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Copper(I) and silver(I) complexes of formulae [Cu(NCCH3)4]+[A]− ([A]− = [B(C6F5)4]− (1), {B[C6H3(CF3)2]4}− (2), [(C6F5)3B–C3H3N2–B(C6F5)3]− (3), and [Ag(NCCH3)4]+[B(C6F5)4]− (4) are examined with particular emphasis on the strength of their M–N bond and its influence on the catalytic performance of these complexes in cyclopropanation and aziridination. To examine the strength of the M–N interactions, vibrational spectra of the related hydrogenated and deuterated species [Cu(NCCH3)4]+, [Cu(NCCD3)4]+, [Ag(NCCH3)4]+, and [Ag(NCCD3)4]+ are also determined. It is found that the metal–nitrile bond strength is an important factor for the catalytic activity of the respective complexes.

Infrared, far-infrared and Raman spectra of Re2(O2CCH3)4X2 (X = Cl, Br) and Re2(O2CCD3)4Cl2 have been recorded. Assignments of the vibrational spectra of Os2(O2CCH3)4Cl2 and its deuterated derivative have been completed together with the Re complexes on the basis of normal-coordinate analysis. Force constant calculation was made for the acetate ion as well as for a four-atomic unit (with the CH3 and CD3 groups considered as point masses) using optimized masses of 16.7, 17.8, 20.5 and 21.6 for 12CH3, 13CH3, 12CD3 and 13CD3 groups, respectively. The force constants of the acetate ion have been adopted to the starting force field of the M2(O2CCH3)4X2 type complexes. The metal–halide (0.889, 0.997 and 1.286 N cm−1) and metal–metal stretching (3.32, 3.34 and 3.57 N cm−1) force constants were obtained for Re2(O2CCH3)4Cl2Re2(O2CCH3)4Br2 and Os2(O2CCH3)4Cl2 complexes, respectively. It was shown that the so-called diatomic approximation in most cases overestimates the M–M stretching force constants by 30–40%. Much better correlation has been obtained to fit these force constants, which produced values very close to those obtained by full normal-coordinate calculations. The Re–Re stretching force constants showed a reasonable correlation with the Re–Re bond distances for 18 rhenium complexes.

A study was launched to clarify the influence of the spatial structure of the alkyl chain on the products of the direct neutralization reactions between zinc hydroxide and several non-cyclic saturated carboxylic acids in the presence of an excess of either the carboxylic acid or zinc hydroxide. The species formed were identified on the basis of their FT-IR spectra in the mid-IR region. Straight-chain acids produced the corresponding zinc bis-carboxylates with polymeric sheet structure under all circumstances. The species present in the products of the branched-chain carboxylic acids depended strongly on the nature of the component in excess and the bulk of the alkyl group. Besides the starting materials the reaction mixtures contained two carboxylate species in various ratios. One of them was the zinc bis-carboxylate of the branched-chain carboxylic acid, characterized by an additional v CO band at around 1630 cm −1 , above the usual two strong carboxylate stretching bands. The other species was the corresponding complex Zn 4 O(RCOO) 6 . The conditions of foundation of these three forms of zinc carboxylates were formulated on the basis of the decreasing possibility of interaction between the neighbouring alkyl chains to form a polyethylene subcell in the sequence of: Zn(RCOO) 2 (polymeric sheet) > Zn(RCOO) 2 (intermediate form) > Zn 4 O(RCOO) 6 (tetranuclear complex).

The bis(carboxylato)zinc(II) salts of even-numbered straight-chain fatty acids (C6C8) were successfully prepared in boiling n-octane by neutralization. The mid-FT-IR spectra of n-octane solutions of the samples were recorded at 388 K. As a consequence of the dissolution process, the coordination of the carboxylate groups changed partially from bidentate to monodentate. The influence of water added to the solution on the solute was studied by means of FT-IR spectroscopy. Formation of Zn4O(RCOO)6 was detected, confirming the general validity of the earlier proposed mechanism of formation of the tetranuclear oxo-centered complexes of aliphatic carboxylic acids. The key factor is the presence of water in the system, which shifts the following equilibrium towards formation of the tetranuclear complex: 4Zn(RCOO)2+H2O ⇌ Zn4O(RCOO)6+(RCOOH)2.

Thermal behaviour of the Fe 2Ru(CO) 12 bimetallic cluster on a SiO 2 support was studied by FT-IR spectroscopy. At room temperature most of the molecules quickly decompose into Ru 0(CO) 2, Ru II(CO) 2 and Ru III(CO) 2 species anchored to the silica surface, similarly to the behaviour of Fe 2Ru(CO) 12 on alumina. A smaller part (ca. 15%) of Fe 2Ru(CO) 12 is stable on the surface at room temperature in a distorted form. When heated in hydrogen and in vacuum a series of surface molecules has been identified: H 2FeRu 3(CO) 13, H 4FeRu 3(CO) 12, H 4Ru 4(CO) 12, and HRu 3(CO) 10( ) anchored surface species. The ranges of thermal stability for the surface species have been given.

In-plane force constants for the planar halidebridge bridged artions [M 2 X 6 ] 2− (M = Pd or Pt, X = Cl, Br or I) have been calculated on the basis of a modified valence force field model, with some constrained interaction constants taken from earlier work on corresponding [MX 4 ] 2− systems. The terminal stretching force constants are larger than the bridge stretching force constants but the difference diminishes for the heavier halidex. The values are compared with those of the monomeric [MX 4 ] 2− systems and it is shown that the relationships correlate with the chemical reactivity of the halide bridges.

As known, on hydrated alumina support the Ru3(CO)12 cluster quickly decomposes into monometallic subcarbonyls. By FT-IR spectroscopy combined with data handling procedures, the structure and thermal behaviour of the bimetallic systems of Fe2Ru(CO)12/ Al2O3 and H2FeRu3(CO)13 together with that of Ru3(CO)12 have been studied. At the end of an interaction with the hydrated alumina surface, iron ruthenium bimetallic clusters decompose into identical ruthenium anchored surface species RuA  RuIII(CO)2, RuBRuII(CO)2 and RuCRu0(CO)2, like pure ruthenium clusters, and no CO bonded to iron has been detected RuB and RuC are stable in a wide temperature range (300–500 K) and they can be interconverted by oxidation and reduction. RuA is less stable (300–400 K). These main molecule-like species, anchored onto uniform sites of the surface, are accompanied by mobile subcarbonyls and stable monocarbonylic species, which occupy a large variety of different sites.

Force constants for planar complexes [MX 3 CO]- (MX = PdCl, PdBr, PtC1, PtBr and PtI) have been calculated using a modified valence force field, with constrained off-diagonal force constants based on results of [MX 4 ] 2− systems. The resulting stretching force constants are shown to have little dependence on choice of skeletal deformation assignments. The stretching force constants to palladium are lower than to platinum. The difference is more marked for the MC bonds than for MX bonds demonstrating the much weaker π-donor ability of 4d orbitals of Pd(ll) than 5d of Pt(II). The relationship between MX force constants in [MX 4 ] 2− [M 2 X 6 ] 2− and [MX 3 CO]− is discussed.

Initial steps of the interaction of Ru 3 (CO) 12 , Fe 3 (CO) 12 , Fe 2 Ru(CO) 12 and H 2 FeRu 3 (CO) 13 clusters with hydrated alumina surfaces have been studied by FT-IR spectroscopy combined with data handling procedures. The first stage of the interaction is a pure physisorption. At the second stage the metal-metal bonds split producing a large variety of mobile subcarbonyls. In the case of Fe 3 (CO) 12 the subcarbonyls form molecular Fe(CO) 5 , while at the bimetallic clusters they form molecular Fe- (CO) 5 and Ru 3 (CO) 12 . Fe(CO) 5 loses CO ligands producing Fe 2+ and Fe 3+ anchored ions. Ru 3 (CO) 12 , through further intermediate subcarbonyls, slowly decomposes into incipient anchored species Ru O - (CO) 2 , Ru II (CO) 2 and Ru III (CO) 2 .

Etude du spectre FT-IR et analyse des donnees du systeme Ru 3 (CO) 12 /Al 2 O 3 , afin d'identifier les structures possibles