Reaktionen einiger Methylmetallhalogenide des Aluminiums,Galliums und Indiums mit Hexamethyldisilazan

Reactions of some Methylmetal Halides of Aluminium, Gallium, and Indium with Hexamethyldisilazane MeAlCl₂ or MeGaBr₂, and bis(trimethylsilyl)amine form the dimeric, mixed-substituted ring molecules (Me(Hal)M^III–N(H)SiMe₃)₂ and one equivalent Me₃SiHal. The NMR (¹H, ¹³C, ²⁹Si) and vibrational spectra (IR, Raman) are measured and the X-ray structure analysis of the compound with M^III = Al and Hal = Cl, has been done as well. Me₂AlCl with an excess of HN(SiMe₃)₂ forms the expected amide (Me₂Al–N(H)SiMe₃)₂, the homologue Me₂GaCl with HMDS, however, gives at 50–55 °C only the cyclic (1 : 1) adduct (Me₂Ga–N(H)SiMe₃) · (Me₂GaCl). This complex crystallizes in the space group Cmc2₁, the unit cell consists of four binucleate molecules with folded Ga–N–Ga–Cl-ring skeletons.     

Monomere Dialkylmetallkomplexe des Typs R2M(NR′)2XR mit M = Al,Ga, In,TI; X = S,C und R,R′ = Alkyl und Silyl

Monomeric Dialkyl Metal Complexes of the R₂M(NR′)₂XR Type with M = Al, Ga, In, Tl; X = S, C and R, R′ = Alkyl and Silyl N,N′-Bis(trimethylsilyl)sulfurdiimide reacts with the trimethyl derivatives of aluminium, gallium, and indium within insertion. Hereby monomeric sulfinic acid imidamidates Me₂M(NSiMe₃)₂SMe (Me = CH₃) are formed. The lithium amidinates Li(NR′)₂CMe (R′ = i-C₃H₇ and SiMe₃) are formed likewise by insertion reactions with LiMe and the corresponding carbodiimides R′N?C?NR′ and were used in reactions with R₂MCl (M = Al to Tl) to synthesize dialkyl metal amidinates R₂M(NR′)₂CMe. The NMR (¹H and ¹³C) and the vibrational spectra (IR and Raman) are discussed and applied to describe the structure of these chelat complexes.     

Darstellung,Eigenschaften und Molekülstrukturen von Dimethylaminomethylferrocenyl‐Verbindungen ausgewählter Elemente der Gruppen 13 und 14

Preparation, Properties, and Molecular Structures of Dimethylaminomethyl Ferrocenyl Compounds of selected Elements of Group 13 and 14 Dimethylmetalchlorides of gallium and indium react with dimethylaminomethylferrocenyllithium (FcNLi) to give the corresponding dimethylmetaldimethylaminomethylferrocenes 1 and 2 [Me₂MFcN; M=Ga, In]. In a similar manner dialkylmetaldichlorides of germanium and tin yield the expected chlordialkylmetaldimethylaminomethylferrocenes 3 – 5 [R₂(Cl)MFcN; M=Ge; R = Me ( 3 ), M=Sn; R=Me ( 4 ), Ph ( 5 )]. In a reaction of Me₃Al and Me₂AlCl with dimethylaminomethylferrocene the formation of the 1 : 1 adducts 7 and 8 could be observed. All compounds were characterised by ¹H and ¹³C nmr spectroscopy. The molecular structures of 1 , 3 , 4 and 7 were determined. 3 and 4 build in contrast to 1 monomeric molecules with chelat rings as a result of the M–N coordination. Compound 7 consist of monomeric molecules with 4 coordinated Al atoms.     

Cooperative GeN Bond Activation in Aluminium‐Functionalised Aminogermanes and Spontaneous Imine Elimination via an Intermediate Germyl Cation

Hydrometallation of iPr₂N?Ge(CMe₃)(C?C?CMe₃)₂ with H?M(CMe₃)₂ (M=Al, Ga) affords alkenyl–alkynylgermanes in which the Lewis‐acidic metal atoms are not coordinated by the amino N atoms but by the α‐C atoms of the ethynyl groups. These interactions result in a lengthening of the Ge?C bonds by approximately 10 pm and a comparably strong deviation of the Ge?C?C angle from linearity (154.3(1)°). This unusual behaviour may be caused by steric shielding of the N atoms. Coordination of the metal atoms by the amino groups is observed upon hydrometallation of Et₂N?Ge(C₆H₅)(C?C?CMe₃)₂, bearing a smaller NR₂ group. Strong M?N interactions lead to a lengthening of the Ge?N bonds by 10 to 15 pm and a strong deviation of the M atoms from the MC₃ plane by 52 and 47 pm, for Al and Ga, respectively. Dual hydrometallation is achieved only with HAl(CMe₃)₂. In the product, there is a strong Al?N bond with converging Al?N and Ge?N distances (208 vs. 200 pm) and an interaction of the second Al atom to the phenyl group. Addition of chloride anions terminates the latter interaction while the activated Ge?N bond undergoes an unprecedented elimination of EtN?C(H)Me at room temperature, leading to a germane with a Ge?H bond. State‐of‐the‐art DFT calculations reveal that the unique mechanism comprises the transfer of the amino group from Ge to Al to yield an intermediate germyl cation as a strong Lewis acid, which induces β‐hydride elimination, with chloride binding being crucial for providing the thermodynamic driving force.     

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.     

Komplexe des Chroms,Molybdäns und Wolframs mit Aminoarsan-Liganden

Complexes of Chromium, Molybdenum, and Tungsten with Aminoarsanes as Ligands The aminoarsanes Me₂As? NMe₂, MeAs(NMe₂)₂, and As(NMe₂)₃ form with the carbonyles of the sub-group VI metals complexes of the general formula (CO)₅M? L (L = aminoarsane; M ? Cr, Mo, W). The cleavage of the As? N bond by reactions with acids HX results in the formation of complexes of the general formula (CO)₅M? As(Me₂)? X, (CO)₅M? As(Me)X₂, and (CO)₅M? AsX₃.     

Dimethylgallium-bis(trimethylsilyl)phosphan Schwingungsspektrum,Kraftkonstanten und Struktur

Dimethylgallium-bis(trimethylsilyl)phosphane, Vibrational Spectrum, Force Constants, and X-Ray Structure Dimeric dimethylgallium-bis(trimethylsilyl)phosphane, [Me₂Ga? P(SiMe₃)₂]₂, (Me = CH₃) is synthesized from Me₂GaCl and P(SiMe₃)₃ in hot toluene. The compound crystallizes in the triclinic space group P1 with the cell parameters a = 909.8(2), b = 960.5(2), c = 971.6(2) pm; α = 76.75(1)°, β = 80.35(1)°, γ = 63.94(1)° and Z = 1 (dimer). The Ga? P distances are 244.8 and 245.2 pm, the ring angles are 91.8° (Ga? P? Ga) and 88.2° (P? Ga? P), respectively. The vibrational spectrum (IR and Raman for the solid) has been measured and assigned; force constants calculations are carried out for the skeleton [C₂Ga? P(SiC₃)₂]₂ using Fleischhauers [26] PC-program.     

Base-freie Tris(trimethylsilyl)methyl-Derivate des Lithiums,Aluminiums, Galliums und Indiums

Base-free Tris(trimethylsilyl)methyl Derivatives of Lithium, Aluminium, Gallium, and Indium Base-free LiR* (R*=-C(SiMe₃)₃) has been prepared from R*Cl and Li-metal in toluene at 85?90°C and used to synthesize the metallanes R*MMe₂ with M = Al, Ga and In, respectively. The NMR (¹H, ¹³C, ²⁹Si) and the vibrational spectra of these trisyl compounds have been discussed. AlCl₃ and LiR*(ratio 1 : 1) forms the metallate metallate Li[R*AlCl₃]. The triclinic unit cell (space group P1 ) consists of a centrosymmetric assoziate, formed by four Li[R*AlCl₃]- units with Al? Cl…?Li bridges, two pairs of Li-atoms differing in their chlorine-coordination and two disordered toluene molecules, inserted in the crystal lattice (R₁wR₂ =0,0444/0,1072). The reaction of GaCl₃ with LiR* (I :1) gives the unusual sesquichloride (R*Ga(Cl_1,33)Me_0,67)₃ in moderate yield. The X-ray structure determination shows a Ga₃Cl₃-skeleton with chairconformation and disordered, terminal gallium ligands (R₁/wR₂= 0,0646/0,2270).     

Acyclische und cyclische Silylhydrazone und Hydrazonylsilane

Acyclic and Cyclic Silylhydrazones and Hydrazonylsilanes Dimethylketone-di-tert-butylmethylsilylhydrazone ( 1 ) is obtained in the reaction of the silylhydrazine and dimethylketone by condensation. Di-tert-butyldifluorosilane reacts with lithiated hydrazones to give fluorosilylhydrazones 2–4 , (CMe₃)₂SiF? NH? N = CRR′, ( 2 : R=Me, R′=CMe₃; 3 : R,R′=CHMe₂; 4 : R,R′=Ph). The bis(hydrazonyl)silane 5 , (CMe₃)₂Si(NH? N=CPh₂)₂, is formed in a molar ratio 1:2. Tris( 6 )- and tetrakis(hydrazonyl)silanes ( 7 ) are obtained from CMe₃SiF₃ ( 6 ), SiF₄ ( 7 ), and lithiated tert-butylmethylketon-hydrazone. The lithium derivatives 8–11 are formed in the reaction of 1–4 with butyllithium. Bis(silyl)hydrazones ( 12–15 ) are the result of the reaction of halogensilanes and the lithium derivatives of 1(8), 2(9) and 3(10); 12 : (CMe₃)₂SiMe(CMe₃SiF₂)-N? N=CMe₂, 13 : (CMe₃)₂MeSi(PhSiF₂)N? N=CMe₂, 14 : (CMe₃)₂SiF(Me₃Si)N? N=C(Me)(CMe₃), 15 : (CMe₃)₂SiF (SiMe₃)N? N=C(CHMe₂)₂. Saltelimination out of 10 und 11 leads to the formation of the first bis(imino)-2,2,4,4-cyclodisilazanes, 16 :[(CMe₃)₂ SiN? N=C(CHMe₂)₂]₂, 17 : [(CMe₃)₂SiN? N=CPh₂]₂. Cyclisation occurs in the reaction of 12 und 14 with tert-butyllithium, 2-silyl-1,2-diaza-3-sila-5-cyclopentenes ( 18 and 19 ) are formed. Dilithiated 1 reacts with SiF₄ to give the spirocyclic compound 20 . HF-elimination from 18 and dimerisation of the intermediate diazasilacyclopentadiens lead to the formation of the tricyclus 21 .     

Neue Hypersilanide der Erdmetalle Aluminium,Gallium und Indium

New Hypersilanides of the Earth Metals Aluminium, Gallium, and Indium The dialkylaluminiumchlorides R₂AlCl (with R = Me, Et; Me = CH₃, Et = C₂H₅) react with base‐free lithium‐tris(trimethylsilyl)silanide (Li–Hsi; Hsi = –Si(SiMe₃)₃), forming the pyrophoric dialkyl aluminiumhypersilanides R₂Al–Hsi. The methyl compound is dimeric in solid state (triclinic space group P1, Z = 1 dimer), as in Al₂Me₆ the association takes place by two Al–Me–Al bridges, forming a centrosymmetric molecule of approximately C_2h point‐symmetry. Contrary to this (Me₂GaCl)₂ and Li–Hsi form a mixture of (MeGa(Hsi)Cl)₂ and [Me₃Ga–Hsi]Li. The monochloride again is a centrosymmetric, chlorine‐bridged dimer (monoclinic space group P2₁/n, Z = 2 dimers). The extremely air sensitive gallate can be prepared from GaMe₃ and Li–Hsi (1 : 1 ratio), as well as the homologous [Me₃Ga–Hsi]Na and [Me₃Ga–Hsi]K from GaMe₃ and the corresponding alkalimetal hypersilanides. The 1 : 1 toluene‐solvat of the sodium salt crystallizes in the orthorhombic space group Pbca (Z = 8) with polymeric zig‐zag‐chains, in which the toluene‐capped Na‐ions act as GaMe…Na…Me₂Ga‐bridges between [Me₃Ga–Hsi]^– anions. The reaction of InCl₃ with Li–Hsi (1 : 3 ratio) mainly gives LiCl, metallic In and the “dihypersilyl” Hsi–Hsi. Ruby‐red (Hsi)₂In–In(Hsi)₂ could also be obtained in low yield and characterized by X‐ray structure elucidation (space group P2₁/c, Z = 4). The ¹H, ¹³C, ²⁹Si and ⁷Li NMR‐ and the vibrational spectra of the hypersilanides have been measured and discussed.     

Zur Reaktion von cyclo‐Tristannazanen, [(CH3)2Sn–N(R)]3, mit den Trimethylderivaten des Aluminiums,Galliums und Indiums

The Reactions of cyclo ‐Tristannazanes, [(CH₃)₂Sn–N(R)]₃, with the Trimethyl Derivatives of Aluminium, Gallium, and Indium The cyclo‐tristannazanes [Me₂Sn–N(R)]₃ (with R = Me, ⁿPr, ⁱPr, ⁱBu) have been prepared from Me₂SnCl₂ and LiN(H)R in a 1 : 2 molar ratio. With MMe₃ (M = Al, Ga, In) they form the dimeric dimethylmetal trimethylstannyl(alkyl)amides [Me₂M–N(R)SnMe₃]₂ in good yields. The mass, NMR (¹H, ¹³C, ¹¹⁹Sn), and vibrational spectra are discussed and compared with the spectra of the tristannazanes. Thermolysis of the gallium amidocompounds splits SnMe₄ to form methylgallium imido derivatives with cage structures. The crystal structures of selected stannylamido complexes have been determined by X‐ray structure analysis.     

Intramolekular schwefelstabilisierte Aluminium‐ und Galliumalkyle

Intramolecularly Sulfur stabilized Aluminum and Gallium Alkyl Derivatives The intramolecularly sulfur stabilized organoaluminum and organogallium compounds Me₂Al(CH₂)₃SEt ( 1 ), Me₂Ga(CH₂)₃SEt ( 2 ), MeClAl(CH₂)₃SEt ( 3 ), MeClGa(CH₂)₃SEt ( 4 ), Cl₂Al(CH₂)₃SEt ( 5 ), and Cl₂Ga(CH₂)₃SEt ( 6 ) are synthesized from Me₂MCl, MeMCl₂, and MCl₃ (M = Al, Ga), respectively, and ClMg(CH₂)₃SEt. The reaction of 5 and of 6 with BrMg(CH₂)₅MgBr yields (CH₂)₅Al(CH₂)₃SEt ( 7 ) and (CH₂)₅Ga(CH₂)₃SEt ( 8 ), respectively. AlCl₃ and GaCl₃ react with two as well as three equivalents of ClMg(CH₂)₃SEt forming ClAl[(CH₂)₃SEt]₂ ( 9 ) and ClGa[(CH₂)₃SEt]₂ ( 10 ) as well as Al[(CH₂)₃SEt]₃ ( 11 ) and Ga[(CH₂)₃SEt]₃ ( 12 ), respectively. The compounds were characterized by elemental analyses, mass spectroscopy, ¹H, ¹³C, and ²⁷Al NMR investigations as well as 6 by single crystal X‐ray structure analysis.     

Dimethylerdmetall‐Heterocyclen als Derivate trimethylsilylierter, ‐germylierter und ‐stannylierter Phosphane und Arsane – Synthesen,Spektren und Strukturen

Dimethyl Earth‐Metal Heterocycles – Derivatives of Trimethyl‐silylated, ‐germylated, and ‐stannylated Phosphanes and Arsanes – Syntheses, Spectra, and Structures The organo earth‐metal heterocycles [Me₂M^III–E(M^IVMe₃)₂]_n with M^III = Al, Ga, In; E = P, As; M^IV = Si, Ge, Sn and n = 2, 3 (Me = CH₃) have been prepared from the dimethyl metal compounds Me₂M^IIIX (X = Me, H, Cl, OMe, OPh) and the pnicogen derivatives H_nE(M^IVMe₃)_3–n (n = 0, 1) according to known preparation methods. The mass, ¹H, ¹³C, ³¹P, ²⁹Si, ¹¹⁹Sn nmr, as well as the ir and Raman spectra have been discussed comparatively; selected representatives are characterized by X‐ray structure analyses. The dimeric species with four‐membered (E–M^III)₂ rings are isotypic and crystallize in the triclinic space group P1, the trimer [Me₂In–P(SnMe₃)₂]₃ with a strongly puckered (In–P)₃‐ring skeleton crystallizes with two formula units per cell in the same centrosymmetric triclinic space group.     

A Dimeric Gallium Hydrazide as an Active Lewis Pair – Complexation and Activation of Me2GaH and Various Heterocumulenes

Treatment of the dimeric gallium hydrazide [Me₂Ga‐N(2‐Ad)‐NC₅H₁₀]₂ ( 5 ) with Me₂GaH resulted in the formation of an adduct 6 by Ga–N bond cleavage and coordination of the metal hydride via a Ga–N and a 3c–2e Ga–H–Ga bond. This reaction reflects the typical behavior of frustrated Lewis pairs. Reactions with heterocumulenes R–N=C=X (R = Ph, CMe₃, Dipp, X = O; R = Ph, X = S) or X=C=X (X = O, S) resulted in the formation of the cyclic Ga–N insertion products Me₂Ga–N(R)C(O)N(2‐Ad)‐NC₅H₁₀ ( 7a – c ), Me₂GaS₂C‐N(2‐Ad)‐NC₅H₁₀ ( 8 ) or Me₂GaX₂C‐N(2‐Ad)‐NC₅H₁₀ [X = O ( 9 ); S ( 10 )] in moderate to good yields. Three different structural motifs were observed in the solid state: Five‐membered GaNCN₂ heterocycles with exocyclic C=O bonds for compounds 7a – c , four‐membered GaSCN or GaSCS heterocycles for compounds 8 and 9 (chelating coordination of the Ga atoms by SCN and CS₂ ligands) and an eight‐membered (GaOCO)₂ heterocycle for the dimeric CO₂ insertion product 10 . Treatment of 5 with PhCN or Ph₂CO resulted in a completely different reaction and afforded a dimeric Ga imide 11a or an alcoholate 11b . These reactions may start by retro‐hydrogallation with the formation of H₁₀C₅N–N=C(C₉H₁₄) and Me₂GaH and proceed by addition of the metal hydride to the polar multiple bonds of the nitrile or ketone.     

Trimethylstannyl- und Dimethylstannyl-substituierte Pyrrole – Synthesen,Spektren und Strukturen

Trimethylstannyl- and Dimethylstannyl-substituted Pyrroles – Synthesis, Spectra, and Structures Monomeric trimethylstannyl pyrroles, Me₃Sn? R (Me = CH₃ and R = ? NC₄H₄, ? NC₄H₂Me₂-2,5, ? NC₄Me₄-2,3,4,5, ? C₄H₃NMe-1), are synthesized by metathesis reactions from Me₃SnCl with 1(N)- and 2(C)-lithium pyrroles, respectively. An almost similar procedure gives monomeric dimethylstannylbis(pyrroles), Me₂SnR₂ ( 1 a – 3 a ), from Me₂SnCl₂ and 1-Li-pyrrolides (1 : 2 molar ratio) in good yields. Lithiated 1,2,5-trimethylpyrrole and Me₃SnCl forms the compound Me₃Sn? CH₂? C₄H₂Me(-5)NMe ( 8 ), the reaction of Me₂SnCl₂ with 2-lithium-1-methylpyrrole gives oligomeric [Me₂Sn? C₄H₂NMe? ]_x, ( 6 a ). The mass-, NMR, and vibrational spectra have been measured and discussed. The results of the X-ray structure determinations of Me₃Sn? NC₄H₄ ( 1 ) and Me₂Sn(? NC₄Me₄)₂ ( 3 a ) are compared with the structures of the known dimethylmetal pyrroles of Al, Ga, and In.     

Kristallstruktur des Bis[lithium-tris(trimethylsilyl)-hydrazids] und Reaktionen mit Fluorboranen, -silanen und -phosphanen

Crystal Structure of Bis[lithium-tris(trimethylsilyl)hydrazide] and Reactions with Fluoroboranes, -silanes, and -phospanes Tris(trimethylsilyl)hydrazine reacts with n-butyllithium in n-hexane to give the lithium-derivative 1 . The reaction of 1 with SiF₄, PhSiF₃, BF₃ · OEt₂, F₂BN(SiMe₃)₂ and PF₃ leads to the substitution products 2–6 . The 1,2-diaza-3-bora-5-silacyclopentane 7 is formed by heating (Me₃Si)₂N? N(SiMe₃)(BFNSiMe₃)₂ ( 5 ) at 250°C. In the reaction of (Me₃Si)₂N? N(SiMe₃)PF₂ ( 6 ) with lithiated tert.-butyl(trimethylsilyl)amine the hydrazino-iminophosphene (Me₃Si)₂N? N = P? N(SiMe₃)(CMe₃) ( 8 ) is obtained. In the molar ratio 2:1 1 reacts with SiF₄ and BF₃ · OEt₂ to give bis[tris(trimethylsilyl)hydrazino]silane 9 and -borane 10 .     

Studien zur Reaktion von [Me2AlP(SiMe3)2]2 mit basenstabilisierten Organogalliumchloriden und ‐hydriden

Investigations on the Reactivity of [Me₂AlP(SiMe₃)₂]₂ with Base‐stabilized Organogalliumhalides and ‐hydrides [Me₂AlP(SiMe₃)₂]₂ ( 1 ) reacts with dmap?Ga(Cl)Me₂, dmap?Ga(Me)Cl₂, dmap?GaCl₃ and dmap?Ga(H)Me₂ with Al‐P bond cleavage and subsequent formation of heterocyclic [Me₂GaP(SiMe₃)₂]₂ ( 2 ) as well as dmap?AlMe_xCl_3?x (x = 3 8 ; 2 3 ; 1 4 ; 0 5 ). The reaction between equimolar amounts of dmap?Al(Me₂)P(SiMe₃)₂ and dmap?Ga(t‐Bu₂)Cl yield dmap?Ga(t‐Bu₂)P(SiMe₃)₂ ( 6 ) and dmap?AlMe₂Cl ( 3 ). 2 – 8 were characterized by NMR spectroscopy, 2 and 6 also by single crystal X‐ray diffraction.     

Bis(dimethylmetall)-N,N′,N″,N‴-tetramethyloxamidine des aluminiums,galliums und indiums; synthese,spektren und röntgenstrukturen

N,N′,N″,N?-Tetramethyloxamidine, (HNMe)₂C₂(NMe)₂, reacts with the trimethyl derivatives of Al, Ga and In, respectively, in a $\text{1}\text{2}$ molar ratio. Monomeric bis(dimethylmetal)oxamidines, [Me₂M]₂C₂(NMe)₄ with M = Al, Ga, In, and methane are formed. According to the vibrational spectra (IR and Raman) and the X-ray structure determinations of all three compounds these molecules consist of two fused five-membered rings, with an essentially planar structure. The results in the homologous series [Me₂M]₂C₂O_4?x(NMe)_x (x = 0, 2 and 4 and M = Ga) are compared.     

Methylmetall-bis(trimethylsilyl)amidoderivate des Aluminiums,Galliums und Arsens

Methyl Metal Bis(trimethylsilyl)amido Derivatives of Aluminium, Gallium, and Arsenic MeAl[N(SiMe₃)₂]₂ (Me ? CH₃) has been prepared by the reaction of AlMe₃ with HN(SiMe₃)₂ in a 1:2 molar ratio. The homologue Gallium compound (as well as the Aluminium derivative) is formed in good yields by the interaction of MeMcl₂ (M = Al, Ga) with Li- and Na[N(SiMe₃)₂], respectively. MeAs[N(SiMe₃)₂]₂ is formed by the reaction of AsCl₃ and Na[N(SiMe₃)₂] in a 1:3 molar ratio. These colourless amido derivatives are monomeric in solution, they have been characterized by analyses, mass, n.m.r. (¹H and ¹³C), and especially by i.r. and Raman spectra.     

Synthesis, structure, and reactivity of a pyridine-stabilized germanone

The first isolable pyridine‐stabilized germanone has been prepared and its reactivity toward trimethylaluminum has been investigated. The germanone adduct results from a stepwise conversion that starts from 4‐dimethylaminopyridine (DMAP) and the ylide‐like N‐heterocyclic germylene LGe: (L=CH{(C?CH₂)(CMe)[N(aryl)]₂}, aryl=2,6‐iPr₂C₆H₃) ( 1 ) at room temperature, and gives the corresponding germylene–pyridine adduct L(DMAP)Ge: ( 2 ) in 91 % yield. The latter reacts with N₂O at room temperature to form the desired germanone complex L(DMAP)Ge?O ( 3 ) in 73 % yield. The Ge? O distance of 1.646(2) Å in 3 is the shortest hitherto reported for a Ge?O species. The reaction of 3 with trimethylaluminum leads solely to the addition product LGe(Me)O[Al(DMAP)Me₂] ( 4 ). The latter results from insertion of the Ge?O subunit into an Al? Me bond of AlMe₃ and concomitant migration of the DMAP ligand from germanium to the aluminum atom. Compounds 2 – 4 have been fully characterized by analytical and spectroscopic methods. Their molecular structures have been established by single‐crystal X‐ray crystallographic analysis.