The Ruthenostannylene Complex [Cp*(IXy)H2Ru‐Sn‐Trip]: Providing Access to Unusual Ru‐Sn Bonded Stanna‐imine,Stannene, and Ketenylstannyl Complexes

Reactivity studies of the thermally stable ruthenostannylene complex [Cp*(IXy)(H)₂Ru Sn Trip] ( 1 ; IXy=1,3‐bis(2,6‐dimethylphenyl)imidazol‐2‐ylidene; Cp*=η⁵‐C₅Me₅; Trip=2,4,6‐iPr₃C₆H₂) with a variety of organic substrates are described. Complex 1 reacts with benzoin and an α,β‐unsaturated ketone to undergo [1+4] cycloaddition reactions and afford [Cp*(IXy)(H)₂RuSn(κ²‐O,O‐OCPhCPhO)Trip] ( 2 ) and [Cp*(IXy)(H)₂RuSn(κ²‐O,C‐OCPhCHCHPh)Trip] ( 3 ), respectively. The reaction of 1 with ethyl diazoacetate resulted in a tin‐substituted ketene complex [Cp*(IXy)(H)₂RuSn(OC₂H₅)(CHCO)Trip] ( 4 ), which is most likely a decomposition product from the putative ruthenium‐substituted stannene complex. The isolation of a ruthenium‐substituted stannene [Cp*(IXy)(H)₂RuSn(Flu)Trip] ( 5 ) and stanna‐imine [Cp*(IXy)(H)₂RuSn(κ²‐N,O‐NSO₂C₆H₄Me)Trip] ( 6 ) complexes was achieved by treatment of 1 with 9‐diazofluorene and tosyl azide, respectively.     

The Ruthenostannylene Complex [Cp*(IXy)H2Ru‐Sn‐Trip]: Providing Access to Unusual Ru‐Sn Bonded Stanna‐imine,Stannene, and Ketenylstannyl Complexes

Reactivity studies of the thermally stable ruthenostannylene complex [Cp*(IXy)(H)₂Ru? Sn? Trip] ( 1 ; IXy=1,3‐bis(2,6‐dimethylphenyl)imidazol‐2‐ylidene; Cp*=η⁵‐C₅Me₅; Trip=2,4,6‐iPr₃C₆H₂) with a variety of organic substrates are described. Complex 1 reacts with benzoin and an α,β‐unsaturated ketone to undergo [1+4] cycloaddition reactions and afford [Cp*(IXy)(H)₂RuSn(κ²‐O,O‐OCPhCPhO)Trip] ( 2 ) and [Cp*(IXy)(H)₂RuSn(κ²‐O,C‐OCPhCHCHPh)Trip] ( 3 ), respectively. The reaction of 1 with ethyl diazoacetate resulted in a tin‐substituted ketene complex [Cp*(IXy)(H)₂RuSn(OC₂H₅)(CHCO)Trip] ( 4 ), which is most likely a decomposition product from the putative ruthenium‐substituted stannene complex. The isolation of a ruthenium‐substituted stannene [Cp*(IXy)(H)₂RuSn(?Flu)Trip] ( 5 ) and stanna‐imine [Cp*(IXy)(H)₂RuSn(κ²‐N,O‐NSO₂C₆H₄Me)Trip] ( 6 ) complexes was achieved by treatment of 1 with 9‐diazofluorene and tosyl azide, respectively.     

Coordination behaviour of the multidentate Schiff base 2,6-bis(2-hydroxyphenyliminomethyl)pyridine towards the fac-[Re(CO)3] and [ReO] cores

The seven-coordinate rhenium(III) complex cation [Re^III(dhp)(PPh₃)₂]⁺ was isolated as the iodide salt from the reaction of cis-[Re^vO₂I(PPh₃)₂] with 2,6-bis(2-hydroxyphenyliminomethyl)pyridine (H₂dhp) in ethanol. In the complex fac-[Re(CO)₃(H₂dhp)Br], prepared from [Re(CO)₅Br] and H₂dhp in toluene, the H₂dhp ligand acts as a neutral bidentate N,N-donor chelate. The complexes were characterized by elemental analysis, infrared and ¹H NMR spectroscopy and X-ray crystallography.     

Solution Equilibria of Ternary Systems Involving Nickel(II) Ion,Picolinic Acid,and the Amino Acids Histidine,Cysteine, Aspartic and Glutamic Acids

Solution equilibria of the ternary systems Ni(II)–picolinic acid (Hpic) and the amino acids aspartic acid (H₂asp), glutamic acid (H₂glu), cysteine (H₂cys) and histidine (Hhis), where the amino acids are denoted as H _i L, have been studied pH-metrically. The formation constants of the resulting mixed ligand complexes have been determined at 25 °C using a ionic strength 1.0 mol·dm^?3 NaCl. In the Ni(II)–Hpic–H₂asp and Ni(II)–Hpic–H₂glu systems, the complexes [Ni(pic)H₂L]⁺, Ni(pic)HL, [Ni(pic)L]^? and [Ni(pic)L(OH)]^2? were detected. In the Ni(II)–Hpic–H₂cys system the complexes [Ni(pic)H₂L]⁺ and [Ni(pic)L]^? are present. Additionally, in the Ni(II)–Hpic–Hhis system the species [Ni(Hpic)HL]²⁺, Ni(pic)L and [Ni(pic)L(OH)]^? were identified. The species distribution diagrams as functions of pH are briefly discussed.     

Novel cyclohexyl‐based aminophosphine ligands and use of their Ru(II) complexes in transfer hydrogenation of ketones

Two new aminophosphines – furfuryl‐(N‐dicyclohexylphosphino)amine, [Cy₂PNHCH₂–C₄H₃O] ( 1 ) and thiophene‐(N‐dicyclohexylphosphino)amine, [Cy₂PNHCH₂–C₄H₃S] ( 2 ) – were prepared by the reaction of chlorodicyclohexylphosphine with furfurylamine and thiophene‐2‐methylamine. Reaction of the aminophosphines with [Ru(η⁶‐p‐cymene)(μ‐Cl)Cl]₂ or [Ru(η⁶‐benzene)(μ‐Cl)Cl]₂ gave corresponding complexes [Ru(Cy₂PNHCH₂–C₄H₃O)(η⁶‐p‐cymene)Cl₂] ( 1a ), [Ru(Cy₂PNHCH₂–C₄H₃O)(η⁶‐benzene)Cl₂] ( 1b ), [Ru(Cy₂PNHCH₂–C₄H₃S)(η⁶‐p‐cymene)Cl₂] ( 2a ) and [Ru(Cy₂PNHCH₂–C₄H₃S)(η⁶‐benzene)Cl₂] ( 2b ), respectively, which are suitable catalyst precursors for the transfer hydrogenation of ketones. In particular, [Ru(Cy₂PNHCH₂–C₄H₃S)(η⁶‐benzene)Cl₂] acts as a good catalyst, giving the corresponding alcohols in 98–99% yield in 30 min at 82 °C (up to time of flight ≤ 588 h^?1). Copyright © 2014 John Wiley & Sons, Ltd.     

A modular design of metal catalysts for the transfer hydrogenation of aromatic ketones

The ability of transition metal catalysts to add or remove hydrogen from organic substrates by transfer hydrogenation is a valuable synthetic tool. Towards a series of novel metal complexes with a P―NH ligand, [Ph₂PNHCH₂―C₄H₃O] derived from furfurylamine were synthesized. Reaction of [Ph₂PNHCH₂―C₄H₃O] 1 with [Ru(η⁶‐p‐cymene)(μ‐Cl)Cl]₂, [Ru(η⁶‐benzene)(μ‐Cl)Cl]₂, [Rh(μ‐Cl)(cod)]₂ and [Ir(η⁵‐C₅Me₅)(μ‐Cl)Cl]₂ gave a range of new monodentate complexes [Ru(Ph₂PNHCH₂―C₄H₃O)(η⁶‐p‐cymene)Cl₂] 2 , [Ru(Ph₂PNHCH₂―C₄H₃O)(η⁶‐benzene)Cl₂] 3 , [Rh(Ph₂PNHCH₂‐C₄H₃O)(cod)Cl] 4 , and [Ir(Ph₂PNHCH₂‐C₄H₃0)(η⁵‐C₅Me₅)Cl₂] 5 , respectively. All new complexes were fully characterized by analytical and spectroscopic methods. ³¹P‐{¹H} NMR, distortionless enhancement by polarization transfer (DEPT) or ¹H‐¹³C heteronuclear correlation (HETCOR) experiments were used to confirm the spectral assignments. Following activation by KOH, compounds 1 , 2 , 3 , 4 catalyzed the transfer hydrogenation of acetophenone derivatives to 1‐phenylethanol derivatives in the presence of iso‐PrOH as the hydrogen source. Notably [Ru(Ph₂PNHCH₂‐C₄H₃O)(η⁶‐benzene)Cl₂] 3 acts as an excellent catalyst, giving the corresponding alcohols in 98–99% yield in 20 min at 82°C (time of flight ≤ 297 h^?1) for the transfer hydrogenation reaction in comparison to analogous rhodium or iridium complexes. Copyright © 2012 John Wiley & Sons, Ltd.     

New C2-Chiral Bidentate Ligands Bridging the gap between donor phosphine and acceptor carbonyl ligands

Two new C₂ chiral bidentate phosphorous ligands have been prepared in enantiomerically pure form. The two phosphorous centers bear electron-withdrawing groups ((CF₃)₂CH? O, C₆F₅) and are linked by a trans-cyclopentane-1,2-diol-derived bridge. Photolysis of [Cr(η⁶-C₆H₆)(CO)₃] in the presence of these two new ligands and of two previously reported bidentate phosphites, and fluorophosphinites (L) afforded [Cr(η⁶-C₆H₆)(CO)L] complexes. IR Spectral comparison of the complexes shows the new ligands to be intermediate in their bonding properties between alkyl phosphites and CO.     

Syntheses,Structures, and Properties of Two Coordination Complexes of a Flexible Ligand with Channel Structure

Two complexes of 3,5‐bis(4‐carboxyphenylmethyloxy) benzoic acid (H₃L) and transition metal ions, [Zn₂(μ₃‐OH)(L)] · H₂O ( 1 ) and (H₃O)[Cu₂(μ₄‐O)(L)] · H₂O ( 2 ) were synthesized under hydrothermal conditions. Their structures were determined by single‐crystal X‐ray diffraction and further characterized by elemental analysis, IR and diffusion UV/Vis/NIR spectroscopy, and TGA. The complexes possess 3D open frameworks with different shapes (rhombus / square) and sizes of channels resulting from the trans/cis‐configurations and coordination modes (μ₈‐η¹:η¹:η¹:η²:η¹:η² for 1 and μ₆‐η¹:η¹:η¹:η¹:η¹:η¹ for 2 ) of the flexible ligand and the property of transition metal ions. In addition, photoluminescence spectra of 1 and 2 were also discussed. In 2 there exists antiferromagnetic interaction showing that μ₄‐O atom in {Cu₂O}_n chain does not favor the magnetic exchange between Cu²⁺ ions.     

Regulation of electron donating ability to metal center: isolation and characterization of ruthenium carbonyl complexes with N,N- and/or N,O-donor polypyridyl ligands

Polypyridyl ruthenium(II) dicarbonyl complexes with an N,O- and/or N,N-donor ligand, [Ru(pic)(CO)₂Cl₂]⁻ (1), [Ru(bpy)(pic)(CO)₂]⁺ (2), [Ru(pic)₂(CO)₂] (3), and [Ru(bpy)₂(CO)₂]²⁺ (4) (pic=2-pyridylcarboxylato, bpy=2,2′-bipyridine) were prepared for comparison of the electron donor ability of these ligands to the ruthenium center. A carbonyl group of [Ru(L1)(L2)(CO)₂]ⁿ (L1, L2=bpy, pic) successively reacted with one and two equivalents of OH⁻ to form [Ru(L1)(L2)(CO)(C(O)OH)]ⁿ⁻¹ and [Ru(L1)(L2)(CO)(CO₂)]ⁿ⁻². These three complexes exist as equilbrium mixtures in aqueous solutions and the equilibrium constants were determined potentiometrically. Electrochemical reduction of 2 in CO₂-saturated CH₃CN–H₂O at −1.5 V selectively produced CO.     

Übergangsmetall-Fulven-Komplexe: XXXI. Die Reaktivität des [η5-(C5H4CHO)M(CO)3]−-Anions (M  Mo,W) gegenüber Carbonsäurechloriden

The reactivity of the (η⁵-formylcyclopentadienyl)M(CO)₃ anions (M  Mo, W) towards acyl chlorides has been studied. Acetyl chloride reacts with the anions to give two different types of substituted cyclopentadienyl complexes: [M(Cl)(η⁵-C₅H₄CH₂OC(O)CH₃)(CO)₃] and [M(η¹-CH₃CO)(η⁵-CH₃CO)(η⁵-C₅H₄CH₂OC(O)CH₃)(CO)₃]. The reaction of the anions with benzoyl chloride only yields the chloro complexes [M(Cl)(η⁵-C₅H₄CH₂OC(O)C₆H₅)(CO)₃]. The molecular structure of [W(Cl)(η⁵-C₅H₄CH₂OC(O)CH₃)(CO)₃] has been determined by X-ray diffraction studies.     

Preparation of Butadienylpyridines by Iridium-NHC-Catalyzed Alkyne Hydroalkenylation and Quinolizine Rearrangement

Iridium(I) N-heterocyclic carbene complexes of formula Ir(κ²O,O’-BHetA)(IPr)(η²-coe) [BHetA=bis-heteroatomic acidato, acetylacetonate or acetate; IPr=1,3-bis(2,6-diisopropylphenyl)imidazolin-2-carbene; coe=cyclooctene] have been prepared by treating Ir(κ²O,O’-BHetA)(η²-coe)₂ complexes with IPr. These complexes react with 2-vinylpyridine to afford the hydrido-iridium(III)-alkenyl cyclometalated derivatives IrH(κ²O,O’-BHetA)(κ²N,C-C₇H₆N)(IPr) through the iridium(I) intermediate Ir(κ²O,O’-BHetA)(IPr)(η²-C₇H₇N). The cyclometalated IrH(κ²O,O’-acac)(κ²N,C–C₇H₆N)(IPr) complex efficiently catalyzes the hydroalkenylation of aromatic and aliphatic terminal alkynes and enynes with 2-vinylpyridine to afford 2-(4R-butadienyl)pyridines with Z,E configuration as the major reaction products (yield up to 89 %). In addition, unprecedented (Z)-2-butadienyl-5R-pyridine derivatives have been obtained as minor reaction products (yield up to 21 %) from the elusive 1Z,3gem-butadienyl hydroalkenylation products. These compounds undergo a thermal 6π-electrocyclization to afford bicyclic 4H-quinolizine derivatives that, under catalytic reaction conditions, tautomerize to 6H-quinolizine to afford the (Z)-2-(butadienyl)-5R-pyridine by a retro-electrocyclization reaction.     

Synthesis,crystal structures and photoluminescence studies of three mixed ligand silver(I) coordination polymers

Three Ag(I) coordination complexes, namely [Ag₃(2-stp)(2-apy)₂·3H₂O]_n (1), [Ag₃(2-stp)(2-apy)₂]_n (2) and [Ag₃(2-stp)(3-apy)(H₂O)]_n (3) (2-NaH₂stp = 2-sulfoterephthalic acid monosodium salt, 2-apy = 2-aminopyridine and 3-apy = 3-aminopyridine), have been synthesized and structurally characterized. They all show two-dimensional network structures. In complex 1, the Ag₃ units are linked by stp ligands to form a 1D chain. Consequently, the 2-apy ligands link the adjacent 1D chain into 2D polymeric sheets. In 2, Ag1 and Ag2 atoms are bridged by stp ligands to form a 2D infinite sheet. In 3, the stp anion adopts a μ₇-(η¹,η²):(η¹,η¹,η⁰):(η¹,η¹) coordination mode to Ag₃ units to 2D layer sheet and the network is consolidated by 3-apy ligands. The thermogravimetric analyses and photoluminescence of the complexes were also investigated.     

Nickel Tetracarbonyl as Starting Material for the Synthesis of NHC-stabilized Nickel(II) Allyl Complexes

A novel, useful in situ synthesis for NHC nickel allyl halide complexes [Ni(NHC)(η³-allyl)(X)] starting from [Ni(CO)₄], NHC and allyl halides is presented. The reaction of [Ni(CO)₄] with (i) one equivalent of the corresponding NHC and (ii) with an excess of the corresponding allyl chloride at room temperature leads with elimination of carbon monoxide to complexes of the type [Ni(NHC)(η³-allyl)(X)]. This approach was used to synthesize the complexes [Ni(tBu₂Im)(η³-H₂C -C (Me)-C H₂)(Cl)] ( 2 ), [Ni(iPr₂Im^Me)(η³-H₂C -C (Me)-C H₂)(Cl)] ( 3 ), [Ni(iPr₂Im)(η³-H₂C -C (Me)-C H₂)(Cl)] ( 4 ), [Ni(iPr₂Im)(η³-H₂C -C (H)-C (Me)₂)(Br)] ( 5 ), [Ni(Me₂Im^Me)(η³-H₂C -C (Me)-C H₂)(Cl)] ( 6 ), and [Ni(EtiPrIm^Me)(η³-H₂C -C (Me)-C H₂)(Cl)] ( 7 ). The complexes 1 to 7 were characterized using NMR and IR spectroscopy and elemental analysis, and the molecular structures are provided for 2 and 7 . The allyl nickel complexes 1 – 7 are stereochemically non-rigid in solution due to (i) NHC rotation about the nickel-carbon bond, (ii) allyl rotation about the Ni–η³-allyl axis and (iii) π–σ–π allyl isomerization processes. The allyl halide complexes can be methylated as was demonstrated by the methylation of a number of the complexes [Ni(NHC)(η³-allyl)(X)] with methylmagnesium chloride or methyllithium, which led to isolation of the complexes [Ni(Me₂Im)(η³-H₂C -C (Me)-C H₂)(Me)] ( 8 ), [Ni(tBu₂Im)(η³-H₂C -C (Me)-C H₂)(Me)] ( 9 ), [Ni(iPr₂Im^Me)(η³-H₂C -C (Me)-C H₂)(Me)] ( 10 ), [Ni(iPr₂Im)(η³-H₂C -C (Me)-C H₂)(Me)] ( 11 ), [Ni(iPr₂Im)(η³-H₂C -C (H)-C (Me)₂)(Me)] ( 12 ), and [Ni(EtiPrIm^Me)(η³-H₂C -C (Me)-C H₂)(Me)] ( 13 ). These complexes were fully characterized including X-ray molecular structures for 10 and 11 .     

Chemical and Photochemical Water Oxidation Catalyzed by Mononuclear Ruthenium Complexes with a Negatively Charged Tridentate Ligand

Two mononuclear ruthenium complexes [RuL(pic)₃] ( 1 ) and [RuL(bpy)(pic)] ( 2 ) (H₂L=2,6‐pyridinedicarboxylic acid, pic=4‐picoline, bpy=2,2′‐bipyridine) have been synthesized and fully characterized. Both complexes could promote water oxidation chemically and photochemically. Compared with other known ruthenium‐based water oxidation catalysts using [Ce(NH₄)₂(NO₃)₆] (Ce^IV) as the oxidant in solution at pH 1.0, complex 1 is one of the most active catalysts yet reported with an initial rate of 0.23 turnover s^?1. Under acidic conditions, the equatorial 4‐picoline in complex 1 dissociates first. In addition, ligand exchange in 1 occurs when the Ru^III state is reached. Based on the above observations and MS measurements of the intermediates during water oxidation by 1 using Ce^IV as oxidant, [RuL(pic)₂(H₂O)]⁺ is proposed as the real water oxidation catalyst.     

Ternary Complex Formation between Vanadium(III), Dipicolinic Acid and Picolinic Acid in Aqueous Solution

Ternary complex species formed by the V³⁺ cation with the picolinic acid (Hpic, HL) and dipicolinic acid (H₂dipic, H₂L) ligands in aqueous solutions have been studied potentiometrically (25 °C, I=3.0 mol⋅dm⁻³ KCl ionic medium) and by spectrophotometric measurements. Application of the least-squares computer program LETAGROP to the experimental emf (H) data, taking into account the hydrolytic V(III) species and the binary V³⁺–picolinic acid and V³⁺–dipicolinic acid complexes, shows that under the investigated conditions the following ternary complexes are formed: [V(dipic)(pic)], [V(dipic)(pic)(OH)]⁻ and [V(dipic)(pic)₂]⁻. The stability constants of the ternary complexes were determined by potentiometric measurements whereas the spectrophotometric measurements were done in order to obtain a qualitative characterization of the complexes formed in aqueous solution.     

Dithiocarbamate complexes of cyclopentadienylcobalt(III), [Co(η-C5H5)(L)(S2CNR2)] (L = ligand)

The reactions of [Co(η-C₅H₅)(L)I₂] with Na[S₂CNR₂] (R = alkyl or phenyl) give [Co(η-C₅H₅)(I)(S₂CNR₂)] (I) when L = CO and [Co(η-C₅H₅)(L)(S₂CNR₂)]I (II) when L is a tertiary phosphine, phosphite or stibine, or organo-isocyanide ligand. In similar reactions [Co(η-C₅H₅)(CO)(C₃F₇)I] gives [Co(η-C₅H₅)(C₃F₇)(S₂CNMe₂)] and [Mn(η-MeC₅H₄)(CO)₂(NO)]PF₆ forms [Mn(η-MeC₅H₄)(NO)(S₂CNR₂)]. The iodide ligands in I may be displaced by L, to give II, or by other ligands such as [CN]^?, [NCS]^?, H₂O or pyridine whilst SnCl₂ converts it to SnCl₂I. The iodide counter-anion in II may be replaced by others to give [BPh₄]^?, [Co(CO)₄]^? or [NO₃]^? salts. However [CN]^? acts differently and displaces (PhO)₃P from [Co(η-C₅H₅){P(OPh)₃}(S₂CNMe)]I to give [Co(η-C₅H₅)(CN)(S₂CNMe₂)] which may be alkylated reversibly by MeI and irreversibly by MeSO₃F to [Co(η-C₅H₅)(CNMe)(S₂CNMe₂)]⁺ salts. Conductivity measurements suggest that solutions of I in donor solvents are partially ionized with the formation of [Co(η-C₅H₅)(solvent)(S₂CNR₂)]⁺ I^? species. The IR and ¹H NMR spectra of the various complexes are reported. They are consistent with pseudo-octahedral “pianostool” molecular structures in which the bidentate dithiocarbamate ligands are coordinated to the metal atoms through both sulphur atoms.     

Effect of Axial Ligands on Easy-Axis Anisotropy and Field-Induced Slow Magnetic Relaxation in Heptacoordinated FeII Complexes

A rational approach to modulating easy-axis magnetic anisotropy by varying the axial donor ligand in heptacoordinated Fe^II complexes has been explored. In this series of complexes with formulae of [Fe(H₄L)(NCS)₂] ⋅ 3 DMF ⋅ 0.5 H₂O ( 1 ), [Fe(H₄L)(NCSe)₂] ⋅ 3 DMF ⋅ 0.5 H₂O ( 2 ), and [Fe(H₄L)(NCNCN)₂] ⋅ DMF ⋅ H₂O ( 3 ) [H₄L=2,2′-{pyridine-2,6-diylbis(ethan-1-yl-1-ylidene)}bis(N-phenylhydrazinecarboxamide)], the axial positions are successively occupied by different nitrogen-based π-donor ligands. Detailed dc and ac magnetic susceptibility measurements reveal the existence of easy-axis magnetic anisotropy for all of the complexes, with 1 [U_eff=21 K, τ₀=1.72×10⁻⁶ s] and 2 [U_eff=25 K, τ₀=2.25×10⁻⁶ s] showing field-induced slow magnetic relaxation behavior. However, both experimental studies and theoretical calculations indicate the magnitude of the D value of complex 3 to be larger than those of complexes 1 and 2 due to the axial bond angle being smaller than that for an ideal geometry. Detailed analysis of the field and temperature dependences of relaxation time for 1 and 2 has revealed that multiple relaxation processes (quantum tunneling of magnetization, direct, and Raman) are involved in slow magnetic relaxation for both of these complexes. Magnetic dilution experiments support the role of intermolecular short contacts.     

Metal dimers as catalysts: IX. The catalysed reaction between [η5-C5H5)Fe(CO)2I] and group 15 donor ligands

The reaction between [η⁵-C₅H₅)Fe(CO)₂I] (I) and 1 equivalent of L (group 15 donor ligand) in the presence of catalysts (e.g. Pd/CaCO₃, PdO, [η⁵-C₅H₅)Fe(CO)₂]₂ (II)) yields [η⁵-C₅H₅)Fe(CO)(L)I] (phosphines, diphosphines, phosphite), [η⁵-C₅H₅)Fe(CO)₂L]I (phosphines) and [η⁵-C₅H₅)Fe(CO)(LL)]I (diphosphines). [η⁵-C₅H₅)Fe(CO)₂L]I can be converted into [η⁵-C₅H₅)Fe(CO)(L)I] in the presence of II. The reaction between [η⁵-C₅H₅)Fe(CO)(PMePh₂)I] or [η⁵-C₅H₅)Fe(CO)₂(PMePh₂)]I and PMePh₂ is also catalysed by II and yields in both instances [η⁵-C₅H₅)Fe(CO)(PMePh₂)₂]I. In the series of catalysed reactions the displacement sequence was found to be PMePh₂ > I⁻ > CO.     

Halide and complex halogeno anions as salts of oxinate chelates of titanium(IV)

(η⁵-Cyclopentadienyl)(η⁵-pyrrolyl)titanium(IV) dichloride, (η⁵-indenyl)-(η⁵-pyrrolyl)titanium(IV) dichloride and (η⁵-cyclopentadienyl)(η⁵-indenyl)-titanium(IV) dichloride, when treated with 8-hydroxyquinoline (oxine) in aqueous medium form ionic derivatives of the type, [(η⁵-R)(η⁵-R′)TiL]⁺ Cl^- (R = C₅H₅, C₉H₇, R′ = C₄H₄N; R = C₅H₅, R′ = C₉H₇; L is the conjugate base of (oxine). A number of halide and complex halogeno anions present in aqueous solution were isolated as salts of these ionic complexes giving derivatives of the type, [(η⁵-R)(η⁵-R′)TiL]⁺ X^- (X = Br^-, I^-, ZnCl₃(H₂O)^-, CdCl₄^2-, HgCl₃^-). Conductivity measurements in nitrobenzene solution indicate that these complexes are electrolytes. Both the IR and ¹H NMR spectral studies demonstrate that the ligand L is chelating. Consequently there is tetrahedral coordination about the titanium(IV) ion.     

Isothiocyanate and selenocyanate complexes of Cu(II), Ni(II), and Co(II) with a pyridylpyrazole-based ligand: synthesis,characterization, and structure

Mononuclear NCS^? containing complexes, [M(NCS)₂L] (L?=?N,N-bis(3,5-dimethylpyrazol-1-ylmethyl)aminomethylpyridine), [Cu(NCS)₂L′] (L′?=?N-(3,5-dimethylpyrazol-1-ylmethyl)aminomethylpyridine), and NCSe^? containing complexes [ML(NCSe)(H₂O)]ClO₄ (M?=?Ni⁺², Co⁺²) have been synthesized and characterized by elemental analysis, spectroscopic, and physico-chemical methods. Structural studies of [Cu(NCS)₂L′] show copper is five coordinate with distorted trigonal bipyramidal geometry with two cis NCS^?. [M(NCS)₂L] and [ML(NCSe)(H₂O)]ClO₄ (M?=?Ni⁺² and Co⁺²) are expected to be octahedral.