Intramolecularly stabilized four‐coordinated organoaluminium, ‐gallium, and‐indium compounds R2MC6H4CH2NR'2‐(2) (1–7), Me2MCH2C6H4NMe2‐(2) (8, 9), Me2MCH2C6H4CH2‐NMe2‐(2) (10, 11), and Me2GaC6H4NMe2 (12) have been synthesized from O ‐[(dialkylamino)methyl]phenyllithium, [O ‐(dimethylamino)phenyl]methyllithium, {O ‐[(dimethylamino)methyl]phenyl}methyllithium and O ‐(dimethylamino)phenyllithium, respectively. The 1H‐, 13CNMR, and mass spectra of the new compounds and the X‐ray crystal structures of 2 and 7 are reported and discussed.

Derivatives of Borole, XVI1),—Bis(borole)nickel Complexes2) The dilithium 1‐(dialkylamino)dihydroborolediides Li2[C4H4‐BNR2] 2a, b: R = Me, Et) react with NiCl2 · DME to give bis(borole)nickel complexes Ni(C4H4BNR2)2. Nucleophilic substitution reactions are used to produce a large variety of derivatives Ni(C4H4BR)2 1 (e.g. R = H, tBu, F, Cl, Br, I, OH, OMe). Treatment of Ni(C4H4BCl)2 (tg) with LiO(CH2)3OLi in THF produces a polymer and a dinuclear complex (μ‐{η5:η5‐[(CH2)3(OBC4H4)2]}2Ni2 (3) which crystallizes from CH2Cl2 as solvate 3 · CH2Cl2. The complexes 1g and 3 · CH2Cl2 are characterized by X‐ray diffraction work. Barriers to internal ring‐ring rotation are measured by variable‐temperature NMR spectroscopy. The B—H bond of Ni(C4H4BH)2 (1a) is remarkably inert and does not react with H2O or with carboxylic acids in THF at room temperature. With PhCHO slow formation of the benzyloxy compound Ni(C4H4BOCH2Ph)2 (1 m) is observed at 100°C. For typical complexes such as the phenyl derivative 1e cyclic voltammetry in CH2Cl2 reveals an irreversible oxidation at 1.32 and a quasi‐reversible reduction at –1.37 V vs. SCE.

A crystal suitable for the crystal structure analysis of 4 was obtained by sublimation in vacuo. Monoclinic, P2,/c, a = 654.6(5), 6 = 963.1(6), c = 1171.1(5)pm.fl= 1 0 3 . 5 2 ( 5 ) " ,~~~,~~ = 1.88gcm-'. R=0.029,RW=O029 (Mo,, = 71.069 pm), 1256 crystallographically independent reflections, 1142 with Fo z 3 u(Fo), anisotropic temperature factors, starting coordinates by Patterson methods [20], full-matrix least squares refinement (SHELX-76) [21]. 100 refined parameters, max. shiftierror 0.002, residual electron density 0.29 e k ' , empirical absorption with the Program DIFABS by D. Sruart and N. Walker 1221. Further details of the crystal structure investigation are available on request from the Fachinformationszentrum Karlsruhe, Gesellschaft fur wissenschaftlich-technische Information mbH, D-7514 Eggenstein-Leopoldshafen 2 (FRG), on quoting the depository number CSD-54273, the names of the authors, and the journal citation.

Intramolecularly base-stabilized four-coordinated metallacyclic organoaluminium, -gallium, and -indium compounds CsHl0-Al(CHz)3NMez (41, C4H8Ga(CHz)&JMe~ (51, Cd-IIOGa(CHz)3N-Mez (S), C,HlOGaCH2CH(Me)CHzNMez (?), C4H8Ga(CHZ),NMez Group III/V semiconductors are of great interest in the optoelectronic industry because of their utility in digital high speed devices'). The production of such semiconducting layers can be achieved by vapor phase epitaxy (MOVPE) by using organometallic compounds as source materials2-'). In general, a group I11 trialkyl compound, like trimethylgallium or triethylindium, is treated with a group V hydride, like PH, or AsH3, at 600-700°C to give the respective III/V product as illustrated in the following equation for the case of GaAs.(CH3)3Ga + ASH, -GaAs + 3 CH, However, owing to their limited chemical and thermal stability, the commonly used group I11 precursors cause difficulties during the epitaxial process. Very often formation of alkoxy impurities due to traces of oxygen is observed, and even spontanous decomposition of the source material may occur. In addition, some compounds likc solid trimethylindium require heating of the bubbler and the gas lines in order to overcome evaporation problems.By the application of intermolecular adducts like solid Me,Ga.NMe3 or Me31n.PEt3 as source materials such side reactions can be reduced drastically; but even these precursors of significantly enhanced thermal stability cause evaporation problems6,'). The use of the concept of intramolecular coordination, however, has been expected to yield monomeric volatile compounds which are liquids at room temperature or very low melting solids.Recently, we have reported on the synthesis and characterization of some novel intramolecularly base-stabilized gallium and indium compounds with the bidentate 3-(dimethy1amino)propyl and 4-(dimethy1amino)butyl ligands as well as on initial results in MOVPESp''). In this paper we report on our detailed studies on metallacyclic compounds of aluminium, gallium and indium. Synthesis and Properties

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