Complexes of tin tetrahalides with phenylhydrazones and azines

The reactions of SnCl₄ and SnBr₄ with benzalazine C₆H₅CHNNCHC₆H₅ (BZA), methylphenyl ketazin

(MPK) and benzaldehyde phenylhydrazone C₆H₅CHNNHC₆H₅ (BPH) have been examined and adducts of the types SnCl₄·BZA and SnX₄·2L (where X=Cl or Br; L=BZA, MPK or BPH) isolated and their physical properties studied. The structures of the adducts have been studied by i.r. (4000-200 cm⁻¹) and NMR spectroscopy.     

Regioselective anion generation and alkylation at carbon α to nitrogen in (CO)5WC[N(CH3)2]C6H4-p-CH3

Treatment of (CO)₅WC[N(CH₃)₂]C₆H₄-p-CH₃ (1) with lithium diisopropylamide (LDA) in THF at −78°C followed by quenching with D₂O leads to incorporation of deuterium into the (E)-N-methyl group only. Reaction of the anion of 1 with benzyl bromide at −78°C followed by quenching with water gave the E-isomer of (CO)₅WC[N(CH₃)CH₂CH₂C₆H₅]C₆H₄-p-CH₃ (2E, 26%) and recovered 1. When a mixture of the anion of 1 and benzyl bromide was warmed from −78°C to ambient temperature, a mixture of the E-isomer of the dibenzylated product (CO)₅WC[N(CH₃)CH(CH₂C₆H₅)₂]C₆H₄-p-CH was obtained. Reaction of the anion of 1 with allyl bromide gave (CO)₅WC[N(CH₃)CH₂CH₂CHCH₂]C₆H₄-p-CH₃ (5, 38%) and with methyl iodide gave a mixture of (CO)₅WC[N(CH₃)CH₂CH₃]C₆H₄-p-CH₃ (6, 7%) and (CO)₅W C[N(CH₃)CH(CH₃)₂]C₆H₄-p-CH₃ (7, 16%).     

C-Phosphinosubstituierte phosphaalkene und ein erstes carbodiphosphan

A series of novel phosphaalkenes, YoshPCHP(X)R (Yosh = 2,4,6-^tBu₃C₆H₂) has been prepared, as well as the first stable carbodiphosphane, YoshPCPYosh, which has been characterized by elemental analysis, NMR and mass spectroscopy.     

Measurement of barriers to aryl rotation in Cp(CO)2FeCHC6H5+ and Cp(CO)2FeCH(p-CH3C6H4)+

The first observation of barriers to rotation about the C_arylC_carbene bonds in aryl-substituted metal carbene complexes is reported. Using variable temperature ¹H NMR, barriers of 9.1 and 10.4 kcal/mol have been determined for Cp(CO)₂FeCHC₆H₅⁺ and Cp(CO)₂FeCH(p-CH₃C₆H₄)⁺, respectively. The data clearly indicate a geometry of the complex in which the aryl ring lies coplanar with FeC_carbeneC_ipso plane.     

Metal—azo and metal—imine compounds : IV. Chemical properties of cyclometallated compounds

The reactions of some cyclometallated azo and imino compounds have been studied. Treatment of [IrHX(PhCCHCHNC₃H₇)(PCy₃)₂] with X₂ (X = Cl, Br) yields substitution products [IrHX(PhCCXCHNC₃H₇)(PCy₃)₂] without rupture of the IrC bond. Treatment of [IrHCl(5-CH₃ · C₆H₃CHNCH₃) (PPh₃)₂] with AgClO₄ and then with CNC₆H₁₁ or CO (= L) leads to the formation of the complexes [IrHL(5-CH₃ · C₆H₃CHNCH₃)(PPh₃)₂]ClO₄, the metallocyclic ring remaining intact. Rupture of the metallocyclic ring is observed when [PdCl(C₆H₄NNPh)]₂ is treated under mild conditions with CNC₆H₁₁, and the insertion product [PdCl(CNC₆H₁₁)₂ {(CNC₆H₁₁)₂C₆H₄NNPh} ] is obtained.Possible mechanisms for the reactions are discussed.     

Studies on novel unsymmetrical azomethines—III : Copper(II) complexes of unsymmetrical tetradentate azomethines

Copper(II) complexes of unsymmetrical bifunctional tetradentate azomethines having the general formulae, (OC₁₀H₆CH:NXN:C(R)C₆H₄O)Cu, (OC₁₀H₆CH:NXN:C(CH₃)CHC(CH₃)OCu, (OC₆H₄CH:NXN:C(CH₃)C₆H₄O)Cu, (OC₆H₄C(R);NXN:C(CH₃)CHC(CH₃)O)Cu (where R = H or CH₃, X = (CH₂)₃, (CH₂)₄, (CH₂)₆ or -oC₆H₄) have been synthesized by the reactions of preformed mixed imine complexes of the type, CuLL′ (where L and L′ are two different imines such as 2-hydroxy-1-naphthaldimine, salicylaldimine, o-hydroxyacetophenonimine or acetylacetonimine) with diamines such as 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane or o-phenylenediamine. These complexes have been characterized by elemental analyses, TLC, conductance, magnetic measurements, IR and electronic spectra.     

The [Cp(CO)2Fe] (Fp) group as a donor in donor/acceptor substituted disilanes: synthesis,structure and electronic properties of FpSi2Me4C6H4CHC(CN)2

UV–vis absorption spectroscopy and cyclic voltammetry are used to study electronic interactions in the donor/acceptor substituted disilane FpSi₂Me₄C₆H₄CHC(CN)₂ (Fp=η⁵-C₅H₅Fe(CO)₂) (1). The synthesis of 1 was achieved by a conventional chemical route, the model substances FpSiMe₃ (2), FpSi₂Me₅ (3) and FpSi₂Me₄C₆H₅ (4) were obtained by the electrolysis of Fp₂ in the presence of the appropriate chlorosilane. The structure of 1, determined by X-ray diffraction, exhibits an all-trans-array of the FeSiSiC_aryl fragment, a basic requirement for optimal through-bond interaction. UV–vis and CV data indicate strong intramolecular donor/acceptor interaction in 1.     

Metal–azo and metal–imine compounds II. : II. Insertion of Ir1 into aromatic and olefinic CH bonds

The reaction of the aromatic azo or imine compounds PhX=NR (X=N or CH; R = alkyl or aryl) and 2-(methylazo)propene, H₂CC(CH₃)N&.zdbnd;NCH₃, with trans-IrCl(N₂)(PPh₃)₂ yields the (ortho) metallated complexes IrHCl(G₆H₄X=NR)(PPh₃)₂ and IrHClCHC(CH₃)-NNCH₃](PPh₃)₂ respectively.The v(N=N) vibration in IrHCl(C₆HZ₄N=NPh)(PPh₃)₂ appears to be drastically lowered with respect to the free ligand vibration. Furthermore, Resonance Raman experiments show that this vibration is strongly coupled to both of the electronic transitions of this compound at longer wavelengths, which therefore must be closely connected with the azo group.¹H and ¹³C NMR spectroscopic data and crystallographic studies of IrHCI(C₆H₄N=NPh)(PPh₃)₂ give strong evidence about the nature of the mechanism of these (ortho) metallation reactions.     

Enzymes immobilisees—IV : Les vanacryls et leur emploi dans la preparation de nouveaux derives insolubles de la trypsine

Treatment of methacrylyl chloride with vanillin gave the corresponding ester 1 which was polymerized (or co-polymerized with allylic alcohol), to give various polyaldehydes, called vanacryls. These polymers were successfully used for immobilizing trypsin according to the probable scheme: PolCHO + H₂NEnz → PolCHNEnz.     

Some diels—alder reactions of η1-bonded cyclopentadienylmetal compounds

Bis(cyclopentadienyl)mercury readily undergoes Diels—Alder reactions with RCCR (R = CO₂Me or CF₃), CF₃CFCFCF₃, CF₃CFCF₂, (CF₃)₂CC(CN)₂, C₂(CN)₄ and Ph$\text{NCONNC}$O to give stable adducts characterised by¹H, ¹⁹F and ¹³C NMR, spectroscopy. Similar reactions of CF₃CCCF₃ and CF₃CFCFCF₃ with the cyclopentadiene derivatives Me₃MC₅H₅ and (Me₃M)₂C₅H₄ (M = Si, Sn) are also described.     

Insertions of nitriles and pyridine into the ZrSi bond of (η5-C5H5)(η5-C5Me5)Zr[Si(SiMe3)3]Me

The zirconium silyl complex CpCpZr[Si(SiMe₃)₃]Me (1; Cp = η⁵-C₅H₅; Cp = η⁵-C₅Me₅) reacts with nitriles RCN (R = Me, CHCH₂, Ph) to form the azomethine derivatives CpCpZr[NC(R)Si(SiMe₃)₃]Me (2, R = Me; 3, R = CHCH₂; 4, R = Ph). Pyridine reacts with 1 to give a 75% yield of CpCpZr[NC₅H₅Si(SiMe₃)₃]Me (5), which results from 1,2-addition of the ZrSi bond of 1 to pyridine. These reactions provide the first examples of nitrile and pyridine insertions into a transition metal-silicon bond. The related silyl complexes Cp₂Zr[Si(SiMe₃)₃]Me and CpCpZr[Si(SiMe₃)₃]Cl are much less reactive toward nitriles and pyridine.     

Preparation and properties of new ferrocenyl heterobimetallic complexes with counterion dependent NLO responses

New ferrocenyl-based bimetallic cationic compounds of the type of (E)-[CpFe(η⁵-C₅H₄)(CHCH)(C₆H₄)CNRuCp(PPh₃)₂]X (X=PF₆, BF₄) and of (E)-[CpFe(η⁵-C₅H₄)(CHCH)(C₆H₄)CNFeCp(CO)₂]PF₆ have been obtained and characterized. The crystal structure of (E)-[CpFe(η⁵-C₅H₄)(CHCH)(C₆H₄)CNRuCp(PPh₃)₂]BF₄ has been established by means of X-ray diffractometry. The NLO responses of the compounds have been studied by the hyper-Rayleigh scattering technique and the hyperpolarizability is found to be dependent on the nature of the counterion.     

Preparation of η2-acetylene- and η1-vinylidene-manganese complexes from p-diethynylbenzene and cymantrene. X-ray crystal and molecular structure of Cp(OC)2MnCCHC6H4CBrCH2

Cp(OC)₂Mn(THF) reacts with p-diethynylbenzene (Deb), yielding Cp(OC)₂Mn(Deb) (I) and [Cp(OC)₂Mn]₂(Deb) (II) with the η²-acetylene coordination of Deb (to both Mn atoms in II). Under the action of PhLi, I and II are isomerized into Cp(OC)₂MnCCHC₆H₄CCH (III) and [Cp(OC)₂MnCCH]₂C₆H₄ (VI). Treatment of I with PhLi, LiBr and an excess of HCl in ether, as well as direct interaction of III with LiBr and HCl/Et₂O, gives Cp(OC)₂MnCCHC₆H₄CBrCH₂ (IV), which has been characterized by an X-ray single-crystal diffraction study. III adds PPh₃, yielding a zwitterionic complex, Cp(OC)₂Mn⁻C(P⁺Ph₃)CHC₆H₄CCH (V).     

Transition metal compounds containing the -OTeF5 and NTeF5 groups.

The electronegative ligand OTeF₅ has been tested on the elements Ti, Mo, W, Ta, Re, Os and others. Compounds such as OMo(OTeF₅)₄, W(OTeF₅)₆, Ta(OTeF₅)₅, ReO₂(OTeF₅)₃, OsO(OTeF₅)₄ are prepared. While ReVII could be stabilized with OTeF₅, the highest oxidation state on Osmium is VI, and Iridium probably IV. OMo(OTeF₅)₄ shows a regular square pyramidal structure with apical double bonded oxygen. Chemistry on the ligand NTeF₅ is based on the synthesis of H₂NTeF₅ and R₃SiNHTeF₅¹. Other new main group derivatives are so far Cl₂NTeF₅, HClNTeF₅, OCN-TeF₅, F₃PNTeF₅, Cl₃NPTeF₅, F₂SNTeF₅ and Cl₂SeNTeF₅, the first compound with a selenium-nitrogen double bond. In the transition metal series the compounds F₄MoNTeF₅ and Cl₄WNTeF₅ (in addition to the longer known polymeric (HgNTeF₅¹) have been prepared. Both have discrete metal nitrogen double bonds.     

The syntheses and coordination properties of M(CO)3X(DAB) (M = Mn,Re; X = Cl,Br, I; DAB = 1,4-diazabutadiene)

M(CO)₅X (M = Mn, Re; X = Cl, Br, I) reacts with DAB (1,4-diazabutadiene = R₁N=C(R₂)C(R₂)′=NR′₁) to give M(CO)₃X(DAB). The ¹H, ¹³C NMR and IR spectra indicate that the facial isomer is formed exclusively. A comparison of the ¹³C NMR spectra of M(CO)₃X(DAB) (M = Mn, Re; X = Cl, Br, I; DAB = glyoxalbis-t-butylimine, glyoxyalbisisopropylimine) and the related M(CO)₄DAB complexes (M = Cr, Mo, W) with Fe(CO)₃DAB complexes shows that the charge density on the ligands is comparable in both types of d⁶ metal complexes but is slightly different in the Fe-d⁸ complexes. The effect of the DAB substituents on the carbonyl stretching frequencies is in agreement with the A′(cis) > A″ (cis) > A′(trans) band ordering.Mn(CO)₃Cl(t-BuNCHCHNt-Bu) reacts with AgBF₄ under a CO atmosphere yielding [Mn(CO)₄(t-BuNCHCHN-t-Bu)]BF₄. The cationic complex is isoelectronic with M(CO)₄(t-BuNCHCHNt-Bu) (M = Cr, Mo, W).     

Synthesis of novel tri-podal mesogenic alkenes and side-chain polysiloxanes

Low molecular weight tri-podal biphenyl- and benzoate-type mesogens [C₆H₅C₆H₄O(CH₂)₅SiMe₂CH₂CH₂SiMe₂]₃CH (4), [C₁₁H₂₃O(C₆H₄)₂O(CH₂)₅SiMe₂]₃CH (5) and [MeOC₆H₄OC(O)C₆H₄O(CH₂)₅SiMe₂]₃CH (6) (C₆H₄ = 1,4-phenylene) were obtained, from branched silyl substituted methane precursors [CH₂CH(Me)₂Si]₃CH (1) and (HMe₂Si)₃CH (2). The biphenyl-containing ones (4) and (5) were converted into terminal alkenes, which were subsequently hydrosilylated with poly(methylsiloxanes). The polymer derived from (5) exhibited mesomorphic properties. Such systems have the potential to significantly increase the density of liquid crystal rod-like structures in side chains of linear polymers (or dendritic liquid crystal polymers).     

Reaction of a bridged ethenylidene diiron complex with tetracyanoethylene. Synthesis and crystal structure of the μ-3,4,4-tricyanobuta-1,3-dienylidene complex [(C5H5)Fe(CO)]2(μ-CO)[μ-CCH(NC)CC(CN)2]

The reaction of μ-ethenylidene [(C₅H₅)Fe(CO)]₂(μ-CO)(μ-CCh₂) 1 with tetracyanoethylene gives the μ-3,4,4-tricyanobuta-1,3-dienylidene complex [(C₅H₅)Fe(CO)]₂(μ-CO)[μ-CCH(NC)CC(CN)₂] (2), whose crystal structure has been determined ESR studies suggests that a radical process may be involved.     

Zur reaktion von metall-koordiniertem kohlenmonoxid mit yliden : VII. Trimethylphosphoranylidenmethyl(trimethylsiloxy)carben-komplexe von chrom,molybdän und wolfram: aufbau einer metallvinyl-einheit durch c(carbanion)c(carben)-π-wechselwirkung und photochemische e/z-isomerisierung

The treatment of the hexacarbonylmetal compounds M(CO)₆ (M = Cr. Mo, W) with two equivalents Me₃PCH₂ yields the phosphonium acylmetalphosphorus ylides Me₄P[(CO)₅MC(O)CHPMe₃] 1a–1c. Their reaction with Me₃SiOSO₂CF₃ leads via O-silylation to formation of the neutral “siloxy(ylidecarbene) complexes” (CO)₅MC(OSiMe₃)CHPMe₃2a–2c, which are protonated by HX (X = Cl, CF₃SO₃) to give the thermolabile carbene complexes [(CO)₅MC(OSiMe₃)H₂CPMe₃]X, 3a, 3b. ¹H, ¹³C NMR and IR data suggest, that delocalization of the ylidic charge to the carbene carbon generates a metal-coordinated vinyl group in the case of 2a–2c. In addition this fact is proved by the X-ray analysis of 2c, for which a C(ylide)C(carbene) bond distance of 133 pm is found. 2a–2c are obtained as pure E-isomers but can be converted to the Z-isomers 2a′–2c′ upon photolysis.     

Reactions of perfluoronitriles. II. Interactions with phenylphosphine

Treatment of perfluoro-n-octanonitrile with phenylphosphine gave tetraphenyltetraphosphine and a spectrum of reduction and interaction products. Fifteen compounds were identified. The imine, (R_fC₇F₁₅) R_fCHNH, and the amine, R_fCH₂NH₂, were the primary reduction products. Secondary phosphorus-free products, some formed following ammonia evolution, were the following: R_fCHNCH₂R_f, R_fCH₂CH(NH₂)R_f, R_fC(NH)NCR_f(NH₂), R_fCH₂NHCR_f(NH), (R_fCN)₃, R_fCHNCR_fNCR_f(NH), R_fCH₂NCR_fNHCH₂R_f, and R_fCH₂NCR_fNHCR_f(NH). Only three phosphorus-containing materials were definitely identified: R_fCH(NH₂)P(C₆H₅)H, R_fCH[P(C₆H₅)H]NCHR_f, and R_fC(NH)P(C₆H₅)CR_f(NH). Depending on reaction conditions, specific phosphorus-containing compounds could be preferentially produced. All the structure assignments are based solely on mass spectral breakdown patterns, since pure compounds were not isolated.     

Komplexchemie reaktiver organischer verbindungen : XXXVII. Metallinduzierter abbau eines σ,π-koordinierten ketens in ein π-allyl/σ-aryl/π-olefin-system

Photolysis of diphenylketene in the presence of pentacarbonyliron yields the π-allyl/σ-acyl type compound [η³:η¹-(C₆H₅)₂CCO)Fe(CO)₃ (III) the molecular structure of which has been established by means of X-ray diffraction techniques. Metal-centered carboncarbon bond breaking and bond making in III is evident from ¹³CO labelling and crossover experiments. The dinuclear compound IV, structurally characterized by the π-allyl/σ-aryl/π-olefin hydrocarbon ligand CH(C₆H₄)C₆H₅, is formed upon irreversible decarbonylation of the ketene precursor III.