Synthese und Struktur von Komplexen mit Nitridobrücken zwischen Rhenium und Zink

Synthesis and Structure of Complexes with Nitrido Bridges between Rhenium and Zinc The reaction of [ReNCl₂(PMePh)₃] with ZnX₂ (X = Cl, Br) in CH₂Cl₂ yields the tetranuclear complexes [(Me₂PhP)₃X₂Re≡N–ZnX₂]₂. In case of the reaction with ZnBr₂ an exchange of the halogen atoms coordinated to the Re atom occurs. [(Me₂PhP)₃Cl₂Re≡N–ZnCl₂]₂ ( 1 ) crystallizes with one centrosymmetric tetranuclear complex in the triclinic unit cell. [(Me₂PhP)₃Br₂Re≡N–ZnBr₂]₂ ( 2 ) forms triclinic crystals with the composition 2 · 2 CH₂Cl₂. The centrosymmetric tetranuclear complexes exhibit analogous structures. Two complexes [ReNX₂(PMe₂Ph)₃] coordinate with the terminal nitrido ligands the Zn atoms of a central unit XZn(μ-X)₂ZnX. The resulting linear nitrido bridges Re≡N–Zn (Re–N–Zn = 178.4° ( 1 ) und 178.0° ( 2 )) are asymmetric with distances Re–N = 170 pm and Zn–N = 199 pm for 1 , and Re–N = 167 pm as well as Zn–N = 201 pm for 2 . The reaction of [ReNCl₂(PMe₂Ph)₃] with ZnI₂ in CH₂Cl₂ presumably first affords [(Me₂PhP)₃ClIRe≡N–ZnI₂]₂, which, however, in the course of crystallization decomposes to yield [(Me₂PhP)₃ClIRe≡N–ZnI₂(OPMe₂Ph)] ( 3 ). Of the two Cl atoms originally coordinated at the Re atom the one in cis position to the nitrido ligand is substituted by iodine. 3 forms monoclinic crystals with the space group P2₁/n. The distances in the linear nitrido bridge (Re–N–Zn = 171.5°) are Re–N = 167.9 pm and Zn–N = 204.9 pm. By the reaction of [ReNCl₂(PMe₂Ph)₃] with ZnX₂ (X = Cl, I) in THF the dinuclear complexes [(Me₂PhP)₃Cl₂Re≡N–ZnCl₂(THF)] ( 4 ) and [(Me₂PhP)₃ClIRe≡N–ZnI₂(THF)] ( 5 ) are obtained. They crystallize isotypically as 4 · THF or 5 · THF in the triclinic space group P1. Their nitrido bridges have the following parameters: Re–N–Zn = 175.2°, Re–N = 167.7 pm, and Zn–N = 202.1 pm for 4 , resp. Re–N–Zn = 174.7°, Re–N = 168.3 pm, and Zn–N = 201.2 pm for 5 .     

Über Usovite Ba2M″ M″ M2″ F14 und die Hochdruckphasen von BaMnVF7 und BaMnFeF7: Verbindungen mit BaMnGaF7-Struktur

On Usovites Ba₂M^IIM′^IIM₂^IIIF₁₄ and the High Pressure Phases of BaMnVF₇ and BaMnFeF₇: Compounds with BaMnGaF₇ Structure The results of complete single crystal structure determinations of the monoclinic BaMnGaF₇ type compounds Ba₂CaCoV₂F₁₄ (and Ba₂CdMn Fe₂F₁₄) are reported: C2/c, Z = 4, a = 1369.7 (1381.2), b = 538.4 (537.2), c = 1491.6 (1489.5) pm, β = 91.49 (91.11)°, Rg = 0.036 (0.038) for 4389 (2521) reflections. The atoms Ca/Co (Cd/Mn) distribute not completely ordered on the 8? and 6?coordinated sites of this “usovite” structure (Ba₂CaMgAl₂F₁₄). This is also evident for Cd/Fe from Mössbauer spectra of Ba₂CdFeAl₂F₁₄. The lattice constants of this and further seven compounds Ba₂M^IIM′^IIM2_IIIF₁₄ (M^II = Ca, Cd; M′^II = Mg, Mn? Cu; M^II = Al, Ga) are given. Two novel representatives of the same structure with M^II = M′^II = Mn could be prepared in the form of the high pressure phases of BaMn VF₇ and BaMnFeF₇. The magnetic properties of both modifications of the iron compound and of BaMnGaF₇ are reported and discussed.     

Mehrkernige Molybdän- und Wolframkomplexe mit Schwefel- und Dithiophosphinatoliganden

Polynuclear Molybdenum and Tungsten Complexes with Sulfur and Dithiophosphinato Ligands Reaction of Mo(CO)₆ and disulfane [R₂P(S)]₂S₂ (R: Et, Pr, Bu) gives disulfidobridged cluster chelates [Mo₃S₇(R₂PS₂)₃]⁺ [R₂PS₂]^? 1 , the anions of which can be easily exchanged. From 1 and Ph₃P sulfido-bridged non-electrolytes [Mo₃S₄(R₂PS₂)₄] 2 are obtained, in which two Mo are additionally bridged by one R₂PS₂^?. By treatment of 2 with S₈ or disulfane 1 is regenerated. As in the conversion 1 ? 2 the formal oxidation state of Mo remains unchanged this process can be reduced to the redox reaction S₂^2? ? 1/8 S₈ + S^2?, which takes place under maintenance of the Mo₃ skeleton. Compounds 2 are coordinatively unsaturated and give 1:1 adducts with pyridine. Under modified reaction conditions M(CO)₆ and disulfane form binuclear complexes Mo₂S₄(R₂PS₂)₂ 3 resp. W₂S₄(R₂PS₂)₂ 4 , of which only 3 undergoes further reaction with M(CO)₆ and disulfane leading to 1 . The results of structural and spectroscopic investigations are reported and discussed.     

Synthese und Struktur von dreikernigen Heterometall-Komplexen mit Nitridobrücken zwischen Re und Sn

Synthesis and Structure of Threenuclear Heterometallic Complexes with Nitrido Bridges between Re and Sn The threenuclear heterometallic complex [(Me₂PhP)₂ClRe(μ-Cl)N]₂SnCl₄ results from the reaction of ReNCl₂(PMe₂Ph)₃ with SnCl₄ in CH₂Cl₂. The brown, air-sensitive complex is diamagnetic. It crystallizes with two solvate molecules as [(Me₂PhP)₂ClRe(μ-Cl)N]₂SnCl₄ · 2 CH₂Cl₂ in the space group P 1 with a = 1189.1(2), b = 1262.3(2), c = 1776.7(3) pm, α = 86.04(2), β = 89.27(2), γ = 72.75(1)°, Z = 2. In the threenuclear complex two fragments (Me₂PhP)₂ClReN, which are connected by two Cl bridges, coordinate with their nitrido ligands one SnCl₄ molecule. The two resulting nitrido bridges complete the coordination of the Sn atom to a distorted octahedron with a cis arrangement of the N atoms. The bent nitrido bridges (Re–N–Sn = 155) are asymmetrical with distances Re–N = 168 pm and Sn–N = 225 pm. An incomplete exclusion of water during the synthesis leads to the formation of [(Me₂PhP)₃ClRe(μ-Cl)N]Sn₂(OH)Cl₇ · 2 CH₂Cl₂ in form of air-stable, red-violett crystals (P 1, a = 1074.1(2), b = 1251.1(3), c = 1685.0(1) pm, α = 99.61(2), β = 91.49(2), γ = 92.69(2)°, Z = 2). In the diamagnetic complex one molecule ReNCl₂(PMe₂Ph)₃ is coordinated by the nitrido ligand and one Cl bridge to the Sn atoms of a unit Sn₂(OH)Cl₇. In this unit the two Sn atoms are connected by one Cl and one OH bridge. The distances in the almost linear nitrido bridge (Re–N–Sn = 164.6) are Re–N = 170.5 pm and Sn–N = 219.8 pm.     

Synthese und Struktur von zwei- und dreikernigen Heterometallkomplexen mit Nitridobrücken zwischen Re und Mo

Synthesis and Structure of Two- and Threenuclear Heterometallic Complexes with Nitrido Bridges between Re and Mo The reaction of ReNCl₂(PMe₂Ph)₃ with MoCl₄(NCEt)₂ yields the heterometallic threenuclear complex [{(Me₂PhP)₃(EtCN)ClRe≡N–}₂MoCl₄][MoNCl₅]. The anion [MoNCl₅]^2– presumably results from a transfer of the nitrido ligand from the Re to the Mo atom. The air-sensitive compound is paramagnetic with μ_eff = 2.87 B. M. at room temperature. A reduction of the magnetic moment to 1.74 B.M at 20 K starts at 140 K. The complex crystallizes in the orthorhombic space group Pca2₁ with a = 2430(1), b = 1328(1), c = 2436.3(2) pm, Z = 4. With bond angles Re–N–Mo of 164° and 167° the nitrido bridges are almost linear. The distances Re–N of 169 and 170 pm can be interpreted with triple bonds. The Mo–N bond lengths of 210 and 211 pm correspond to single bonds. In the anion [MoNCl₅]^2– the distance Mo≡N is 167 pm. Hydrolysis of the threenuclear complex results in a cleavage of one of the nitrido bridges to yield (Me₂PhP)₃(EtCN)ClRe≡N–MoOCl₄. The compound is paramagnetic with μ_eff = 1.71 B.M. at room temperature. It crystallizes in the orthorhombic space group Pbca with a = 1718.5(4), b = 2037(1), c = 2041.1(7) pm, Z = 8. In the dinuclear complex the [MoOCl₄]^– unit is only weakly coordinated to the nitrido ligand with Mo–N = 246.5 pm, while the distance of the Re≡N bond of 168.1 pm is almost unchanged in comparison with a terminal bond. The bond angle Re≡N–Mo is 165.6°.     

Enantioselektive Cyclopropanierung von 1,1-Diphenylethylen und Diazoessigester mit Kupfer-Katalysatoren

Copper(II) compounds catalyze the reaction of 1,1-diphenylethylene with diazoacetic acid ethylester. The main product is 2,2-diphenylcyclopropane carboxylic acid ethylester. The formation of the carbene dimerization products fumaric and maleic acid diethylester can be suppressed by the continuous addition of diazoacetic acid ester to 1,1-diphenylethylene.37 optically active ligands, partly new, were combined with copper(II)-acetate to givein-situ-catalysts. In five cases isolated copper complexes were used as catalysts. The best optical inductions in the formation of 2,2-diphenylcyclopro-pane carboxylic acid ethylester with up to 65.6% ee were achieved withSchiff base ligands, which derive from salicylaldehyde and amino alcohols, obtained from amino acid esters and phenylGrignard.

Prof. Dr.Karl Schlögl, Universität Wien, mit den besten Wünschen zum 60. Geburtstag gewidmet.     

Umsetzungen von Δ-triazolinen und von ringketon-anilen mit isocyanaten und isothiocyanaten

Δ²-Triazolines, derived from cyclopentene and aryl azides, react with isocyanates and isothiocyanates giving 1-arylamino-2-carboxamido- and 1-arylamino-2-thiocarboxamido-cyclopentenes respectively. Cyclopentanone anils, which are formed from the triazolines by thermal loss of nitrogen, are intermediates. In contrast, the Δ²-triazoline from norbornene and phenyl azide undergoes induced loss of nitrogen on treatment with phenylisocyanate. The product, a 1:1 adduct less N₂, has been investigated chemically and spectroscopically; the final structural elucidation however requires further experiments.     

Synthese und Eigenschaften von Metallocen‐ und Halbsandwich‐Komplexen mit pyridinhaltigen Brücken bzw. Seitenketten

Synthesis and Properties of Metallocene and Half Sandwich Complexes with Pyridine‐containing Bridges or Side Chains 2,6‐Bis(chlormethyl)pyridine ( 1 ) reacts with 4 equivalents of indenyllithium with formation of 2,6bis(methylenindenyl)pyridine‐dilitihium ( 2 ) from which with MCl₄ · 2 thf (M = Zr, Hf) the corresponding metallocene dichlorides 3 and 4 can be obtained. At reaction of 1 with 2 equivalents of C₅H₅Na only one Cl atom is replaced by a C₅H₅Na unit. Following reactions with indenyl lithium and ZrCl₄ · 2 thf give the unsymmetric complex [C₅H₃N–2,6‐CH₂‐(2‐C₅H₄)–(6‐C₉H₆)ZrCl₂] ( 7 ). – Picolylcyclopentadiene ( 8 ) and 1‐(picolyl)‐indene ( 9 ) are synthesized from 2‐chlomethyl‐pyridinium chloride and C₅H₅Na or indenyl lithium respectively, which are transferred in the half sandwich complexes (C₅H₄N–CH₂C₅H₄)MCl₃ (M = Ti 10 , Zr 11 ) and (C₅H₄–CH₂C₉H₆)ZrCl₃ ( 12) . The compounds were characterized by elemental analysis, ¹H n.m.r., ms, ir, and raman spectra. N → M interactions are discussed.