Yi‐Hung Tsay

The preparation, reactions and structure of bis[bis(tricyclohexylphosphine)nickel] dinitrogen, {[(C6H11)3P]2Ni}2N2

Abstract The treatment of nickel acetylacetonate with trimethylaluminium in the presence of tricyclohexylphosphine and nitrogen gives the dinitrogen complex {[(C6H11)3P]2Ni}2N2 (I). Intermediate methyl-nickel complexes can be isolated, and provide an insight into the mechanism of formation of (I). The nitrogen molecule is readily displaced to give [(C6H11)3P]2Ni. The reactions of this coordinatively unsaturated species are described. The structure of the dinitrogen complex has been determined by X-ray crystallography from 5977 reflections using an automatic diffractometer, and refined anisotropically for all 80 atoms to a final R-value of 11%. The molecule is shown to contain a linear Ni-N-N-Ni system in which the nitrogen molecule is enclosed in a cage formed by four of the cyclohexyl rings. The NN bond distance is 1.12 A.

Metallacycloalkanes: I. Preparation and characterisation of α,α′-bipyridyl-5-nickela-3,3,7,7-tetramethyl-trans-tricyclo[4.1.0.02,4]heptane

Abstract Oxidative addition of 2 molecules of 3,3-dimethylcyclopropene (I) to α,α′-bipyridyl(1,5-cyclooctadiene)nickel(0) (III) gave the title compound (IV) in over 90% yield. Complex IV was characterized by mass, 1 H NMR and 13 C NMR spectroscopy. Its structure was determined by X-ray diffraction ( a 13.7081(2), b 14.638(2), c 9.5139(1) A, β 110.82(1)°, C 2/ c , R = 0.05 for 1614 reflections).

The synthesis and crystal structure of Sn(C6H4CH2NMe2-o)2, and its reaction with Co(η5-C5H5) (η2-C2H4)2

Treatment of SnCp2 or SnCl2 with o-LiC6H4CH2NMe2 gave the new monomeric stannylene Sn(C6H4CH2NMe2-o)2 (1). The reaction between Co(η5-C5H5)(η2-C2H4)2 and the stannylene 1 yielded Co(η5-C5H5)(η2-C2H4)[Sn(C6H4CH2NMe2-o)2] (3). The crystal structure of 1 and 3 has been determined by X-ray diffraction. 1: C18H24N2Sn, a 10.096(1) A, b 10.056(1) A, c 17.665(1) A, β 95.37(1)°, space group P21/c (No. 14), Z = 4, monoclinic; R = 0.031 for 3402 observed reflections. 3: C25H33CoN2Sn, a 9.735(2) A, b 19.917(4) A, c 12.429(1) A, β 90.36(1)°, space group P21/a (No. 14), Z = 4, monoclinic; R = 0.046 for 4171 observed reflections. The geometry about tin in 1 is distorted ψ-trigonal bipyramidal, and that in 3 is distorted trigonal bipyramidal. Both of the C6H4CH2NMe2 ligands in 1 and 3 act as chelates by bonding of their nitrogen atom to tin.

The molecular structure of a complex of tetramethylcyclobutadiene and aluminium chloride, containing a σ-AlC bond

Abstract The molecular structure of the primary reaction product of 2-butyne and aluminium cloride has been deduced from single crystal X-ray diffraction data (1148 reflections) ( a = 15.664(8); b = 10.886(4), c = 7.222(2) A, Z = 4, space group Pnma ). The aluminium chloride is coordinated via a σ-aluminium carbon bond (1.979 A) to a non-planar tetramethylcyclobutadiene moiety. The bond length pattern indicates a charge dislocation within the four-membered ring.

The molecular and crystal structure of bis(ethylene)(tricyclohexylphosphine)nickel

Abstract The molecular and crystal structure of bis(π-ethylene)(tricyclohexylphosphine)nickel has been determined by direct methods and refined anisotropically to a final R value of 6.48%. The nickel atom shows slightly distorted trigonal symmetry with planar arrangement of the ligands. Relatively short contacts exist between the two olefin molecules as well as between the olefins and the phosphorus. Both thylenes have the same CC distance (1.41 a) and distances from the nickel atom (1.987–2.042 a) the nickel-phosphorus bond is 2.196 a, the phosphorus having a slightly distorted tetrahedral geometry. All cyclohexyl rings are in the chair form and bonded equatorially to the phosphorus. Some short intermolecular contacts of the olefins across a center of symmetry are discussed.

Nickela-heteroringe aus nickel(0) und phenylisocyanat

Abstract Phenylisocyanate reacts with (Lig)Ni0 systems in various ways depending on the ligand (Lig). Thus, with TMEDA as ligand, headtail linkage of the isocyanates occurs to give the nickela-5-ring (II), whereas triethylphosphine ligand causes the formation of a nickela-6-ring (V). The structure of II was determined chemically and that of V by X-ray analysis. The properties of these novel cyclic nickela compounds are described and the reaction courses are discussed.

Molecular and crystal structure of bis(1,3-cyclohexadiene)monocarbonyliron

Abstract The crystal and the molecular structure of bis(1,3-cyclohexadiene)monocarbonyliron, (C 6 H 8 ) 2 FeCO, have been elucidated from three-dimensional X-ray diffraction data by Patterson and Fourier methods. The crystals used were orthorhombic, space group P 2 1 2 1 2 1 , with a = 17.089 ± 0.005, b = 8.495 ± 0.004 and c = 7.545 ± 0.004 A Z = 4. Least-squares refinement of all positional and anisotropic thermal parameters using 1697 non-zero reflections resulted in a final R -value of 3.3%. The two 1,3-cyclohexadiene entities are bonded to the Fe in the same fashion as in related butadiene compounds. The rings are arranged around the central atom with the saturated part pointing towards the carbonyl group. Although the diene entities are planar, a torsional angle of 3° remains in the strained ring systems. Both rings differ slightly in geometry as well as in their bonding to the iron atom.

η3-Allyl complexes of molybdenum—IV. Preparation and crystal structures of some substituted-cyclopentadienyl molybdenum allyl derivatives

Abstract A series of substituted-cyclopentadienyl molybdenum allyl derivatives has been prepared by reacting (η 3 -C 3 H 5 ) 3 MoCl with substituted-cyclopentadienyl and -indenyl alkali metal salts. In general, the isolated products are of the type Cp′Mo(η 3 -C 3 H 5 ) 2 and in three cases this has been confirmed by crystal structure determinations. Spectroscopic evidence suggests that at low temperatures compounds have the composition Cp′Mo(η 3 -C 3 H 5 ) 2 (η 1 -C 3 H 5 ) are also formed. The reaction with potassium fluorenyl is anomalous: the NMR spectra and a crystal structure determination show that the product (η 3 -fluorenyl)Mo(η 3 -C 3 H 5 ) 3 , contains four η 3 -allyl groups bonded unsymmetrically to the metal atom.

Darstellung, Eigenschaften und bindungsverhältnisse von benzophenonimino-nickel(0)-komplexen

Abstract Benzophenonimine (I) can be bonded to nickel(0), by treatment with (COD)2Ni (II) in the presence of 2,2′-bipyridine (bipy) (III) to give (bipy)Ni-(C6H5)2CNH (IV). In the absence of (III) a 2 1 complex Ni[(C6H5)2CNH]2 (V) is formed. The structures of (IV) and (V) were established by IR, 1H and 13C NMR spectroscopic methods. (V) is monomeric in solution whereas in the solid state an X-ray structural analysis shows the presence of trimeric {Ni-[(C6H5)2CNH]2}3 units which form (NiN)3 six-membered rings.

Organochromium π-complexes. VI: The preparation of Cp'(η3-allyl)2Cr compounds and their reactions with donor ligands

Abstract The title compounds have been prepared by reacting a Cp′CrCl2 or a (η3-allyl)2CrCl species with either an allylmagnesium halide or a substituted cyclopentadienyllithium derivative. The compounds react further at room temperature to give the dinuclear species [Cp′(μ-η3-allyl)Cr]2, and with P-donor ligands with reductive coupling of the allyl groups to give Cp′(η2,η2-1,5-hexadiene)CrPR3 species. Diene exchange is observed upon reacting the hexadiene compounds with butadiene or cyclohexadiene. The crystal structures of [Cp(μ-η3-C3H5)Cr]2, [(η5-indenyl)(μ-η3-C3H5)Cr]5)Cr2, (η5-indenyl) (η2,η2-1,5-hexadiene)CrP(OMe)3 and three compounds containing a 1,3-diene, viz. Cp(η4-1,3-C4H6)CrPMe3, (η5-Me5C5)(η4-1,3-C4H6)CrCO and Cp(η4-1,3-cyclohexadiene)CrP(OMe)3 have been established by X-ray diffraction.