Zsuzsa Nagy-Magos

Study of carbon monoxide insertion into the carbon—cobalt bond

(Triphenylphosphine)benzylcobalt tricarbonyl can be carbonylated at atmospheric pressure and room temperature to form (triphenylphosphine)(phenylacetyl)cobalt tricarbonyl. Using 13CO as carbonylating agent it was shown, that the acyl group is formed by incorporation of a carbonyl ligand, whereas the carbon monoxide from the gas phase enters the coordination sphere of the cobalt atom as a new ligand. The acyl complex can be easily decarbonylated at somewhat elevated temperatures.

Amino acid dicarbonylrhodium(I) complexes

SummaryDicarhonyrhodium(I) complexes of eleven amino acids were prepared from [AcORh(COD)]2 and the appropriate amino acid by carboxylato ligand exchange followed by treatment with CO. All complexes are light coloured substances of composition (XY)Rh(CO)2 (where XYH = amino acid) with square planar geometry andcis-carbonyl ligands, The compounds are transformed by IICI into deep coloured hydrochlorides with more complex structures.

Phosphinerhodium complexes as homogeneous catalysts: IX. Asymmetric hydrogenation of an olefin with catalysts formed from a chiral rhodium(I) car☐ylate and non-chiral phosphines

Abstract Rhodium car☐ylate complexes of the type [Rh(COD)(OOCR)]2 have been prepared and used with phosphines to provide in situ catalysts for olefin hydrogenation. Asymmetric hydrogenation of α-acetamido cinnamic acid methyl ester has been observed using the car☐ylate complex prepared from l (+)-mandelic acid. The highest optical yield (13%) was achieved with trimethylphosphine as non-chiral ligand.

Homogeneous hydrogenation of ketones using chromium hexacarbonyl as catalyst precursor in the presence of bases

Abstract The hydrogenation of ketones at 100–120°C and 100 bar H 2 is catalyzed by Cr(CO) 6 in methanol solution in the presence of NaOMe. The reaction is inhibited by CO and the rate increases with increasing H 2 pressure and base: chromium ratio. In a stoichiometric reaction at 75°C, HCr(CO) 5 hydrogenates ketones to alcohols, while forming Cr 2 (CO) 10 2− . A catalytic cycle involving alkoxychromium complexes, R 2 CHOCr(CO) 5 − , as intermediates is proposed. Similar hydrogenation catalysts are obtained from W(CO) 6 and Mo(CO) 6 ; the latter is the most active and may be used even at 70–80°C.

Synthesis and molecular structure of carbonyl derivatives of iron(II) thiolates containing nitrogen-donor ligands

Abstract Several carbonyl derivatives of iron(II) thiolates containing N-donor ligands with the general formula FeS2N2(CO)2 were prepared in methanol solution starting from FeSO4·7H2O, the appropriate thiol (S) and nitrogen-donor ligand (N), carbon monoxide and a base. The structures of two representatives Fe(SC6H4- NH2-o)2(CO)2 (1) and Fe(SPh)2(H2NC2H4NH2)- (CO)2 (2) were determined. Complex 1 crystallizes with one molecule of THF in the triclinic space group P1, a=5.659(3), b=8.960(6), c=10.624(6) A, α= 105.15(5), β=103.23(5), γ=94.35(5)°, V=500.86 A3, Z=1, Dcalc=1.43 g cm−3. Complex 2 crystallizes in the monoclinic space group P21/c, a=11.739(2), b=9.725(2), c=15.868(2) A, β=101.583(8)°, V= 1774.6 A3, Z=4, Dcalc=1.44 g cm−3. Final agreement factors, R=0.0300, Rw=0.0304 (1787 reflections) for 1; R=0.0368, Rw=0.0369 (2147 reflections) for 2; the absolute configuration of 1 was determined. The octahedral complexes contain the two CO ligands in cis position and the coordinated N atoms are trans to the CO groups. A necessary condition for the stability of such complexes is the presence of at least one chelating ligand; all complexes lose CO on heating and this reaction is (in part) reversible.

Iron(II) thiolates as reversible carbon monoxide carriers

Abstract Solutions of several iron(II) thiolato complexes in methanol, dimethylformamide or 2-ethoxyethanol reversibly absorb and release carbon monoxide at atmospheric pressure and 20–50 °C. Solutions of Fe(SPh) 2 (H 2 NCH 2 CH 2 NH 2 ) (CO) 2 and of an anionic complex tentatively formulated as [Fe 2 (SPh) 5 (CO) 4 ] − in 2-ethoxyethanol and of Fe(L-SCH 2 CH(NH 2 )COOEt) 2 (CO) 2 in dimethylformamide were found to be most effective for the separation of CONe 2 gas mixtures.

Hydrogenation of Schiff bases with group 6 metal carbonyls and sodium methoxide as catalyst precursors

SummarySchiff bases are hydrogenated to secondary amines by H2 in the presence of [M(CO)6](M=Cr, Mo or W) and NaOMe in methanol solution at 60–160 °C andca. 100 bar H2 pressure. The reaction is significantly slower in the absence of NaOMe. In a stoichiometric reaction, [HCr(CO)5]− hydrogenatesN- benzylidene-aniline at 75 °C toN-benzylaniline forming [Cr2(CO)10]2−.