Reaction Behavior of Decacarbonyldimetalates(2‐) (M = Cr and Mo) towards the Nitrosyl Carbonyls of Iron and Cobalt

The reaction of the nitrosyl carbonyl complexes [Fe(NO)₂(CO)₂] and [Co(NO)(CO)₃] with the decacarbonyldimetalates [M₂(CO)₁₀]^2– (M = Cr and Mo) in THF as the solvent at room temperature was investigated. Thereby a substitution of one nitrosyl ligand towards carbon monoxide was observed in each case. Both reactions afforded the known metalate complexes [Fe(NO)(CO)₃]^– and [Co(CO)₄]^–, respectively. These species were isolated as their corresponding PPN salts [PPN⁺ = bis(triphenylphosphane)iminium cation] in nearly quantitative yields. The products were unambiguously identified by their IR spectroscopic and elemental analytic data as well as by their characteristic colors and melting points.     

η-C5H5(CO)LFe-substituted imidates of acrylic acid. Synthesis and structure

Ethylation of Cp(CO)₂FeCHCHCONR₂ (I) yields the imidates [Cp(CO)₂FeCHCHC(OEt)NR₂]⁺X^? (II). A photochemical reaction between I and PPh₃ yields Cp(CO)(PPh₃)FeCHCHCHCONR₂ (III) from which the corresponding imidates (IV) can be obtained.Spectral data suggest that the positive charge in II and IV is localized mainly at the imidate group and that the participation of the Cp(CO)LFe substituent in the stabilization of the positive charge is insignificant, particularly in the case of cations lI.This conclusion is confirmed by X-ray analysis of IIb. Determination of the exact structure of IIb also reveals the absence of a direct interaction between the metal and the cationic center even though the complex has cis geometry. A reaction between Ic and Fe₂(CO)₉ yields a binuclear complex (IV). The initial complexes I were obtained by substitution of the anion [CpFe(CO)₂]^? for chlorine in ClCHCHCONR₂. These reactions are stereospecific.     

First steps of the reactions of alkanes and arenes with adamantyl cations in sulfuric acid in comparison with other reagents

Solutions of 1-adamantanol in sulfuric acid at T < 100 °C interact with alkanes (RH, [H₂SO₄] > 85%) and arenes (ArH, [H₂SO₄] > 59%). The data on the kinetics, kinetic isotope effect (KIE), effects of the structure of RH and ArH and acidity of the medium, and the observation of 1,4-cis-dimethylcyclohexane isomerization indicate that adamanyl cations (Ad⁺) serve as reactive species. In the reactions with alkanes, the Ad⁺ cation abstracts the hydride ion from RH in the rate-determining step. Compensation dependences appear between the activaion parameters for the KIE and “effect 5/6” (ratio of the rate constants for the C–H bond cleavage in cyclopentane and cyclohexane) in the reactions of cycloalkanes with Ad⁺ and other electrophilic reagents, such as “anthracene” (An₂)H⁺ and hydroxymethyl (CH₂OH)⁺ cations and Hg^II ions, including the points of the lower selectivity limit (k _H/k _D) = 1.4, (“5/6”) = 1. In the reactions with the Ad⁺ cation, the bond selectivity 3⁰: 2⁰ of alkanes is higher, while 2⁰: 2⁰ is lower compared to other reagents. In the first case, the selectivity is probably determined predominantly by the energies of the cleaved C–H bonds, whereas in the second case it is determined by steric hindrances. Judging by the kinetic and selectivity data in the series benzene—toluene—o-xylene—m-xylene and the absence of the reaction with p-xylene, mesitylene, and pseudocumene, it can be concluded that the main contribution to the Ad⁺ + ArH interaction is made by adamantylation to the para- and meta-positions of the benzene ring, whereas the ortho-positions are inaccessible to the attack because of steric hindrances. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1581–1596, August, 2008.     

Synthesis of Bis(tricarbonylcyclopentadienylmolybdenum)bismuth(III) Chloride and Its Reaction with Metals

Polynuclear organometallic compounds [CpMo(CO)₃]₂BiCl and [CpMo(CO)₃]BiCl₂ were prepared by reaction of bismuth with tricarbonylcyclopentadienylmolybdenum chloride in dimethyl sulfoxide (DMSO). [CpMo(CO)₃]₂BiCl is reduced with magnesium or indium in tetrahydrofuran to give bismuth, [CpMo(CO)₃]₃Bi, and magnesium or indium chloride. In the presence of DMSO, the reaction of [CpMo(CO)₃]₂BiCl with magnesium or indium yields bismuth and the organomolybdenum derivative of magnesium or lithium, respectively.     

Zur reaktion von metall-koordiniertem kohlenmonoxid mit yliden: XXI. Ambidentes verhalten von eisenacyl-phosphor-yliden gegenüber methylfluorsulfonsäureester: Umwandlung in eisenacyl-phosphoniumsalze oder β-phosphoniovinyl- eisenkomplexe

]The reaction of the acyliron phosphorus ylide Cp(CO)₂FeC(O)CHPMe₃ with MeOSO₂F yields the acyliron phosphonium salt [Cp(CO)₂FeC(O)C(Me)- HPMe₃]SO₃F, while Cp(CO)₂FeC(O)C(Me)PEt₃ undergoes exclusively O-alkylation to the complex salt [Cp(CO)₂FeC(OMe)C(Me)PEt₃]SO₃F, (A). The acyliron ylides Cp(CO)₂FeC(O)C(R)PR₃ (R  R′  Me; or R  H, R′  Et) are converted to a mixture of the O- and C-methylated products. According to spectroscopic data and X-ray diffraction analysis of A the O- alkylation products have to be described as phosphoniovinyliron complexes.     

Organometallic chemistry in a conventional microwave oven: the facile synthesis of group 6 carbonyl complexes

Syntheses proceeding by reflux may be improved, accelerated and simplified, by carrying out the reaction in a modified conventional microwave oven. To demonstrate the potential of this method, the synthesis of over 20 group 6 organometallic compounds is reported. Hexacarbonyls, most notably Mo(CO)₆, react with a range of mono, and bi, and tridentate ligands in a modified conventional microwave oven. They generally proceed without an inert atmosphere, yields are high and reaction times are short. For example, cis-[Mo(CO)₄(dppe)] is prepared in >95% yield in 20 min. Reaction of Mo(CO)₆ with dicyclopentadiene affords a simple one-step synthesis of [CpMo(CO)₃]₂ in >90% yield, which reacts further with alkynes in toluene to produce dimetallatetrahedrane derivatives, [Cp₂Mo₂(CO)₄(μ-RC₂R)]; presumably via the in situ formation of air-sensitive [CpMo(CO)₂]₂. Dimolybdenum tetra-acetate is also prepared in 48% yield in 45 min, however, this reaction requires an inert atmosphere. While W(CO)₆ reacts rapidly with amines to give cis diamine adducts in high yields, direct reactions with phosphines are not so clean. Bis(phosphine) complexes are, however, cleanly formed when a small amount of piperidine is added to the reaction mixture, presumably via the bis(piperidine) complex cis-[W(CO)₄(pip)₂]. Reactions with Cr(CO)₆ generally require an inert atmosphere and proceed less cleanly, although the important synthon [Cr(CO)₅Cl][NEt₄] was prepared in 30 min (74% yield), while [(η⁶-C₆H₅OMe)Cr(CO)₃] can be prepared in 45% after 4 h.     

NSF3 und NSF2NMe2 als Liganden in der metallorganischen Chemie

Thiazyltrifluoride NSF₃ and Thiazyldifluoridedimethylamide NSF₂NMe₂: Ligands in Organometallic Chemistry From the reaction of [Re(CO)₅SO₂]⁺AsF₆^? ( 1 ) and [CpFe(CO)₂SO₂]⁺AsF₆^? ( 6 ) with NSF₃ ( 2 ) and NSF₂NMe₂ ( 4 ) the complexes [Re(CO)₅NSF₃]⁺AsF₆^? ( 3 ), [Re(CO)₅NSF₂NMe₂]⁺AsF₆^? ( 5 ), [CpFe(CO)₂NSF₃]⁺AsF₆^? ( 7 ), and [CpFe(CO)₂NSF₂NMe₂]⁺AsF₆^? ( 8 ) were obtained. The compounds have been characterised by X-ray crystallography, the ligand properties of 2 and 4 are discussed.     

Metallkomplexe mit anionischen Liganden von Elementen der 4. Hauptgruppe. IX. Zum komplexchemischen Verhalten von Trichlorstannid-und Trichlorgermid-Ionen gegenüber Komplexen von Übergangsmetallen in niedrigen Oxydationsstufen

Metal Complexes with Anionic Ligands of the Main Group IV Elements. IX. Reactions of Trichlorostannide and Trichlorogermide Ions with Complexes of Transition Metals in Low Oxidation States Carhonyl trichlorostannido- and carbonyl trichlorogermido-metalate complexes have been synthesized both by photochemical and thermical substitution reactions of [ECl₃]^? ions (E = Sn, Ge) with M(CO)₆, (M = Cr, Mo, W), Fe(CO)₅ Fe₃(CO)₁₂, Co₂(CO)₈, as well as with the metalcarbonyl derivatives (π-arene)M(CO)₃, (M = Cr, Mo), (h⁵-C₅,H₅,)V(CO)₄, Mn(CO)₅,Cl, Co(NO)(CO)₃, and Fe(NO)₂,(CO)₂. Mainly the bonding properties of the [ECl₃]^? ligands are discussed by means of i.r. spectroscopic investigations. The progress of the reactions and the necessary reaction conditions show that the nucleophilic properties oft both anions [ECl₃]^? are unexpectedly small. The slightly weaker hasicity of [SnCl₃]^? compared with [GeC1₃]^? arreared, when both anions were reacted with Co₂,(CO)₈, forming the substitution product. [Co₂,(CO)₇,SnCl₃]^? and the products of a “base reaction” Cl₃GcCo(CO)₄, and [Co(CO)₄]^?.     

Gas-phase chemistry of electron deficient organometallic anions: the reactions of [Cr(CO)3]− ˙ and [Cr(CO)4]− ˙ with aldehydes,ketones, esters and ethers

Reactions in the gas phase of the 13- and 15-electron radical anions [Cr(CO)₃]^{? ˙} and [Cr(CO)₄]^{? ˙} with a series of 27 aldehydes, ketones, esters and ethers have been examined. Sequential alkane eliminations and metal-bonded CO ligand displacements were the principal reactions identified for the RCHO/[Cr(CO)₃]^{? ˙} systems with the latter reaction also common to the RCHO/[Cr(CO)₄]^{? ˙} systems. While [Cr(CO)₄]^{? ˙} was generally unreactive towards ketones R · R'CO, the principal products identified for [Cr(CO)₃]^{? ˙}/ketone reactions were the metal-decarbonylated species, respectively [R · R'CO · Cr(CO)_x]^{? ˙} with x = 0–3, and [R · (R' - H₂)CO · Cr(CO)₂]^{? ˙}. The reaction of [Cr(CO)₃]^{? ˙} with esters RCOOR' proceeds via metal insertion into the alkoxy C? O bond to give end products of the type [R'O · Cr · R(CO)₂]^? and [R'O? Cr(CO)₃]^? while the sole ionic products of dialkyl ether/[Cr(CO)₃]^{? ˙} reactions were identified as the alkoxytricarbonylchromium species [RO · Cr(CO)₃]^?.     

Mechanistic Study of Oxidation of Palladium(II) by Cerium(IV) in Aqueous Acid

The kinetics of oxidation of Pd^II by Ce^IV have been studied spectrophotometrically in HClO₄ media at 40 °C. The reaction is first order each in [Ce^IV] and [Pd^II] at constant [H⁺]. Increasing [H⁺] accelerates the reaction rate with fractional order in [H⁺]. The initially added products, palladium(IV) and cerium(III) do not have any significant effect on the reaction rate. At constant acidity, increasing the added chloride concentration enhances the rate of reaction. H₃Ce(SO₄)₄⁻ and PdCl₄²⁻ are the active species of oxidant and reductant respectively. The possible mechanisms are proposed and the reaction constants involved have been determined.     

Haloalkyl complexes of the transition metals : II. Some new chloromethyl and methoxymethyl complexes of manganese,rhenium and ruthenium

The reactions of Na[Mn(CO)₅] or Na[Mn(CO)₄(PPh₃)] with CH₂ClI yield the new chloromethyl complexes Mn(CO)₅CH₂Cl and Mn(CO)₄(PPh₃)CH₂Cl. Reaction of Na[Re(CO)₅] or Na[CpRu(CO)₂] with ClCH₂OMe yields Re(CO)₅CH₂Cl and CpRu(CO)₂CH₂Cl respectively, in addition to the corresponding methoxymethyl complexes (Cp = η⁵-C₅H₅). Reaction of CpRu(CO)₂CH₂OMe with HCl yields the corresponding chloromethyl complex.     

Comparative studies of the photochemical and thermal reactivities of the molybdenum-molybdenum single bond in [Mo2(η5-C5H5)2(CO)6] and triple bond in [Mo2(η5-C5H5)2(CO)4] towards nitrite and nitrate

Irradiation at λ = 507 and 391 nm of [Mo₂(η⁵-C₅H₅)₂(CO)₆] in a degassed tetrahydrofuran (THF) or THF-MeOH solution containing nitrite gives [Mo(η⁵-C₅H₅)₂NO] and several oxo complexes including [{Mo(η⁵-C₅H₅)(O)₂}₂O] in good yields. The quantum yields for the disappearance of [Mo₂(η⁵-C₅H₅)₂(CO)₆] in the reaction with NO₂⁻ depend on the nitrite concentration, thus suggesting participation of the metal-radical intermediate in the reduction of nitrite. Reactions of [Mo₂(η⁵-C₅H₅)₂(CO)₄] with nitrite or nitrate in the dark give the same nitrosyl and oxo complexes as above. An oxygen atom in nitrite or nitrate is mainly transferred onto the molybdenum atom both in the photochemical and the dark reactions.     

Syntheses of indolo[3,2,1-d,e]phenanthridines and isochromeno[3,4-a] carbazoles: palladium catalyzed intramolecular arylation via C-H functionalization

A new synthetic route has been developed for the preparation of indolo[3,2,1-d,e]phenanthridines and isochromeno[3,4-a]carbazoles via palladium catalyzed intramolecular biaryl coupling reactions. The coupling reactions proceeded smoothly and in high yields under ligand-free conditions with the catalytic system Pd(OAc)₂/Cs₂CO₃/TBAB. Under optimized reaction conditions no halogen-reduced products were observed.     

Reactions of nitrosonium ion with anionic carbonyl monomers and clusters. Crystal and molecular structure of FeCo2(μ3-NH)(CO)9

The reactions of several mono- and poly-nuclear carbonyl metallates with nitrosonium ion have been studied. Besides simple substitution of a carbon monoxide with NO⁺ some reactions yielded products containing other nitrogeneous ligands. When [CoRu₃(CO)₁₃]^? reacts with NO⁺, low yields of the new nitrido cluster CoRu₃N(CO)₁₂ are formed. Prior conversion of [CoRu₃(CO)₁₃]^? to the new hydrido cluster [H₂CoRu₃(CO)₁₂]^? under hydrogen, followed by nitrosylation, forms the new imido cluster H₂Ru₃(NH)(CO)₉ in very low yield. The reaction of [FeCO₃(CO)₁₂]^? with NO⁺ also generates an imido cluster, FeCo₂(NH)(CO)₉, in 15% yield. This cluster has been characterized by X-ray crystallography and was found to be similar to the tricobalt alkylidyne clusters. (Triclinic crystal system, P$\text{1}$ space group, Z=2, a 6.787(1), b 8.016(1), c 13.881(2) Å, α 95.50(1), β 100.77(1), γ 107.93(1)°. Modifications of the nitrosylations using NO⁺ were studied. In particular, the addition of triethylamine or N-t-butylbenzaldimine allowed the use of NO⁺ in THF without solvent decomposition. With [CpMo(CO)₃]^? and [CpFe(CO)₂]^? the N-nitrosoiminium species appears to form transient alkylmetals which further react to give the dimers [CpMo(CO)₃]₂ and [CpFe(CO)₂]₂.     

Carbonylate anion [(μ-H)Os<Subscript>3</Subscript>(CO)<Subscript>10</Subscript>L]<Superscript>−</Superscript> as a precursor in the synthesis of heterometallic Os<Subscript>3</Subscript>M clusters

A new method for the synthesis of heterometallic clusters Os₃M is developed. The reactions of hydridocarbonyl cluster (μ-H)₂Os₃(CO)₁₀ (I) with binuclear carbonyls Co₂(CO)₈ and Fe₂(CO)₉ in the presence of 1,4-diazabicyclo[2.2.2]octane (Dabco) afford anionic complexes [Os₃Co(CO)₁₃]⁻ (II) and [HOs₃Fe(CO)₁₃] (III) with the counterion N₂C₆H₁₃⁺. Similar reactions with halide complexes [MCp*Cl₂]₂ (M = Rh and Ir) yield neutral complexes [Os₃M(CO)₁₀(μ-H)(μ-Cl)] (M = Rh(IV) and Ir(V)). The reactions occur rapidly at room temperature with high yields. The newly obtained clusters are characterized by the data of IR and ¹H NMR spectroscopy, elemental analysis, and X-ray diffraction analysis.     

An Efficient and Green One‐pot Synthesis of 12‐Aryl‐8,9,10,12‐tetrahydrobenzo[a]xanthen‐11‐one Derivatives Promoted by Sulfamic Acid in [BMIM]BF4 Ionic Liquid

An efficient and green procedure for the synthesis of novel 12‐aryl‐8,9,10,12‐tetrahydrobenzo[a]xanthen‐11‐one derivatives has been described through one‐pot condensation of 2‐naphthol, arylaldehyde and 5,5‐dimethyl‐cyclohexane‐1,3‐dione in the presence of sulfamic acid (NH₂SO₃H) in ionic liquid 1‐n‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIM]BF₄). These reactions proceed with good yields under short reaction time. Furthermore, the green catalytic system can be recycled specific times with no decreases in yields and reaction rates.     

Umsetzungen einiger Schwefel-Fluor-Verbindungen mit Verbindungen von übergangsmetallen; Darstellung und spektroskopische Untersuchung von Sulfito-Komplexen mit MnII,Mo0 und W0

Reactions of some Sulfur-Fluorine Compounds with Compounds of Transition Metals; Synthesis and Spectroscopic Investigation of Sulfito Complexes, involving Mn^II, Mo⁰, and W⁰ In the oxidative addition reactions of sulfuryl fluoride ( 1 ) and of methanesulphonic acid fluoride ( 2 ) with η²-ethylene-bis(triphenylphosphine)platinum(0) the novel ionic binuclear tetrakis(triphenylphosphine)-(μ-fluoro)-(μ-peroxo)-platinum(II)-fluorosulfonate and -methylsulfonate complexes 3 a and 3 b were formed. O,O-Sulfito-manganese(II) tricarbonyl 5 a and the binuclear μ-disulfito-dimanganese decacarbonyl complex 6 a were obtained in the reaction of disulfuryl difluoride ( 4 ) with the carbonyl metalate complex, Na⁺[Mn(CO)₅]^?. In this redox reaction several further products (e.g., CO, SO₂F₂ ( 1 ) and Mn₂(CO)₁₀) were formed and were determined quantitatively. In the presence of acetonitrile the acetonitrile-O,O-sulfito-manganese(II) tricarbonyl complex 5 b was isolated. The new binuclear complexes, bis(η⁵-cyclopentadienyl)-μ-disulfito-dimetalhexacarbonyls ( 6 b : metal = Mo⁰ and 6 c : metal = W⁰) were obtained in the reaction of 4 with the carbonyl metalates Na⁺[CpM(CO)₃]^? (M?Mo¹, W¹; Cp = cyclopentadienyl). Further products (e.g., CO, SO₂F₂ ( 1 ) and [CpM(CO)₃]₂, M?Mo, W) were formed and were determined quantitatively. The validity of the concept of hard and soft acids and bases (HSAB-concept) and of the 18-valence-electron rule (18-VE-rule) could not be confirmed in all cases. The characterization of 3a, 3b, Sb, 6b and 6c was based on their IR and NMR spectra, and in one case, on the mass spectra ( 5b ). For 3a and 3b the dynamic behaviour at room temperature in CD₂Cl₂ and CD₃OD was studied by ³¹P-NMR spectroscopy. The results are interpreted in terms of exchange processes in solution between the coordinated μ-fluoride and the solvent ligand or the uncoordinated anion. 5a and 6a and the by-products (e.g., CO and SO₂F₂ ( l )), which were formed in the redox reactions, were identified by their infrared spectra.     

Synthesis,characterization, and metal complexes of polyacetylenes with pendant 2,2′‐bipyridyl groups

5‐Ethynyl‐2,2′‐bipyridine ( 1 ; bpyC≡CH) polymerized in the presence of catalytic amounts of [RhF(COD)(PPh₃)] or [Rh(μ‐OH)(COD)]₂ (COD = 1,5‐cyclooctadiene) in 74–91% yields. In contrast, [Rh(μ‐X)(NBD)]₂ (X = Cl or OMe; NBD = norbornadiene) did not catalyze the polymerization of 1 or gave low yields of the polymer. The obtained polymer, poly(5‐ethynyl‐2,2′‐bipyridine) [ 2 ; (bpyC?CH)_n], was highly stereoregular with a predominant cis–transoidal geometry. Random copolyacetylenes containing the 2,2′‐bipyridyl group with improved solubility in organic solvents were obtained by the treatment of a mixture of 1 and phenylacetylene ( 3 ) or 1‐ethynyl‐4‐n‐pentyl‐benzene with catalytic amounts of [RhF(COD)(PPh₃)]. A block copolymer of 1 and 3 was prepared by the addition of 1 to a poly(phenylacetylene) containing a living end. The reaction of 2 with [Mo(CO)₆] produced an insoluble polymer containing [Mo(CO)₄(bpy)] groups, whereas with [RuCl₂(bpy)₂] or [Ru(bpy)₂(CH₃COCH₃)₂](CF₃SO₃)₂, it gave soluble metal–polymer complexes containing [Ru(bpy)₃]²⁺ groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43:3167–3177, 2005     

Shock-tube studies of the reactions of NO2 with NO2, SO2, and CO

The thermal decomposition of NO₂ and its atom-transfer reactions with SO₂ and CO have been studied behind incident shock waves using photometric detection methods. From the decomposition study it is possible to obtain information on the rate of the reaction 2NO₂ → antisymmetric-NO₃ + NO. The results on the reaction, NO₂ + SO₂ → NO + SO₃ extend the earlier work of Armitage and Cullis to about 2000°K. The reaction with CO [NO₂ +] [CO NO + CO₂] at shock temperatures is somewhat faster than predicted from available low-temperature data and provides a modification of the rate-constant expression that is applicable over a wide temperature range.