Synthesis, crystal structures and in vitro antitumor activities of some organoantimony arylhydroxamates

A series of novel organoantimony arylhydroxamates with the formulae [Ar₃SbL₂]⁻[HNEt₃]⁺ (LH = arylhydroxamic acid; Ar = C₆H₅, 4-CH₃C₆H₄, 3-CH₃C₆H₄, 4-ClC₆H₄, 4-FC₆H₄) and (4-CH₃C₆H₄)₄SbL were synthesized and characterized by elemental analysis, IR, ¹H NMR and mass spectroscopy. The crystal structures of (4-CH₃C₆H₄)₄SbL and [Ph₃SbL₂]⁻[HNEt₃]⁺ were determined by X-ray diffraction. The in vitro antitumor activities of all compounds against three human cancer cells are reported.     

Synthesis of pyridine N-imine complexes of methylcobaloxime and reactions of bis(dimethylglyoximato)methyl(Pyridine N-imine)cobalt with acid anyhydrides and acetylenedicarboxylic acid dimethyl ester

Pyridine N-imine complexes of methylcobaloxime, CH₃Co(Hdmg)₂(R¹— C₅H_nN⁺N^?H) (n = 4; R¹ = H, 2-CH₃, 3-CH₃, 4-CH₃: n = 3; R¹ = 2,6-CH₃), have been synthesized by the reaction of CH₃Co(Hdmg)₂S(CH₃)₂ with a pyridine N-imine which is generated from a pyridine, hydroxylamine-O-sulfonic acid and K₂CO₃. The reactions of CH₃Co(Hdmg)₂(C₅H₅N⁺N^?H) with acid anhydrides form new methylcobaloxime complexes with N-substituted pyridine N-imines, CH₃Co(Hdmg)₂(C₅H₅N⁺N^?R²) R² = COPh, COMe, COEt). With maleic anhydride, (pyridine N-acryloylimine)carboxylic acid is formed. With acetylenedicarboxylic acid dimethyl ester, 1,3-dipolar cycloaddition of the ligand gives pyrazolo[1,5-a]pyridine-2,3-dicarboxylic acid dimethyl ester.     

Hydrogen bonding and halogen bonding co-existing in the reaction of heptafluorobenzyl iodide with N,N,N,N-tetramethylethylene diamine

Two novel assembling systems 3 and 4, with the structures of C₆F₅CF₂⁻?H⁺N(Me)₂CH₂CH₂(Me₂)N⁺H?⁻CF₂C₆F₅ and C₆F₅CF₂I?N(Me)₂CH₂CH₂(Me)₂N?ICF₂C₆F₅, respectively, have been generated from the solution of heptafluorobenzyl iodide 1 and N,N,N^′,N^′-tetramethylethylenediamine 2 in dichloromethane. Their structures have been characterized by X-ray diffraction analysis, NMR and IR spectroscopy. Intermolecular N?I halogen bond and F?H hydrogen bond are revealed to be the driving forces for their formation.     

1-Methyl-4-ferrocenylmethyl-3,5-diphenylpyrazole: A versatile ligand for palladium(II) and platinum(II)

The syntheses and characterization of two novel ferrocene derivatives containing 3,5-diphenylpyrazole units of general formula [1-R-3,5-Ph₂-(C₃N₂)-CH₂-Fc] {Fc = (η⁵-C₅H₅)Fe(η⁵-C₅H₄) and R = H (2) or Me (3)} together with a study of their reactivity with palladium(II) and platinum(II) salts or complexes under different experimental conditions is described. These studies have allowed us to isolate and characterize trans-[Pd{1-Me-3,5-Ph₂-(C₃N₂)-CH₂-Fc]}₂Cl₂] (4a) and three different types of heterodimetallic complexes: cis-[M{1-Me-3,5-Ph₂-(C₃N₂)-CH₂-Fc]}Cl₂(dmso)] {M = Pd (5a) or Pt (5b)}, the cyclometallated products [M{κ²-C,N-[3-(C₆H₄)-1-Me-5-Ph-(C₃N₂)]-CH₂-Fc}Cl(L)] with L = PPh₃ and M = Pd (6a) or Pt (6b) or L = dmso and M = Pt (8b) and the trans-isomer of [Pt{1-Me-3,5-Ph₂-(C₃N₂)-CH₂-Fc]}Cl₂(dmso)] (7b). In compounds 4a, 5a, 5b and 7b, the ligand behaves as a neutral N-donor group; while in 6a, 6b and 8b it acts as a bidentate [C(sp²,phenyl),N(pyrazole)]⁻ group. A comparative study of the spectroscopic properties of the compounds, based on NMR, IR and UV-Visible experiments, is also reported.     

Mononuclear and dinuclear chiral vanadium(V) complexes with tridentate Schiff bases derived from R(−)-1,2-diaminopropane: Synthesis,structure, characterization and catalytic properties

A series of vanadium(V) complexes with unsymmetrical tridentate Schiff base ligands, obtained by the single condensation of R(−)-1,2-diaminopropane with salicylaldehyde and its derivatives, 2-hydroxy-1-naphthaldehyde, 2-hydroxyacetophenone, 1-hydroxy-2-acetonaphthone and 2-hydroxybenzophenone, were prepared. The complexes were characterized by elemental analysis and by their IR, CD, UV–Vis, 1D (¹H, ⁵¹V) and 2D (COSY, NOESY, gHSQC) NMR spectra. Crystal structures of the mononuclear complex {R(−)-2-amino-1-N-[(2′-oxido-κO-4′,6′-dimethoxyphenyl)methylene]aminopropane-κ²N}dioxidovanadium(V), VO₂(C₁₂H₁₇N₂O₃), 4, and of the dinuclear complex, di-μ-oxido-bis({R(−)-2-[1-(2-aminopropylimino)ethyl]-4-methylphenolato-κ³N,N′,O}oxidovanadium(V)), V₂O₄(C₁₁H₁₅N₂O)₂, 5, have been obtained by X-ray diffraction studies. The structure of 4 was revealed to be a distorted trigonal–bipyramidal coordination geometry, rarely encountered in VO₂(tridentate Schiff base) complexes. Complexes 2 and 3 have the ability to catalyze the oxidation of prochiral sulfide substrates PhSR (R = Me, Bz) utilizing hydrogen peroxide or cumene hydroperoxide (CHPO) as the oxidant.     

Cyclopalladation of N-phenyl-4-ferrocenylmethylpyrazoles: Crystal structure of [Pd{κ-C,N-C6H4-1-[(3,5-Me2-C3N2)-CH2-(η-C5H4)Fe(η-C5H5)]}Cl(PPh3)] · CH2Cl2

The synthesis and characterization of pyrazole derivatives of general formula [C₆H₄-4-R-1-{(3,5-Me₂-C₃N₂)-CH₂-(η⁵-C₅H₄)Fe(η⁵-C₅H₅)}] [R = OMe (1a) or H (1b)] with a ferrocenylmethyl substituent are described.The study of the reactivity of compounds 1 with palladium(II) acetate has allowed the isolation of complexes (μ-AcO)₂[Pd{κ²-C,N-C₆H₃-4-R-1-[(3,5-Me₂-C₃N₂)-CH₂-(η⁵-C₅H₄)Fe(η⁵-C₅H₅)]}]₂ (2) [R = OMe (2a) or H (2b)] that contain a bidentate [C(sp², phenyl), N]⁻ ligand and a central “Pd(μ-AcO)₂Pd” unit.Furthermore, treatment of 2 with LiCl produced complexes (μ-Cl)₂[Pd{κ²-C,N-C₆H₃-4-R-1-[(3,5-Me₂-C₃N₂)-CH₂-(η⁵-C₅H₄)Fe(η⁵-C₅H₅)]}]₂ (3) [R = OMe (3a) or H (3b)] that arise from the replacement of the acetato ligands by the Cl⁻.Compounds 2 and 3 also react with PPh₃ giving the monomeric complexes [Pd{κ²-C,N-C₆H₃-4-R-1-[(3,5-Me₂-C₃N₂)-CH₂-(η⁵-C₅H₄)Fe(η⁵-C₅H₅)]}X(PPh₃)] {X⁻ = AcO⁻ and R = OMe (5a) or H (5b) or X⁻ = Cl⁻ and R = OMe (6a) or H (6b)}, where the phosphine is in a cis-arrangement to the metallated carbon atom. Treatment of 3 with thallium(I) acetylacetonate produced [Pd{κ²-C,N-C₆H₃-4-R-1-[(3,5-Me₂-C₃N₂)-CH₂-(η⁵-C₅H₄)Fe(η⁵-C₅H₅)]}(acac)] (7) [R = OMe (7a) or H (7b)]. Electrochemical studies of the free ligands and the cyclopalladated complexes are also reported. The dimeric complexes 3 also react with MeO₂C-CC-CO₂Me (in a 1:4 molar ratio) giving [Pd{(MeO₂C-CC-CO₂Me)₂C₆H₃-4-R-1-[(3,5-Me₂-C₃N₂)-CH₂-(η⁵-C₅H₄)Fe(η⁵-C₅H₅)]}Cl] (8) [R = OMe (8a) or H (8b)], which arise from the bis(insertion) of the alkyne into the σ{Pd-C(sp², phenyl)} bond of 3.     

Synthesis, structural characterization of some germanium substituted chiral diethyltin derivatives

Some new bimetallic carboxylates of tin and germanium with general formula where R¹ = m-CH₃C₆H₄, p-CH₃C₆H₄, C₆H₅, R² = o-CH₃C₆H₄, p-CH₃C₆H₄, o-CH₃OC₆H₄, C₆H₅, CH₃, have been prepared by the condensation reaction of diethyltin oxide and triarygermyl(substituted)propanoic acid in 1:2 mole ratio, respectively, and characterized by multinuclear (¹H, ¹³C, ¹¹⁹Sn) NMR, ^119mSn Mössbauer and IR spectroscopy. The X-ray crystal structure of the ligand I₄ [(C₆H₅)₃GeCH(o-CH₃OC₆H₄)CH₂COOH] delineate four coordinated germanium atom with a peculiarity of having a molecule of solvent (CHCl₃). The chiral center in the synthesized compounds was identified on the basis of ¹H NMR data and measurements of angle of rotations.     

Synthesis and characterization of chromium(I) bis(η-toluene) derivatives containing sterically demanding anions

The reaction of Cr(η⁶-CH₃C₆H₅)₂ with 1-benzoyl-6-hydroxy-6-phenyl fulvene, dbcpH, and with pentakis(methoxycarbonyl)cyclopentadiene, pcmcpH, proceeds with evolution of dihydrogen and the formation of the ionic derivatives [Cr(η⁶-CH₃C₆H₅)₂][X] ([X]⁻ = 1,2-dibenzoylcyclopentadienyl, [dbcp]⁻, pentakis(methoxycarbonyl)cyclopentadienyl, [pcmcp]⁻), which have been characterized by IR and EPR spectroscopies, X-ray diffraction and electrochemical techniques. The sterically demanding anions do not affect the structural and electronic properties of the cations in solution but strongly influence crystal packing. In fact, a rare cis-eclipsed conformation of the toluene rings is found for [Cr(η⁶-CH₃C₆H₅)₂][dbcp] · THF, whereas two independent complexes are observed in the unit cell of [Cr(η⁶-CH₃C₆H₅)₂][pcmcp], one with toluene rings in a cis-eclipsed conformation and the other in a staggered conformation (projections of methyl groups form an angle of 151°).     

Synthesis and structures of o-phenylene-bridged Cp/phosphinoamide titanium complexes

Addition of R′₂PCl to anilines substituted with di- or trimethylcyclopentadienyl unit at ortho-position affords ortho-phenylene-bridged Me₂Cp or Me₃Cp/phosophinoamide ligands, 2-(RMe₂C₅H₂)C₆H₄NHPR′₂ (R = Me or H; R′ = Ph, iPr, or Cyclohexyl). Successive addition of Ti(NMe₂)₄ and Me₂SiCl₂ to the ligands affords the desired dichlorotitanium complexes, [2-(η⁵-RMe₂C₅H)C₆H₄NPR′ ₂− κ²N,P]TiCl₂ (R = H, R′ = Ph, 9; R = Me, R′ = Ph, 10; R = H, R′ = iPr, 11; R = Me, R′ = iPr, 12; R = H, R′ = Cy, 13; R = Me, R′ = Cy, 14). By using Zr(NMe₂)₄ instead of Ti(NMe₂)₄, a zirconium complex, [2-(η⁵-Me₃C₅H)C₆H₄NP(iPr)₂−κ²N,P]ZrCl₂ (15) is prepared. Molecular structures of 10, 14 and [2-(η⁵-Me₂C₅H₂)C₆H₄NPPh₂− κN]Ti(NMe₂)₂ (16) were determined. The metric parameters determined on the X-ray crystallographic studies and the chemical shifts of the ³¹P NMR signal indicate that the phosphorous atom coordinates to the titanium in the dichloro-complexes 9-15. The titanium and zirconium complexes show negligible activity in ethylene and ethylene/1-hexene (co)polymerization when activated with MAO or iBu₃Al/[Ph₃C][B(C₆F₅)₄].     

Dynamic H NMR study of 4-methylphenoxyimidoyl azides: conformational or configurational isomerisation?

Dynamic ¹H NMR (500 MHz) investigation of 4-methylphenoxyimidoyl azides (4-CH₃-C₆H₄-O-CN-Y)-N₃, Y=4-CH₃-C₆H₄-SO₂-, 4-Br-C₆H₄-SO₂-, C₆H₅SO₂-, CH₃-SO₂-, -CN in acetone-d₆ at temperature range of 195-280 K is reported. The observed free energy barrier (almost 12 kcal mol⁻¹) is attributed to conformational isomerisation about the N-S bond for Y=4-CH₃-C₆H₄-SO₂-, 4-Br-C₆H₄-SO₂-, C₆H₅SO₂-, CH₃-SO₂- and (almost 14 kcal mol⁻¹) to configurational isomerisation (E/Z) about CN bond for Y=-CN.     

Synthesis and crystal structures of novel lithium- and palladium-1-azaallyls

Treatment of (RH₂C)₂C₅H₃N-2,6 (R=SiMe₃) with BuⁿLi followed by addition of Me₃SiCl gave the tetrasilyl pyridine derivative (R₂HC)₂C₅H₃N-2,6 1 in high yield. Further lithiation of 1 with BuⁿLi and reaction of the intermediate with PhCN led to the new lithium-1-azaallyl [Li{N(R)C(Ph)C(R)(C₅H₃N-2,6)(CHR₂)}]₂2, while metallation of the previously described di-lithium compounds [Li{N(R)C(R^′)CH}₂(C₅H₃-2,6)]Li(tmen)_n (R=SiMe₃, R^′=Bu^t, n=1 or R=SiMe₃, R^′=Ph, n=2) with PdCl₂(PhCN)₂ yielded the novel metallacycles [Pd{{N(H)(R)C(R^′)CH}{N(SiMe₂CH₂)C(R^′)CH}C₅H₃N-2,6}] 3 (R^′=Bu^t) and [Pd{{N(R)C(R^′)CH}{N(R)(H)C(R^′)CH}C₅H₃N-2,6}₂] (R^′=Ph) 4 in moderate to low yield. Compound 3 is unusual in being the first example of a crystallographically characterised PdNSiC heterocycle which is believed to be formed via an intramolecular CH-activation of a trimethylsilyl group by Pd(II). All four compounds were fully characterised by NMR-spectroscopy, microanalysis (not 4) and X-ray diffraction.     

C-S bond formation catalyzed by N-heterocylic carbene palladium phosphine complexes

N-Heterocyclic carbenes (NHCs) are known to be useful ligands for palladium-complex catalysis. It was found that [(NHC)Pd(PPh₃)Cl₂] is an effective pre-catalyst in Pd-catalyzed C-S cross coupling reactions to produce the functionalized sulfides in excellent yields. The turn over frequency (TOF) for the coupling of p-CH₃C₆H₄Br with p-CH₃C₆H₄SH reaches to 6.25 (mol of product) (mole of catalyst)⁻¹ h⁻¹.     

Anionic alkyl diglycoldiamides with covalently bonded cobalt bis(dicarbollide)(1−) ions for lanthanide and actinide extractions

Ionic diamides composed of a N,N′-dialkyl diglycolyl complexing group and two cobalt bis(dicarbollide)(1−) anions were synthesized with the aim to develop efficient extraction agents for liquid-liquid extraction of polyvalent cations, i.e. lanthanides and actinides from high-level activity nuclear waste. Compounds of general formulation [{(N,N-(8-CH₂-CH₂O)₂-1,2-C₂B₉H₁₀)(1′,2′-C₂B₉H₁₁)-3,3′-Co)(N′,N′-R)NCOCH₂}₂O]Na₂, where R = n-C₄H₉, n-C₈H₁₇, n-C₁₂H₂₅ and 1-C₆H₄-4-CH₃ (1-4), were prepared and characterized by combination of ¹¹B ¹H, ¹³C NMR spectroscopy, ESI-MS, HPLC and other techniques. Effects of different nitrogen substitution in the structures of 1-4 on the extraction properties were tested. The study resulted in the observation that the compounds are significantly (2-3 orders in magnitude) more efficient extractants for Eu(III) and Am(III) than synergic mixtures of organic N,N′-tetra n-octyl diglycolic acid diamide (TODGA) and chlorinated cobalt bis(dicarbollide) at the same concentrations of both groups. Low polar mixtures of n-dodecane (D) and hexyl methyl ketone (HMK) can be applied as an auxiliary solvent for extraction, replacing thus the polar and less environmentally friendly nitro-, fluoro- and chloro- solvents used in the current dicarbollide liquid-liquid extraction process.     

Reaction chemistry of tricarbonyl-η-pentadienylmanganese: Straightforward synthesis of stable manganese carbonyl terminal thiolates and a dinuclear bis(ethylenediaminyl) complex

Tricarbonyl-η⁵-pentadienylmanganese reacts with mercaptans RSH, R = Ph, C₆F₅, m-NH₂C₆H₄, p-NH₂C₆H₄, and HSCH₂CH₂ in the presence of ECH₂CH₂E, E = -PPh₂ or -NH₂ to give novel stable terminal thiolate mononuclear complexes fac-Mn(CO)₃(SR)(Ph₂PCH₂CH₂PPh₂-κ²-P,P′) for R = Ph, C₆F₅, m-NH₂C₆H₄, p-NH₂C₆H₄, and HSCH₂CH₂ and fac-Mn(CO)₃(SR)(H₂NCH₂CH₂NH₂-κ²-N,N′) for R = Ph and C₆F₅. Upon reaction of tricarbonyl-η⁵-pentadienylmanganese with ethylenediamine a dinuclear complex [fac-Mn(CO)₃(μ-H₂NCH₂CH₂NH-κ²-N,N′)]₂ was formed wherein the diaminyl ligand functions in the capacity of chelating and bridging ligand.     

Photochemistry of methyl- and n1-benzyl-n5-cyclopentadienyltricarbonyltungstein(II)

Irradiation of solutions of n⁵-C₅H₅W(CO)₃R (R  CH₃n1-CH₂C₆H₅) in cyclohexane at ca. 310490 nm leads to the formation of [n⁵-C₅H₅W(CO)₃]₂ and methane and of n⁵-C₅H₅W₅(CO)₂(n³-CH₂C₆H₅) and some [n⁵-C₅H₅W(CO)₃]₂, respectively. When the irradiation is carried out in the presence of excess P(C₆H₅)₃, the photoproducts are n⁵-C₅H₅W(CO)₂[P(C₆H₅)₃]CH₃ (R  CH₃) and n⁵-C₅H₅W(CO)₂(n₃-CH₂C₆H₅) and trace [n⁵-C₅H₅W(CO)₃]₂ (R  n¹-CH₂C₆H₅). Photolysis of the n⁵-C₅H₅W(CO)₃R in the presence of benzyl chloride affords n⁵-C₅H₅W(CO)₃Cl (R  CH₃) and both n⁵-C₅H₅W(CO)₂(n³-CH₂C₂H₅) and n⁵-C₅H₅W(CO)₃Cl (R  n¹-CH₂C₆H₅), the relative amounts of the latter products depending on the quantity of added C₆H₅CH₂Cl. Irradiation of n⁵-C₅H₅W(CO)₃-CH₃ in the presence of both P(C₆h₅)₃ and C₆H₅CH₂Cl affords n⁵-C₅H₅W(CO)₂-[P(C₆H₅)₃]CH₃, but no n⁵-C₅H₅W(CO)₃Cl. It is proposed that the primary photo-reaction in these transformations is dissociation of a CO group from n⁵-C₅H₅W-(CO)₃R to generate n⁵-C₅H₅W(CO)₂R, which can either combine with L to form a stable 18 electron complex, n⁵-C₅H₅W(CO)₂(L)R (L  CO, P(C₅H₅)₃; LR  n³-CH₂C₆H₅), or lose the group R in a competing, apparently slower step. This proposal receives support from the observation that, light intensifies being equal, n⁵-C₅H₅W(CO)₃CH₃ undergoes a considerably faster photoconversion to [n⁵-C₅H₅W(CO)₃]₂ under argon than under carbon monoxide.     

Complexes derived from the general copper(II)/maleamic acid/N,N′,N′′-chelate reaction systems: Synthetic,reactivity, structural and spectroscopic studies

The synthetic investigation of the Cu^II/maleamate(−1) ion (HL⁻)/N,N′,N′′-chelate general reaction system has allowed access to compounds [Cu₂(HL)₂(bppy)₂](ClO₄)₂·H₂O (1·H₂O), [Cu(HL)(bppy)(ClO₄)] (2) and [Cu(HL)(terpy)(H₂O)](ClO₄) (4) (bppy = 2,6-bis(pyrazol-1-yl)pyridine, terpy = 2,2′;6′,2′′-terpyridine). In the absence of externally added hydroxides, compound [Cu₂(L′)₂(bppy)₂](ClO₄)₂ (3) was obtained from MeOH solutions; L′⁻ is the monomethyl maleate(−1) ligand which is formed in situ via the Cu^II-assisted HL⁻ → L′⁻ transformation. In the case of tptz-containing (tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine) reaction systems, the Cu^II-assisted hydrolysis of tptz to pyridine-2-carboxamide (L1) afforded complex [Cu(L1)₂(NO₃)₂] (5). The crystal structures of 1–5 are stabilized by intermolecular hydrogen bonding and π–π stacking interactions. Characteristic IR bands of the complexes are discussed in terms of the known structures and the coordination modes of the ligands.     

Re-visiting of 5-[(E)-2-(aryl)-1-diazenyl]-quinolin-8-ol with tweaking of Sn-Ph groups: Synthesis, spectroscopic characterization and X-ray crystallography

Reactions of sodium 5-[(E)-2-(aryl)-1-diazenyl]quinolin-8-olates (LH, where the aryl group is an R-substituted phenyl ring such that for L¹H: R = H; L²H: R = 2′-CH₃; L³H: R = 3′-CH₃; L⁴H: R = 4′-CH₃; L⁵H: R = 4′-OCH₃ and L⁶H: R = 4′-OC₂H₅) with Ph₃SnCl in a 1:1 molar ratio yielded complexes of composition Ph₃SnL. The complexes have been characterized by ¹H, ¹³C, ¹¹⁹Sn NMR, IR and ^119mSn Mössbauer spectroscopic techniques in combination with elemental analyses. The crystal structures of Ph₃SnL¹ · 0.5C₆H₆ (1), Ph₃SnL² (2), Ph₃SnL⁵ · C₆H₆ (5) and Ph₃SnL⁶ · 0.5C₆H₆ (6) were determined. The results of the X-ray studies indicated that the benzene solvated compounds 1, 5 and 6 are distorted square pyramid, with one of the phenyl C atoms in the apex while the ligand arrangement around central Sn atom in 2 is distorted trigonal-bipyramidal, with a phenyl C and the oxinato N atoms in axial positions.     

Complexes derived from the copper(II)/succinamic acid/N,N′,N″-chelate tertiary reaction systems: Synthesis,structural and spectroscopic studies

The use of succinamic acid (H₂sucm) in Cu^II/N,N′,N″-donor [2,2′:6′,2″-terpyridine (terpy), 2,6-bis(3,5-dimethylpyrazol-1-yl)pyridine (dmbppy)] reaction mixtures yielded compounds [Cu(Hsucm)(terpy)]_n(ClO₄)_n (1), [Cu(Hsucm)(terpy)(MeOH)](ClO₄) (2), [Cu₂(Hsucm)₂(terpy)₂](ClO₄)₂ (3), [Cu(ClO₄)₂(terpy)(MeOH)] (4), [Cu(Hsucm)(dmbppy)]_n(NO₃)_n·3nH₂O (5^.3nH₂O), and [CuCl₂(dmbppy)]·H₂O (6·H₂O). The succinamate(−1) ligand exists in four different coordination modes in the structures of 1–3 and 5, i.e., the μ₂-κO:κO′:κO″ in 1 and 5 which involves asymmetric chelating coordination of the carboxylato group and ligation of the amide O-atom leading to 1D coordination polymers, the μ₂-κ²O:κO′ in 3 which involves asymmetric chelating and bridging coordination of the carboxylato group, and the asymmetric chelating mode in 2. The primary amide group, either coordinated in 1 and 5, or uncoordinated in 2 and 3, participate in hydrogen bonding interactions, leading to interesting crystal structures. Characteristic IR bands of the complexes are discussed in terms of the known structures and the coordination modes of the Hsucm⁻ ligands. The thermal decomposition of complex 5·3nH₂O was monitored by TG/DTG and DTA measurements.     

New types of asymmetrical bromonium salts [RF(RF′)Br]Y where RF and/or RF′ represent perfluorinated aryl, alkenyl, and alkynyl groups

A series of previously unknown asymmetrical fluorinated bis(aryl)bromonium, alkenyl(aryl)bromonium, and alkynyl(aryl)bromonium salts was prepared by reactions of C₆F₅BrF₂ or 4-CF₃C₆H₄BrF₂ with aryl group transfer reagents Ar′SiF₃ (Ar′ = C₆F₅, 4-FC₆H₄, C₆H₅) or perfluoroorganyl group transfer reagents R_F′BF₂ (R_F = C₆F₅, trans-CF₃CFCF, C₃F₇C≡C) preferentially in weakly coordinating solvents (CCl₃F, CCl₂FCClF₂, CH₂Cl₂, CF₃CH₂CHF₂ (PFP), CF₃CH₂CF₂CH₃ (PFB)). The presence of the base MeCN and the influence of the adducts R_F′BF₂·NCMe (R_F = C₆F₅, CF₃C≡C) on reactions aside to bromonium salt formation are discussed. Reactions of C₆F₅BrF₂ with Alk_F′BF₂ in PFP gave mainly C₆F₅Br and Alk_F′F (Alk_F′ = C₆F₁₃, C₆F₁₃CH₂CH₂), presumably, deriving from the unstable salts [C₆F₅(Alk_F′)Br]Y (Y = [Alk_F′BF₃]⁻). Prototypical reactivities of selected bromonium salts were investigated with the nucleophile I^-and the electrophile H⁺. [4-CF₃C₆H₄(C₆F₅)Br][BF₄] showed the conversion into 4-CF₃C₆H₄Br and C₆F₅I when reacted with [Bu₄N]I in MeCN. Perfluoroalkynylbromonium salts [C_nF_2n+1C≡C(R_F)Br][BF₄] slowly added HF when dissolved in aHF and formed [Z-C_nF_2n+1CFCH(R_F)Br][BF₄].     

Reductive elimination reaction of rhenium complexes trans-(η-C5Me5)Re(CO)2(chloroaryl)Cl

Thermal reaction of the chloroaryl-chloride complexes trans-(η⁵-C₅Me₅)Re(CO)₂(Ar^Cl)Cl (Ar^Cl = 3-ClC₆H₄, 3-ClC₆H₃(4-Me) and 3,5-Cl₂C₆H₃) in acetonitrile did not interconvert to the cis isomer, instead the complex ReCl(CO)₂(NCMe)₃ and the corresponding 5-Ar^Cl-1,2,3,4,5-pentamethylcyclopentadiene were formed. Similar reductive elimination products were obtained when the starting rhenium complexes were reacted with trimethylphosphite in toluene.