‐2‐yl)glyoxal (big) Bis(1‐methylimidazol‐2‐yl)glyoxal (big) which has hitherto not been used in coordination chemistry crystallizes to form two perpendicular 1‐methylimidazol‐2‐yl‐carbonyl molecular halves. Out of the various possibilities for mono‐ and bis‐chelate coordination the N,N′‐alternative with a seven‐membered chelate ring is realized in [Cp*Cl(big)Rh](PF₆) as evident from crystal structure analysis. The iridium analogue reacts under hydration of big and elimination of HCl to form a complex cation [Cp*(bigOH)Ir]⁺ which dimerizes in the crystal through hydrogen bonding and contains one five‐ and one six‐membered chelate ring involving the alcoholate‐O. Cu(ClO₄)₂ and the ligand big yield a complex ion [Cu(big)₂]²⁺ with an ESR spectrum that suggests the coordination of the central metal by four N atoms in an approximately planar setting.     

Crystallographic report: [N,N′‐Bis‐(6‐methylpyrid‐2‐ylium)‐(1R,2R)‐1,2‐diaminocyclohexane] bis‐[(p‐cymene)‐ trichlororuthenate(II)]

The chiral compound (H₂cydiampy)[RuCl₃(p‐cymene)]₂ has been obtained in high yield by treating [RuCl₂(p‐cymene)]₂ with an excess of hydrochloric acid in the presence of one equivalent of N,N′‐bis‐(6‐methylpyrid‐2‐yl)‐(1R,2R)‐1,2‐diaminocyclohexane (cydiampy). It crystallizes in the chiral tetragonal space group P4₃2₁2, with half of the atoms of the dication related to the other half by a crystallographic C₂ axis that also makes equivalent the two anionic metal moieties. Copyright © 2005 John Wiley & Sons, Ltd.     

Three transition‐metal complexes with the macrocyclic ligand meso‐5,7,7,12,14,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane (L): [Cu(ClO4)2(L)], [Zn(NO3)2(L)] and [CuCl(L)(H2O)]Cl

The three transition‐metal complexes, (meso‐5,7,7,12,14,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane‐κ⁴N)bis(perchlorato‐κO)copper(II), [Cu(ClO₄)₂(C₁₈H₄₀N₄)], (I), (meso‐5,7,7,12,14,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane‐κ⁴N)bis(nitrato‐κO)zinc(II), [Zn(NO₃)₂(C₁₈H₄₀N₄)], (II), and aquachlorido(meso‐5,7,7,12,14,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane‐κ⁴N)copper(II) chloride, [CuCl(C₁₈H₄₀N₄)(H₂O)]Cl, (III), are described. The molecules display a very similarly distorted 4+2 octahedral environment for the cation [located at an inversion centre in (I) and (II)], defined by the macrocycle N₄ group in the equatorial sites and two further ligands in trans‐axial positions [two O–ClO₃ ligands in (I), two O–NO₂ ligands in (II) and one chloride and one aqua ligand in (III)]. The most significant difference in molecular shape resides in these axial ligands, the effect of which on the intra‐ and intermolecular hydrogen bonding is discussed. In the case of (I), all strong hydrogen‐bond donors are saturated in intramolecular interactions, while weak intermolecular C—H...O contacts result in a three‐dimensional network. In (II) and (III), instead, there are N—H and O—H donors left over for intermolecular interactions, giving rise to the formation of strongly linked but weakly interacting chains.     

Synthesen und Eigenschaften von Pentafluorethylkupfer(I)‐ und ‐(III)‐Verbindungen: Cu(C2F5) · D, [Cu(C2F5)2]– und (C2F5)2CuSC(S)N(C2H5)2

Syntheses and Properties of Pentafluoroethylcopper(I) and ‐copper(III) Compounds: CuC₂F₅ · D, [Cu(C₂F₅)₂]^–, and (C₂F₅)₂CuSC(S)N(C₂H₅)₂ The reactions of Cd(C₂F₅)₂ · D and Zn(C₂F₅)₂ · D (D = 2 CH₃CN, 2 DMF), respectively, with copper(I) halides in the presence of halides quantitatively yield the CuC₂F₅ compounds CuC₂F₅ · D and [Cu(C₂F₅)₂]^–. The CuC₂F₅ complexes are identified by NMR spectroscopy, while [Cu(C₂F₅)₂]^– is isolated as PNP salt (PNP = (C₆H₅)₃PNP(C₆H₅)₃⁺). Both compounds are excellent C₂F₅ group transfer reagents, even at low temperature. Oxidation of [Cu(C₂F₅)₂]^– with [(C₂H₅)₂NC(S)S]₂ yields the crystalline Cu(III) compound (C₂F₅)₂CuSC(S)N(C₂H₅)₂ (monoclinic, C2/c).     

Heterokuban‐Cluster‐Verbindungen (NEt4){Y=M[(μ3‐S)Re(CO)3]3(μ3‐E)} (M = W oder Mo,Y = O oder S,E = S oder Se): Strukturen,Spektroskopie und Elektrochemie

Heterocubane Cluster Compounds (NEt₄){Y=M[(μ₃‐S)Re(CO)₃]₃(μ₃‐E)} (M = W or Mo, Y = O or S, E = S or Se): Structures, Spectroscopy, and Electrochemistry Thiometallates [MS₄]^2– (M = Mo, W) or [WOS₃]^2– react with Re(CO)₅(O₃SCF₃) and Li₂E (E = S or Se) to yield the following compounds which were structurally characterized: (NEt₄){S=W[(μ₃‐S)Re(CO)₃]₃(μ₃‐S)}(NEt₄) ( 1 ), (NEt₄){O/S=W[(μ₃‐S)Re(CO)₃](μ₃‐S)}(NEt₄) ( 1 / 2 ), (mixed crystals), (NEt₄){S=W[(μ₃‐S)Re(CO)₃]₃(μ₃‐Se)}(NEt₄) ( 3 ) and (NEt₄){S=Mo[(μ₃‐S)Re(CO)₃]₃(μ₃‐S)}(NEt₄) ( 4 ). The heterocubane anions 1 – 4 contain electron‐rich centers such as rhenium(I) or sulfide whereas molybdenum(VI) or tungsten(VI) act as acceptor sites. Accordingly, the absorption spectra show long‐wavelength metal‐to‐ligand charge transfer transitions, and cyclic voltammetry reveals a quasi‐reversible reduction of the clusters. Although both six‐coordinate rhenium(I) and four‐coordinate metal(VI) centers are present in the clusters there is no evidence for significant metal‐to‐metal charge transfer interaction.     

Regioselective [3+3] Cyclization of 1,3‐Bis(silyloxy)buta‐1,3‐dienes with 1,1,1‐Trifluoro‐4‐(silyloxy)alk‐3‐en‐2‐ones: New and Convenient Synthesis of Functionalized 5‐Alkyl‐3‐(trifluoromethyl)phenols

Functionalized 5‐alkyl‐3‐(trifluoromethyl)phenols were prepared by formal [3+3] cyclization of 1,3‐bis(silyloxy)buta‐1,3‐dienes with 1,1,1‐trifluoro‐4‐(silyloxy)alk‐3‐en‐2‐ones derived from 1,1,1‐trifluoroalkane‐2,4‐diones. The latter were prepared by condensation of the dianion of 1,1,1‐trifluoropentane‐2,4‐dione with alkyl halides.     

Synthesis of 5‐(Arylselanyl)‐2‐(arylsulfanyl)benzoates by [3+3] Cyclocondensation of 3‐(Arylsulfanyl)‐1‐(silyloxy)buta‐1,3‐dienes with 2‐(Arylselanyl)‐3‐(silyloxy)alk‐2‐en‐1‐ones

Functionalized 5‐(arylselanyl)‐2‐(arylsulfanyl)benzoates were prepared by [3+3] cyclocondensation of 3‐(arylsulfanyl)‐1‐(silyloxy)buta‐1,3‐dienes with 2‐(arylselanyl)‐3‐(silyloxy)‐alk‐2‐en‐1‐ones.