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.     

Benzyl-tris(trimethylsilyl)methylzinndihalogenide, {(CH3)3Si}3C(C6H5–CH2)SnHal2 mit Hal = Cl,Br, I

Benzyl-tris(trimethylsilyl)methyl Tin Dihalides, {(CH₃)₃Si}₃C(C₆H₅–CH₂)SnHal₂ with Hal = Cl, Br, I The tin tetrahalides SnHal₄ (Hal = Cl, Br, I) react with base-free tris(trimethylsilyl)methyllithium (Tsi–Li) solved in toluene to form the trihalides Tsi–SnHal₃. But when the reaction is carried out in a 1 : 2 molar ratio at 60 °C in toluene, Tsi–H, Tsi–Hal and benzyl-trisyl tin-dihalides are formed in good yields, respectively. The nmr (¹H, ¹³C, ²⁹Si, ¹¹⁹Sn) and the Raman spectra are discussed, the X-ray structure analyses of the dibromide as well as the diiodide have been measured.     

Modellrechnungen von Kraftkonstanten der Tetramethyl-Verbindungen (CH3)4−nM(CD3) n,M=Si,Ge, Sn,Pb

Fromthe experiemntal fundamental vibrational frequencies of (CH₃)₄ M, (CD₃)₄ M and (CH₃)₃ MCD₃,M=Si, Ge, Sn, Pb, and of (CH₃)₂Si(CD₃)₂ and CH₃Si(CD₃)₃ a transferable local symmetry type force field for (CH₃)_4–n M groups has been calculated. Applications involving differentM atoms and numbersn of CH₃ groups are presented.

     

[{(CH3)3Si}3C–Li–C{Si(CH3)3}3][Li · 3(OC4H8)] und {(CH3)3Si}3C–Li · O=C(Si(CH3)3)2, zwei neue Addukte des Lithium‐trisylmethanids

[{(CH₃)₃Si}₃C–Li–C{Si(CH₃)₃}₃][Li · 3(OC₄H₈)] and {(CH₃)₃Si}₃C–Li · O=C(Si(CH₃)₃)₂, two New Adducts of Lithium Trisylmethanide Sublimation of (Tsi–Li) · 2 THF (Tsi = –C(Si(CH₃)₃)₃) at 180 °C and 10^–4 hPa gives (Tsi–Li) · 1.5 THF in very low yield. The X‐ray structure determination shows an almost linear [Tsi–Li–Tsi]^– anion connected by short agostic Li…C contacts with the threefold THF‐coordinated Li‐cation. Base‐free Tsi–Li, solved in toluene is decomposed by oxygen, forming the strawberry‐colored ketone O=C(SiMe₃)₂, which forms an 1 : 1 adduct with undecomposed Tsi–Li. The X‐ray structure elucidation of this compound is also discussed.     

Die Kristallstruktur des Trimethylzinn-methansulfinats, (CH3)3Sn02SCH3

The Crystal Structure of Trimethyltin Methanesulfinate, (CH₃)₃SnO₂SCH₃ Trimethyltin methanesulfinate, (CH₃)₃SnO₂SCH₃ crystallizes orthorhombie in the space group A2₁22. The lattice constants are: a = 7.98 ± 0.01, b = 12.59 ± 0.02 and c = 17.83 ± 0.02 Å Within the crystal structure the Sn atoms are linked together via bridging RSO₂ groups to form a helical chain along [l00]. Each Sn atom is surrounded by three C and two 0 atoms in a trigonal bipyramidal arrangement. The Sn? C distances are in the range from 2.09 to 2.18 Å the Sn? 0 distance amounts to 2.23 Å.     

Synthese,NMR‐Spektren und Molekülstruktur von [(CH3)2Ga{μ‐P(H)Si(CH3)3}2Ga(CH3)2{μ‐P(Si(CH3)3)2}Ga(CH3)2]

Synthesis, NMR Spectra and Structure of [(CH₃)₂Ga{μ‐P(H)Si(CH₃)₃}₂Ga(CH₃)₂{μ‐P(Si(CH₃)₃)₂}Ga(CH₃)₂] The title compound has been prepared in good yield by the reaction of [Me₂GaOMe]₃ (Me = CH₃) with HP(SiMe₃)₂ in toluene (ratio 1 : 1,1) and purified by crystallization from pentane or toluene, respectively. This organogallium compound forms (Ga–P)₃ ring skeletons with one Ga–P(SiMe₃)₂–Ga and two Ga–P(H)SiMe₃–Ga bridges and crystallizes in the monoclinic space group C2/c. The known homologous Al‐compound is isotypic, both (M^III–P)₃ heterocycles have twist‐conformations, the ligands of the monophosphane bridges have trans arrangements.     

Protolyses of (CH3)3SnM(CH3)3 (M = Sn,Ge, Si,C)

Product and kinetic studies on the reactions of hydrogen chloride in methanol solution with the substrates (CH₃)₃SnM(CH₃)₃ (M = Sn; Ge and Si) show that both SnM and SnCH₃ cleavage reactions occur, at similar rates, and are followed by other reactions giving complex but explicable mixtures of products. Similar behaviour is observed for trifluoroacetolysis in carbon tetrachloride solution, and some intermediates are observable. Trifluoroacetolysis of (CH₃)₃SnC(CH₃)₃ results in exclusive SnCH₃ cleavage. The very slow apparent solvolysis in acetic acid solution is thought to involve reaction with dissolved oxygen.     

Dimethylarsenazid (CH3)2AsN3, Dimethylwismutazid (CH3)2BiN3 und Dimethylthalliumzid (CH3)2TiN3

The reaction of (CH₃)₂AsJ and AgN₃ yields (CH₃)₂AsN₃; a colourless liquid (b. p. 136°C) which dissolves as a monomeric in benzene. (CH₃)₂BiN₃ is precipitated in form of colourless needles (dec. temp. 150°C) from an etherical solution of Bi(CH₃)₃ and HN₃. According to its vibrational and mass spectra the molecules are not associated although the (CH₃)₂BiN₃ is not soluble; dipole association of this polar molecules is assumed for the crystal structure. (CH₃)₂TlN₃ can be obtained from TI(CH₃)₃ and ClN₃ as well as from (CH₃)₂TlOH and HN₃ in form of colourless needles and leaves (dec. temp. 245°C). According to its vibrational spectra it has an ionic structure, (CH₃? Tl? CH₃)⁺N^?₃.     

NMR investigations on Stannabicycloundecanes of the type RSn(CH2CH2CH2)3N

The ¹H, ¹³C, and ¹¹⁹Sn NMR data of seven stannabicycloundecanes of the type RSn(CH₂CH₂CH₂)₃N (1, R = Cl; 2 , R = Br; 3 , R = I; 4 , R = OH; 5 , R = SPh; 6 , R = Me; 7 , R = Sn(CH₂CH₂CH₂)₃N) are reported. From ¹H NMR coalescence data at low temperature the free activation enthalpies for the racemisation of the bicyclo[3.3.3]skeleton were estimated to be 37 ± 1 kJ/mol. They are independent of the substituent R. However, it decreases when the tin atom is replaced by silicon for R = Me.     

Das Schwingungsspektrum des Ti[N(CH3)2]4

Zusammenfassung Die Infrarot- und Ramanspektren von Ti[N(CH₃)₂]₄ werden mitgeteilt, zugeordnet und mit den Spektren der analogen Dimethylamino-Verbindungen von Si, Ge und Sn verglichen.

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The IR and Raman spectra of Ti[N(CH₃)₂]₄ are reported, assigned and compared with those of the Si, Ge and Sn analoga.

     

Bildung und Eigenschaften von Li2P7R (R = Si(CH3)3, CH3, C(CH3)3)

Formation and Properties of Li₂P₇R (R = Si(CH₃)₃, CH₃, C(CH₃)₃) The reaction of P₇(Sime₃)₃ with Li₃P₇ in the molar ratio of 2:1 yields LiP₇(Sime₃)₂, and in the molar ratio of 1:2 Li₂P₇Sime₃ is formed. Li₂P₇me and Li₂P₇Cme₃ (me = CH₃) are obtained by reaction of white phosphorus with Lime, or LiCme₃, respectively [2]. The compounds Li₂P₇R (R = Sime₃, Cme₃, me) show typical valence tautomerism, as established by ³¹P-n.m.r. spectroscopy at various temperatures. Also LiP(Sime₃)₂ transforms P₇(Sime₃)₃ to yield Li₂P₇Sime₃ but in this reaction considerable cleavage of P? P bonds occurs, too.     

Infrarot-und Raman-Spektren von unvollständig und vollständig deuterierten Tetramethyl-Verbindungen (CH3) n M(CD3)4-n der ElementeM=Si,Ge, Sn und Pb

The infrared andRaman spectra of theM(CH₃)₄ andM(CD₃)₄ species,M=Si, Ge, Sn and Pb, have been reinvestigated. The spectra of the mixed tetramethyl compounds (CH₃)₃ MCD₃,M=Si, Ge, Sn and Pb, and of (CH₃)₂Si(CD₃)₂ and CH₃Si(CD₃)₃ have been recorded in the gaseous (i.r.) and liquid states (Raman). The proposed assignment is supported by a normal coordinate analysis.

     

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.     

Synthese und Strukturbestimmung von (tBuP)4Sn(CH3)2 und (CH3)2Sn[(tBu)P?P(tBu)]2Sn(CH3)2

Synthesis and Structure Analysis of (tBuP)₄Sn(CH₃)₂ and (CH₃)₂Sn[(tBu)P? P(tBu)]₂Sn(CH₃)₂ The diphosphides K₂[(tBu)P? (tBuP)₂? P(tBu)] 7 or K₂[(tBu)P? P(tBu)] 8 react with (CH₃)₂SnCl₂ in a molar ratio of 1 : 1 to form the binary 5-membered ring system P₄Sn 4 a and the 6-membered ring system Sn(P₂)₂Sn 5 a respectively. When (CH₃)₂SnCl₂, however, is treated with 8 in a molar ratio of 2 : 1 the 4-membered ring system P₃Sn 2 a is formed which includes the fragmentation of the intermediate K₂[(CH₃)₂Sn ((tBu)P? P(tBu))₂] 9. 4 a and 5 a could be obtained in a pure form and characterized NMR spectroscopically and by X-ray structure analyses; 2 a was identified only NMR spectroscopically.     

Spectres de vibration de composes organiques des elements de la colonne IVB : XI. Discussion de la structure des composes (CH3)3MN(CH3)2 (M = Si,Ge, Sn) a partir des spectres et du calcul des modes normaux de vibration

The normal modes of (CH₃)₃MN(CH₃)₂ (M= Si, Ge or Sn) compounds are discussed using infrared and Raman spectra analysis. A valence force field model has been utilized to calculate the frequencies and potentiel energy distribution for each molecule in different structural hypotheses.Experimental results and calculated values are in good agreement when the dihedral angle ψ between the two MNC planes decreases from silicon (144°) to germanium (130°) to tin (120°).The differences in the molecular geometries may be related to the basicity and to the P_π → d_π interactions of these compounds.     

Über Bildung und Reaktionen der CH2Li‐Derivate von tBu2P–P=P(CH3)tBu2 und (Me3Si)tBuP–P=P(CH3)tBu2

Formation and Reactions of the CH₂Li‐Derivatives of ^tBu₂P–P=P(CH₃)^tBu₂ and (Me₃Si)^tBuP–P=P(CH₃)^tBu₂ With ⁿBuLi, (Me₃Si)^tBuP–P=P(CH₃)^tBu₂ ( 1 ) and ^tBu₂P–P=P(CH₃)^tBu₂ ( 2 ) yield (Me₃Si)^tBuP–P=P(CH₂Li)^tBu₂ ( 3 ) and ^tBu₂P–P=P(CH₂Li)^tBu₂ ( 4 ), wich react with Me₃SiCl to give (Me₃Si)^tBuP–P=P(CH₂–SiMe₃)^tBu₂ ( 5 ) and ^tBu₂P–P=P(CH₂–SiMe₃)^tBu₂ ( 6 ), respectively. With ^tBu₂P–P(SiMe₃)–P^tBuCl ( 7 ), compound 3 forms 5 as well as the cyclic products [H₂C–P(^tBu)₂=P–P(^tBu)–P^tBu] ( 8 ) and [H₂C–P(^tBu)₂=P–P(P^tBu₂)–P(^tBu)] ( 9 ). Also 3 forms 8 with ^tBuPCl₂. The cleavage of the Me₃Si–P‐bond in 1 by means of C₂Cl₆ or N‐bromo‐succinimide yields (Cl)^tBuP–P=P(CH₃)^tBu₂ ( 10 ) or (Br)^tBuP–P=P(CH₃)^tBu₂ ( 11 ), resp. With LiP(SiMe₃)₂, 10 forms (Me₃Si)₂P–P(^tBu)–P=P(CH₃)^tBu₂ ( 12 ), and Et₂P–P(^tBu)–P=P(CH₃)^tBu₂ ( 13 ) with LiPEt₂. All compounds are characterized by ³¹P NMR Data and mass spectra; the ylide 5 and the THF adduct of 4 additionally by X‐ray structure analyses.     

Vibrational spectra and normal co-ordinate analysis of CF3 compounds. Trimethyl(trifluoromethyl)silane,CF3Si(CH3)3 and CF3Si(CD3)3

The i.r. gas and Raman liquid spectra of CF₃Si(CH₃)₃ and CF₃Si(CD₃)₃ are reported and assigned for C_3vsymmetry. Force constants have been calculated by a combined analysis of both isotopomers yielding ƒ (SiCF₃) 2.63, ƒ (SiCH₃) 3.07 and ƒ (CF) 5.70 N cm⁻¹. The apparent weakness of the SiCF₃ bond confirms the results obtained on other CF₃ silanes and is discussed with respect to related molecules.     

Synthese,Spektren und Strukturen einfacher Derivate des Tris(bis(trimethylsilyl)methyl)indiums,In(CH(Si(CH3)3)2)3

Syntheses, Spectra, and Structures of Simple Derivatives of Tris(bis(trimethylsilyl)methyl Indium, In(CH(Si(CH₃)₃)₂)₃ Like trimethyl- or triethylindium tris(disyl)indium, In(CH(SiMe₃)₂)₃ (≙ InR₃) also reacts with equimolar amounts of water, D₂O, MeOH, HCl and HCOOH, respectively, in ether solution at room temperature to form the corresponding alkane, here (Me₃Si)₂CH₂, and the simple monosubstitution products R₂InX. With the dibasic oxalic and sulfuric acid the multinuclear derivatives (R₂In)₂C₂O₄ and [RIn(R₂In)₂(SO₄)₂]₂ are formed, respectively. The halogenides R₂InCl, RInCl₂, and RInBr₂ have been prepared by metathesis from InHal₃ and InR₃ (molar ratios 1 : 2 and 2 : 1). The ¹H, ¹³C, and ²⁹Si NMR- as well as the vibrational spectra (IR, Raman) are discussed. According to the X-ray structure elucidations the monosubstitution products R₂InX (with X = OH, OMe, Cl) are dimeric in the solid state and consist of planar, centrosymmetric fourmembered In₂X₂ skeletons. The dibromide RInBr₂ forms a polymeric chain structure with five-fold co-ordinated metal centres and vertex linked, alternately appearing planar as well as slightly folded In₂Br₂-moities. The “sesquisulfate” [R₅In₃(SO₄)₂]₂ has an uncommon, cage-like structure with four as well as five-fold co-ordinated In atoms. The structural data could not be optimally refined due to the highly disordered disyl groups.     

Absolute Rate Constants for the Addition of Cyanomethyl (·CH2CN) and (tert-Butoxy)carbonylmethyl (·CH2CO2C(CH3)3) radicals to alkenes in solution

Absolute rate constants and their temperature dependence were determined by time-resolved electron spin resonance for the addition of the radicals ·CH₂CN and ·CH₂CO₂C(CH₃)₃ to a variety of mono- and 1,1-disubstituted and to selected 1,2- and trisubstituted alkenes in acetonitrile solution. To alkenes CH₂?CXY, ·CH₂CN adds at the unsubstituted C-atom with rate constants ranging from 3.3·10³ M ^?1S ^?1 (ethene) to 2.4·10⁶ M ^?1S ^?1 (1,1-diphenylethene) at 278 K, and the frequency factors are in the narrow range of log (A/M ^?1S ^?1) = 8.7 ± 0.3. ·CH₂CO₂C(CH₃)₃ shows a very similar reactivity with rate constants at 296 K ranging from 1.1·10⁴ M ^?1S ^?1 (ethene) to 10⁷ M ^?1S ^?1 (1,1-diphenylethene) and frequency factors log (A/M ^?1S ^?1) = 8.4 ± 0.1. For both radicals, the rate constants and the activation energies for addition to CH₂?CXY correlate well with the overall reaction enthalpy. In contrast to the expectation of an electro- or ambiphilic behavior, polar alkene-substituent effects are not clearly expressed, but some deviations from the enthalpy correlations point to a weak electrophilicity of the radicals. The rate constants for the addition to 1,2- and to trisubstituted alkenes reveal additional steric substituent effects. Self-termination rate data for the title radicals and spectral properties of their adducts to the alkenes are also given.