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The reactions of three-mercury anticrown (o-C6F4Hg)3 (1) with acetoacetic ester (AE), malonic ester (ME), and malonodinitrile (MN) afford 1: 1 complexes {[(o-C6F4Hg)3](AE)} (3), {[(o-C6F4Hg)3](ME)} (4), and {[(o-C6F4Hg)3](MN)} (5). The structures of complexes 3–5 were determined by X-ray diffraction analysis. Complex 3 has a discrete structure in the solid state, whereas complexes 4 and 5 form in the crystal extended stacks representing polydecker sandwiches with alternating molecules of 1 and ME or MN. According to the X-ray diffraction and IR spectral data, the molecule of AE in complex 3 is in the keto form.

The interaction of the Negishi reagent Cp2ZrBun 2 with 1,4-bis(tert-butyl)butadiyne ButC≡C-C≡CBut leads to four products: a five-membered zirconacyclocumulene complex Cp2Zr(η4-ButC4But) (2) synthesized earlier by another method, the previously unknown seven-membered zirconacyclocumulene Cp2Zr[η4-ButC4(But)-C(C2But)=CBut] (3) as well as small amounts of the zirconocene binuclear butatrienyl complex Cp2(Bun)Zr(ButC4But)Zr(Bun)Cp2 (4), and the dimeric acetylide [Cp2ZrC≡CBut]2 (5). The structure of complexes 2–5 was established by X-ray diffraction studies.

η 5 -6- N -Dimethylamino-2,3-benzofulvenchromium tricarbonyl has been synthesized. The rotational isomerism of the complex and the parent fulvene and the kinetic parameters of the barriers to rotation about the bond have been determined by dynamic 1 H NMR spectroscopy. π-Coordination increases the free energy of the rotational barrier, i.e. increases the degree of double-bond character between the C(6) and N atoms and, hence, enhances the π-electron polarization of the exocyclic double bond. Electron impact mass spectra of the complex and the parent fulvene have been investigated.

Rotational isomerization of 6-dimethylaminofulventungsten tricarbonyl in media of various acidities has been studied by dynamic 1H NMR spectroscopy, and the kinetic parameters of the rotation about the C(6)N bond have been determined. The rate of rotation about this bond increases in weakly acidic media and decreases in strongly acidic solutions with respect to that in the parent complex. This dependence indicates that the complex has dual reactivity in protonation, i.e. in weakly acidic media the protonation involves the nitrogen atom, and in highly acidic solutions the tungsten atom. On increasing the acidity of the medium the ammonium form of the complex is converted into the W-protonated complex. A study of deuterium exchange in acidic media has shown that the H or D atom attached to the W atom may be readily exchange for the deuteron (or the proton, respectively) of the acid, while the H atoms of the cyclopentadienyl ring do not undergo deuterium exchange under the conditions investigated. Protonation involving the Cp ring of the complex was not observed.

1 H NMR spectroscopy was used in studying the rotational isomerism of 6-dimethylaminofulvene and its complexes with carbonyls of chromium, molybdenum and tungsten. The energy parameters for the barriers to rotation about the c(6)N bond were determined. It is shown that the coordination of 6-dimethylaminofulvene with Group VIB metal carbonyls increases the free energy for the barrier to rotation about the C(6)N bond, that is, it increases the degree of double-bond character between the C(6) and N atoms. The free energy for the rotational barriers, and hence, the degree of double-bond character, are strongly dependent on the nature of the central metal atom, increasing in the sequence W

Aminoglycoside antibiotics belong to the class of pseudo-oligosaccharides, which is a chemotherapeutically important group of antibiotics with a broad spectrum of antimicrobial activity. The review surveys and gives a systematic account of the literature data relevant to the chemical properties of aminoglycosides. Particular attention has been devoted to the chemical transformations of natural antibiotics. The bibliography includes 323 references.

Protonation of 6-dimethylaminofulvenic complexes of chromium (I), molybdenum (II) and tunsten (III) carbonyls in trifluoroacetic and acetic acid solutions of differing acidity in methylene chloride has been studied using PMR and IR spectroscopy. It has been established that the complexes are protonated at the metal atom and that the protonation rate is linearly dependent on the acidity of the medium. Comparison of the basicities of complexes I–III has shown that their basicity ratio is I/II/III ⋍ 1/150/1800.

For the primary alkyl halides (R=from C2H5 to n-C9H19; halogen=C1, Br, and I) and the simplest aryl halides (R=C6H5 and p-CH3C6H4) it was shown that the organomagnesium synthesis in absence of catalysts for the Grignard reaction can be applied with success to the preparation of heteroorganic compounds of elements of Groups II–IV (mercury, boron, aluminum, silicon, germanium, tin, phosphorus, arsenic, antimony).

Some dialkylphosphinic acids, dialkylphosphinous esters, and alkylenebis(dialkylphosphine) P,P'-dioxides were synthesized via organomagnesium compounds prepared in absence of ether and other catalysts for the Grignard reaction.

1. An increase in the barriers of rotation around the\(C\dddot ---N\) bond is observed when dimethylaminofulvene is coordinated with transition metal (Cr, Mo, W) carbonyls. 2. In weakly acid media, where the complexes are protonated at the N atom, the barrier of rotation decreases, while in strongly acid media, where the metal atom is protonated, it increases.