Reaktion des hydridodicobalt-kations [(C5H5Co)2(μ-PMe2)2(μ-H)]+ mit C2(CO2Me)2: Bildung und kristallstruktur eines zweikernkomplexes mit O=C(OMe)CH=C(CO2Me)PMe2 als 6-elektronen-donorligand

[(C₅H₅Co)₂(μ-PMe₂)₂(μ-H)]BF₄ ([II]BF₄) reacts with C₂(CO₂Me)₂ to give the products III and IV. The ionic compound III which formally is a $\text{1}\text{1}$ adduct of [II]BF₄ and C₂(CO₂Me)₂ has been characterized by X-ray structure analysis. III contains the group O=C(OMe)CH=C(CO₂Me)PMe₂ as a 6-electron donor ligand chelated to a cobalt atom and π-bonded to the other cobalt atom. Complex IV is a neutral compound which also can be obtained from [C₅H₅Co(μ-PMe₂)]₂ (I) and C₂(CO₂Me)₂.     

Oxygenation of p-nitrophenylhydrazones with Co(II)-schiff base complexes

$\text{p}$-Nitrophenylhydrazones, unsusceptible to autoxidation, are readily oxygenated in the presence of a five-coordinate cobalt(II)-Schiff base complex, Co(II)(MeOSalen) (Py) leading to quantitative formation of novel 1-($\text{p}$-nitrophenylazo)-1-peroxy Co(III) complexes 2, which were isolated as crystals. A plausible mechanism involving hydrogen abstraction by Co(III)(O₂^?.) from the substrate followed by formation of a substrate anion Co(III) complex intermediate is proposed.     

Selective formation of peroxy-p-quinolato Co(III) complexes in the oxygenation of 4-alkyl-2,6-di-t-butylphenols with Co(II)-Schiff's base complexes

The oxygenation of 4-alkyl-2,6-di-$\text{t}$-butylphenols ($\text{2}$) with Co(II)-Schiff's base complexes in aprotic solvents such as CH₂Cl₂, THF, Py, and DMF leads to highly selective formation of the corresponding peroxy-$\text{p}$-quinolato Co(III) complexes. The reaction proceeds by mechanism involving a rate determining hydrogen abstraction by superoxo Co(III) species from $\text{2}$ giving phenoxy radical, rapid step of electron transfer from Co(II) complex to the phenoxy radical, and dioxygen incorporation into phenolato Co(III) complex thus formed.     

Reaction of superoxo Co(III) complex with quinones formation of a semiquinone Co(III) complex

The superoxo complex [Co(CN)₅O₂]^3- was found to act as a reducing agent towards quinones. One-electron reduction took place with $\text{o}$-quinones whereas two-electrons reduction with $\text{p}$-quinones. 3,5-Di-$\text{t}$-butyl-$\text{o}$-benzoquinone gave the corresponding semiquinone Co(III) complex quantitatively.     

Reaction of superoxo Co(III) complexes with 2,6-di-t-butyl-p-benzoquinone methides

Superoxo Co(III) complexes derived from Co(Salpr) and [Co(CN)₅]^3? reacted with 2,6-di-$\text{t}$-butyl-$\text{p}$-benzoquinone methides to give 2,6-di-$\text{t}$-butyl-$\text{p}$-benzoquinone and 2,6-di-$\text{t}$-butyl-2,5-cyclohexadienonespirooxiranes as the main products, which are considered to result from nucleophilic attack by the superoxo species on the exo double bond of the quinone methides.     

Cis-trihetero-tris-σ-homobenzenes as tridentate ligands - X-ray crystal. Structure analyses of the Co(C6H9N3)2(NO3)3 and Ba(C6H6O3)4(ClO4)2-complexes

According to X-ray crystal structure analyses “cis-benzenetrisimine” ($\text{2}$) and “cis-benzenetrioxide” ($\text{1}$) act as tridentate ligands in their 2:1- and 4:1-complexes $\text{7}$ (Co(C₆H₉N₃)₂(NO₃)₃) and $\text{8}$ (Ba(C₆H₆O₃)₄(ClO₄)₂), resp. The latter is the rare example of an organic complex with the (approximate) T-symmetry.     

Extraction of cobalt(II) and nickel(II) with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one (HPMBP) and tri-n-octylamine (TOA)

The extraction of Co(II) with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one ((H)PMBP) and tri-n-octylamine (TOA) is investigated in order to explore the influence of diluents and inorganic anions with synergistic acidic extractant + liquid anion exchanger systems. Although it is proved that the same species [HTOA]⁺ [Co(PMBP)₃]^? is extracted from various inorganic media, with toluene as the diluent, the presence of ClO₄^? SO₄^2? or Cl^? anion modifies the distribution of the anions which are associated to (HTOA)⁺ in the organic phase, leading to different synergistic equilibria; with Cl^? or SO₄^2?: $\text{CO(PMBP)}{}_2$ + $\text{(HTOA}{}^{\mathrm{+}}$,PMBP^?) ?$\text{(HTOA}{}^{\mathrm{+}}$,Co(PMBP)₃^? (log K = 6.10) and with ClO₄^? : $\text{Co(PMBP)}{}_2$ + $\text{HPMBP}$ + $\text{(HTOA}{}^{\mathrm{+}}$,ClO₄^? ? $\text{(HTOA}{}^{\mathrm{+}}$,Co(PMBP)₃^? + H⁺ + ClO₄^? (log K = 2.34) The same synergistic equilibrium is observed for the extraction of Ni(II) from ClO₄^? medium, with a comparable value of the constant (log K = 2.45). The synergistic effect is cancelled in n-octanol.     

Oxygenation of 4-(N-alkylimino)methyl-2,6-di-t-butylphenols mediated by Co(II)-Schiff base complex

4-(N-Alkylimino)methyl-2,6-di-$\text{t}$-butylphenols ($\text{1}$), Schiff bases of 3,5-di-$\text{t}$-butyl-4-hydroxybenzaldehyde can be oxygenated in the presence of Co(Salpr), a five coordinate Co(II)-Schiff base complex to give N-alkyl-3-$\text{t}$-butyl-5-formyl-2-hydroxy-2-pivaloyl-1,2-dihydropyridines ($\text{2}$ as the main product together with 3-formyl-2,5-di-$\text{t}$-butyl-2,4-cyclopentadienone ($\text{3}$) and 2,6-di-$\text{t}$-butyl-4-formyl-6-hydroxy-4,5-epoxy-2-cyclohexenone ($\text{4}$). These products result from dioxygen incorporation into the ortho position of $\text{1}$.     

The preperation and coordination properties of 1,4-diaza-3-methylbutadiene-2-ylpalladium(II) complexes with different substituents on the imino nitrogen atoms

The complexes trans-[PdCl{$\text{C(=NR)C}$(ME)=NR'} (PPh₃)₂] (R=C₆H₁₁,p-C₆H₄OMe; R$\text{.}\text{?}$=p-C₆H₄OMe, Me) containing a σ-bonded 1,4-diaza-3-menthyl-butadiene-2-yl group with different substituents on the nitrogen atoms have been prepared by two routes. The first involves initial methylation of the mixed isonitrile complex [PdCl₂(CNR)(CNR')]by HgMe₂, followed by reaction with PPh₃ ($\text{Pd}\text{PPh}{}_3$molar ratio $\text{1}\text{2}$). The second method involves condensation of primary aliphatic amines with the carbonyl group of the 1-azabut-1-en-3-one-2-yl moiety of the complex trans-[PdCl{$\text{C(=NR)C}$(Me) = 0} (PPh₃)₂]. The 1,4-diaza-3-methylbutadiene-2-yl derivatives act through their imino nitrogen atoms as chelating ligands towards anhydrous metal chlorides MCl₂ (M = Co, Ni, Cu, Zn). Magnetic moment measurements and the far-infrared and electronic spectra of these adducts indicate an essentially pseudo-tetrahedral configuration at M in the solid and in solution. With the ZnCl₂ adducts, the ¹H NMR pattern for the phenyl protons of the p-methoxyphenyl N-substituents dependss upon the position of the substituent i the 1,4-diazabutadiene chain.     

Substitution in barium-fluoride apatite: The crystal structures of Ba10(PO4)6F2, Ba6La2Na2(PO4)6F2 and Ba4Nd3Na3(PO4)6F2

The crystal structures of the apatites Ba₁₀(PO₄)₆F₂(I), Ba₆La₂Na₂(PO₄)₆F₂(II) and Ba₄Nd₃Na₃(PO₄)₆F₂ (III) have been determined by single-crystal X-ray diffraction. All three compounds crystallize in a hexagonal apatite-like structure. The unit cells and space groups are: I, a = 10.153(2), c = 7.733(1)Å, $\text{P6}{}_3\text{m}\text{; a = 9.9392(4), c = 7.4419(5)}$Å, $\text{P}\text{6}$; III, a = 9.786(2), c = 7.281(1)Å, $\text{P}\text{3}$. The structures were refined by normal full-matrix crystallographic least squares techniques. The final values of the refinement indicators R_w and R are: I, R_w = 0.026, R = 0.027, 613 observed reflections; II, R_w = 0.081, R = 0.074, 579 observed reflections; III, R_w = 0.062, R = 0.044, 1262 observed reflections.In I, the Ba(1) atoms located in columns on threefold axes, are coordinated to nine oxygen atoms; the Ba(2) sites form triangles about the F site and are coordinated to six oxygen atoms and one fluoride ion. The fluoride ions are statistically displaced ～0.25 Å from the Ba(2) triangles. This displacement of the F ions is analogous to the displacement of OH ion in Ca₁₀(PO₄)₆(OH)₂.The structures of II and III contain disordered cations. In II there is disorder between La and Na in the column cation sites as well as triangle sites. In III, Nd and Na ions are ordered in the column sites, but there is disorder among Ba and the remaining Nd and Na ions in the triangle sites to give an average site population of $\text{2}\text{3}\text{Ba}\text{,}\text{1}\text{6}\text{Nd}\text{,}\text{1}\text{6}\text{Na}$. The coordination of the rare earth ions and Na ions in the ordered column sites are nine and six oxygens, respectively, in accord with the greater charge of the rare earth ions as compared with Na. The F ions in both II and III suffer from considerable disorder in position, and their locations are not precisely known.     

Oxygenation of 2,6-di-t-butylphenols with superoxo Co(III) complexes

Superoxo Co(III) complexes, [Co(CN)₅O₂][X]₃ where X = Et₃N⁺ and (Ph₃P)₂N⁺, mediate the dioxygen incorporation into 2,6-di-$\text{t}$-butylphenols ($\text{1}$) with the same regioselectivity as that in the base-catalyzed oxygenation of $\text{1}$. The superoxo species acts as a base but is not incorporated into the substrate.     

The synthesis of a cationic ylide complex of platinum(II) by the reaction of tetrakis(triphenylphosphine)platinum(O) with choloroiodomethane.

The reaction of Pt(PPh₃)₄ with CH₂Cl1 in benzene yields the cationic ylide complex $\text{cis}$-[Pt(PPh₃)₂(CH₂PPh₃)Cl]I in high yield. This complex has been converted to $\text{cis}$-[(PPh₃)₂(CH₂PPh₃)X]X (X  Br or I) by reaction with LiBr or NaI. Reaction of $\text{cis}$-[Pt(PPH₃)I]I with iodine yields $\text{cis}$-[Pt(PPh₃)₂(CH₂PPh₃)I]I₃. Nmr data are given in support of the suggested structures.     

Synthesis,Reactions and Catalytic Activities of a Cationic Acrylonitrile-Rhodium(I) Complex

Reaction of RhCl (CO)(Ph₃P)₂(Ph₃P = triphenylphosphine) with AgClO₄ in acrylonitrile at 30°C produces a new cationic rhodium(I) complex, [Rh(CH₂CHCN)(CO) (Ph₃P)₂]ClO₄ ($\text{1}$) and AgCl. The ¹H-NMR and IR spectra of $\text{1}$ suggest that acrylonitrile is coordinated to rhodium through the π-system of the vinyl group. The complex $\text{1}$ reacts with molecular hydrogen to give a propionitrile-rhodium(I) complex, [Rh(CH₃ CH₂CN) (CO)(Ph₃P)₂ClO₄($\text{2}$) where the coordination of propionitrile through nitrogen is suggested by the ¹H-NMR and IR spectral data. The coordinated acrylonitrile in $\text{1}$ is readily replaced with triphenylphosphine and propionitrile to give [Rh(CO)(Ph₃P)₃] ClO₄ and $\text{2}$, respectively. The complex $\text{1}$ is catalytically active for the hydrogenation and polymerization of acrylonitrile at 25°C under the atmospheric pressure of hydrogen.     

Mechanism of selective p-quinol formation in the cobalt schiff base complex-catalyzed oxygenation of 4-alkyl-2,6-di-t-butylphenols

The selective formation of $\text{p}$-quinols in the Co(Salpr)-catalyzed oxygenation of 4-alkyl-2,6-di-$\text{t}$-butylphenols in MeOH has been found to involve the rate determining reduction of peroxy-$\text{p}$-quinolato Co(III) complex formed in the initial fast step. An ionic mechanism of the reduction of the OO bond in the peroxy complex by MeOH has been discussed based on kinetic studies. The reactive species in the catalytic cycle is found to be [Co(III)(Salpr)(OH)].     

Methylated multibridged [2n]cyclophanes. All alternate synthesis of [26](1,2,3,4,5,6) cyclophane (superphane)

A sequence of formylation followed by a carbene insertion reaction has led to the stepwise introduction of additional ethano bridges into 4,5,7,8- tetramethyl [2₂](1,4)cyclophane ($\text{1}$), providing syntheses of 5,7,8-trimethyl- [2₃](l,2,4)cyclophane ($\text{6}$), a mixture of 5,8-dimethyl[2₄(1,2,4,5)cyclophane ($\text{10}$) and 5,7-dimethyl[2₄(1,2,3,5)cyclophane ($\text{11}$, and-4-methyl[2₅](1,2,3,4,5)-cyclophane ($\text{14}$). This route to $\text{14}$ completes a formal eight-step synthesis of [2₆](1,2,3,4,5,6)cyclophane ($\text{15}$, superphane) with an overall yield of 17%. A Birch reduction of $\text{6}$ readily gave 12,15-dihydro-5,7,8-trimethyl[2₃](1,2,4)-cyclophane ($\text{7}$) in 85% yield.     

Carbonyl complexes of manganese(I) with chelating phosphino-alkyl or -acyl ligands. Crystal and molecular structure of [Ph2PCH2CH2(O)CMn(CO)2(dppm)l

The phosphine Ph₂PCH₂CH₂Cl reacts with fac-[XMn(CO)₃(dppm)] (X = Cl or Br) in refluxing toluene to give the complexes cis,cis-[XMn(CO)₂(dppm)(Ph₂PCH₂CH₂Cl)] (I). Treatment of those species with Na amalgam in THF leads to the alkyl complex [Ph₂$\text{PCH}{}_2\text{CH}{}_2\text{M}$n(CO)₂(dppm)] (II), which does not react with CO under normal conditions but can be converted into cis,cis-[ClMn(CO)₂(dppm)(PPh₂Et)] by reacting with HCl (g) in ether. If the reduction of I with Na/Hg is carried out in the presence of CO the compound cis-[Ph₂$\text{PCH}{}_2\text{CH}{}_2\text{(O)CM}$n(CO)₂(dppm)] (III) is obtained. The latter has also been prepared directly from fac-[BrMn(CO)3(dppm)], Ph₂PCH₂CH₂Cl, and Na/Hg in THF, and characterized by X-ray crystallography. The crystals are monoclinic, space group P2₁/n; refinement gave R = 0.053 for 2593 reflections with I ? 2.5σ(I). The reaction of the complex fac-[O₃ClOMn(CO)₃(dppm)] with Ph₂PCH₂CH₂Cl in Cl₂CH₂ gives the salt fac-[Mn(CO)₃(dppm)(Ph₂PCH₂CH₂Cl)]ClO₄ which isomerizes to mer-[Mn(CO)₃(dppm)(Ph₂PCH₂CH₂Cl)]ClO₄ in boiling butanol. Both cationic carbonyl complexes give the acyl species III upon reduction with Na amalgam.     

Copper(II) in organic synthesis. IV Reaction of the copper(II) acetate complex of isatin-3-arylhydrazones with dimethyl acety-lenedicarboxylate.

The copper(II) acetate complex of isatin-3-phenylhy-drazone (2a) reacted with dimethyl acetylenedicarboxylate (DMAD) by two competitive pathways: a Cu⁺⁺ oxidation of the ligand and a [2+2] cycloaddition. The former reaction gave 3-car- benindolin-2-one (13) which reacted with DMAD in a l,3-dipolar cycloaddition, to give 3a. This was synthesized by an independent route. The phenyl radical, generated in the same process, was trapped by three DMAD and gave $\text{4a}$. The [2+2] cycloaddition gave a spiro adduct 10 which, by electrocyclic ring opening and intramolecular cyclization, allowed isolation of a pyridazino [3,4-b] indole (|5a). The reaction was performed on $\text{p}$-chlorophe-nylhydrazone 1b and the structure of 5b was demonstrated by X-ray analysis. A rationalization of the reactivity was attempted in terms of MO interactions of the reactants.     

Bis(dimethylmetall(III)glyoximato)metallate(II) (metall(III) = Al,Ga, In,metall(II) = Ni,Pd, Pt,Cu)

When the trimethyl derivatives of aluminium, gallium and indium react with glyoximato metallates, (R₂C₂N₂(O)OH)₂Met^II (R = H, CH₃; Met^II = Ni, Pd, Pt, Cu), in a $\text{2}\text{1}$ molar ratio, 2 mol of methane are evolved and monomeric bis(dimethylmetal(III)glyoximato)metallates(II) (metal(III) = Al, Ga, In) are formed in high yields. The vibrational and NMR spectra of the new complexes were measured and were partly resolved. The X-ray structure determinations of two of these compounds show non-planar structures of approximate C_2h and C₂ symmetry, respectively, with weak metal(III)?metal(II) π-interactions.     

Reactions of o-tolyl isocyanide with isocyanate and isothiocyanate syntheses of n-substituted indole-3-carboxamides and indole-3-thiocarboxamides

o-Lithomethylphenyl isocyanide is reacted at ?78° with isocyanates and isothiocyanates to produce o-isocyanophenyl-acetamides $\text{(2a)}$ and -acetothioamides $\text{(2b)}$. Isocyanides $\text{(2a)}$ and $\text{(2b)}$ are cyclized to indole-3-carboxamides $\text{(3a)}$ and -3-thiocarboxamides $\text{(3b)}$ via lithiathion, respectively. Isocyanides $\text{2a}$ are also cyclized by Cu₂O catalyst to produce 4,5-dihydro-1,3-benzodiazepin-4-ones $\text{(4a)}$ with $\text{(3a)}$.     

Kinetics of the reaction of aluminum EDTA and cobalt(II) EDTA with calmagite

The reaction of aluminum EDTA with calmagite was found to be first-order in calmagite, half-order in aluminum EDTA, and zero-order in excess EDTA. The three-halves-order apparent rate constant at pH 9.48 and 20°C with ionic strength 0.30 was 0.232 ± 0.0141^{$\text{1}\text{2}$} · mol^{$\text{1}\text{2}$} · s^?1. The activation energy was 3.2 ± 0.3 kcal/mol. The pH dependence was complex between 8 and 10. The mechanism proposed is a rapid dissociation of a dimer of aluminum EDTA to a monomer followed by a rate-determining displacement of the EDTA by calmagite. The reaction of Co(II) EDTA with calmagite was confirmed to be first-order in Co(II) EDTA and first-order in calmagite with an activation energy of 7.5 ± 0.6 kcal/mol.