The Other Face of Bunsen's Cacodyl Disulfide,Me2As(S)‐S‐AsMe2: The Lewis‐Base Behaviour Towards Heavy Metal Cations

The reaction of Bunsen's cacodyl disulfide, Me₂As(S)‐S‐AsMe₂, with heavy metal cations in methanol produces insoluble salts (complexes) of dimethyldithioarsinic acid, Me₂AsS₂H, and dimethyl arsenium ion, Me₂As:⁺. This arsenium ion prefers to react with Me₂As(S)‐S‐AsMe₂, when in excess, compared to AcO^? or MeOH/H₂O and it is also reactive towards sulfur (S_x, x = 1‐8) producing the stabilized dimethylarsino sulfenium cation, . The complexes (Me₂AsS₂)_xM (x = 1 or 2) are unstable in the presence of their own heavy metal cations decomposing to colored solids. In an attempt to prepare salts of Me₂AsSH, the reactions of (Me₂AsS₂)_xM with triphenylphosphine and trimethyl phosphite gave the metal sulfide and Me₂As‐S‐AsMe₂ instead.     

Reactions of Polyfluoroarenes with MenE‐MMe3 Reagents (MenE = Me2As,Me2P,Me2N,and MeS; M = Si,Sn): Synthesis of Polyfluoroaryl MenE Compounds

Trimethylsilyldimethylarsane Me₃SiAsMe₂ was used as a reagent for the substitution of fluorine in polyfluoroarenes C₆F₅X (X = F, H, Cl) and C₅NF₅ by the Me₂As group. The reactions occur between 50 — 180 °C, either in benzene or without solvent, to give as a rule 4‐X‐1‐(dimethylarsano)tetrafluorobenzenes XC₆F₄AsMe₂, ( 1—3 ) and 4‐dimethylarsano‐tetrafluoropyridine C₅NF₄AsMe₂ ( 4 ), respectively, in yields between 43 and 94 %. In the case of C₆F₆, also double substitution is observed affording 1, 4‐bis(dimethylarsano)tetrafluorobenzene 5 in addition to the monosubstituted derivative. The time and temperature dependencies of the reactions increase in the sequence: C₆F₆< C₆F₅H < C₆F₅Cl < C₅NF₅. The arsanes 1 and 4 were transformed to the potentially valuable bidentate ligands 1‐(dimethylarsano)‐4‐(dimethylphosphano)tetrafluorobenzene 6 and 4‐(dimethylarsano)‐2‐(dimethylphosphano)trifluoropyridine 8 by reaction with trimethylsilyl‐dimethylphosphane Me₃SiPMe₂. 6 reacts with oxygen to yield the corresponding phosphane oxide 7 . Trimethylsilyl‐dimethylamine Me₃SiNMe₂ also was successfully tested as a reagent for the dimethylamination of polyfluoroarenes C₆F₅X [X = F, H, Cl, CF₃, P(S)Me₂], 1‐P(S)Me₂‐4‐H‐C₆F₄ and 4‐X‐C₅NF₄ [X = F, PMe₂, P(S)Me₂]. Sulfuration of the new Me₂P derivatives 8 and 20 leads to the corresponding thiophosphanes 9 and 21 (Schemes 2 and 3). Furthermore, the recently reported very efficient one‐pot synthesis of Me₂P substituted polyfluoroarenes (e.g. XC₆F₄PMe₂ with X = F, Me₂PC₆F₄) was extended to the preparation of Me₂As and MeS derivatives of pentafluoropyridine using a mixture of Me₃SnH, As₂Me₄ (or S₂Me₂) and C₅NF₅ as precursors for the one‐pot reaction. The expected products 4‐(dimethylarsano)tetrafluoropyridine 4 and 4‐(methylthio)tetrafluoropyridine 22 , respectively, were obtained in 84 and 82 % isolated yields. The novel compounds were characterized by spectroscopic (NMR, MS) and analytical data. Compounds 5 , 7 , 9 and 21 could be isolated in form of single crystals and their structures have been studied by X‐ray diffraction.     

Zur Strukturchemie der Alkyl- und Arylhalogenoarsenate(III), [Me2As2Cl5]–, [RAsCl3]–, [R2As2Br6]2– (R = Me,Et, Ph) und [Ph2AsX2]– (X = Cl,Br)

Structural Chemistry of the Alkyl- and Arylhaloarsenates(III) [Me₂As₂Cl₅]^–, [RAsCl₃]^–, [R₂As₂Br₆]^2– (R = Me, Et, Ph) and [Ph₂AsX₂]^– (X = Cl, Br) The alkyl- and arylhaloarsenates(III) [Ph₄P][Me₂As₂Cl₅] ( 1 ), [Ph₄P][RAsCl₃] (R = Me, Et, Ph, 2 – 4 ), [Me₃PhN][PhAsCl₃] ( 5 ), [Ph₄P]₂[R₂As₂Br₆] (R = Me, Et, Ph, 6 – 8 ), [n-Pr₄N][Ph₂AsCl₂] ( 9 ) and [n-Bu₄N][Ph₂AsBr₂] ( 10 ) have been prepared and their structures established by X-ray diffraction. In contrast to the chloroarsenates(III) 2 – 5 , which all contain isolated ψ-trigonal bipyramidal anions [RAsCl₃]^–, the analogous bromoarsenates(III) 6 – 8 exhibit dimeric structures. Whereas the trans sited As–Cl distances in 2 and 3 are very similar a pronounced degree of asymmetry is apparent for the Cl–As–Cl three-centre bonds in 4 and 5 [2.396(1) and 2.602(1) Å in 5]. In 6 and 7 C_i symmetry related RAsBr₂ units are connected through long As…Br bonds [2.926(1) and 3.116(2) Å in 6 ]. The bromophenylarsenate(III) anion of 8 which contains two effectively undistorted ψ-trigonal bipyramids [PhAsBr₃]^– associated by weak As…Br interactions [3.117(2) Å]. In view of its very long bridging As…Cl distances the [Me₂As₂Cl₅]^– anion in 1 can, as 6 an 7 , be regarded as two MeAsCl₂ molecules weakly linked through a chloride ion.     

Reaktive E=C(p‐p)π‐Systeme. 54 [1] Reaktionen des Perfluor‐2‐arsapropens,F3CAs=CF2 (1), mit H‐aciden Verbindungen Me2EH (E = N,P, As) und MeE′H (E′ = O,S, Se)

Reactive E=C(p‐p)π‐Systems. 54 [1] Reactions of perfluoro‐2‐arsapropene, F₃CAs=CF₂ (1), with H‐acidic compounds Me₂EH (E = N, P, As) and MeE′H (E′ = O, S, Se) The reactions of the perfluoro‐2‐arsapropene ( 1 ) with H‐acidic compounds Me₂EH (E = N, P, As) and MeE′H (E′ = O, S, Se), respectively, proceed via addition to the As=C double bond yielding either secondary arsanes F₃C(H)AsCF₂X (X = NMe₂, PMe₂, OMe, SMe) or AsX derivatives (X = AsMe₂, SeMe). Me₂‐AsH is obviously a border case nucleophile because, besides the AsX derivative as main product, small amounts of the arsane are formed indicative for the reverse addition pathway. With the strong base Me₂NH, the addition is followed immediately by HF elimination producing the fairly stable arsaalkene F₃CAs=C(F)NMe₂ ( 4 ) which had already been obtained by reaction of HAs(CF₃)₂ with three equivalents of Me₂NH. The novel rather labile compounds were identified by spectroscopic (NMR, GC/MS) investigations. – Quantum chemical DFT calculations [B3LYP/6‐311+G(d,p)] were carried out to determine the relative energy of the isomeric products and the thermodynamics of the addition reactions.     

cis‐trans‐Isomerie bei (Me4Sb)2[Ph2Sb2I6]

cis‐trans‐Isomerism in (Me₄Sb)₂[Ph₂Sb₂I₆] Crystals of cis‐(Me₄Sb)₂[Ph₂Sb₂I₆] ( 1 a ) are formed by reaction of PhSbI₂ and Me₄SbI in ethanol/petroleum ether at –7 °C. In ethanol/acetone crystals of trans‐(Me₄Sb)₂[Ph₂Sb₂I₆] · acetone ( 1 b ) form. The X‐ray crystal structure analyses reveal that both isomers consist of tetrahedral cations and of dimeric anions with the geometry of two edge sharing tetragonal pyramids. The phenyl groups possess apical cis ( 1 a ) or trans ( 1 b ) positions relative to the I₂SbI₂SbI₂ plane. The acetone molecules in 1 b are non coordinating.     

Untersuchungen an Polyhalogeniden. XXII [1]. Dimethyldiphenylammoniumpolyiodide (Me2Ph2N)In mit n = 3, 13/3, 6, 8: Darstellung und strukturelle Charakterisierung eines Triiodids (Me2Ph2N)I3, Tridecaiodids (Me2Ph2N)3I13, Dodecaiodids (Me2Ph2N)2I12 und Hexadecaiodids (Me2Ph2N)2I16

Studies of Polyhalides. 22. On Dimethyldiphenylammoniumpolyiodides (Me₂Ph₂N)I_n with n = 3, 13/3, 6, and 8: Preparation and Crystal Structures of a Triiodide (Me₂Ph₂N)I₃, Tridecaiodide (Me₂Ph₂N)₃I₁₃, Dodecaiodide (Me₂Ph₂N)₂I₁₂, and Hexadecaiodide (Me₂Ph₂N)₂I₁₆ The new compounds [(CH₃)₂(C₆H₅)₂N]I₃, [(CH₃)₂(C₆H₅)₂N]₃I₁₃, [(CH₃)₂(C₆H₅)₂N]₂I₁₂ and [(CH₃)₂(C₆H₅)₂N]₂I₁₆ have been prepared by the reaction of dimethyldiphenylammonium iodide [(CH₃)₂(C₆H₅)₂N]I with iodine I₂ in ethanol. Their crystal structures have been determined by single crystal X-ray diffraction methods. The structure of the triiodide may be described as a layerlike packing of pairs of nearly linear symmetric anions and tetraedral cations. The tridecaiodide forms zig-zag chains of iodide ions and iodine molecules with the iodide ion also weakly coordinated by two pentaiodide groups. The dodecaiodide is built from two pentaiodide-groups, which are bridged by an iodine molecule and connected with secondary bonds forming double chains. The hexadecaiodide ion forms layers built up from two heptaiodide groups and one iodine molecule. Thus the dimethyldiphenylammonium cation stabilizes a unique series of polyiodides of extraordinary composition and structure.     

Alternativ-Liganden. XXVI [1]. M(CO)4L-Komplexe (M  Cr,Mo, W) der Chelatliganden Me2ESiMe2(CH2)2E′Me2 (Me  CH3; E  P,As; E′  N,P, As)

Alternative Ligands. XXVI. M(CO)₄ L-Complexes (M ? Cr, Mo, W) of the Chelating Ligands Me₂ESiMe₂(CH₂)₂E′ Me₂ (Me ? CH₃; E ? P, As; E′ ? N, P, As) The reaction of M(CO)₄NBD (NBD = norbornadiene; M ? Cr, Mo, W) with the ligands Me₂ESiMe₂(CH₂)₂E′ Me₂ yields the chelate complexes (CO)₄M[Me₂ESiMe₂]) for E,E′ ? P, As, but not for E and /or E′ ? N. The NSi group is not suited for coordination because of strong (p-d)π-interaction. In the case of the ligands with E ? P or As and E′ ? N chelate complexes can be detected in the reaction mixture, but isolable products are complexes with two ligands coordinated via the E donor group. The new compounds are characterized by analytical and spectroscopic (IR, NMR, MS) investigations. The spectroscopic data are also used to deduce the coordinating properties of the ligands. X-ray diffraction studies of the molybdenum complexes (CO)₄Mo[Me₂ESiMe₂(CH₂)₂AsMe ₂] (E ? P, As) in accord with the observed coordination effects show only small differences between SiE and CE donor functions. Attempts to use the ligands Me₂ESiMe₂(CH₂)₂AsMe₂ (E ? P, As) for the preparation of Fe(CO)₃L complexes result in the fission of the SiE bonds and the formation of the binuclear systems Fe₂(CO)₆(EMe₂)₂ (E ? P, As) together with the disilane derivative [Me₂Si(CH₂)₂AsMe₂]₂.     

Crystal Structures and Spectral Studies of [Ph3Sn(O2AsMe2)], [Bu2ClSn(O2AsMe2)] and [PhClSn(O2AsMe2)(μ‐OMe)]2

[Ph₃Sn(O₂AsMe₂)] ( 1 ) and [PhClSn(O₂AsMe₂)(μ‐OMe)]₂ ( 3 ) have been synthesized by treatment of Ph₃SnCl and Ph₂SnCl₂ with Na(O₂AsMe₂) in methanol, respectively. [Bu₂ClSn(O₂AsMe₂)] ( 2 ) has been prepared by the reaction of Bu₂SnCl₂ with HO₂AsMe₂ in methanol. X‐ray diffraction studies show 1 to crystallize in the monoclinic space group P2₁/n with a = 699.8(1), b = 1961.4(2), c = 1433.6(2) pm, β = 95.17(1)°, and Z = 4. 2 also crystallizes monoclinic in the space group P2₁/m, the cell parameters being a = 480.6(1), b = 1992.7(2), c = 808.8(1) pm, β = 103.726(5)°, and Z = 2. Both compounds form infinite chains with alternating (Me₂AsO₂)^? and (R₃Sn)⁺ or (R₂ClSn)⁺ units. The dimer 3 consists of 8‐membered (OSnOAs)₂ rings in which the tin atoms are bridged by methanolate bridges. It crystallizes triclinic in the space group with a = 822.8(2), b = 910.4(2), c = 929.2(2) pm, α = 77.04(3)°, β = 82.35(3)°, γ = 68.69(3)°, and Z = 1 for the dimer. The vibrational and mass spectra of 1 , 2 and 3 are given and discussed.     

Variable Bonding Modes of Pyrimidine‐2‐thione in PdII/PtII Complexes [M(η2‐N,S‐pymS)(η1‐S‐pymS)(PPh3)] and [M(η1‐S‐pymS)2(L‐L)] (L‐L = dppm,dppe)

Reactions of pyrimidine‐2‐thione (HpymS) with Pd^II/Pt^IV salts in the presence of triphenyl phosphine and bis(diphenylphosphino)alkanes, Ph₂P‐(CH₂)_m‐PPh₂ (m = 1, 2) have yielded two types of complexes, viz. a) [M(η²‐N, S‐ pymS)(η¹‐S‐ pymS)(PPh₃)] (M = Pd, 1 ; Pt, 2 ), and (b) [M(η¹‐S‐pymS)₂(L‐L)] {L‐L, M = dppm (m = 1) Pd, 3 ; Pt, 4 ; dppe (m = 2), Pd, 5 ; Pt, 6 }. Complexes have been characterized by elemental analysis (C, H, N), NMR spectroscopy (¹H, ¹³C, ³¹P), and single crystal X‐ray crystallography ( 1 , 2 , 4 , and 5 ). Complexes 1 and 2 have terminal η¹‐S and chelating η²‐N, S‐modes of pymS⁻, while other Pd/Pt complexes have only terminal η¹‐S modes. The solution state ³¹P NMR spectral data reveal dynamic equilibrium for the complexes 3 , 5 and 6 , whereas the complexes 1 , 2 and 4 are static in solution state.     

Synthese,Struktur und Eigenschaften der Komplexe [(H2O)Cl4Os≡N‐IrCl(C5Me5)(AsPh3)], [(Ph3Sb)Cl4Os≡N‐IrCl(C5Me5)(SbPh3)], [(Ph3Sb)2Cl3Os≡N‐IrCl(COD)] und [{(Me2PhP)2(CO)Cl2Re≡N}2ReNCl2(PMe2Ph)]

Synthesis, Crystal Structure, and Properties of the Complexes [(H₂O)Cl₄Os≡N‐IrCl(C₅Me₅)(AsPh₃)], [(Ph₃Sb)Cl₄Os≡N‐IrCl(C₅Me₅)(SbPh₃)], [(Ph₃Sb)₂Cl₃Os≡N‐IrCl(COD)] and [{(Me₂PhP)₂(CO)Cl₂Re≡N}₂ReNCl₂(PMe₂Ph)] The dinuclear complexes [(H₂O)Cl₄Os≡N‐IrCl(C₅Me₅)(AsPh₃)]·H₂O ( 1 ·H₂O), [(Ph₃Sb)Cl₄Os≡N‐IrCl(C₅Me₅)(SbPh₃)] ( 2 ), and [(Ph₃Sb)₂Cl₃Os≡N‐IrCl(COD)] ( 3 ) result from the reaction of the nitrido complexes [(Ph₃As)₂OsNCl₃] and [(Ph₃Sb)₂OsNCl₃] with the iridium compounds [IrCl₂(C₅Me₅)]₂ and [IrCl(COD)]₂ in dichloromethane. 1 crystallizes as 1 ·H₂O in form of green platelets in the monoclinic space group Cm and a = 1105.53(6); b = 1486.76(9); c = 2024.88(10) pm, β = 97.191(4)°, Z = 4. The formation of 1 in air involves a ligand exchange, and the coordination of a water molecule in trans position to the Os‐N triple bond. The resulting complex fragments [(H₂O)Cl₄Os≡N] and [IrCl(C₅Me₅)(AsPh₃)] are connected by an asymmetric nitrido bridge Os≡N‐Ir. The nitrido bridge is characterised by an Os‐N‐Ir bond angle of 173.7(7)°, and distances Os‐N = 168(1) pm and Ir‐N = 191(1) pm. 2 crystallizes in clumped together brown platelets with the space group and a = 1023.3(3), b = 1476.2(3), c = 1872.5(6) pm, α = 74.60(2), β = 73.84(2), γ = 76.19(2)°, Z = 2. In 2 the asymmetric nitrido bridge Os≡N‐Ir joins the two complex fragments [(Ph₃Sb)Cl₄Os≡N] and [IrCl(C₅Me₅)(SbPh₃)], which are formed by a ligand exchange reaction. 3 forms dark green crystals with the triclinic space group and a = 1079.4(1), b = 1172.3(1), c = 1696.7(2) pm, α = 101.192(9),β = 92.70(1), γ = 92.61(1)°, Z = 2. The distances in the almost linear nitrido bridge (Os≡N‐Ir = 175.3(7)°) are Os‐N = 171(1) pm and Ir‐N = 183(1) pm. The reaction of [ReNCl₂(PMe₂Ph)₃] with [Mo(CO)₃(NCMe)₃] unexpectedly affords the trinuclear complex [{(Me₂PhP)₂(OC)Cl₂Re≡N}₂ReNCl₂(PMe₂Ph)] ( 4 ) as the main product. It forms triclinic brown crystals with the composition 4 ·2THF and the space group (a = 1382.70(7), b = 1498.58(7), c = 1760.4(1) pm, α = 99.780(7), β = 99.920(7), γ = 114.064(6)°, Z = 2). In the trinuclear complex, the central fragment, [ReNCl₂(PMe₂Ph)] is joined in trans position to two nitrido complexes [(Me₂PhP)₂(CO)Cl₂Re≡N], giving an almost linear Re≡N‐Re‐N≡Re arrangement. The bond angles and distances in the nitrido bridges are Re‐N‐Re = 167.8(3)°, Re‐N = 171.1(8) pm and 204.2(8) pm; and Re‐N‐Re = 168.1(4)°, Re‐N = 170.9(9) and 203.5(9) pm respectively. As expected, the Re‐N bond length to the terminal nitrido ligand on the central Re atom is much shorter at 161.2(9) pm than the triple bonds of the asymmetric bridges.     

Reaktion von (R,R)‐(N,N′)‐Diisopropylcyclohexyl‐1,2‐diamin mit Me2MCl (M = Ga,In)

Reaction of (R,R)‐(N,N′)‐Diisopropylcyclohexyl‐1,2‐diamine with Me₂MCl (M = Ga, In) (R,R)‐(N,N′)‐Diisopropylcyclohexyl‐1,2‐diamine (H₂L) was reacted with Me₂GaCl and Me₂InCl in boiling toluene, respectively. In both cases the salt [Me₂M(H₂L)][Me₂MCl₂] [M = Ga ( 1 ), In ( 2 )] was formed. 1 and 2 were characterized by NMR and vibrational spectroscopy. In addition, an X‐ray structure determination was applied on 2 . According to the spectroscopical and structural findings 1 and 2 consist of cations [Me₂M(H₂L)]⁺ and anions [Me₂MCl₂]^?.     

[Et4N][7‐Me2S‐nido‐B11H12]

Tetraethyl­ammonium 7‐di­methyl­sulfanyl‐nido‐dodeca­hydro­undecaborate, [Et₄N][7‐Me₂S‐nido‐B₁₁H₁₂] or C₈H₂₀N⁺·C₂H₁₈B₁₁S⁻, is a product of the deprotonation of [7‐Me₂S‐nido‐B₁₁H₁₃] with KHBEt₃ and precipitation with tetraethyl­ammonium chloride. The effect of removing one endo‐terminal H atom is to cause a general contraction of the open‐face B—B distances.     

Iodination of cyclo‐E5‐Complexes (E=P,As)

In a high‐yield one‐pot synthesis, the reactions of [Cp*M(η⁵‐P₅)] (M=Fe ( 1 ), Ru ( 2 )) with I₂ resulted in the selective formation of [Cp*MP₆I₆]⁺ salts ( 3 , 4 ). The products comprise unprecedented all‐cis tripodal triphosphino‐cyclotriphosphine ligands. The iodination of [Cp*Fe(η⁵‐As₅)] ( 6 ) gave, in addition to [Fe(CH₃CN)₆]²⁺ salts of the rare [As₆I₈]^2? (in 7 ) and [As₄I₁₄]^2? (in 8 ) anions, the first di‐cationic Fe‐As triple decker complex [(Cp*Fe)₂(μ,η^5:5‐As₅)][As₆I₈] ( 9 ). In contrast, the iodination of [Cp*Ru(η⁵‐As₅)] ( 10 ) did not result in the full cleavage of the M?As bonds. Instead, a number of dinuclear complexes were obtained: [(Cp*Ru)₂(μ,η^5:5‐As₅)][As₆I₈]_0.5 ( 11 ) represents the first Ru‐As₅ triple decker complex, thus completing the series of monocationic complexes [(Cp^RM)₂(μ,η^5:5‐E₅)]⁺ (M=Fe, Ru; E=P, As). [(Cp*Ru)₂As₈I₆] ( 12 ) crystallizes as a racemic mixture of both enantiomers, while [(Cp*Ru)₂As₄I₄] ( 13 ) crystallizes as a symmetric and an asymmetric isomer and features a unique tetramer of {AsI} arsinidene units as a middle deck.     

Halogenid‐Ionen als Katalysator: Metallzentrierte C–C‐Bindungsknüpfung ausgehend von Acetontril

Halide Ions as Catalyst: Metalcentered C–C Bond Formation Proceeded from Acetonitril AlMe₃ reacts at 20 ?C in acetonitrile to the complex [Me₃Al(NCMe)] ( 1 ). By addition of cesium halides (X^– = F^–, Cl^–, Br^–) a trimerisation to the heterocycle [Me₂Al{HNC(Me)}₂C(CN)] ( 2 ) has been observed. The reaction might be carried out under catalytic conditions (1–2 mol% CsX). The gallium complex [Me₂Ga{HNC(Me)}₂ · C(CN)] ( 3 ), generated under similar reaction conditions, can be converted to the silylated compound [Me₂Ga{Me₃SiNC(Me)}₂C(CN)] ( 4 ) by successive treatment with two equivalents n‐butyllithium and Me₃SiCl. 3 reacts under hydrolysis conditions (1 M hydrochloric acid) to the iminium salt [{H₂NC(Me)}₂C(CN)]Cl ( 5 ). A mixture of H₂O, Ph₂PCl and 3 in THF/toluene leads in a unusual conversion to the diphospane derivative [Ph₂P–P(O)(Me₂GaCl)] ( 6 ). 1 , 2 , 4 , 5 and 6 have been characterized by NMR, IR and MS techniques. X‐ray structure analyses were performed with 1 , 2 , 4 and 6 · 0.5 toluene. According this 1 possesses an almost linear axis AlNCC [Al1–N1–C3: 179,5(2)?; N1–C3–C4: 179,7(4)?]. 2 is an AlN₂C₃ six‐membered heterocycle with two iminium fuctions. One N–H group is responsible for a intermolecular chain‐formation through hydrogen bridges to an adjacent nitrile group along the direction [010]. The basic structural motif of the heterocycle 3 has been maintained after silylation to 4 . In 6 · 0.5 toluene an unit Me₂GaCl, originated from 3 , is coordinated to the oxygen atom of the diphosphane oxide Ph₂P–P(O)Ph₂.     

Ringkontraktion durch NHC‐induzierte Pnictogen‐Abstraktion

Die Reaktion von [Cp′′′Co(η⁴‐P₄)] ( 1 ) (Cp′′′=1,2,4‐tBu₃C₅H₂) mit ^MeNHC (^MeNHC=1,3,4,5‐tetramethylimidazol‐2‐ylidene) führt über eine NHC‐induzierte Phosphorkationen‐Abstraktion zum Ringkontraktionsprodukt [(^MeNHC)₂P][Cp′′′Co(η³‐P₃)] ( 2 ), welches das erste Beispiel eines anionischen CoP₃‐Komplexes repräsentiert. Solche von NHCs induzierten Ringkontraktionsreaktionen lassen sich ebenfalls auf Tripeldecker‐Sandwich‐Komplexe anwenden. So werden die Komplexe [(Cp*Mo)₂(μ,η^6:6‐E₆)] ( 3 a , 3 b ) (Cp*=C₅Me₅; E=P, As) zu den Komplexen [(^MeNHC)₂E][(Cp*M)₂(μ,η^3:3‐E₃)(μ,η^2:2‐E₂)] ( 4 a , 4 b ) transformiert, wobei 4 b das erste strukturell charakterisierte Beispiel eines NHC‐substituierten As^I‐Kations darstellt. Darüber hinaus führt die Reaktion des Vanadium‐Komplexes [(Cp*V)₂(μ,η^6:6‐P₆)] ( 5 ) mit ^MeNHC zur Bildung der neuartigen Komplexe [(^MeNHC)₂P][(Cp*V)₂(μ,η^6:6‐P₆)] ( 6 ), [(^MeNHC)₂P][(Cp*V)₂(μ,η^5:5‐P₅)] ( 7 ) bzw. [(Cp*V)₂(μ,η^3:3‐P₃)(μ,η^1:1‐P{^MeNHC})] ( 8 ).     

Herstellung von 1,2,4‐Trithiolan‐, 1,2,4,5‐Tetrathian‐ sowie 1,2,3,5,6‐Pentathiepan‐S‐oxiden und deren Reaktionen mit (Ph3P)2Pt(η2‐C2H4). Kristallstrukturanalyse von 3,3,5,5‐Tetraphenyl‐1,2,4‐trithiolan‐1‐oxid

Metal Complexes of Functionalized Sulfur‐containing Ligands. XVII Synthesis of S ‐Oxides of 1,2,4‐Trithiolane, 1,2,4,5‐Tetrathiane as well as 1,2,3,5,6‐Pentathiepane, and their Reactions with (Ph₃P)₂Pt(η²‐C₂H₄). X‐Ray Structure Analysis of 3,3,5,5‐Tetraphenyl‐1,2,4‐trithiolane 1‐oxide 3,3,5,5‐Tetraphenyl‐1,2,4‐trithiolan ( 1 ) was oxidized using m‐chloroperbenzoic acid to give, selectively, the 3,3,5,5‐tetraphenyl‐1,2,4‐trithiolane 1‐oxide ( 2 ). 2 was characterized structurally. The reaction of octamethyl tetrathiadispiro[3.2.3.2]dodecane‐2,9‐dione ( 3 ) with trifluoroperacetic acid at –50 °C yielded the corresponding 5‐oxide 4 . Oxidation of octamethyl pentathiadispiro[3.3.3.2]tridecane‐2,9‐dione ( 5 ) with m‐chloroperbenzoic acid at 0 °C gave the 12‐oxide 6 . Treatment of 2 with two equivalents of (Ph₃P)₂Pt(η²‐C₂H₄) ( 7 ) afforded a mixture (1 : 1) of the complexes (Ph₃P)₂PtSCPh₂S ( 8 ) and (Ph₃P)₂Pt(η²‐Ph₂C=S=O) ( 9 ), respectively.     

Phosphine‐NHC Manganese Hydrogenation Catalyst Exhibiting a Non‐Classical Metal‐Ligand Cooperative H2 Activation Mode

Deprotonation of the Mn^I NHC‐phosphine complex fac‐[MnBr(CO)₃(κ²P,C‐Ph₂PCH₂NHC)] ( 2 ) under a H₂ atmosphere readily gives the hydride fac‐[MnH(CO)₃(κ²P,C‐Ph₂PCH₂NHC)] ( 3 ) via the intermediacy of the highly reactive 18‐e NHC‐phosphinomethanide complex fac‐[Mn(CO)₃(κ³P,C,C‐Ph₂PCHNHC)] ( 6 a ). DFT calculations revealed that the preferred reaction mechanism involves the unsaturated 16‐e mangana‐substituted phosphonium ylide complex fac‐[Mn(CO)₃(κ²P,C‐Ph₂P=CHNHC)] ( 6 b ) as key intermediate able to activate H₂ via a non‐classical mode of metal‐ligand cooperation implying a formal λ⁵‐P–λ³‐P phosphorus valence change. Complex 2 is shown to be one of the most efficient pre‐catalysts for ketone hydrogenation in the Mn^I series reported to date (TON up to 6200).     

Die Reaktionen von tBu2P–P=P(Me)tBu2 und (Me3Si)tBuP–P=P(Me)tBu2 mit PR3

The Reactions of ^tBu₂P–P=P(Me)^tBu₂ and (Me₃Si)^tBuP–P=P(Me)^tBu₂ with PR₃ ^tBu₂P–P=P(Me)^tBu₂ ( 1 ) reacts at 20 °C with PMe₃, PEt₃, P(c‐Hex)₃, P(p‐Tol)₃, PPh₂Me, PPh₂Et, PPhEt₂, PPh₂ⁱPr, PPh₃ and P(NEt₂)₃ yielding ^tBu₂P–P=PR₃ and ^tBu₂PMe; however, P^tBu₃, P^tBu₂(SiMe₃) and ^tBu₂PCl don't. ^tBu₂PH and 1 form ^tBu₂P–PH–P^tBu₂ which yields ^tBu₂P–P=PEt₃ when treated with PEt₃. Ph₂PH, ^tBuPH₂, PH₃, Ph₂PCl and EtOH don't substitute the ^tBu₂PMe group in 1 , instead, the molecule is decomposed. With PEt₃, (Me₃Si)^tBuP–P=P(Me)^tBu₂ forms (Me₃Si)^tBuP–P=PEt₃. The compounds ^tBu₂P–P=PR₃ decompose at 20 °C to different degrees giving P‐rich consecutive products of the phosphinophosphinidene.     

Über Reaktionen von Hexachlorodiberyllat mit Trimethylsilyl‐N‐dimethylamid. Die Kristallstrukturen von (Ph4P)3[Be2Cl5(OSiMe3)][BeCl3(Me2NSiMe3)], (Ph4P)[BeCl3(HNMe2)] und (Ph4P)(H2NMe2)[BeCl4]

On Reactions of Hexachlorodiberyllate with Trimethylsilyl‐N‐dimethylamide. Crystal Structures of (Ph₄P)₃[Be₂Cl₅(OSiMe₃)][BeCl₃(Me₂NSiMe₃)], (Ph₄P)[BeCl₃(HNMe₂)], and (Ph₄P)(H₂NMe₂)[BeCl₄] Reactions of bis‐tetraphenylphosphonium hexachlorodiberyllate, (Ph₄P)₂[Be₂Cl₆], with trimethylsilyl‐N‐dimethylamide under different conditions lead to the novel chloroberyllate derivatives (Ph₄P)₃[Be₂Cl₅(OSiMe₃)][BeCl₃(Me₂NSiMe₃)] ( 1 ), (Ph₄P)[BeCl₃(HNMe₂)] ( 2 ), and (Ph₄P)(H₂NMe₂)[BeCl₄] ( 3 ). 1 ‐ 3 were characterized by IR spectroscopy and crystal structure determinations. 1· 4CH₂Cl₂: Space group P1¯, Z = 2, lattice dimensions at 193 K: a = 1115.6(1), b = 2110.7(2), c = 2145.0(3) pm, α = 71.38(1)°, β = 85.66(1)°, γ = 85.24(1)°, R₁ = 0.0732. The [Be₂Cl₅(OSiMe₃)]^2— ion in the structure of 1 is derived from the [Be₂Cl₆]^2— ion by substitution of a μ‐Cl ligand by the oxygen atom of the (OSiMe₃)^— group. The second anion, [BeCl₃(Me₂NSiMe₃)]^—, can be described as donor acceptor complex with a short Be—N bond of 179(1) pm. 2 : Space group P1¯, Z = 2, lattice dimensions at 193 K: a = 1063.1(1), b = 1072.0(1), c = 1238.3(1) pm, α = 87.55(1)°, β = 74.86(1)°, γ = 69.73(1)°, R₁ = 0.0299. The anion of 2 forms a centrosymmetric dimer [BeCl₃(HNMe₂)]₂^2— via N—H···Cl bridges of the two donor acceptor complex units with Be—N separations of 175.2(2) pm. 3 : Space group Pbca, Z = 8, lattice dimensions at 193 K: a = 926.9(1), b = 2164.7(1), c = 2732.7(1) pm, R₁ = 0.0495. The structure of 3 contains centrosymmetric ion quadrupoles [(Me₂NH₂)(BeCl₄)]₂^2— forming by N—H···Cl bridges between (Me₂NH₂)⁺ and [BeCl₄]^2— ions.     

Sterically Tuned P‐Phosphanylamino Phosphaalkenes (Me3Si)2C=PN(R)PPh2 and (iPrMe2Si)2C=PN(R)PPh2

Deprotonation of the aminophosphanes Ph₂PN(H)R 1a – 1h [R = tBu ( 1a ), 1‐adamantyl ( 1b ), iPr ( 1c ), CPh₃ ( 1d ), Ph ( 1e ), 2,4,6‐Me₃C₆H₂ (Mes) ( 1f ), 2,4,6‐tBu₃C₆H₂ (Mes*) ( 1g ), 2,6‐iPr₂C₆H₃ (DIPP) ( 1h )], followed by reactions of the phosphanylamide salts Li[Ph₂PNR] 2a , 2b , 2g , and 2h with the P‐chlorophosphaalkene (Me₃Si)₂C=PCl, and of 2a – 2g with (iPrMe₂Si)₂C=PCl, gave the isolable P‐phosphanylamino phosphaalkenes (Me₃Si)₂C=PN(R)PPh₂ 3a , 3b , 3g , and (iPrMe₂Si)₂C=PN(R)PPh₂ 4a – 4g . ³¹P NMR spectra, supported by X‐ray structure determinations, reveal that in compounds 2a , 2b , 3a , and 3b , with bulky N‐alkyl groups the Si₂C=P–N–P skeleton is non‐planar (orthogonal conformation), whereas 3g , 3h , and 4g with bulky N‐aryl groups exhibit planar conformations of the Si₂C=P–N–P skeleton. Solid 3g and 4g exhibit cisoid orientation of the planar C=P–N–C units (planar I) but in solid 3h the transoid rotamer is present (planar II). From 3g , 4d , and 4g mixtures of rotamers were detected in solution by pairs of ³¹P NMR patterns ( 3h : line broadening).