Darstellung und charakterisierung von verbindungen des typs (CH3)3ME(CF3)2 (M = Si,Ge, Sn; E = P,As)

Various preparative routes for the synthesis of (CH₃)₃SiP(CF₃)₂ are discussed. The most favourable method, reaction of (CH₃)₃MPH₂ with HE(CF₃)₂, provides a good yield of (CH₃)₃ME(CF₃)₂ compounds (M = Si, Ge, Sn; E = P, As). The reaction rate is dependent on M (Si < Ge <Sn) und E (P < As). The stability and reactivity of the (CH₃)₃ME(CF₃)₂ compounds are discussed. The new compounds were characterized by NMR and IR spectra and by cleavage reactions of the M-E bond. ¹H, ¹⁹F NMR and IR spectral data are reported.     

Intermediates in the reactions of electron-rich germylenes with an acyl azide: An MNDO-SCF-MO investigation

The experimentally known reaction between the electron-rich germylene [(Me₃Si)₂N]₂Ge andp-CH₃C₆H₄SO₂N₃ has been modeled computationally by MNDO calculations on the reaction intermediates formed by [CH₃Si)₂E]₂Ge (E=N or CH) and CH₃CON₃. Molecular and electronic structures have been established for the acyclic germaketimines [(CH₃Si)₂E]₂Ge=N-N=N-COCH₃ (the primary 11 adducts formed by the reactants) and [CCH₃Si)₂E]₂Ge=N-COCH₃, and for the cyclic species [(H₃Si)₂E]₂Ge-N=N-N=C(CH₃)-O, [(H₃Si)₂E]₂Ge-N=N-N(COCH₃), and [(H₃Si)₂E]₂-Ge-N=C(CH₃-O. The intermediates [(H₃Si)₂E]₂-GeN(N₂)COCH₃ were found, upon formation, to undergo smooth dissociation along the N()-N() bond, with loss of N₂, to provide acyclic [H₃Si)₂E]₂Ge=N-COCH₃; the polymerizations of these latter species to form polygermazanes are extremely exothermic.     

Neue Synthesen von Me2SbX (X = Cl,I) und Kristallstrukturen von Me2SbI und [(Me3Si)2CH]2SbCl

Novel Syntheses of Me₂SbX (X = Cl, I) and Crystal Structures of Me₂SbI and [(Me₃Si)₂CH]₂SbCl The crystal structures of Me₂SbI (Me = CH₃) and [(Me₃Si)₂CH]₂SbCl have been determined by X‐ray methods. Both molecules are pyramidal. The Me₂SbI molecules are associated to chains through short intermolecular Sb…I distances (366,7(1) pm) with linear I–Sb…I units (171,87(4)°) and bent Sb–I…Sb bridges (116,83(3)°).     

Reactions of (triethylstannylthioalkyl)trialkoxysilanes and (triethylstannylthioalkyl)trialkoxysilatranes with methyl iodide

Reactions of (triethylstannylthioalkyl)trimethoxysilanes Et₃SnS(CH₂)_nSi(OMe)₃ (n = 1, 2) and (triethylstannylthioalkyl)trialkoxysilatranes Et₃Sn(CH₂) _n Sa [hereinafter Sa = Si(OCH₂CH₂)₃N is silatranyl group] with methyl iodide are studied for the first time. The results of the investigation of the reaction of 1-(2-alkylthioethyl)silatranes RSCH₂CH₂Sa (R = Me, Et) with methyl iodide are also discussed.     

Bis[bis(trimethylsilyl)amino]sulfan 1. Darstellung und Charakterisierung

Inhaltsübersicht. Die Titelverbindung[(CH₃)₃Si]₂N–S–N[Si(CH₃)₃]₂ wurde durch Reaktion von Lithium-bis(trimethylsilyl)arnid mit Schwefeldichlorid hergestellt. Elektronenabsorptions-, Infrarot-, Kernresonanz- (¹H, ¹³C, ²⁹Si, ¹⁵N) und Massenspektren werden mitgeteilt. Die Reaktivität der Verbindung wurde untersucht. Bis[bis (trimethylsilyl) amino] sulfane. 1. Synthesis and Characterization Abstract, The title compound [(CH₃)₃Si]₂N–S–N[Si(CH₃)₃]₂ has been prepared by reaction of lithium bis(trimethylsilyl)amide with sulfur dichloride. Electron absorption, infrared, nuclear magnetic resonance (¹H, ¹³C, ²⁹Si, ¹⁶N), and mass spectra are given. The reactivity of the compound has been studied. Im Zusammenhang mit unseren Untersuchungen [1–3] über S-Bis(trimethyl-eilyl)aminoester von Dithiocarbamidsäuren RR′N–CS–S–N[Si(CH₃)₃]₂ haben wir uns mit dem Bis[bis(trimethylsilyl)amino]sulfan [(CH₃)₃Si]₂N-S-N[Si(CH₃)₃]₂ befaßt. Diese Verbindung wurde erstmals 1962 von Wannagat u. Kückertz [4] hergestellt und kurz beschrieben. Wolmershäuser u. Mitarb. [5] teilten einige wenige spektroskopische Daten mit; vgl. auch [6, 7].     

Synthese und Kristallstruktur des heterobimetallischen Diorganozinndichlorids (FcN,N)2SnCl2 (FcN,N—: (η5‐C5H5)Fe{(η5‐C5H3[CH(CH3)N(CH3)CH2CH2NMe2]‐2}—)

Synthesis and Crystal Structure of the Heterobimetallic Diorganotindichloride (FcN, N)₂SnCl₂ (FcN, N^—: (η⁵‐C₅H₅)Fe{η⁵‐C₅H₃[CH(CH₃)N(CH₃)CH₂CH₂NMe₂]‐2}^—) The heterobimetallic title compound [(FcN, N)₂SnCl₂] ( 1 ) was obtained by the reaction of [LiFcN, N] with SnCl₄ in the molar ratio 1:1 in diethylether as a solvent. The two FcN, N^— ligands in 1 are bound to Sn through a C‐Sn σ‐bond; the amino N atoms of the side‐chain in FcN, N^— remain uncoordinated. The crystals contain monomeric molecules with a pseudo‐tetrahedral coordination at the Sn atom: Space group P2₁/c; Z = 4, lattice dimensions at —90 °C: a = 9.6425(2), b = 21.7974(6), c = 18.4365(4) Å, β = 100.809(2)°, R1_obs· = 0.051, wR2_obs· = 0.136.     

Actinide–Pnictide (An−Pn) Bonds Spanning Non‐Metal,Metalloid, and Metal Combinations (An=U,Th; Pn=P,As, Sb,Bi)

The synthesis and characterisation is presented of the compounds [An(Tren^DMBS){Pn(SiMe₃)₂}] and [An(Tren^TIPS){Pn(SiMe₃)₂}] [Tren^DMBS=N(CH₂CH₂NSiMe₂Bu^t)₃, An=U, Pn=P, As, Sb, Bi; An=Th, Pn=P, As; Tren^TIPS=N(CH₂CH₂NSiPrⁱ₃)₃, An=U, Pn=P, As, Sb; An=Th, Pn=P, As, Sb]. The U?Sb and Th?Sb moieties are unprecedented examples of any kind of An?Sb molecular bond, and the U?Bi bond is the first two‐centre‐two‐electron (2c–2e) one. The Th?Bi combination was too unstable to isolate, underscoring the fragility of these linkages. However, the U?Bi complex is the heaviest 2c–2e pairing of two elements involving an actinide on a macroscopic scale under ambient conditions, and this is exceeded only by An?An pairings prepared under cryogenic matrix isolation conditions. Thermolysis and photolysis experiments suggest that the U?Pn bonds degrade by homolytic bond cleavage, whereas the more redox‐robust thorium compounds engage in an acid–base/dehydrocoupling route.     

Actinide–Pnictide (An−Pn) Bonds Spanning Non‐Metal,Metalloid, and Metal Combinations (An=U,Th; Pn=P,As, Sb,Bi)

The synthesis and characterisation is presented of the compounds [An(Tren^DMBS){Pn(SiMe₃)₂}] and [An(Tren^TIPS){Pn(SiMe₃)₂}] [Tren^DMBS=N(CH₂CH₂NSiMe₂Bu^t)₃, An=U, Pn=P, As, Sb, Bi; An=Th, Pn=P, As; Tren^TIPS=N(CH₂CH₂NSiPrⁱ₃)₃, An=U, Pn=P, As, Sb; An=Th, Pn=P, As, Sb]. The U−Sb and Th−Sb moieties are unprecedented examples of any kind of An−Sb molecular bond, and the U−Bi bond is the first two‐centre‐two‐electron (2c–2e) one. The Th−Bi combination was too unstable to isolate, underscoring the fragility of these linkages. However, the U−Bi complex is the heaviest 2c–2e pairing of two elements involving an actinide on a macroscopic scale under ambient conditions, and this is exceeded only by An−An pairings prepared under cryogenic matrix isolation conditions. Thermolysis and photolysis experiments suggest that the U−Pn bonds degrade by homolytic bond cleavage, whereas the more redox‐robust thorium compounds engage in an acid–base/dehydrocoupling route.     

Mass spectrometry of organic compounds in the group V elements—I: Straight chain aliphatic derivatives

Comparative investigations of the mass spectra of eEH₂, Me₂EH, Et₂EH(E = N, P); Me₃E, Et₃E(E = N, P, As, Sb, Bi). (n-Pr)₃E(E = Sb, Bi); (n-Bu)₃E(E = P, As); (n-C₅H₁₁)₃As and (n-C₆H₁₃)₃As as well as Et₂AsBr have been carried out. Deuteroanalogues, metastable transitions and low voltage spectra were used for elucidation of the fragmentation paths. The mass spectra of MeN(CH₂)₂ and CD₃N(CH₂)₂ were studied to analyse the structure of the fragments. The main degradation path of amines, i.e. α-cleavage, was shown to be untypical for P, As, Sb and Bi derivatives.     

Heavy Carbene Analogues: Donor‐Free Bismuthenium and Stibenium Ions

Kinetically stabilized congeners of carbenes, R₂C, possessing six valence electrons (four bonding electrons and two non‐bonding electrons) have been restricted to Group 14 elements, R₂E (E=Si, Ge, Sn, Pb; R=alkyl or aryl) whereas isoelectronic Group 15 cations, divalent species of type [R₂E]⁺ (E=P, As, Sb, Bi; R=alkyl or aryl), were unknown. Herein, we report the first two examples, namely the bismuthenium ion [(2,6‐Mes₂C₆H₃)₂Bi][BAr^F₄] ( 1 ; Mes=2,4,6‐Me₃C₆H₂, Ar^F=3,5‐(CF₃)₂C₆H₃) and the stibenium ion [(2,6‐Mes₂C₆H₃)₂Sb][B(C₆F₅)₄] ( 2 ), which were obtained by using a combination of bulky meta‐terphenyl substituents and weakly coordinating anions.     

Alternativ-Liganden. XXV. Neue Chelatliganden des Typs Me2ESiMe2(CH2)2E′Me2 (E=P,As; E′=N,P, As)

Alternative Ligands. XXV. New Chelating Ligands of the Type Me₂ESiMe₂(CH₂)₂E′Me₂ (E=P, As; E′=N, P, As) Chelating ligands of the type Me₂EsiMe₂(CH₂)₂E′ Me₂, have been prepared by the following routes: Starting from Me₂Si(Vi)Cl, the compounds with E=N and E′ =N ( 1 ), P ( 2 ), As ( 3 ) are obtained in yields of 65 to 78% by aminolysis to yield Me₂NSiMe₂Vi, followed by the LiE′ Me₂ catalyzed addition of He′Me₂ to the vinyl group. The intermediates ClSiMe₂(CH₂)E′Me₂ [E′=N ( 4 ), P ( 5 ), As ( 6 )] are produced by the reactions of 1 to 3 with PhPCl₂. 5 and 6 can be prepared in a purer form by the photochemical addition of HPMe₂ and HAsMe₂, respectively, to the vinyl group of Me₂Si(Vo)Cl. 4 to 6 react with LiEMe₂, in situ prepared from n-BuLi and HEMe₂, to yield the ligands Me₂ESiMe₂(CH₂)₂E′Me₂ ( 7–12 ) (E=P, As; E′=N, P, As). The new compounds have been characterized by analytical and spectroscopic investigations (NMR, MS).     

Synthese und strukturuntersuchungen von zwei stannylwolframpentacarbonylen R2Sn-W(CO)5 (R = (o-dimethylaminomethyl)phenyl bzw. (o-diphenylphosphinomethyl)phenyl)

The compounds [o-C₆-H₄CH₂E]₂Sn-W(CO)₅, (E = NMe₂ (1) or PPh₂ (2)) have been prepared by reaction of o-LiC₆H₄CH₂E with pentacarbonyltungsten tin(II) chloride (CO)₅WSnCl₂. The complexes were characterized by ¹³C, ³¹P, and ¹¹⁹Sn NMR spectroscopy and by X-ray diffraction analyses. 1 crystallizes monoclinically in the space group C/c (no. 15) with a 1310.2(4), b 1552.1(4), c 1202.9(4) pm, β 90.11(4)°, and Z = 4. 2 crystallizes monoclinically in the space goup P2₁/n (no. 14) with a 2108.1(4), b 1707.7(4), c 1283.7(3) pm, β 97.47(2)° and Z = 4. The structures were refined to final R values of 0.029 and 0.039, respectively.The SnW bond distances of 274.9 and 276.2 pm are very similar in both complexes. The Sn atoms are penta-coordinated by 2C, 2N and W in 1 and by 2C, 2P and W in 2. The penta-coordination comprises one SnW and two SnC single bonds, and either a SnN (in 1) or a SnP bond (in 2) of bond order 0.45. In the stannyl group of 1 the SnN bond distances both are identical by symmetry (256.4 pm), whereas the two SnP bond lengths of 2 differ to some extent (283.1 and 301.2 pm).     

Multinuclear NMR spectra of (CH3)3SnCH2M(CH3)3 (MSn,Ge, Si,C) and some halogenated derivatives

Chemical shift and scalar coupling constant information has been obtained from the ¹H, ¹³C, ²⁹Si and ¹¹⁹Sn NMR spectra of a series of compounds (CH₃)₃SnCH₂M(CH₃)₃, where M = Sn, Ge, Si or C and with one or two CH₃? (Sn) groups replaced by Cl, Br or I. The (CH₃)₃M and (CH₃)₃MCH₂ groups appear to have opposite substituent effects on chemical shifts.     

Synthesis of hydroxy‐terminated,oligomeric poly(silarylene disiloxane)s via rhodium‐catalyzed dehydrogenative coupling and their use in the aminosilane–disilanol polymerization reaction

A series of oligomeric, hydroxy‐terminated silarylene–siloxane prepolymers of various lengths were prepared via dehydrogenative coupling between 1,4‐bis(dimethylsilyl)benzene [H(CH₃)₂SiC₆H₄Si(CH₃)₂H] and excess 1,4‐bis(hydroxydimethylsilyl)benzene [HO(CH₃)₂SiC₆H₄Si(CH₃)₂OH] in the presence of a catalytic amount of Wilkinson's catalyst [(Ph₃P)₃RhCl]. Attempts to incorporate the diacetylene units via dehydrogenative coupling polymerization between 1,4‐bis(dimethylsilyl)butadiyne [H(CH₃)₂Si? C?C? C?C? Si(CH₃)₂H] and the hydroxy‐terminated prepolymers were unsuccessful. The diacetylene units were incorporated into the polymer main chain via aminosilane–disilanol polycondensation between 1,4‐bis(dimethylaminodimethylsilyl)butadiyne [(CH₃)₂N? Si(CH₃)₂? C?C? C?C? (CH₃)₂SiN(CH₃)₂] and the hydroxy‐terminated prepolymers. Linear polymers were characterized by Fourier transform infrared, ¹H and ¹³C NMR, gel permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis, and they were thermally crosslinked through the diacetylene units, producing networked polymeric systems. The thermooxidative stability of the networked polymers is discussed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1334–1341, 2002     

Kristall- und molekülstruktur einiger pentacarbonyl(organometallchalkogenid)chrom- und -wolfram-komplexe

The structures of the isostructural compounds [(CH₃)₃Sn]₂SCr(CO)₅, [(CH₃)₃Sn]₂SeW(CO)₅, [(CH₃)₃Ge]₂SW(C0)₅ and [(CH₃)₃Pb]₂SW(CO)₅ have been determined by single crystal X-ray analyses. The compounds crystallize in the monoclinic system, space group P2₁/n. The substitution of one carbonyl group of the corresponding metal hexacarbonyls by the organometal chalcogenide causes a distortion of the M(CO)₅ group. The metal—chalcogen bonds are single bonds without significant π-bond contributions. The coordination around the chalcogen atoms is nearly tetrahedral.     

Some reactions of tris(trimethylstannyl)- and tetrakis(trimethylstannyl)-methane

With a variety of electrophilic reagents reaction occurs exclusively at the CH₃Sn bonds of [(CH₃)₃Sn]₄C and [(CH₃)₃Sn]₃CH. While the inner SnC bonds remain intact, methyl groups may be progressively cleaved off, one from each of the trimethylstannyl groups; in the case of bromine a second Me group may be cleaved from each of the SnMe₂Br groups. The various products were identified by ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy.     

Nature of the Arsonium‐Ylide Ph3As=CH2 and a Uranium(IV) Arsonium–Carbene Complex

Treatment of [Ph₃EMe][I] with [Na{N(SiMe₃)₂}] affords the ylides [Ph₃E=CH₂] (E=As, 1As ; P, 1P ). For 1As this overcomes prior difficulties in the synthesis of this classical arsonium‐ylide that have historically impeded its wider study. The structure of 1As has now been determined, 45 years after it was first convincingly isolated, and compared to 1P , confirming the long‐proposed hypothesis of increasing pyramidalisation of the ylide‐carbon, highlighting the increasing dominance of E⁺?C^? dipolar resonance form (sp³‐C) over the E=C ene π‐bonded form (sp²‐C), as group 15 is descended. The uranium(IV)–cyclometallate complex [U{N(CH₂CH₂NSiPrⁱ₃)₂(CH₂CH₂SiPrⁱ₂CH(Me)CH₂)}] reacts with 1As and 1P by α‐proton abstraction to give [U(Tren^TIPS)(CHEPh₃)] (Tren^TIPS=N(CH₂CH₂NSiPrⁱ₃)₃; E=As, 2As ; P, 2P ), where 2As is an unprecedented structurally characterised arsonium‐carbene complex. The short U?C distances and obtuse U‐C‐E angles suggest significant U=C double bond character. A shorter U?C distance is found for 2As than 2P , consistent with increased uranium‐ and reduced pnictonium‐stabilisation of the carbene as group 15 is descended, which is supported by quantum chemical calculations.     

Aminostannanes and aminostannylenes containing a C,N-chelated ligand

Aminotin(II and IV) compounds {[(2,6-i-Pr-C₆H₃)(H)N]-μ-(Sn)-Cl}₂, {2-[(CH₃)₂NCH₂]C₆H₄}₂Sn[N(H)(2,6-i-Pr-C₆H₃)]₂ and {2-[(CH₃)₂NCH₂]C₆H₄}Sn[N(2,6-i-Pr-C₆H₃)(SiMe₃)] were prepared by lithium halide elimination from tin halides and corresponding lithium complexes. [(2,6-i-Pr-C₆H₃)(H)N]Li (1) reacts with one half of molar equivalent of SnCl₂ to give {[(2,6-i-Pr-C₆H₃)(H)N]-μ-(Sn)-Cl}₂. The same lithium amide (1) gave with R₃SnCl corresponding aminostannanes. Further reactions of these compounds with n-butyllithium gave the starting 1 and tetraorganostannanes. {2-[(CH₃)₂NCH₂]C₆H₄}₂SnBr₂ reacts with two equivalents of 1 to {2-[(CH₃)₂NCH₂]C₆H₄}₂Sn[N(H)(2,6-i-Pr-C₆H₃)]₂. The dimeric heteroleptic stannylene {[(2,6-i-Pr-C₆H₃)(SiMe₃)N](μ₂-Cl)Sn}₂ reacts with 2-[(CH₃)₂NCH₂]C₆H₄Li to the monomeric {2-[(CH₃)₂NCH₂]C₆H₄}Sn[N(2,6-i-Pr-C₆H₃)(SiMe₃)]. The structure in the solid state and in solution and reactivity of products is also discussed. The unique decatin cluster has been isolated by hydrolysis of {[(2,6-i-Pr-C₆H₃)(H)N]-μ-(Sn)-Cl}₂. The structure of some compounds was also evaluated by theoretical DFT methods.     

SCHWEFELDIIMIDE MIT SILYL-, GERMYL-, STANNYL- UND PHOSPHINYL-HETEROSUBSTITUENTEN. SYNTHESE UND NMR-SPEKTROSKOPISCHE CHARAKTERISIERUNG

Abstract

Reactions of the salts K₂SN₂ and K[(NSN)R] (R = ′Bu, SiMe₃ and P′Bu₂) with organoelement chlorides R′R′ěl have been used to prepare four series of model sulfur diimides: R′R″E(NSN)ER″R′, ′Bu(NSN)ER″R′, Me₃Si(NSN)E″R′ and ^tBu₂P(NSN)ER″R′, respectively (E = C, Si, Ge, Sn; R′ and R″ = alkyl or aryl group). All compounds have been characterized by ′H and ¹³C NMR and—if possible—by ³¹P, ²⁹Si and ¹¹⁹Sn NMR spectroscopy. The configuration (Z or E) of the substituents R and E″R′ has been assigned in several cases using ^tBu(NSN)^tBu (1) as a reference. The E,Z assignment of ¹H, ¹³C and ¹⁵N nuclei in 1 is based on selectively ¹H-decoupled refocused INEPT ¹⁵N NMR and two-dimensional (2D) ¹³C/¹H heteronuclear shift correlations. The sulfur diimides under study are in general fluxional in solution.     

Systematic Access of Ternary Organotetrel-Copper Chalcogenide Clusters by [PhTE3]3− Anions (T=Si,Sn; E=S,Se)

Fragmentation reactions of organotetrel chalcogenide heteroadamantane-type clusters [(PhT)₄E₆] (T/E=Si/S ( 1 ); Si/Se; Sn/S, and Sn/Se) by addition of the corresponding sodium chalcogenide gave salts of the general formula Na₃[PhTE₃], with T/E=Si/S ( 2 ); Si/Se ( 3 ); Sn/S ( A ); Sn/Se ( 4 ). Reaction of these salts with [Cu(PPh₃)₃Cl] gave a series of organotetrel–copper chalcogenide clusters [(CuPPh₃)₆(PhTE₃)₂] with T/E=Si/S; ( 5 ), Si/Se ( 6 ), Sn/S ( 7 ) and Sn/Se ( 8 ). Compounds 5 – 8 share a common structural motif with two intact {PhTE₃} units coordinating a Cu₆ moiety, which was previously reported with other ligands, and for the Sn and Ge congeners only. If the Sn/Se reaction system was allowed to crystallize more slowly, single crystals of compound [(CuPPh₃)₆(PhSnSe₃)₃Cu₃SnSe] ( 9 ) were obtained, which are based on a larger cluster structure. Hence, 9 might form from 8 through incorporation of additional cluster fragments. The experimentally and quantum chemically determined optical properties were compared to related clusters.