Synthese und Koordinationschemie von Diisocyanmethan

Synthesis and Coordination Chemistry of Disocyanomethane Disocyanomethane ( 1 ) was synthesized starting from bis(formylamido)methane by the Ugi method. 1 decomposes vigourously above its melting point (−15 °C) into a brown insoluble solid. The isocyanide can be stabilized by coordination to a transition metal complex fragment. The complexes (CO)₅Cr(CN‐CH₂‐NC) ( 2 ), (CO)₅Cr(CN‐CH₂‐NC)Cr(CO)₅ ( 3 ), CpMn(CO)₂(CN‐CH₂‐NC) ( 4 ), CpMn(CO)₂(CN‐CH₂‐NC)(CO)₂MnCp ( 5 ), CpMn(CO)₂‐(CN‐CH₂‐NC)Cr(CO)₅ ( 6 ), CpMn(CO)₂(CN‐CH₂‐NC)Cu(pz*)₃BH ( 7 ) and (CO)₅Cr(CN‐CH₂‐NC)Cu(pz*)₃BH ( 8 ) (pz* = 3, 5‐dimethylpyrazolyl) were synthesized and characterized spectroscopically. The structures of bis(formylamido)methane, monoclinic, P2₁/c, a = 9.189(5), b = 6.881(3), c = 7.616(2)Å, β = 91.24(4)°, R₁ = 0.0475, wR₂ = 0.1748, and the diisocyanomethane complexes 2 , monoclinic, C2/c, a = 24.996(7), b = 5.882(2), c = 20.572(6)Å, β = 134.62(2)°, R₁ = 0.0582, wR₂ = 0.1357, 4 , monoclinic, P2₁/a, a = 12.143(4), b = 5.848(2), c = 14.301(5)Å, β = 97.77(3)°, R₁ = 0.0355, wR₂ = 0.0972, 6 monoclinic, P2₁/c, a = 11.537(7), b = 12.248(5), c = 12.54(2)Å, β = 102.75(8), R₁ = 0.1333, wR₂ = 0.3024 and 7 , triclinic, P1¯, a = 9.8841(9), b = 9.9517(9), c = 16.2479(15)Å, α = 104.790(2), β = 90.530(2), γ = 98.213(2)°, R₁ = 0.0416, wR₂ = 0.1198 were determined by single crystal X‐ray diffraction.     

Synthese,Strukturuntersuchung und Koordinationschemie von Isocyanacetonitril

Synthesis, Structure, and Coordination Chemistry of Isocyanoacetonitrile Isocyanoacetonitrile 1 was synthesized starting from aminoacetonitrile by the Ugi method. The structure and relative energies of 1 were calculated by ab initio methods (MP2/6‐31G**) in comparison with malonodinitrile and diisocyanomethane. 1 crystallizes on cooling below –14 °C forming a colourless solid, monoclinic, Pn, a = 614.9(2), b = 756.3(1), c = 786.4(3) pm, β = 98.99(4)°, Z = 4, R = 0.054, wR₂ = 0.132, with two molecules representing the asymmetric unit. 1 polymerizes readily at ambient temperature forming a dark‐brown almost insoluble solid 2 . 1 can be stabilized by coordination to metal fragments. The metal complexes (CO)₅M(CNCH₂CN) ( 3 ) ( a , M = Cr; b , M = W), CpMn(CO)₂(CNCH₂CN) ( 4 ) and fac‐(CO)₃W(CNCH₂CN)₃ ( 5 ) were synthesized and characterized by spectroscopic methods. The structures of 3 a , monoclinic, C2/c, a = 2481.4(7), b = 582.2(2), c = 2053.3(6) pm, β = 134.57(2)°, R₁ = 0.0368, wR₂ = 0.1001, and 4 , monoclinic, P2₁/a, a = 1223.7(2), b = 586.0(1), c = 1446.3(3) pm, β = 97.81(2)°, R₁ = 0.0459, wR₂ = 0.1190, were determined by single crystal X‐ray diffraction.     

Koordinationschemie funktioneller phosphorylide: III. Neue mangan- und rhenium-komplexe mit triphenylphosphonio-alkandithiocarboxylat-liganden

As strong nucleophiles, phosphorus ylids easily attack heteroallenes. The addition of isopropylidene triphenylphosphorane to carbon disulfide yields the zwitterionic adduct Ph₃PCMe₂CS₂^?, which reacts to bis(isopropylidene)-1,2,4-trithiolane by thermal or, coordinated to transition metals, photochemical activation according to a cycloaddition mechanism. By reaction of the betaine with manganese and rhenium carbonyl halides under exclusion of light, stable monomeric and dimeric fac-tricarbonyl complexes with the composition (CO)₃M?(X)S₂CCMe₂PPh₃ (M = Mn, Re; X = Cl, Br) are obtained which are distinguished by their spectra (IR, NMR, UV). The monomeric bromomanganese and -rhenium complexes are isomorphous and crystallize in the space group P2_frcase1/c (monoclinic, Z = 4).     

Die elektrochemische Reduktion von CSSe und CSe2 in Dimethylformamid: Heterocyclische 1,2-Dichalkogenolate und ihre Koordinationschemie

Electrochemical Reduction of CSSe and CSe₂ in Dimethylformamide: Heterocyclic 1,2-Dichalcogenolates and their Coordination Chemistry Starting from carbon diselenide or carbon selenidesulfide the electrochemical preparation (electrosynthesis) of heterocyclic dichalcogenolates C₃X₅^2? (X = Se: dsis; X = S/Se: C₃S_xSe_y^2?) is outlined. The 1,2-dichalcogenolate compounds were isolated and characterized as dibenzoyl derivatives. Bis- or tris-chelates of general type A_m[M(C₃X₅)_n] (with A = Bu₄N⁺, Ph₄As⁺; M = Zn^II, Pt^II, Pd^II, Ni^III, Cu^III, Au^III, In^III; X = Se, S/Se; m = 1, 2, 3; n = 2, 3, respectively) are available directly from methanolic solutions of the dibenzoylates after hydrolytic cleavage of the latter with sodium methanolate. In addition bis-chelates Bu₄N[Ni(C₃X₅)₂] (X = Se, S/Se) have been characterized by cyclovoltammetry and epr spectroscopy and compared with the corresponding all-sulfur ligand compound Bu₄N[Ni(dmit)₂] (X = S). Arguments are given for the fact that the allselenium ligand dsis (X = Se) yields the Cu^III or Ni^III chelate at once whereas with dmit using identical conditions the metal(II) compounds are formed.     

Koordinationschemie von Dinitroresorcin mit Kupfer-, Kobalt-, Nickel-, Eisen- und Zinksalzen

The reactions of the bidentate dinitrosoresorcinol (DNR) with copper, cobalt, nickel, iron and zinc salts were investigated. This ligand was found to react with these metal salts in aqueous media where hydrogen ion was confirmed to be liberated except in case of iron. The solid complexes were prepared in alcoholic media. Chemical analyses, magnetic and spectral data were compatible to determine the structure of these complexes and their mode of chelation.

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