Radical ions : XXVIII. Tris(trimethylsilylmethyl)aminium,N(CH2Si(CH3)3)3: A stable fluxional aminium radical cation

The first ionization potentials of 11 silylmethyl-substituted amines R_3?nN(CH₂Si(CH₃)₃)_n as determined photoelectron spectroscopy range from 9.07 eV to 7.66 eV. The most easily ionized molecule, N(CH₂Si(CH₃)₃)₃, can also be oxidized with AlCl₃ in H₂CCl₂ solution to its aminium radical cation. The ESR spectra recorded between 180 K and 310 K display a strong temperature dependence due to rotations around the >NCH₂bonds.     

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.

     

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.     

Zur solvensfreien Darstellung von Tetramethylammoniumsalzen: Synthese und Charakterisierung von [N(CH3)4]2[C2O4], [N(CH3)4][CO3(CH3)], [N(CH3)4][NO2], [N(CH3)4][CO2H] und [N(CH3)4][O2C(CH2)2CO2(CH3)]

Solvent-free Synthesis of Tetramethylammonium Salts: Synthesis and Characterization of [N(CH₃)₄]₂[C₂O₄], [N(CH₃)₄][CO₃CH₃], [N(CH₃)₄][NO₂], [N(CH₃)₄][CO₂H], and [N(CH₃)₄][O₂C(CH₂)₂CO₂CH₃] A general procedure to synthesize tetramethylammonium salts is presented. Several tetramethylammonium salts were prepared in a crystalline state by solvent-free reaction of trimethylamine and different methyl compounds at mild conditions: [N(CH₃)₄]₂[C₂O₄] (cubic; a = 1 114.8(3) pm), [N(CH₃)₄][CO₃CH₃] (P2₁/n; a = 813.64(3), b = 953.36(3), c = 1 131.3(4) pm, β = 90.03(1)°), [N(CH₃)₄][NO₂] (Pmmn; a = 821.2(4), b = 746.5(3), c = 551.5(2) pm), [N(CH₃)₄][CO₂H] (Pmmn; a = 792.8(7), b = 791.7(3), c = 563.3(4) pm) and [N(CH₃)₄][O₂C(CH₂)₂CO₂CH₃] (P2₁; a = 731.1(2), b = 826.4(3), c = 1 025.2(3) pm, β = 110.1(1)°). The tetramethylammonium salts were characterized by IR-spectroscopy and X-ray diffraction. The crystal structures of the methylcarbonate and the nitrite are described.     

Polysulfonylamine. XXXVII. Darstellung von Quecksilberdimesylamiden. Kristall- und Molekülstrukturen von Hg[N(SO2CH3)2]2, Hg[{N(SO2CH3)2}2(DMSO)2] und Hg[{N(SO2CH3)2}2(HMPA)]

Polysulfonyl Amines. XXXVII. Preparation of Mercury Dimesylamides. Crystal and Molecular Structures of Hg[N(SO₂CH₃)₂]₂, Hg[{N(SO₂CH₃)₂}₂(DMSO)₂], and Hg[{N(SO₂CH₃)₂}₂(HMPA)] Hg[N(SO₂CH₃)₂]₂ ( 1 ) and Hg₂[N(SO₂CH₃)₂]₂ ( 2 a ) are formed as colourless, sparingly soluble precipitates when solutions of Hg(NO₃)₂ or Hg₂(NO₃)₂ in dilute nitric acid are added to an aqueous HN(SO₂CH₃)₂ solution. By a similar reaction, Hg₂[N(SO₂C₆H₄ ? Cl? 4)₂]₂ is obtained. 1 forms isolable complexes of composition Hg[N(SO₂CH₃)₂]₂ · 2 L with L = dimethyl sulfoxide (complex 3 a ), acetonitrile, dimethyl formamide, pyridine or 1,10-phenanthroline and a (1/1) complex Hg[N(SO₂CH₃)₂]₂ · HMPA ( 4 ) with hexamethyl phosphoramide. Attempted complexation of 2 a with some of these ligands induced formation of Hg⁰ and the corresponding Hg^II complexes. Crystallographic data (at -95°C) are for 1: space group 14₁/a, a = 990.7(2), c = 2897.7(8) pm, V = 2.844 nm³, Z = 8, D_x = 2.545Mgm^?3; for 4a: space group P1 , a = 767.8(2), b = 859.2(2), c = 925.2(2)pm α = 68.44(2), β = 86.68(2), γ = 76.24(2)°, V = 0.551nm³, Z = 1, D_x = 2.113 Mgm^?3; for 4: space group P2₁/c, a = 1041.3(3), b = 1545.4(3), c = 1542.5(3) pm, β = 100.30(2)°, V = 2.474nm³, Z = 4, D_x = 1.944Mgm³. The three compounds form molecular crystals. The molecular structures contain a linear or approximately linear, covalent NHgN moiety; the Hg? N distances and N? Hg? N angles are 206.7(4) pm and 176.3(2)° for 1, 207.2(2) pm and 180.0° for 3a, 205.7(4)/206.7(4) pm and 170.5(1)° for 4. In the complexes 3a and 4, the 0-ligands are bonded to the Hg atoms perpendicularly to the N? Hg? N axes, leading in 3a to a square-planar trans-(N₂O₂) coordination with Hg? 0 261.2(2) pm and N? Hg? O 92.3(1)/87.7(1)°, in 4 to a slightly distorted T-shaped (N₂O) geometry with Hg? 0 246.2(4)pm and N? Hg? 0 96.7(1)/92.0(1)°. In all three structures, the primary coordination is extended to a severely distorted (N₂O₄) hexacoordination by the appropriate number of secondary, inter- and/or intramolecular Hg…?0 inter-actions (0 atoms from sulfonyl groups, Hg…?O distances in the range 280—300pm). The intramolecular Hg…?O interactions give rise to nearly planar four-membered [HgNSO] rings. The molecule of 1 has a two-fold axis through the bisector of the N? Hg? N angle, the molecule of 3a an inversion center at the Hg atom. The molecule of 4 has no symmetry.     

[{(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 Reaktion des [(Me3Si)2CH]2Al?CH2?Al [CH(SiMe3)2]2 mit Neopentyllithium: Bildung des {[(Me3Si)2CH]2Al?CH2?Al [CH(SiMe3)2]2CH2CMe3}⊖ [Li(TMEDA)2]⊕

Reaction of [(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂ with Neopentyllithium: Formation of {[(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂CH₂CMe₃} ? [Li(TMEDA)₂]⊕ The recently synthesized methylene bridged dialuminium compound [(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂ reacts with neopentyl lithium in the presence of TMEDA to give the stable {[(Me₃Si)₂CH]₂Al? CH₂? Al [CH(SiMe₃)₂]₂CH₂ · CMe₃}? [Li(TMEDA)₂]⊕ decomposing at 115°C. The aluminium atoms therein are not additionally bridged, but the new substituent is occupying a terminal position as detected by crystal structure determination. A compound is formed containing a saturated, fourfold coordinated neighbouring a formally unsaturated, threefold coordinated aluminium atom. Due to high sterical restrictions the Al? C bonds are lengthened up to 209.0(3) pm at the alanate site and the Al? C? Al angle in the methylene bridge is extraordinarily enlarged to 144.4(2)°.     

Die Kristallstruktur von Diethylaluminiumhypersilanid, [(C2H5)2Al–Si{Si(CH3)3}3]2

The Crystal Structure of Diethylaluminium Hypersilanide [(C₂H₅)₂Al–Si{Si(CH₃)₃}₃]₂ [Et₂Al–Hsi]₂ (Et = C₂H₅, Hsi = –Si(SiMe₃)₃), prepared from [Et₂AlCl]₂ and equimolar amounts of base‐free Li–Hsi in n‐pentane, crystallizes in the triclinic space group P 1 with two independent dimers per unit cell. One of these molecules is disordered. The dimers consist of planar Al₂C₂‐skeletons with Al–C–Al bridging bonds of 212,9(2) and 221,2(2) pm, respectively, and with intramolecular C–H…Al contacts of 202(2) pm.     

Tris(tris(trimethylsilyl)silyl)gallium,Ga{Si(Si(CH3)3)3}3

The title compound has been prepared in good yield by the reaction of gallium trichloride with base‐free hypersilyl lithium (Li–Si(SiMe₃)₃, Me = CH₃) in a 1 : 3 molar ratio. Ga(Si(SiMe₃)₃)₃ is monomeric in solution and in the solid state. The compound has been characterized with NMR, IR and Raman techniques as well as by an X‐ray structure determination (planar GaSi₃‐skeleton, monoclinic space group P2₁/c, Z = 4, d(Ga–Si) = 249,8 ± 0,2 pm).     

Synthesis and characterization of ferrocenylalkoxygermatranes and crystal structures of FcCH2OGe (OCH2CH2)3N and FcCH(CH3)OGe(OCH2CH2)3N1

Germatranes bearing a ferrocenylalkoxyl moiety have been obtained by the reaction of HOGe(OCH₂CH₂)₃N with various ferrocenyl alcohols. A convenient new synthesis method of FcCH₂OGe(OCH₂CH₂)₃N was reported. FcCH₂OGe(OCH₂CH₂)₃N was prepared in 93% yield when FcCH₂OH reacted with HOGe(OCH₂CH₂)₃N in chloroform at room temperature in the presence of molecular sieves (3 Å) as a dehydrating agent. All compounds were characterized by elemental analysis, ¹H NMR and IR spectroscopy. The molecular structures of FcCH₂OGe(OCH₂CH₂)₃N and FcCH(CH₃)OGe(OCH₂CH₂)₃N have been determined by X‐ray diffraction. The antitumor activities of FcCH₂OGe(OCH₂CH₂)₃N and p‐FcC₆H₄CH₂OGe(OCH₂CH₂)₃N were determined. Copyright © 2005 John Wiley & Sons, Ltd.     

Schwingungsspektren und Kraftkonstanten der Übergangsreihen OP(N(CH3)2)3 – OP(CH3)3 und SP(N(CH3)2)3 – SP(CH3)3

Vibrational Spectra and Force Constants of the Series OP(N(CH₃)₂)₃ – OP(CH₃)₃ and SP(N(CH₃)₂)₃ – SP(CH₃)₃ The vibrational spectra (IR and Raman) of the compounds of the title series are recorded and assigned to the normal vibrations. By a simplified force field the valence force constants are calculated and discussed. The results are compared with those of the NMR spectroscopy.     

Oxide promoted isomerisation of an isonitrile complex,H2Os3(CO)10[CN(CH2)3Si(OEt)3]

The isomerisation of H₂Os₃(CO)₁₀[CN(CH₂)₃Si(OEt)₃] to HOs₃(CO)₁₀-[CN(H)(CH₂)₃Si(OEt)₃] is accelerated by interaction with some oxides; both complexes afford HOs₃(CO)₁₀[CN(H)(CH₂)₃Si(OEt)_3it-x(O)x] as oxide supported clusters.     

Zur Chemie des Titan(III)-Komplexes [{(Me3Si)2N}2TiCH2SiMe2NSiMe3]–. Insertions-Reaktionen in die Ti–C-Bindung und Redox-Reaktionen

On the Chemistry of the Titanium(III) Complex [{(Me₃Si)₂N}₂TiCH₂SiMe₂NSiMe₃]^–. Insertion Reactions into the Ti–C Bond and Redox Reactions [Na(12-crown-4)₂][{(Me₃Si)₂N}₂TiCH₂SiMe₂NSiMe₃] ( 1 ) reacts with CO and the isonitrile CNCy (Cy = Cyclohexyl) under insertion into the Ti–C bond. After rearrangement planar five-membered titana(III)-heterocycles TiOCSiN and TiNCSiN with exocyclic C=CH₂ groups are formed. On the other hand, the insertion of CNBu^t leads to the primary insertion product [Na(12-crown-4)₂][{(Me₃Si)₂N}₂TiC(NBu^t)CCH₂SiMe₂NSiMe₃] ( 4 ) forming a new Ti(III)–C-bond. With NOBF₄ the anion of 1 can be oxydized to form the molecular complex [{(Me₃Si)₂N}₂TiCH₂SiMe₂NSiMe₃] ( 5 ), while with phenylacetylene redox disproportionation occurs, in the course of which the mixed ligand complex [Na(12-crown-4)₂][{(Me₃Si)₂N}₂Ti(NSiMe₃)(CH₂SiMe₂C≡C–Ph)] ( 6 ) can be isolated. 6 and the insertion products [Na(12-crown-4)₂][{(Me₃Si)₂N}₂TiOC(CH₂)SiMe₂NSiMe₃] ( 2 ) and [Na(12-crown-4)₂][{(Me₃Si)₂N}₂TiNCyC(CH₂)SiMe₂NSiMe₃] ( 3 ) are characterized by crystal structure determinations.     

Diazabutadienes as ligands: I. Compounds of aluminium: coordination of diazabutadienes to Al(CH3)3 and subsequent intramolecular insertion and rearrangement reactions leading to (CH3)2AIR—N—CH(CH3)—C(R')=N—R(R'= H,CH3) and (CH3)2AIR—N—CH2—C(CH3)=N—R

Reaction of R—N=CH—CH=N—R with [(CH₃)₃Al]₂ affords the coordination product (CH₃)₃AlRN=CH—CH=NR (A) for R = 2,6-(CH₃)₂C₆H₃ and 2,4,6(CH₃)₃C₆H₂. For R = 4 ClC₆H₄, 4-CH₃C₆H₄ and 4-CH₃OC₆H₄, insertion takes place, giving the complexes (CH₃)₂A$\text{lRN—CH(CH}{}_3\text{)—CH=N}$—R (B), in which Al is part of a five-membered chelate ring. Depending on the temperature both the addition and insertion products rearrange intramolecularly to the complexes (CH₃)₂-A$\text{lR—N—CH}{}_2\text{—C(CH}{}_3\text{)=N}$—R (C), in which Al is also part of a five-membered chelate ring. Reactions of the asymmetric (CH₃)₂HC—N=CH—C(CH₃)=N—CH-(CH₃)₂ with [Al(CH₃)₃]₂ also leads to an insertion product, (CH₃)₂A$\text{lRN-—CH(CH}{}_3\text{)—C(CH}{}_3\text{)=N}$—R (B') (R = (CH₃)₂CH), but there is no subsequent rearrangement in this case.A mechanism involving hydrogen migration is tentatively proposed to account for the observed isomerization, which increases in rate in the order:R = (CH₃)₃C>2,4,6-(CH₃)₃C₆H₂> 2,6-(CH₃)2C₆H₃ (A → C)andR = 4-CH₃OC₆H₄>4-CH₃C₆H₄>4-ClC₆H₄ (B → C)Hydrolysis of isomer C gives the unknown imino amines R—NH—CH₂-C(CH₃)=N—R in quantitative yield.     

Formation of a rhenium(III) carbonyl complex by electrophilic attack on rhenium isocyanides. Synthesis and molecular structure of {Re[N(CH2CH2S) 3][CNC(CH3) 3]} and {Re[N(CH2CH2) 3](CO)}

Treatment of the trigonal-bipyramidal complex {Re[N(CH₂CH₂S)₃](CNCH₂COOEt)} (1a) with LiOH in THF leads to ester hydrolysis and yields the complex {Re[N(CH₂CH₂S)₃](CNCH₂COOH)} (2). Attempts to hydrolyze the ester in 1a in the two-phase system toluene/concentrated hydrochloric acid proceeded under electrophilic attack at the isocyanide nitrogen atom and formation of the carbonyl complex {Re[N(CH₂CH₂S)₃](CO)} (3). Complex 3 was also obtained by treatment of {Re[N(CH₂CH₂S)₃][CNC(CH₃)₃]} (1b) with toluene/hydrochloric acid. The molecular structures of 1b and 3 were established by X-ray structure analysis.     

The Synthesis of (η3‐C3H5)Pd{Si[N(tBu)CH]2}Cl and the Catalytic Property for Heck Reaction

Treatment of N‐heterocyclic silylene Si[N(^tBu)CH]₂ ( 1 ) and [(η³‐C₃H₅)PdCl]₂ in toluene led to the formation of the mononuclear complex (η³‐C₃H₅)Pd{Si[N(^tBu)CH]₂}Cl ( 3 ), the silicon analogue to N‐heterocyclic carbene complex (η³‐C₃H₅)Pd{C[N(^tBu)CH]₂}Cl ( 2 ). Complex 3 was characterized with ¹H NMR and ¹³C NMR. Investigation shows that (η³‐C₃H₅)Pd{Si[N(^tBu)CH]₂}Cl is an active catalyst for Heck coupling reaction of styrene with aryl bromides.     

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.     

EPR of gamma irradiated (CH3)3NHClO4, (CH3)3NHBF4 and [(CH3)4N]2ZnCl4 single crystals

Gamma irradiation damage centres in (CH₃)₃NHClO₄, (CH₃)₃NHBF₄ and [(CH₃)₄N]₂ZnCl₄ were investigated by electron paramagnetic resonance spectroscopy at room temperature. The centres were found to be (CH₃)₃N^+. and the hyperfine structure parameters for methyl protons and the nitrogen nucleus were determined. The results indicated that the (CH₃)₃N^+. radical wholly performs reorientational motions around its C_3v axis in addition to the reorientatonal motions of the methyl groups around their C_3v axes. These results were compared with the earlier studies on (CH₃)₃N^+. radical and discussed. Low temperature measurements on the first two of the title compounds were assessed.     

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.     

Synthesis,Characterization, and Crystal Structures of [N(CH3)4]2[B12H12] and [N(CH3)4]2[B12H12] · CH3CN

Bis(tetramethylammonium) dodecahydrododecaborate, [(CH₃)₄N]₂[B₁₂H₁₂], and bis(tetramethylammonium) dodecahydrododecaborate acetonitrile, [(CH₃)₄N]₂[B₁₂H₁₂] · CH₃CN, were synthesized and characterized via Infrared, ¹H and ¹¹B NMR spectroscopy. [(CH₃)₄N]₂[B₁₂H₁₂] crystallizes isopunctual to the alkali metal dodecaborates. The crystal structure of [(CH₃)₄N]₂[B₁₂H₁₂] · CH₃CN was determined from single crystal data and refined in the orthorhombic crystal system (Pcmn, no. 62, a = 898.68(8), b = 1312.85(9) c = 1994.5(1) pm, R(|F| , 4σ) = 5.9%, wR(F²) = 18.3%). Here, the geometry of the dodecaborate anion is that of an almost ideal icosahedron, less distorted than most other dodecaborates known. By low‐temperature Guinier‐Simon diffractometry phase transitions were detected for [(CH₃)₄N]₂[B₁₂H₁₂] and [(CH₃)₄N]₂[B₁₂H₁₂] · CH₃CN at –70 and –15 °C, respectively.