The synthesis and spectroscopic examination of telluronium salts based on the 1-organo-3,4-benzo-1-telluracyclopentane cation

The syntheses of a new range of telluronium salts based on the 1-organo-3,4-benzo-1-telluracyclopentane cation are reported (C₈H₈TeRX: R  CH₃, CH₂CH₃, X  I; R  CH₃, X  PhCOO; R  CH₃, X  ClO₄; R  CH₃, X  BPh₄; R  Ph, X  BPh₄; R  CH₂Ph, CH₂CHCH₂, CH₂COPh, X  Br.) Solution studies using ¹H, ¹³C and ¹²⁵Te NMR spectroscopy in conjunction with conductivity and molecular weight measurements show the salts to be associated via weak “ionic” bonds in solvents of lower polarity such as chloroform but to be more ionic and strongly solvated in DMSO. Solvents such as DMF provide an intermediate and more complex situation.Mass spectra indicate that association can extend to the gas phase and some novel features in the spectra are discussed. Infrared studies indicate polymorphism for 1-methyl-3,4-benzo-1-telluracyclopentane perchlorate with one form containing perchlorate ions interacting with tellurium.     

The partial hydrogenation of small unsaturated molecules by osmium cluster compounds. The reaction of diispropylcarbodiimide with H2Os3(CO)10

The products (μ-H)[μ-η²-(CH₃)₂CHNHCNCH(CH₃)₂]Os₃(CO)₁₀, I, and (μ-H)- [μ-η²-(CH₃)₂CHNHCO]Os₃(CO)₉[CNCH(CH₃)₂], II have been obtained from the reaction of H₂Os₃(CO)₁₀ with diisopropylcarbodiimine. Both products have been investigated by infrared and ¹H NMR spectroscopies, and by single crystal X-ray diffraction analyses. For I: Space group, P2₁/c, a12.840(4), b  15.724(4), c 12.638(4) Å, β 106.91(2)°, V  2441(2) ų, Z4, ? calc  2.66 g/cc. For 2869 reflections, R  0.051 and R_w  0.052. I contains an N-hydrido, N-isopropylamidinyl ligand bridging one edge of a triangular cluster of three osmium atoms. It was apparently formed by the incorporation of one carbodiimide molecule into the coordination sphere of the cluster followed by the transfer of one hydride ligand to one of the nitrogen atoms. For II: Space group P2 ₁/n;a  13.936(7), b  12.146(2), c  15.509(6) Å, β  105.20(4)°, V  2533(3) Å, Z  4, ?calc  2.57 g/cc. For 3065 reflections, R  0.052 and R_w  0.057. II contains an N-hydrido, N-isopropylformamido ligand bridging one edge of a triangular cluster of three osmium atoms and an isopropylisocyanide ligand. The molecule appears to have been formed by the cleavage of an NCH(CH₃)₂ moeity from one carbodiimide molecule and the transfer of it together with one hydride ligand to the carbon atom of a carbonyl group. The resultant formamido ligand bridges an edge of the cluster. The remaining fragment of the carbodiimide molecule bonds to one of the metal atoms of the cluster as a terminal isocyanide ligand. When heated, I loses one mole of carbon monoxide and forms the new cluster complex (μ-H)[μ₃-η²-(CH₃)₂CHNHCNCH-(CH₃)₂]Os₃(CO)₉ III. On the basis of electron counting schemes, III is believed to contain a triply-bridging amidinyl ligand serving as a five electron donor. Most importantly, no II was formed from I indicating that it is not a precursor -to II. A mechanism for the formation of I and II is presented and discussed.     

Structural study of iron carbonyl derivatives: IV. Synthesis and crystal and molecular structure of syn-[μ-(SCH3)Fe(CO)2P(CH3)3]2

Dimeric palladium(I) complexes of the type [μ-(η³-C₅H₅)-μ-XPd₂(PR₃)₂](X  Br, R  i-Pr, Ph, Cy; X  Cl, I, R  i-Pr) have been prepared by reduction of the complexes [(ν⁵-C₅H₅)(PR₃)PdX] with a variety of reducing agents (Mg,Na/Hg, LiAlH(t-BuO)₃, LiAlH₄, NaBH₄, n-BuMgBr). PMR and IR data and some properties of the new complexes are reported.     

The 31P NMR spectra of ArCr(CO)2P(C6H5)3 compounds in neutral and acidic media

The ³¹P NMR spectra of C₆H₅XCr(CO)₂P(C₆H₅)₃ (X = H, CH₃, OCH₃, N(CH₃)₂, COOCH₃) (I), p-C₆H₄X₂Cr(CO)₂P(C₆H₅)₃ (X = COOCH₃)(II) and C₆H₃X₃Cr(CO)₂P(C₆H₅)₃ (X = CH₃) (III) complexes in neutral and acidic media were investigated. The protonation of complexes I and III in trifluoroacetic acid results in the greater upfield shielding of ³¹P{¹H} signal. In this case the complexes I (X = H, CH₃, OCH₃) are completely protonated at the metal, complex I (X = COOCH₃)is partially protonated, while no protonation occurs in the case of complex II.Temperature-dependence of the ³¹P{¹H} NMR spectra was investigated for complexes I (X = H, OCH₃) in a 1/10 mixture of trifluoroacetic acid and toluene and for complexes I (X = COOCH₃) and II in trifluoroacetic acid. The degree of protonation was found to increase with decreasing temperature.     

Cleavage of iron2-alkenyl and iron2-alkynyl bonds by mercury(II) chloride

Reactions of HgCl₂ with η⁵-C₅H₅Fe(CO)₂R (R  CH₂CHCH₂ and CH₂C(CH₃)CH₂) in THF at 25°C rapidly afford $\text{1}\text{1}$ adducts of the two reactants. These adducts were converted to the corresponding PF₆^? salts, [η⁵-C₅H₅Fe(CO)₂(η²-CH₂C(R)CH₂HgCl)]⁺ PF₆^? (R  H and CH₃), for characterization. Slower reactions with cleavage of the ironcarbon σ bond and elimination of the R group from η⁵-C₅H₅Fe(CO)₂R occur for R  CH₂CHC(CH₃)₂, CH₂CHCHC₆H₅, and CH₂CCC₆H₅. Both elimination and $\text{1}\text{1}$ adduct formation are observed when R  CH₂CHCHCH₃. The kinetics of the cleavage reactions are presented and possible mechanisms for both cleavage and $\text{1}\text{1}$ adduct formation are discussed.     

Reactions and properties of some trimethyleneplatinum(IV) complexes: X. Reaction with iodide and thiocyanate ions

The reaction between the platinacyclobutanes [$\text{PtX}{}_2\text{(CH}{}_2\text{CRR′C}$H₂)L₂] (X  Cl, Br; L  C₅H₅N, 4-CH₃C₅H₄N; R, R′  H, CH₃; R  H, R′  CH₃, C₆H₅) and iodide and thiocyanate ions in methyl cyanide solution has been studied. The C₃ moiety is eliminated as the cyclopropane and the process is first order with respect to the platinacyclobutanes and zero to half order with respect to the salt (MY). With the iodides the rate increases in the order Li < Na < K, Et₄N, and methyl substitution in the cyclobutane ring reduces the rate of reaction with Et₄NI. Added pyridine retards the reaction when L  C₅H₅N (X  Cl; R, R′  H) and added dimethylsulphoxide accelerates it.The mechanism suggested involves dissociation of an L ligand and attack of Y^? ions and of M⁺Y^? ion pairs on the five-coordinate intermediate formed.     

Disubstituted vinylidene complexes of iron and ruthenium: nucleophilic properties of ν1-acetylide ligands

The η¹-acetylide complexes (C₅H₅)ML₂(CCR) (M  Fe, Ru; L  PPh₃, L₂  Ph₂PCH₂CH₂PPh₂) are nucleophilic at the β-carbon and react with a variety of mild electrophiles to yield the corresponding disubstituted vinylidene complexes [(C₅H₅)ML₂ (CCR′) PF₆.     

S,N,N′-Substituted sulfurdiimines as ligands: II. Compounds [(ν3-RC3H4)Pd{R1NS(R2)NR1}] (R  H,CH3;R1  aryl; R2  CH3, t-C4H9) and some related triazenido and amidino compounds of palladium(II)

The complexes [(ν³-RC₃H₄)Pd{R¹NS(R²)NR¹}] (R  H, CH₃;R¹  aryl; R²  CH₃, t-C₄H₉) have been obtained from the reaction of [(ν³-RC₃H₄)PdCl]₂ with [Li{R¹NS(R²)NR¹}]; two isomers are produced, differing in the orientation of the allyl group. The sulfurdiimino group has some π-allylic character. The compounds decompose in solution into azo—arenes and [(ν³-RC₃H₄)Pd(SR²)]₂, and this is shown to be dependent upon steric and electronic factors.The properties of the sulfurdiimino compounds are compared with those of the compounds [(ν³-RC₃H₄)Pd(R³N₃R³)]₂ and [(ν³-RC₃H₄)Pd(R³NC(R⁴)NR³)]₂ (R  H, CH₃;R³  CH₃, aryl; R⁴  H, CH₃), which have been prepared by new methods.     

Errata

Treatment of 1,1,4,4-tetramethyl-1,4-distanna-2,5-cyclohexadiene with organoboron dihalides or boron trihalides generally leads to organoboron polymers and (CH₃)₂SnX₂ (X  Cl, Br). Ferrocenyldibromoborane, FcBBr₂ (Fc  (C₅H₅)Fe(C₅H₄)), reacts atypically with formation of FcB(CH  CH)₂BFc, which on controlled methanolysis affords CH₃OB(CH  CH)₂BOCH₃. The new 1,4- dibora-2,5-cyclohexadienes are characterized as nickel complexes Ni[FcB(CH  CH)₂BFc](CO)₂ and Ni[CH₃OB(CH CH)₂BOCH₃]₂, respectively.     

Properties and reactivity in groups of the periodic system: Ion-molecule reactions CH3X + CH3X+· (X = F through At)

The reactions indicated in the title have been studied in terms of direct processes and complex formation. Quantum-chemical methods have been applied to the passage of an acid (H⁺, CH, X⁺) from CH₃X^+· to CH₃X, and the abstraction of a radical (H^· CH, X^·) from CH₃X by CH₃X^+·. It has been shown that a complex represented by a dimer of a methyl-halide radical cation, (CH₃X), with a two-center three-electron bond X? X, has fairly high stability. These investigations were based on non-empirical quantum-chemical calculations, the results being systematically compared with experimental determinations. Some calculations included all electrons (X=F, Cl, Br), others were based on relativistic pseudopotentials (X=F through At). The two sets of calculations agree qualitatively with each other and with experimental observations.     

Synthesis, structure of functionalized N-heterocyclic carbene complexes of Fe(II) and their catalytic activity for ring-opening polymerization of ε-caprolactone

The reaction of anhydrous FeBr₂ with two equivalents of in situ generated anionic aryloxo-functionalized N-heterocyclic carbene [NaO-4,6-di-C(CH₃)₃-C₆H₂-2-CH₂{C(NCHCHNR)}] (R = CH(CH₃)₂, NaL¹; R = CH₂Ph, NaL²) affords two bis-ligand Fe(II) complexes (1) and (2) in good yield, respectively. Attempt to synthesize mono-ligand Fe(II) bromide by the 1:1 molar ratio of NaL to FeBr₂ is unsuccessful, the same complexes of 1 and 2 were obtained. Both of 1 and 2 have been fully characterized by elemental analysis, ¹H NMR spectra and X-ray structure determination. Preliminary studies show that 1 can catalyze the ring-opening polymerization of ε-caprolactone as a single component catalyst. The mechanism of the present ROP of ε-caprolactone has been investigated by the end group analysis.     

Zur reaktion von metall-koordiniertem kohlenmonoxid mit yliden: XII. Eisenkomplexe mit η1-koordinierter vinylgruppe: spontane zweif achmethylierung des β-kohlenstoffs mit methyliodid oder methylfluorsulfonsäureerster

The reaction of vinyl complexes Cp(CO)(R₃P)FeC(OMe)CH₂ (R  Me, R  Ph) with the methylating reagents MeX (X  OSO₂F, I) in the molar ratio 1/1 affords a mixture of the carbene complexes [Cp(CO)(R₃P)FeC(OMe)R]X (R  Me, Et, i-Pr). Their formation is explained via a series of acid/base equilibria established between vinyl and carbene complexes.     

Carbamoyl and alkoxycarbonyl complexes of palladium(II) and platinum(II)

Carbamoyl and alkoxycarbonyl complexes of palladium(II) and platinum(II) of the type M(pnp)(CONHR)Cl (pnp = 2,6-bis(diphenylphosphinomethyl)pyridine; M Pd, R  C₆H₅, p-CH₃C₆H₄, p-CH₃OC₆H₄, C₆H₁₁, t-Bu; M  Pt, R  C₆H₅), Pd(pnp)[CON(Pr)₂]Cl (Pr = propyl), M(pnp)(COOR)Cl (M  Pd, R  C₆H₅, CH₃; M  Pt, R  CH₃), Pd(pnp)(COOCH₃)₂ result from reaction of M(pnp)Cl₂ with carbon monoxide and amines or alkoxides at room temperature and atmospheric pressure.The carbamoyl complexes react with bases to give urethane or diphenylurea depending upon the experimental conditions.     

STUDIES ON THE BACTERIAL ACTIVITY OF COBALT(III) COMPLEXES. PART III. COBALT(III) CARBOXYLATE COMPLEXES

Abstract

Cobalt(III) complexes of the type [Co(en)₂(chel)]X.nH₂O where en = ethylenediamine, chel = phthalato = C₆H₄CO₂)^2? ₂, maleato = (O₂CCH = CHCO₂)^2?, succinato = (O₂CCH₂CH₂CO₂)^2?, homophthalato = (O₂CC₆H₄(CH₂)CO₂)^2?, citraconato = (O₂CC(CH₃) = CHCO₂)^2?, itaconato = (CH₂ = C(CO₂)CH₂CO₂)^2?, X = NO^? ₃, Br^?, (O₂CC₆H₄CO₂H)^?, (O₂CHC = CHCO₂H)^?, (O₂C(CH₂)₂CO₂H)^?, (O₂CC₆H₄(CH₂)CO₂H)^?, (O₂CHC = C(CH₂)-CO₂H)^?, and (O₂C-CH₂?C(= CH₂)-CO₂H)^?, [Co(en)₂(malonato)]X.2H₂O (where malonato = (O₂CCH₂CO₂)^2?, X = Cl^?, Br^?, and NO^? ₃) and [Co(en)₂CO₃]Cl.2H₂O have been investigated for their bacterial activity against Escherichia coli B growing on EMB agar and in minimal glucose media both in lag and log phases. Among the most active are where chel = phthalato and homophthalato. The effects are distinct from those known for compounds of Pt, e.g., cis?[Pt(NH₃)₂Cl₂] and rhodium, e.g., trans?[Rh(C₅H₅N)₄,Cl₂].6H₂O. Antagonisms are reported.     

A theoretical study of the elimination process of methane from a platinum complex

A theoretical analysis of the dissociative reaction cis-PtH(CH₃)(PX₃)₂ → Pt(PX₃)₂ + CH₄ is presented. Several aspects of the effect on the mechanism of this reductive elimination when the substituent X is changed (X₃  (CH₃)₃, case I and X₃  CH₂Cl(CH₃)₂, case II), are considered and compared with the corresponding experimental facts. This indicates the following: the kinetic barrier for case I is small and even if a concerted mechanism is implied, an almost spontaneous process is strongly indicated. The activation energy is lowered in case II, where the presence of an electronegative substituent makes even easier the performance of a spontaneous process. The study of the reaction pathway was carried out through an Extended Hückel calculation.     

Bond energies and thermal decomposition of [Pt(X)(CH3)(P(C2H5)3)2] complexes

The thermal decomposition of the complexes trans-[Pt(X)(CH₃)L₂] (L  P(C₂H₅)₃; X  Cl, Br, I, CN) in decalin at 170 and 200°C affords methane platinum metal and [Pt(X)₂L₂]. The kinetics of the decomposition of the complexes were determined by monitoring the appearance of methane by GLC. The observed first-order rate constant was found to be independent on the nature of the ligand X. The thermal decomposition of the trideuteriomethyl complexes [Pt(X)(CD₃)L₂] (X  I, CN) in decalin-d₁₈ at 170 and 200°C was studied by GLC/MS. The thermolysis affords CD₃H and CD₄ in ratios which are independent of the nature of X and of the temperature used. The mass spectra of the complexes were also examined. A relative scale of platinum-to-methyl bond dissociation energies has been established by measuring the appearance potential of the fragment ion [Pt(X)L₂]⁺ and the ionization energies in the series [Pt(X)(CH₃)L₂]. Ionization potentials and PtCH₃ bond energies show a clear dependence on the nature of X which is not reflected in corresponding changes in the decomposition rates.     

Hyperfine Shifts of the 13C-NMR. in Protoporphyrin IX Iron (III) Dicyanide and Deuteroporphyrin IX Iron (III) Dicyanide

The ¹³C-NMR. in Zn(II) (Protoporphyrin IX), Fe(III) (Protoporphrin IX) (CN)₂, Zn(II) (Deuteroporphyrin IX dimethylester), and Fe(III) (Deuteroporphyrin IX) (CN)₂ have been identified, and the ¹³C hyperfine shifts in the iron complexes evaluated. In a partial analysis of these data the parameters Q^H, Q_CCH^H, and Q_C′CH^C, which characterize the isotropic coupling through hyperconjugation between the ¹H and ¹³C nuclei of the porphyrin side chains and the unpaired electron spin density on the aromatic ring carbon atoms, have been re-examined. This paper is part of an investigation of the electronic states in low spin ferric hemes and hemoproteins, and the relations between the electronic structures and the biological roles of these molecules.     

Relative kinetics of the radical addition of benzyl bromide to unsaturated compounds

The relative rate constants of the addition of the C₆H₅CH₂ radical to unsaturated compounds CH₂=CHX (X = C₄H₉, SiMe₃, CF₃, CO₂Me, CN) were determined under the conditions of initiation by the Fe(CO)₅ + DMF system or by benzoyl peroxide. Depending on the values of the relative addition rate constants, the monomers can be arranged into the following series (X): CF₃C₄H₉32Me5 + DMF system, the addition stage proceeds by a free radical mechanism.A. N. Nesmeyanov Institute of Heteroorganic Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 2017–2022, September, 1992.