Preparation and characterization of dichlorobis(N-alkyl-substituted salicylideneaminato)manganese(IV) complexes

A series of dichlorobis(N-alkyl-substituted salicylideneaminato)manganese(IV) complexes, Mn(N-R-Xsal)₂Cl₂, was prepared by the reaction of Mn(NRXsal)₂Cl complexes with hydrogen chloride, where R can be n-C₈H₁₇ (Oct), n-C₁₂H₂₅ (Dod), n-C₁₈H₃₇ (Octd), and CH₂C₆H₅ (Bz) and X can be 5-bromo, 5-nitro, and 5,6-benzo groups. These complexes were characterized by the magnetic susceptibilities, IR and electronic spectra, and cyclic voltammograms.     

A carbon-13 NMR study of some metal carbonyl compounds containing one-electron ligands

Carbon-13 NMR spectral data for complexes having the general formula CpM(CO)_nX (Cp = η⁵-C₅H₅; M = Mo or W, n = 3; M = Fe, n = 2; X = halogen, methyl or acetyl) and their phosphine and isocyanide substitution products are reported. For CpM(CO)₃X complexes two carbonyl resonances (1 : 2 ratio) are observed in all cases, consistent with the retention of the “piano-stool” geometries observed in the solid state. Substituted complexes CpM(CO)₂(L)X (M = Mo or W; L = PR₃ or cyclohexyl isocyanide) are unequivocally assigned cis or trans geometries on the basis of the number of observed carbonyl resonances and values of ²J(PC) for the phosphine substituted derivatives. Spectral data for [M(CO)₅X]^? (M = Cr, Mo or W; X = Cl, Br or I) and η⁷-C₇H₇Mo(CO)₂X and the halide derivatives above generally show an increase in the shielding for carbonyls adjacent to the halide ligand in the order Cl < Br < I. Carbonyl resonances are more shielded in isostructural complexes in the order Cr < Mo < W (triad effect).     

Constrained phosphite ester complexes of π-cyclopentadienylmolybdenum tricarbonyl halides

The synthesis of complexes of the type π-C₅H₅Mo(CO)₂LX and π-C₅H₅Mo(CO)L₂X, where XCl, Br, or I and LP(OCH₂)₃CR (RCH₃, C₂H₅, or C₃H₇), is reported. Infrared and conductance data verified that all compounds existed as covalent species in solution. Each of the three π-C₅H₅Mo(CO)₂LCl complexes was isolated as an inseparable mixture of cis and trans isomeric forms. Only the trans forms of the remaining π-C₅H₅Mo(CO)₂LX complexes were observed in solution, as indicated by infrared and PMR spectra. All of the π-C₅H₅Mo(CO)L₂X compounds apparently exist in primarily one isomeric form in solution; their PMR spectra, which exhibited a sharp triplet resonance for the ?OCH₂? protons of the phosphite ligands and a single sharp π-C₅H₅ proton signal, indicated a predominantly trans arrangement of the phosphite ligands at room temperature.     

Diorganotin(VI) complexes of N-acetylamino acids

Sixteen complexes of general formula R₂SnL₂ and R₂(L)SnOSn(L)R₂ (where L = N-acetyl-L-leucine or N-acetyl-L-phenylalanine) R = CH₃, C₂H₅, n-C₄H₉, or n-C₈H₁₇) have been prepared by interaction between the ligand and R₂SnO in 2:1 or 1:1 molar ratio. The complexes were characterized by IR, ₁H NMR and ¹¹⁹Sn Mössbauer spectroscopy. All the 2:1 complexes are assigned six-coordinate, distorted octahedral geometry with chelating carboxylate groups, while the 1:1 complexes have oxygen-bridged binuclear five-coordinate, trigonal-bipyramidal configurations. The amido ?CO and ?NH groups are hydrogen bonded in the solid state.     

The solid state structure of arene-mercury(II) complexes from magic-angle spinning carbon-13 NMR and the solution carbon-13 NMR of some complexes of mercury(II) with arenes having bulky aliphatic substituents

The cross-polarization magic angle spinning ¹³C NMR spectra of Hg(SbF₆)₂ - 2 Arene (Arene = C₆HMe₅, 1,2,4,5-C₆H₂Me₄, 1,2,3,4-C₆H₂Me₄, or C₆H₆) have been measured. The spectra of the complexes of C₆HMe₅ and 1,2,4,5-C₆H₂Me₄ are consistent with static η¹-bonding of the mercury to the arene at an unsubstituted carbon atom, while the spectra of the 1,2,3,4-C₆H₂Me₄ and C₆H₆ complexes show the arene to have time-averaged C_s or C₂, and C₆ symmetry respectively, at the temperature of measurement (300 K).The reduced temperature ¹³C NMR spectra of Hg(Arene)_n²⁺ (n = 1 or 2; Arene = 1,3,5-C₆H₃R₃ (R = Me, i-Pr, or t-Bu)) in SO₂ solution are also reported and affirm that in these intramolecularly mobile species the mercury bonds in an η¹-manner, with unsubstituted aryl carbon atoms being the strongly preferred point of mercury attachment. This site preference is further demonstrated by the solution ¹³C NMR spectra of Hg(Arene)_n²⁺ (Arene = 1,2,3,4-C₆H₂-Me₄, n = 1 or 2; Arene = 1,4-C₆H₄R₂, R = Me or t-Bu, n = 1). The spectra of the 1,4-C₆H₄R₂ complexes and Hg(p-C₆H₄-t-BuMe)²⁺ provide clear evidence for steric influence of the binding site.Like Hg(C₆Me₆)₂²⁺, but unlike most of the complexes of substituted benzenes which have been studied, Hg(1,3,5-C₆H₃-i-Pr₃)₂²⁺ exchanges only slowly with excess free ligand.     

Amidinato and triazenido complexes of ruthenium(II): X-ray crystal structure of the N,N′-diphenylformamidine fragmentation product [RuCl(NH2Ph){PhNC(H)NPh}(Me2SO)2]

N,N′-Diphenylamidines, PhNC(R)NHPh (R=H, Me, Et, Ph), and 1,3-diaryltriazenes, ArNNNHAr (Ar=p-C₆H₄X, X=H, Cl, Me, OMe) react with ruthenium(II) complexes, [RuCl₂(C₇H₈)]_n, [RuCl₂(CO)₂]_n and [RuCl₂(Me₂SO)₄] in the presence of a base (NEt₃ or Na₂CO₃) to afford a selection of bis(chelate) products [Ru{PhNC(R)NPh}₂L₂] and [Ru(ArNNNAr)₂L₂] (L=CO, Me₂SO; L₂=C₇H₈). In contrast one particular combination — [RuCl₂(Me₂SO)₄]/PhNC(H)NHPh/NEt₃ — in refluxing dimethylformamide yields a novel amidine fragmentation product [RuCl(NH₂Ph){PhNC(H)NPh}(Me₂SO)₂] which has been characterised by X-ray diffraction methods.     

Säureinduzierte carbin-acylumwandlung

The reaction of dicarbonyl- and carbonyl(trimethylphosphine)(cyclopentadienyl)-carbyne complexes of molybdenum and tungsten η⁵-C₅H₅(CO)_2−n(PMe₃)_nMCR (n = 0, 1; M = Mo, W; R = CH₃, C₆H₅, C₆H₄CH₃, C₃H₅) with protic nucleophiles HX (X = Cl, CF₃COO, CCl₃COO) leads, through a combined protonation/carbon-carbon coupling reaction, to η²-acyl complexes η⁵-C₅H₅(CO)_1−nX₂(PMe₃)_n-M(η²-COCH₂R). The reaction conditions, the results of the spectroscopic measurements and the X-ray structure of η⁵-C₅H₅(CO)(Cl₂)W(η²-COCH₂CH₃) are reported.     

The reactions of [Fe2(η-C5H5)2(CO)4−n(CNMe)n] (n = 0–4) complexes with halogens and mercury(II) salts

Halogens, X₂, and HgY₂ (X = Cl, Br, I; Y = X, F, NO₃, BF₄) cleave the metalmetal bonds in [Fe₂(η-C₅H₅)₂(CO)_4−n(CNMe)_n] complexes (n = 0–4). Typically, e.g., when n = 2, X₂ electrophiles give [Fe(η-C₅H₅)(CO)(CNMe)X] (a) and [Fe(η-C₅H₅)(CO)(CNMe)₂]X (b) in relative yields which depend on X, the reaction solvent and n, but HgY₂ give equimolar amounts of [Fe(η-C₅H₅)(CNMe)₂Y] (c and [Fe(η-C₅H₅)(CO)₂HgY] only. Hg(CN)₂ reacts more slowly than other HgY₂, and [Hg(PPh₃)₂I₂] does not react at all. It is suggested that the reactions which give rise to products of type (a), (b) or (c) are all two-electron oxidation which proceed by way of adducts containing μ-CA → X₂ or μ-CA → HgX₂ groups (Ca = CO or CNMe). One of these adducts has been isolated, namely [Fe₂(η-C₅H₅)₂(CNMe)₂{μ-CN(Me)HgCl₂}₂] · CHCl₃.     

X-ray photoelectron spectroscopic and magnetic susceptibility study of cis-bis ethylenediaminoalkylamino nitrito cobalt(III) nitrate

X-ray photoelectron spectra of cis-[Co(en)₂(RNH₂)(NO₂)] (NO₃)₂ complexes, where R = CH₂CHCH₂, CH₃, n-C₂ H₅, n-C₄H₉, n-C₅H₁₁ and C₆H₁₃ have been recorded on a VG scientific ESCA-3MK II electron spectrometer to study the relative covalent bonding between the metal ion and the alkylamine group (RNH₂) and to study the degree of π-back bonding from metal to ligand nitrite. The magnetic susceptibility of all these complexes was also measured by the Faraday method at room temperature.     

PMR of complexes of organohalostannanes with N-vinyl-N-ethylimidazole

The chemical shifts and spin-spin coupling constants of the protons of the vinyl and ethyl groups and of the imidazole ring in the PMR spectra of complexes R_4–n·SnX_n · mB, where R=C₂H₅, C₄H₉;X=Cl, Br, I; B is N-vinylimidazole or N-ethylimidazole; and n=1 (m=1) and 2 (m=2), are compared. The electronic and geometrical structures of these complexes are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 391–394, March, 1973.     

Alkinylverbindungen von übergangsmetallen : XXXIX. Planare palladium(II) komplexe des typs trans-[p-C6H4(CCPd(X)(PEt3)2)2](n+2)+ (n = summe der ionenladungen von X)

Preparation and properties of the diamagnetic planar complexes trans-[p-C₆H₄(CCPd(X)(PEt₃)₂)₂] (X = Cl, Br, I, NCS) and trans-[p-C₆H₄(CCPd(X)(PEt₃)₂)₂](ClO₄)₂ (X = PEt₃, pyridine) are described. The structures of the compounds have been determined by ³¹P and ¹H NMR spectroscopy. The IR spectra are discussed.     

Alkane loss from collisionally activated alkylmethyleneimmonium ions

The collision-induced dissociation (CID) spectra of five alkylmethyleneimmonium ions (H₂C-N⁺R¹R², (a) R¹ = R² = C₂H₅, (b) R¹ = n-C₃H₇, R² = H, (c) R¹ = n-C₃H₇, R² = CH₃, (d) R¹ = n-C₃H₇, R² = C₂H₅, (e) R¹ = R² = n-C₃H₇) are reported and discussed in terms of the mechanism of alkane loss. The most abundant alkane losses result from 2-azaallylic bond cleavages within R¹ and R² leading to daughter ions of m/z 84. Ion d (R¹ = n-C₃H₇, R² = C₂H₅) was chosen for a deuterium-labelling study because it exhibited methane loss nearly free from interferences with other fragmentations. The methane lost consists to a great extent (95%) of the methyl moiety of R². Whereas the methyl moiety obviously stays intact during the fragmentation process, the hydrogen additionally needed originates from all positions of R¹ and the double-bonded methylene in an approximately random distribution, suggesting extensive hydrogen migrations preceding the transfer step.     

Reactions of cationic vinylidene complexes [Fe{=C=C(R1)R2}(η-C5H5)(dppm)]+[dppm = bis(diphenylphosphino)methane] with nucleophiles: stereoselective synthesis and crystal structure of the alkenyl complex (E)-[Fe{C(H)=C(Me)Ph}(η-C5H5)(dppm)]

The reactivity of the cationic vinylidene complexes [Fe{CC(R¹)R²}(η-C₅H₅(dppm)]⁺ toward different nucleophiles has been investigated. Whereas the disubstituted complexes (R¹ = Me; R² = Ph or ^tBu) are unreactive with water and methanol, the addition of the anion hydride proceeds stereoselectively to give the alkenyl E isomers. The structure of (E)-[Fe{C(H)C(Me)Ph}(η-C₅H₅(dppm)] has been determined by an X-ray diffraction study. Nucleophilic additions to the unsubstituted complex (R¹ = R² = H) have also been examined.     

NMR investigation of bis(2,3-alkanedione dioximato)-bis(pyridine)cobalt(III) iodide complexes: 1H and 13C NMR spectra and 13C spin-lattice relaxation time measurements

The complexes of trans-[Co(III)(R,CH₃-dioxH)₂(py)₂]I2 (R = CH₃, C₂H₅, n-C₃H₇ and n-C₄H₉) were investigated in solution by ¹H and ¹³C NMR spectra and ¹³C spin-lattice relaxation time measurements. The ¹H and ¹³C-resonances of the R = C₂H₅, n-C₃H₇ and n-C₄H₉) groups were shifted to higher field than those of the free ligands by the complexation; it was attributable to the ring current shielding due to the axial pyridine ligands of the complexes. ¹³C spin-lattice relaxation times were interpreted as due to movement of the axial pyridine ligands as if they twist around the CoN (pyridine nitrogen) bond axis and the above R groups were moving segmentally. These segmental movements allowed the R groups to approach closely toward the axial pyridine ring plane to experience the ring current shielding.     

119Sn mössbauer,IR, 1H NMR spectroscopic and thermal decomposition studies on organotin(IV) adducts with glycylglycine

The complexes R₂SnCl₂·(H₂glygly), (H₂glygly = glycylglycine) (R = Me, Buⁿ, Octⁿ, Ph) and RSnCl₃·(H₂glygly)     

Electron-impact studies of organometallic molecules—VIII: Some transition metal derivatives of polyfluorobenzenes

The mass spectra of (π-C₅H₅)₂Ti(C₆F₅)X (X ? Cl and C₆F₅), C₆F₅Re(CO)₅, R_fFe(CO)₂(π-C₅H₅) (R_f ? C₆F₅, 4-HC₆F₄, and three isomeric H₂C₆F₃), and C₆F₅Ru(CO)₂(π-C₅H₅) are compared to those of C₆F₅X (X ? F, Cl, Br, I) and the three isomers of C₆F₄H₂. Significant differences occur, apparently depending on the relative thermodynamic stabilities of the various fragments which may be formed. Comparison of the mass spectra of pentafluorophenyl- and pentafluorobicyclo[2.2.0]hexa-2,5-dien-2-yl-Re(CO)₅ show that similar ions are produced by both complexes, perhaps because of thermal isomerisation before ionisation.     

MnIIILx/t-BuOOH-induced activation of dioxygen for the oxygenation of cyclohexene

Several manganese (III) complexes (Mn^IIIL_x) in combination with tert-butyl hydroperoxide (t-BuOOH) activate dioxygen (O₂) to oxygenate cyclohexene (c-C₆H₁₀) to its ketone, alcohol, and epoxide. The product profiles depend on the ligand and solvent matrix. With picolinate (PA), bipyridine (bpy), or triphenylphosphine oxide (OPPh₃) as the ligand in py/HOAc (2:1 molar ratio) dominant product is the ketone [c-C₆H₈(O)] whereas Schiff–base complexes produce c-C₆H₈(O), c-C₆H₉(OH) and the epoxide in almost equal yields. However, in MeCN c-C₆H₈(O) is the dominant product for all of the complexes.     

Mono- and bi-iron chalcogenocarboxylate complexes

A series of thiocarboxylato and selenocarboxylato monomeric CpFe(CO)₂ECORCOCl and dimeric [CpFe(CO)₂ECO]₂R iron complexes have been synthesized and characterized. The interaction of (μ-E_x)[CpFe(CO)₂]₂ (E = S; x = 2–4. E = Se; x = 1) with di-acid chlorides (ClCORCOCl) in a 1:1 molar ratio gave the monomeric complexes CpFe(CO)₂ECORCOCl for R = 1,3-C₆H₄, 2,6-C₅H₃N, 1,2-C₆H₄. However, the dimeric complexes [CpFe(CO)₂ECO]₂R were obtained from the same reactants in a 2:1 metal-to-ligand molar ratio in which R is 1,3-C₆H₄, 2,6-C₅H₃N or C₂H₄. The monomer versus dimer production mainly depends on the electronic and steric factors of the R-moiety. The new monomeric and dimeric thio- and selenocarboxylato iron complexes have been characterized by spectroscopic techniques (¹H- and ¹³C-NMR, IR) and by elemental analysis. The structures of [CpFe(CO)₂SCO]₂(1,3-C₆H₄) and its seleno analogue [CpFe(CO)₂SeCO]₂(1,3-C₆H₄) were determined by X-ray structure determination.     

Tantalum dicyclopentadienyl hydrides containing the TaSn σ-bond. Crystal and molecular structure of (η5-C5H5)2TaH2Sn(CH3)Cl2

Interaction of Cp₂TaH₃ (Cp = η⁵-C₅H₅) with Me_nSnCl_4-n (n = 0–2) in benzene leads to heterometallic complexes with the composition Cp₂TaH₂(SnMe_nCl_3-n). The complex Cp₂TaH₂(SnMe₂Cl) can be obtained only when the HCl eliminated is fixed with triethylamine. The Mössbauer, IR and ¹H NMR spectroscopy data show that these compounds have a symmetrical structure with two terminal TaH bonds and a central TaSn σ-bond. The Cp₂TaH₂(SnMeCl₂) complex was studied by X-ray analysis. The crystals of this compound are rhombic with the unit cell parameters a 7.7361(1), b 10.552(1), c 16.943(3) Å, space group P_cmn, R = 0.0264, R_w = 0.0278. The molecule Cp₂TaH₂(SnMeCl₂) possesses a mirror symmetry plane which passes through the centers of the Cp cycles and the Ta, Sn, and C atoms of the methyl group: d(TaSn) 2.752(1), d(Ta-H) 1.61(10) Å. On the basis of spectroscopic and structural data the TaSn bond is concluded to have increased s character.     

New carborane-containing acids and amines

Alkylation of nido-carborane methyl sulfide derivative [9-MeS-7,8-C₂B₉H₁₁]^– was used to synthesize a series of new carborane-containing acids 9-HOOC(CH₂) _n (Me)S-7,8-C₂B₉H₁₁ (n = 1—4) and amines 9-H₂N(CH₂) _n (Me)S-7,8-C₂B₉H₁₁ (n = 2, 3). The compounds obtained can be used for the development of BNCT agents.