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Infrared and Raman spectra of (π-C4H4N)Mn(CO)3 and IR spectra of (π-C4D4)Mn(CO)3 have been studied, and an assignment of the vibrational frequencies has been made. The frequencies of C4H4N ligand closely resemble those of the C5H5 ring in (π-C5H5)Mn(CO)3. The replacement of the CH group by nitrogen scarcely affects the mechanical properties of the ring. In spite of the lowering of local symmetry of the ligand from C5u to Cs, splitting of the degenerate modes was not observed. However, the modes, active only in the Raman spectrum for the Cp-ring, for the pyrrolyl ligand also appear in the IR spectrum. On the basis of comparison of the spectra of PTM and CTM and the new investigation of Raman spectra of CTM, a reassignment of some CTM vibrational modes is offered.

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.

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.

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.

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.

1. We synthesized and characterized the binuclear heterometallic complexes of some Group VIB metal carbonyls containing π-pyrrolyltricarbonylmanganese (PTM) as the p-ligand. 2. The p-coordination of PTM with the W(CO)5 fragment leads to retarding the rate of the acid isotopic hydrogen exchange of the pyrrolyl ligand by nearly 40 times when compared with the starting PTM, in which connection the reactivity of the α and β positions remains practically the same. 3. It was shown by the IR spectroscopy method that in acid medium the complex (CO)5W· PTM is protonated at the W atom, which testifies to the high donor properties of PTM as a p-ligand.

Metallation of azaferrocene by n-butyllithium in ether (both in the presence and absence of TMEDA) with subsequent treatment of the reaction mixture with benzophenone gives 2-(diphenyloxymethyl)azaferrocene as the sole product. Its structure was established by an X-ray diffraction study.

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.

The previously unknown chromium π-arenecarbonyl complexes containing π-pyrrolylmanganesetricarbonyl as a two-electron ligand, C6H6Cr(CO)2NC4H4Mn(CO)3, Me3C6H3Cr(CO)2NC4H4Mn(CO)3, and PhCOOMeCr(CO)2NC4H4Mn(CO)3, have been synthesized and characterized by spectroscopic methods.

Trinuclear organometallic complexes of palladium and platinum dichlorides with azacymantrene and azaferrocene as the n-ligands were synthesized and characterized.

The first substitution reactions in azaferrocene have been found to be metallation with n-butyllithium. Substitution of hydrogen for lithium occurs both in the cyclopentadienyl and pyrrolyl (α-position) ligands of the complex at comparable rates.

1. Cymanthrene and its derivatives containing phosphines or a nitrosyl group as ligands at the metal atom or a substituent in the cyclopentadienyl ring undergo complete hydrogenolysis in acid medium with Pd/C catalyst at 1 atm H2 and temperatures up to 50°C to form cyclopentane and small amounts of cyclopentene. 2. The hydrogenolysis of azaferrocene proceeds under the same conditions, but cyclopenta-dienylrhenium tricarbonyl does not undergo this reaction.