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.