Tris(oxinato) complexes of aluminium(III) and gallium(III) have been prepared from 8-oxyquinoline (OxH) and its six C-methylated derivatives from aqueous solutions of the metal chlorides or nitrates and an ammonium acetate buffer. Crystalline monohydrates or (upon precipitation with methanol) mono-methanol adducts are obtained. Single crystal X-ray diffraction studies reveal a meridional tris(chelate) structure for the two (isomorphous) tris(oxinates) Al(Ox)3 · MeOH and Ga(Ox)3 · MeOH with distinct differences in the individual dimensions. (The MeOH molecules form strong hydrogen bonds with one of the oxygen atoms.) For these species and those of the substituted ligands 3-MeOx, 4-MeOx, 5-MeOx, 6-MeOx, and 7-MeOx a similar meridional structure was confirmed by low temperature 1H NMR spectroscopy, which showed three inequivalent sets of ligands in each case. The collaps of these signals at elevated temperatures indicates a ligand-equilibrating process, with the mechanism probably comprising a dissociation of a pyridine function from the metal, to give a fluctional pentacoordinate species with free rotation about the intact M—O bond, and an M—N recombination at a random octahedral site. For the 2-MeOx ligands, however, the facial structure is preferred at lower temperature, but with the meridional isomer present as a component of an equilibrium. This indicates the strong steric influence of substituents in 2-position of the 8-oxy-quinoline.

1‐Naphthylquecksilberchlorid (1) und 1,8‐Naphthalindiylbis‐(quecksilberchlorid) (2) werden aus den zugehörigen Naphthyllithium‐Verbindungen und HgCl2 mit ca. 80% Ausbeute erhalten. Alternativ kann 2 auch aus 1,8‐Naphthalindiyldiborsäureanhydrid und HgCl2 gewonnen werden (Ausbeute 85%). Von 2·DMSO wurde die Kristallstruktur bestimmt. Es liegen diskrete Addukte vor, in denen die beiden Hg‐Atome durch das O‐Atom des DMSO überbrückt werden. Die HgCl‐Einheiten sind durch Verzerrungen im Naphthalingerüst, durch Winkelung der Achsen CHgCl und durch deren Auslenkung aus der Naphthalinebene voneinander weggebogen, so daß ein Hg·· Hg‐Kontakt von 3.102(1) Å resultiert. – 2 symmetrisiert sich bei der Einwirkung von NaI in wäßrigem Ethanol unter Bildung von Bis(μ‐1,8‐naphthalindiyl)diquecksilber (3). Bei der Strukturanalyse dieser im Kristall zentrosymmetrischen Verbindung wurde der bisher kürzeste „nichtbindende”︁ Hg··Hg‐Kontakt von 2.797(1) Å gefunden. Auch in 3 sind die CHgC‐Achsen abgewinkelt [CHgC = 173.3(5)°], und das Naphthalingerüst ist verzerrt.

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The title compound 4 has been prepared from readily available 2,3‐bis(diphenylphosphinyl)‐1,3‐butadiene (1) through double cyclopropanation using Me2S(CH2)O to give 1,1′‐bis(diphenylphosphinyl)bicyclopropyl (2), followed by reduction using HSiCl3/NEt3. Addition of sulfur to compound 4 yields the disulfide 5, and reaction with tetrahydrofuran – borane affords the 1:2 adduct with BH3 (6). Quaternization reactions with MeI or CH2I2 give the double quaternary salts 7 and 8, respectively. Single dehydrohalogenation employing nBuLi converts 8 into the cyclic semiylide salt 9. 4 is an excellent ligand for lowvalent late transition‐metal cations. With PdI2 the 1:1 complex LPdI2 (10, with L = 4), and with [(CO)2RhCl]2 the ionic 2:1 complex L2Rh+Cl‐ (11) are obtained. Experiments with (CO)AuCl yield the 1:2 complex L(AuCl)2 (12), X‐ray structure analyses were performed with single crystals of the disulfide 5, as well as the rhodium(I) and gold(I) complexes 11 and 12. 5 has a conformation between s‐cis and s‐trans with the PS functions pointing away from each other at opposite ends of the molecule. By contrast, in the gold(I) complex the ligand approaches an s‐cis conformation, and through rotations about P–C and C–C bonds – as referred to the conformation of 5 – the metal atoms are brought into close contact: Au…Au = 3.085 Å. Through temperature‐dependent NMR investigations of compounds 5 and 12, and by comparison with values calculated or experimentally determined for related bicyclopropyl compounds (available in the literature), the energy of the Au…Au attraction has been estimated to be ca. 6 kcal/mol. Compound 11 features a square‐planar, double‐chelate cation.

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