Metal exchange reactions of the magnesium complexes (dpp-BIAN)Mg(THF) n , (dtb-BIAN)Mg(THF) n , and (bph-BIAN)Mg(THF) n with GeCl2(dioxane) afford the stable germylenes (dpp-BIAN)Ge (1), (dtb-BIAN)Ge(Et2O) (2), and (bph-BIAN)Ge (3), respectively (dpp-BIAN = 1,2-[(2,6-iPr2C6H3)N]2C12H6, dtb-BIAN = 1,2-[(2,5-tBu2C6H3)N]2C12H6, bph-BIAN = 1,2-[(2-PhC6H4)N]2C12H6). Compound 1 is also obtained from (dpp-BIAN)Na4 and GeCl4 in Et2O. The germylenes 1−3 were characterized by elemental analyses, 1H NMR, 13C NMR, and IR spectroscopy, and X-ray crystal structure analyses. In the monomeric molecules the two imino nitrogen atoms coordinate the germanium atom. The aryl(N) groups are arranged rather orthogonal to the acenaphthenediimine plane. Compound 3 shows an anti geometry with the ortho phenyl substituents of both N-phenyl rings positioned on opposite sides of the acenaphthenediimine plane. The bite angles N−Ge−N are 85.2° (1) and 85.0° (3), respectively. The Ge−N bond distances in 1−3 range from 1.878 to 1.915 Å.

The new rigid bidentate nitrogen ligands 1,2-bis [(2,5-ditert-butylphenyl)imino]acenaphthene (1) (dtb-BIAN) and 1,2bis[(2-biphenyl)imino]acenaphthene (2) (bph-BIAN) have been synthesized by condensation of 1,2-acenaphthylenedione with 2,5-ditert-butylaniline and 2-aminobiphenyl, respectively. Reduction of 1 and 2 with magnesium and calcium results in the formation of the monomeric metal complexes [(dtb-BIAN)Mg(THF) 2 ] (3), [(bph-Monomere Magnesium-und Calciumkomplexe mit 1,2-Bis[(2,5-di-tertbutylphenyl)imino]acenaphthen (dtb-BIAN) und 1,2-Bis[(2-biphenyl)imino]acenaphthen (bph-BIAN) als starre, dianionische Liganden Inhaltsübersicht. Die neuen, starren und zweizähnigen Stickstoffliganden 1,2-Bis[(2,5-di-tert-butylphenyl)imino]acenaphthen (1) (dtb-BIAN) und 1,2-Bis[(2-biphenyl)imino]acenaphthen (2) (bph-BIAN) werden durch Kondensation von 1,2-Acenaphthylendion mit 2,5-Di-tert-butylanilin bzw. 2-Aminobiphenyl erhalten. Die Reduktion von 1 und 2 mit Magnesium oder Calcium verläuft unter * Prof. Dr. I. L. Fedushkin G. A. Razuvaev 501 BIAN)Mg(DME) 2 ] (4), and [(bph-BIAN)Ca(THF) 3 ] ( 5). Compounds 1 ؊ 5 have been characterized by C/H analyses, IR, 1 H NMR, and 13 C NMR spectra, the structures of 2, 3, and 5 have been estimated by single crystal X-ray diffraction.

The germanium(II) compound (dpp-BIAN)GeCl (1), which contains the radical anion of dpp-BIAN can be prepared either by reacting free dpp-BIAN ligand with 2 equiv of GeCl2(1,4-dioxane) in Et2O or by metathetical reaction of the sodium salt of dpp-BIAN with germanium dichloride in Et2O or benzene. The reaction of benzene solutions of 1 with 2 or 3 equiv of HCl led to protonation of the dpp-BIAN ligand affording [(dpp-BIAN)(H)2]*+[GeCl3]- (2) and [[(dpp-BIAN)(H)2*+]2(Cl-)]+ [GeCl3]- (3), which incorporate the radical cation of the protonated ligand. Compounds 1-3 have been characterized by elemental analysis, IR, UV-vis, and electron spin resonance (ESR) spectroscopy. Molecular structures of 1-3 were determined by single-crystal X-ray diffraction. In molecule 1, the Ge atom is positioned at the apex of the slightly distorted trigonal pyramid. The Ge-N bond lengths in 1 are 2.0058(19) and 2.004(2) A. The molecular structure of 2 consists of contact ions [(dpp-BIAN)(H)2]+ and [GeCl3]-. In the molecular structure of 3, two radical cations of [(dpp-BIAN)(H)2]+ are "coordinated" by the chlorine anion. The ESR signal of 1 indicates the presence of a dpp-BIAN radical anion and shows a hyperfine structure due to the coupling of an unpaired electron to 14N, 73Ge, 35Cl, 37Cl, and 1H nuclei (AN=0.48 (2 N), AGe=0.96, ACl=0.78 (35Cl), ACl=0.65 (37Cl), AH=0.11 (4 H) mT, g=2.0014). Both 2 and 3 reveal ESR signals of radical cation [(dpp-BIAN)(H)2]*+ (septet, AN=0.53, AH=0.48 mT, g=2.0031).

The use of a rigid bidentate ligand allows oxidative addition of an acetylene derivative to a non‐transition‐metal complex, not through oxidation of the metal atom, but through σ‐bond metathesis from ML: and HC to form HL⋅⋅⋅MC (see scheme; Ar=2,6‐iPr2C6H3).

Reactions of diimines dtb BIAN and dph BIAN with GeCl 2 afford germanium(II) com plexes with radical anionic ligands, (dtb BIAN)GeCl (5) and (dph BIAN)GeCl (6a), re spectively, where dtb BIAN is 1,2 bis[(2,5 di tert butylphenyl)imino]acenaphthene and dph BIAN is 1,2 bis[(2 biphenyl)imino]acenaphthene. The latter reaction gives 6a along with [(dph BIAN)GeCl] + [GeCl 3 ] -(6b). The reactions of tin(II) and antimony(III) chlorides with dtb BIAN and dpp BIAN produce complexes of these halides with neutral coordinated diimines, viz., (dtb BIAN)SnCl 2 (7) and (dpp BIAN)SbCl 3 (8) (dpp BIAN is 1,2 bis[(2,6 di isopropyl phenyl)imino]acenaphthene). Paramagnetic complexes 5 and 6a were studied by ESR spec troscopy. Diamagnetic compounds 7 and 8 were characterized by 1 H NMR spectroscopy. The structures of complexes 5, 6a,b, 7, 8, and (dpp BIAN)Ge (9) were established by X ray diffraction analysis.

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Molybdenum hexacarbonyl reacts with 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (, dpp-BIAN) and 1,2-bis[(trimethylsilyl)imino]acenaphthene (, tms-BIAN) in toluene to produce (dpp-BIAN)Mo(CO)(4) () and (tms-BIAN)Mo(CO)(4) (), respectively. The reaction of [CpNi(CO)](2) with yields (dpp-BIAN)NiCp (). Metathesis between Li(2)(tms-BIAN) and NiCl(2)(dppe) affords the Ni(0) complex (tms-BIAN)Ni(dppe) (). The diamagnetic compounds , and have been characterized by (1)H, (29)Si and (31)P NMR spectroscopy, IR spectroscopy and elemental analysis. The ESR spectrum of the paramagnetic compound indicates the presence of Ni(i) coordinated by Cp and a neutral dpp-BIAN ligand. The molecular structures of have been determined by single-crystal X-ray analysis.

Ein starrer zweizähniger Ligand ermöglicht die oxidative Addition eines Alkins an einen Hauptgruppenmetallkomplex. Hierbei wird nicht das Magnesiumzentrum oxidiert, sondern es findet eine σ‐Bindungsmetathese statt: Aus ML und HC wird HL⋅⋅⋅MC (siehe Schema; Ar= Ar=2,6‐iPr2C6H3).