A. G. Ginzburg

Protonation of metal carbonyl complexes : III. Cyclopentadienyl carbonyl complexes of manganese

Abstract Using IR spectroscopy, the phosphine derivatives of cyclopentadienylmanganese tricarbonyl have been shown to undergo protonation in solutions of trifluoroacetic acid and in mixtures of this solvent with methylene chloride, protonation at the metal atom being the most probable. Ease of protonation increases with increasing electron-releasing properties of both the π-ring substituents and the phosphine ligands attached to the manganese atom. The basicity of manganese in these cyclopentadienylmanganese tricarbonyl compounds is less than that of chromium in the corresponding benzenechromium tricarbonyl derivatives.

Protonation of metal carbonyl complexes

Abstract 13 C and 31 P NMR techniques have been applied to the complexes CpMn(CO)L 2 and CpMn(CO) 2 L (where L 2 is a bidentate tertiary phosphine, L is a monodentate tertiary phosphine, and Cp is cyclopentadienyl). It is shown that the complexes are protonated reversibly, when dissolved in CH 2 Cl 2 in the presence of CF 3 COOH, with the proton attacking the manganese atom.

Protonation of metal carbonyl complexes : VII. Proton NMR spectra and stereochemistry of protonated forms of π-cyclopentadienylphosphinemanganese complexes☆

Abstract 1H NMR measurements show that protonation of the complexes π-C5H5Mn-CO)3-n(PR3)n (n = 1 and 2) with CF3COOH occurs at the manganese atom, the spectra revealing “hydride” signal at δ values of -4 to -6 ppm. The stereochemistry of the protonated forms has been determined from the 1H  31P couling pattern.

Interaction of cyclopentadienyl carbonyl phosphine complexes of manganese with Lewis acids. Infrared Spectra

From IR-spectroscopic studies it is shown that phosphine derivatives of cyclopentadienylmanganese tricarbonyl interact reversibly with SnCl4 and another Lewis acids in CH2Cl2 solution. The structures of the resulting complexes are discussed. Complex formation is favoured as the electron-donor properties of both the π-ring substituents and of the phosphine ligands attached to manganese atom are increased. The ability of Lewis acids to undergo such complex formation follows the series: SnCl4 > SbCl3 > HgCl2 > GeCl4.

A new heterobimetallic palladium–[60]fullerene complex with bidentate bis-1,1′-[P]2-ferrocene ligand

Abstract A new heterobimetallic palladium–[60]fullerene complex with ferrocene bis-phosphine ligand was prepared using alternative paths: either via addition reaction of Pd 2 (dba) 3 ·C 6 H 6 (dba=dibenzylidenacetone) in the presence of 1,1′-bis(diphenylphosphino)ferrocene ( dppf ) to C 60 , or via electrochemical activation of C 60 to generate C 60 2− anions, which then react with PdCl 2 and dppf to yield the target complex. The obtained (η 2 -C 60 )Pd( dppf ) complex was characterized by 1 H- and 31 P-{ 1 H}-NMR and electronic spectroscopy as well as electrochemically.

The effect of donor ligands on the reactivity of π-aromatic ligands in manganese and chromium complexes

Abstract The effect of ER3 ligands (where E=P, As or Sb and R=alkyl or phenyl) on the reactivity of π-cylopentadienyl or π-benzene rings in the complexes π-C5H5-Mn(CO)n(ER3)3−n and π-C6H5XCr(CO)2ER3 during hydrogen isotopic exchange reactions with acids is discussed. A reaction mechanism is proposed.

Basicity of transition metal carbonyl complexes: XVI. Reactions of η-cyclopentadienylmanganese complexes with mercury trifluoroacetate

Abstract Cyclopentadienyl manganese tricarbonyl, CpMn(CO) 3 , reacts with excess mercury trifluoroacetate in methylene chloride or in ether at 20°C, giving exhaustive mercuration of all five hydrogen atoms of the Cp ligand to give (CO) 3 MnC 5 (HgOCOCF 3 ) 5 . Conversely, the complex CpMn(CO) 2 PPh 3 in which the basicity of the metal is considerably higher due to the presence of the donor phosphine ligand, forms an adduct. The structure of the dimeric compound [CpMn(CO) 2 PPh 3 ·Hg(OCOCF 3 ) 2 ] 2 has been established by an X-ray study. The crystals are triclinic, cell parameters (at −120°C): a = 9.472(5), b = 9.369(7), c = 16.813(9) A, α = 92.06(5), β = 103.01(4), γ = 91.59(5)°, V = 1452(1) A 3 , Z = 2, space group P 1 .

Basicity of metal carbonyl complexes: XIX. Co substitution in azacymantrene and reactions of (η5-C4H4N)Mn(CO)2PPh3 with electrophiles. X-ray crystal structure of [(PPh3)(CO)2Mn(η5-C4H4N)]2PdCl2

Abstract A convenient method for substituting a CO ligand in azacymantrene, (η 5 - C 4 H 4 N)Mn(CO) 3 (I), by the interaction of I with PPh 3 in the presence of Me 3 NO has been found. The reactions of (η 5 -C 4 H 4 N)Mn(CO) 2 PPh 3 (II) with electrophiles were studied. The nitrogen atom of the η-pyrrolyl ligand was shown to be the site having the largest basicity with respect to the proton (protonation in CF 3 CO- OH/CH 2 Cl 2 ) and aprotic acids (Zn, Cd, Hg, Al, Ga, Sn, Pd salts) in II. The structure of the trinuclear complex [(PPh 3 )(CO) 2 Mn(η 5 -C 4 H 4 N)] 2 PdCl 2 was established by an X-ray study: the crystals are monoclinic, a 9.0165(5), b 15.748(1), c 16.179(1) A, β 103.37(1)°, Z = 2, space group P 2 1 / c ; the palladium coordination environment is square-planar, PdN 2.033(2) and PdCl 2.306(1) A.

Chemistry of vinylidene complexes X. Synthesis and characterization of the vinylidene bridged complexes Cp(CO)2MnPt(μ-CCHPh)(PP) with chelating diphosphine ligands PPdppm, dppe or dppp at the platinum atom

The binuclear μ-vinylidene complex Cp(CO)2MnPt(μ-CCHPh)(PPh3)2 reacts with diphosphines PP Ph2P(CH2)nPPh2, where n=1 (dppm), 2 (dppe) or 3 (dppp), at room temperature to give new complexes of the type Cp(CO)2MnPt(μ-CCHPh)(PP) with chelating disphosphine ligands PP at the Pt atom in quantitative yields. All complexes are characterized by IR and 1H, 13C and 31P NMR spectra. The influence of the nature of the ligands at the Pt atom on the bonding between Pt and the semi-bridging carbonyl group is discussed.

First optically active organometallic free radical in the cymantrene series

Abstract Replacement of one CO ligand in the enantiomeric 2-methylcymantrenecarboxylic acid ester for a radical ligand PhS results in the preparation of stable and optically active odd-electron complex CH3C5H3COOCH3Mn(CO)2SPh]. fully characterized by electron spin resonance, mass spectroscopy, UV-visible spectroscopy, IR spectroscopy and circular dishroism spectroscopy. This is the first example of an optically active organometallic free radical.