V.N. Setkina

π-Complexes as ligands in transition metal compounds : I. π-Pyrrolyltricarbonylmanganese, a new two-electron ligand

Abstract It has been established that the nitrogen atom in π-pyrrolyltricarbonylmanganese can form a donor—acceptor bond with transition metals. This property was used to synthesize novel binuclear complexes in which a pyrrolyl ring performs two functions: a π-ligand to the manganese atom and an n -ligand to another metal.

Acylation of pyrrolyltricarbonylmanganese. Structure of the acylation product

Abstract The acylation of pyrrolyltricarbonylmanganese (PTM) is studied. The reaction proceeds in an unusual manner; introduction of an acetyl group into the α-position of the PTM pyrrolyl ligand is accompanied by extensive rearrangement of bonds resulting in the formation of a binuclear complex (π-C 4 H 4 N)Mn(CO) 3 (CH 3 COC 4 H 3 N)Mn(CO) 3 (I) Coordination of the acetylpyrrolyl ligand to the manganese atom is of the chelate type and involves atoms of heterocyclic nitrogen and of acetyl oxygen. The ligand, therefore, is not a five-electron but a three-electron donor. The manganese atom is additionally coordinated to three carbonyl groups and one molecule of the initial PTM (by a donor—acceptor bond through a nitrogen atom), thus acquiring a 18-electron shell. A scheme for complex I formation is proposed.

Basicity of transition metal carbonyl complexes : XI. Reactions of C5H5Mn(CO)2L with stannic chloride and structure of reaction products

Abstract Adducts of 1 : 2 composition were obtained by reacting C 5 H 5 Mn(CO) 2 L complexes (L = tertiary phosphines, AsPh 3 and SbPh 3 ) with stannic chloride. The crystal and molecular structure of C 5 H 5 Mn(CO) 2 PPh 3 · 2SnCl 4 was established by X-ray structural analysis. It has an ionic structure that corresponds to formula [C 5 H 5 Mn(CO) 2 (PPh 3 )(SnCl 3 )] + SnCl 5 − . The coordination environment of the manganese atom is a distorted square pyramid with a C 5 H 5 ligand at the apex. Using IR spectroscopy it was established that in certain cases a mixture of two isomers is formed in solution. In C 5 H 5 Mn(CO) 2 L complexes the central manganese atom is the site of attack by aprotic acids and is the most basic site of the molecule.

π-Complexes as ligands in transition metal compounds : II. Bis-(π-pyrrolyltricarbonylmanganese)tricarbonylmanganese halides

Abstract The trinuclear complexes, bis-(π-pyrrolyltricarbonylmanganese)tricarbonylhalomanganese (halo = I, Br)hhave been obtained. The comprise two molecules of π-pyrrolyltricarbonylmanganese acting as N -ligands at the central manganese atom due to the formation of donor—acceptor MnN bonds.

Preparation of η5-C5H5COOH(CO)2Fe-η1-R carboxylic acids

Abstract η 5 -C 5 H 4 (COOH)(CO) 2 FeR (R = Ph, C 5 H 4 Mn(CO) 3 or CH 2 Ph) carboxylic acids were obtained in high yields via metallation with BuLi followed by treatment with CO 2 .

π-complexes as ligands in transition metal compounds IV. Metallation of π-pyrrolyltricarbonylmanganese ☆

Abstract The metallationof π-pyrrolyltricarbonylmanganese (PTM) with n-butyl-lithium has been studied. The metallizing agent has been shown to attack the carbonyl group of PTM, forming a trinuclear complex (I) as a reaction product. The complex contains the initial and the CO group-metallated molecules of PTM as n-ligands. The possible routes of formation of I are discussed.

Cyclopentadienyl ring metalation in cyclopentadienyliron carbonyl complexes

The cyclopentadienyl ligands in Cp(CO)2FePh, Cp(CO)2FeCH2Ph and [Cp(CO)2Fe]2 were metalated by BuLi in THF at −78°C. With Cp(CO)2FePh it was possible to employ the reaction for the synthesis of cyclopentadienyl carbonyl complexes substituted on the Cp ligands.

π-complexes as ligands in transition metal compounds V. Interaction of π-pyrrolyltricarbonylmanganese with picric acid

Abstract It has been found that interaction of π-pyrrolyltricarbonylmanganese (PTM) with picric acid gives the binuclear complex I in which the central manganese atom is coordinated with three CO ligands, a PTM molecule, and a picrate anion; the latter two acting as two- and three-electron ligands, respectively.

Metallocenic thioketones as two-electron ligands : III .13 C nmr spectra and structure of a cymantrene derivative with a cymantrenylphenylthioketone ligand

13 C NMR spectra of cymantrenylphenylthioketone and a binuclear complex (η 5 -C 5 H 5 )(CO) 2 Mn ← SC(Ph)C 5 H 4 Mn(CO) 3 (I), produced by substitution of the CO ligand in cymantrene by this thioketone, have been studied. A complete X-ray structural investigation of complex I has been performed. It is suggested that in solution both E and Z isomers of complex I are present.

The crystal and molecular structure of (π-methyl benzoate)(triphenylphosphine)chromium dicarbonyl

Abstract The crystal and molecular structure of the title compound was determined by the direct method on the basis of 2192 reflections measured by an automatic diffractometer. Least-squares anisotropic (isotropic for hydrogens) refinement led to R  0.040. The bond lengths and angles are usual. The Cr(CO)2PPh3 fragment is in an eclipsed orientation relative to the almost planar η6-methyl benzoate ligand. The molecule has no specific conformational features to explain its unusually fast isotopic hydrogen exchange.