Tobias Gerfin

Synthesis and structure of new chiral ferrocenylphosphines for asymmetric catalysis

Abstract The reaction of ( R )-1-[( S )-(diphenylphosphino)ferrocenyl]ethyl acetate ( 1 ) or N,N -dimethyl-( R )-1-[( S )-(diphenylphosphino)ferrocenyl]ethylamine ( 2a ) with secondary phosphines in acetic acid leads to the diphosphines 5 in moderate to good yields. Two of these ligands, ( R )=1[( S )-(diphenylphosphino)ferrocenyl]ethyl-dicyclohexylphosphine ( 5a ) and ( R P , R )-1[( S )-(diphenylphosphino)ferrocenyl]ethyl-phenyl-(2-methoxyphenyl)phosphine ( 5g ), as well as the complexes [Rh( 5a )(NBD)]BF 4 ·2CH 2 Cl 2 ( 9 ), [Pd(η 3 -C 3 H 5 ) ( 5a )]OTf ( 10 ) and [PtCl 2 ( 5a )] ( 11 ), have been characterized by X-ray diffraction. Crystals of 5a, 9, 10 and 11 are orthorhombic, space group P 2 1 2 1 2 1 , with four molecules in the unit cell. 5a : a =10.772(1), b =15.278(1), c =21.069(2) A; 9 : a =18.166(2), b =17.540(2), c =14.564(1); 10 : a =10.995(4), b =14.021(8), c =25.410(11) A; 11 : a =15.077(14), b =15.122(16), c =16.188(11) A. The stereogenic-at-phosphorus derivative 5g crystallizes in the monoclinic system, space group P 2 1 , with two pairs of symmetry independent molecules per the unit cell with a =7.896(1), b =25.667(2), c =15.654(1) A and β=92.39(1)°. Very similar conformations of the chelate rings in the complexes 9–11 are observed, this being indicative of the relative rigidity of the ligand 5a .

Growth of iridium films by metal organic chemical vapour deposition

Abstract Thin films of metallic iridium were grown by thermal metal organic chemical vapour deposition in a horizontal hot-wall reactor. The new solid compound Ir(2,2,6,6-tetramethyl-3,5-heptadione)(1,5-cyclooctadiene) was used as the iridium source. Evaporation rate experiments showed a rather poor volatility of this compound compared with Ir(acetylacetone)(1,5-cyclooctadiene). However, high growth rates of 0.25 μ h −1 could be realized at substrate temperatures of 350 °C using a graphite susceptor coated with iridium andisopropanol as a component of the reaction gas. The films were pure metallic, as shown by emission spectroscopy for chemical analysis, and had typical sheet resistances of 50 μω □ −1 .

Synthetic methodologies for tripodal phosphines. The preparation of MeSi(CH2PPh2)3 and n-BuSn(CH2PPh2)3 and a comparison of their rhodium(I) and ruthenium(II) coordination chemistry. The X-ray crystal structures of [Rh(NBD){n-BuSn(CH2PPh2)3}](OTf) and [Rh(NBD){MeSi(CH2PPh2)3}](OTf)☆

Abstract The preparation of the new tripodal ligands MeSi(CH2PPh2)3 (Si-triphos) and n-BuSn(CH2PPh2)3 (Sn-triphos) and their complexes of rhodium(I) of the type [Rh(NBD)(tripod)](OTf) (NBD  norbornadiene, OTf  triflate) and of ruthenium(II) of the type [Ru(O2CCF3)2(tripod)], is reported. The coordination chemistry of the new tripodal phosphines, and in particular that of Sn-triphos, differs significantly from that of MeC(CH2PPh2)3 (triphos). A comparison of the X-ray structure of [Rh(NBD)(triphos)](OTf) with those of the new complexes [Rh(NBD)(Sn-triphos)](OTf) and [Rh(NBD)(Si-triphos)](OTf) shows that the steric requirements of the ligands RE(CH2PPh2)3 (E  C, Si and Sn), increas from the carbon to the tin compound. The coordination chemistry of ruthenium(II) indicates that, relative to triphos, Sn-triphos displays an enhanced steric bulk which, however, is not sufficient to stabilize the mononuclear, five-coordinate dichloro complexes.

Synthesis and X-ray crystal structure of the heterometallic platinum-mercury cluster Pt4(μ-CO4(PMe2Ph)4{μ3-HgI2]

Abstract The bicapped cluster Pt4(μ-CO)4(PMe2Ph)4{μ3-HgI2}] (1) was obtained by reacting the cluster compound [Pt4(μ-CO)5(PMe2Ph)4] with one equivalent of [Hg2I2]. The IR and multinuclear NMR data as well as the X-ray crystal structure of the compound are reported. This compound crystallizes in the monoclinic space group P21/m with Z = 4, a = 10.086(2), b = 18.739(4), c = 24.764(5) A , and β = 90.94(3)° . The structure was refined to R = 0.0787 for 3303 observed reflections (I ⩾ 3.0 σ(I)).

The synthesis of the tripodal phosphine CH3C{CH2P(m-CF3C6H4)2}3 and its rhodium coordination chemistry

Abstract The new tripodal phosphine CH3C{CH2P(m-CF3C6H4)2}3, CF3PPP, was prepared by reacting CH3C(CH2Br)3 with Li+P(m-CF3C6H4)2−, the latter being best obtained by adding Li+NiPr2− to PH(m-CF3C6H4)2. The rhodium complexes [RhCl(CO)(CF3PPP)], [Rh(LL)(CF3PPP)](CF3SO3) (LL = 2 CO or NBD), [RhX3(CF3PPP)], [RhX(MeCN)3(CF3PPP)](CF3SO3)2 (X = H and Cl), [RhCl2(MeCN)(CF3PPP)](CF3SO3) and [Rh(MeCN)3(CF3PPP)](CF3SO3)3 were prepared and characterized. The X-ray crystal structure of [Rh(NBD)(CF3PPP)](CF3SO3) is reported. The lower oxygen sensitivity of the CF3PPP rhodium(I) complexes, relative to the corresponding species with the parent ligand CH3C(CH2PPh2)3, is attributed to the higher effective nuclear charge on the metal centers caused by the presence of the six CF3 substituents on the terdentate phosphine. A similar effect may be responsible for the easier hydrolysis of the CF3PPP-containing, cationic rhodium(III) complexes relative to the corresponding compounds of the parent ligand.