Synthesis and characterization of some ferrocene-containing telluroether ligands: crystal structure of 1,1′-bis(phenyltelluro)ferrocene

A series of five monodentate ferrocene tellurium ligands of the type Fe(C₅H₅)(C₅H₄TeR) and five bidentate 1,1′-disubstituted ferrocene tellurium ligands of the type Fe(C₅H₄TeR)₂ (R = Me, ⁿBu, C₆H₅, p-MeOC₆H₄, p-EtOC₆H₄) has been prepared by the reaction of 1,1′-dilithioferrocene with the appropriate ditellurides R₂Te₂. The ligands have been characterized by their elemental analyses, ¹H and ¹³C NMR spectra, mass spectra and cyclic voltammetry studies. The structure of Fe(C₅H₄TeC₆H₅)₂ has been determined by single-crystal X-ray diffraction study.     

Perhalophenyl complexes of palladium(II) containing keto-stabilized phosphorus ylides of the type Ph2P(CH2)nPPh2CHC(O)R

From suitable perhalophenyl derivatives of palladium(II), viz.: Pd(C₆F₅)₂-(SC₄H₈)₂, [Pd(μ-X′) (C₆X₅)₂]₂(NBu₄)₂, [Pd(μ-Cl)(C₆X₅)(SC₄H₈)]₂ (X = F, Cl, X′ = Cl, Br), new complexes of various types have been prepared, viz.: trans-Pd(C₆F₅)₂(Y)₂, Pd(C₆X₅)₂(Y), PdCl(C₆X₅)(Y) (X = F, Cl). The neutral ligand Y is a keto-stabilized phosphorus ylide of the type Ph₂P(CH₂)_nPPh₂CHC(O)R (n = 1, R = CH₃, C₆H₅; n = 2, R = C₆H₅) acting in a terminal monodentate P-donor or a bidentate chelate P,C-donor mode. The reaction of PdCl(C₆F₅)(Y) complexes with HCl leads to the corresponding PdCl₂(C₆F₅)(YH) complexes in which the phosphonium cation [YH]⁺ behaves as monodentate P-donor at its phosphinic end.IR and ³¹P NMR spectroscopy were used to decide the coordination mode of the ligands and, in some cases, to reveal the presence of two isomers.     

Characterization of an aluminium(III)–citrate species by means of ion chromatography with inductively coupled plasma-atomic emission spectrometry detection

The aluminium(III)–citrate complex (NH₄)₄[Al₂(C₆H₄O₇)(C₆H₅O₇)₂]·4H₂O was characterized using anion exchange chromatography on-line coupled with the element specific ICP-AES detector. Time-dependent monitoring of individual species in aqueous solution at different temperatures gave information about the species stability and the decomposition pathway. The aluminium–citrate complex (NH₄)₄[Al₂(C₆H₄O₇)(C₆H₅O₇)₂]·4H₂O disintegrated via an unknown intermediary Al(III)–citrate species from which the thermodynamically stable complex [Al₃(C₆H₄O₇)₃(OH)(H₂O)]⁴⁻ was formed. The activation energy for the decomposition reaction and the pre-exponential factor were determinated to be E_a = 81.95 kJ mol⁻¹ and A = 3.62 × 10¹³ s⁻¹.     

The formation of the anilinium ion from the ammonium ion in the ammonia chemical ionization of substituted benzenes

Compounds C₆H₅X(X ? F, Cl, Br, NO₂, CN, OCH₃) have been studied under chemical ionization conditions with ammonia as reagent gas. A pulsed electron beam and time resolved ion collection has allowed the determination of the reaction leading to the formation of [C₆H₅NH₃]⁺ (m/z 94). [NH₄]⁺ reacts with C₆H₅X(X ? F, Cl, Br) to yield m/z 94 but C₆H₅X (X ? CN, NO₂) forms this ion only by reactions involving either [NH₃]⁺ or [C₆H₅X]⁺. C₆H₅OCH₃ does not form m/z 94.     

Molybdenum Bisphosphonates with Cr(III) or Mn(III) Ions

The synthesis of Mo^VI bisphosphonates (BPs) complexes in the presence of a heterometallic element has been studied. Two different BPs have been used, the alendronate ligand, [O₃PC(C₃H₆NH₃)(O)PO₃]^4? (Ale) and a new BP derivative with a pyridine ring linked to the amino group, [O₃PC(C₃H₆NH₂CH₂C₅H₄N)(O)PO₃]^4? (AlePy). Three compounds have been isolated, a tetranuclear Mo^VI complex with Cr^III ions, (NH₄)₅[(Mo₂O₆)₂(O₃PC(C₃H₆NH₃)(O)PO₃)₂Cr]·11H₂O (Mo₄(Ale)₂Cr), its Mn^III analogue, (NH₄)_4.5Na_0.5[(Mo₂O₆)₂(O₃PC(C₃H₆NH₃)(O)PO₃)₂Mn]·9H₂O (Mo₄(Ale)₂Mn), and a cocrystal of two polyoxomolybdates, (NH₄)₁₀Na₃[(Mo₂O₆)₂(O₃PC(C₃H₆NH₂CH₂C₅H₄N)(O)PO₃)₂Cr]₂[CrMo₆(OH)₆O₁₈]·37H₂O ([Mo₄(AlePy)₂Cr]₂[CrMo₆]). In this latter compound an Anderson-type POM [CrMo₆(OH)₆O₁₈]^3? is sandwiched between two tetranuclear Mo^VI complexes with AlePy ligands. The protonated triply bridging oxygen atoms bound to the central Cr^III ion of the Anderson anion develop strong hydrogen bonding interactions with the oxygen atoms of the bisphosphonate complexes. The UV–Vis spectra confirm the coexistence in solution of both POMs. Cyclic voltammetry experiments have been performed, showing the reduction of the Mo centers. In strong contrast with the reported Mo^VI BP systems, the presence of trivalent cations in close proximity to the Mo^VI centers dramatically impact the potential solid-state photochromic properties of these compounds.     

Nitrosyl Rhenium Complexes Syntheses,Properties, and Structures of Oxalato Derivatives

The free acid, H[Re(NO)(C₂O₄)(OH)₂(H₂O)] has been prepared from the reaction of Re(NO)(OH)₃ ? H₂O with oxalic acid in aqueous medium. The K⁺, NH₄⁺ and Pb²⁺ salts of the acid have been isolated. Nonelectrolytic diimino derivatives, Re(NO)(C₂O₄)X · L (X = 1, 10-phenanthroline, 2,2′-dipyridyl; L ? OH^?, Cl^?) have been synthesized. The complexes have been characterised through elemental analyses, spectral (u.v., vis., i.r.) properties, magnetic and conductance data and their structures are proposed.     

[2,6(9)-B10H8>(O)2CCH3]− and [2,7(8)-B10H8(OC(O)CH3)2]2− derivatives in synthesis of position isomers of the [B10H8(OC(O)CH3)(OH)]2− anion with the 2,6(9)- and 2,7(8)-arrangement of functional groups

The interaction of Cat₂B₁₀H₁₀ (Cat = Ph₄P⁺, Ph₄As⁺) with acetic acid has been studied. Disubstituted closo-decaborate derivatives with a bidentately bound acetate group, Cat[2,6(9)-B₁₀H₈>(O)₂CCH₃], or two monodentate acetate groups, Cat₂[2,7(8)-B₁₀H₈(OC(O)CH₃)₂], have been isolated (Cat = Ph₄P⁺, Ph₄As⁺). Hydrolysis of these compounds has led to the position isomers of the [B₁₀H₈(OC(O)CH₃)(OH)]^2? anion with the hydroxo and acetate groups in the 2,6(9)- and 2,7(8)-positions. The structures of {Pb(Bipy)₂[2,6(9)-B₁₀H₈(OC(O)CH₃)(OH)]}₂ · 3H₂O, (Ph₄As)₂[2,6(9)-B₁₀H₈(OC(O)CH₃)(OH)] · 0.4C₂H₅OH · 0.25H₂O, and (Ph₄As)₂[2,7(8)-B₁₀H₈(OC(O)CH₃)(OH)], as well as of the product of the reaction of the B₁₀H ₁₀ ^2? anion with formic acid (Ph₄P)₂[2-B₁₀H₉OC(O)H] · CH₃CN, have been determined by X-ray crystallography.     

Reactions of [η:σ-Me2C(C5H4)(C2B10H10)]Ru(COD) with Lewis bases: Synthesis, structure, and electrochemistry of ruthenium amine, nitrile, carbene, phosphite and phosphine complexes

Treatment of [η⁵:σ-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru(COD) (1) with phosphites, phosphines, amines or N-heterocyclic carbene in THF afforded the COD displacement complexes [η⁵:σ-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru[P(OEt)₃]₂ (2), [η⁵:σ-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru[PPh₂(OEt)]₂ (3), [η⁵:σ-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru[NH₂CH₂CH₂Prⁱ]₂ (4), [η⁵:σ-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru(NH₂Prⁿ)₂ (5), [η⁵:σ-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru (η²-NH₂CH₂CH₂NH₂) (6), [η⁵:σ-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru[η²-NH(CH₃)CH₂CH₂NH(CH₃)] (7) or [η⁵:σ-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru[NHC]₂ (8, NHC = 1,3,4,5-tetramethylimidazol-2-yilidene), respectively. Ruthenium-amine complexes were much more labile than 1. Upon exposure to moisture, 5 was converted into [{η⁵:σ-Me₂C(C₅H₄)(C₂B₁₀H₁₀)}Ru(μ-H₂O)]₂ (9). Reactions of 5 with PR₃ (R = PPh₃, Cy), TMEDA (TMEDA = N,N,N′,N′-tetramethylethylenediamine) and CH₃CN afforded the corresponding amine replacement products[η⁵:σ-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru(NH₂Prⁿ)(PPh₃) (10), [η⁵:σ-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru(NH₂Prⁿ)(PCy₃) (11), [η⁵:σ-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru(TMEDA) (12) and [η⁵:σ-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru(NCCH₃)₂ (13). These results indicated that the steric factor dominated these substitution reactions. The electrochemical studies showed that the electron richness of the Ru atom decreased in the order L₂Ru(NHC)₂ > L₂Ru(amine)₂ > L₂Ru(NCMe)₂ > L₂Ru(P)₂. All of these complexes were fully characterized by various spectroscopic techniques and elemental analyses. The molecular structures of 2, 3, 5-10, 12 and 13 were further confirmed by single-crystal X-ray analyses.     

Cyclopentadienylnickel thiolate complexes: synthesis, molecular structures and electrochemical detection of sulfur dioxide adducts

Simple reactions between Ni(η⁵-C₅H₅)(PR₃)Br and the Schiff-base thiols, 4-HSC₆H₄NC(H)C₄H₂SBr-4^′ (1) and 4-HSC₆H₄NC(H)C₄H₃S (2), or organothiols, HSC₆H₄F-4 and HSC₆H₄NH₂-4, produced cyclopentadienylnickel thiolates of the formulae, Ni(η⁵-C₅H₅)(PR₃)(SC₆H₄NC(H)C₄H₂SBr-4) (3), Ni(η⁵-C₅H₅)(PR₃)(SC₆H₄NC(H)C₄H₃S) (4) or Ni(η⁵-C₅H₅)(PR₃)(SC₆H₄X-4) (R=Ph, X=F (6) or NH₂ (7) and R=Bu, X=F (5) or NH₂ (8)) which were characterized by a combination of analytical techniques. Complexes 3, 6 and 7 were structurally characterized by X-ray crystallography, showing that they possess the familiar trigonal geometry around the nickel center. These complexes react with sulfur dioxide, with 5, 6, 7 and 8 exhibiting substantial differences between the redox potentials of the pre- and post-SO₂ compounds to suggest that these complexes can be developed as potentiometric SO₂ sensors.     

Synthesis and Characterization of 1,3,2‐Bis (arylamino) phospholidine, 2‐oxide Derivatives: Crystal Structures of $\rm Cl(O)\overline{PN(p-Me-C_{6}H_{4})CH_{2}CH_{2}N}(p-Me-C_{6}H_{4})$ and $\rm ((CH_{2}C_{6}H_{5})(O)\overline{PN(p-Me-C_{6}H_{4})CH_{2}CH_{2}N}(p-Me-C_{6}H_{4})$

Using phosphoryl chloride as a substrate, a family of 1,3,2‐bis(arylamino) phospholidine, 2‐oxide of the general formula ; (X=Cl, 6a ; X=NMe₂, 1b ; X=N(CH₂C₆H₅)(CH₃), 2b ; X=NHC(O)C₆H₅, 3b ; X=4Me‐C₆H₄O, 4b ; X=C₆H₅O, 5b ; X=NHC₆H₁₁, 6b ; X=OC₄H₈N, 7b ; X=C₅H₁₀N, 8b ; X=NH₂, 9b ; X=F, 10b and Ar=4Me‐C₆H₄) was prepared and characterized by ¹H, ¹⁹F, ³¹P and ¹³C NMR and IR spectroscopy, and elemental analysis. A general and practical method for the synthesis of these compounds was selected. The structures of 6a and 2b were determined by single‐crystal X‐ray diffraction techniques. The low temperature NMR spectra of 2b revealed the restricted rotation of P‐N bond according to two independent molecules in crystalline lattice.     

Rate coefficients at 297 K for proton transfer reactions with H2O. Comparisons with classical theories and exothermicity

Rate coefficients for proton transfer reactions of the type XH⁺ + H₂O → H₃O⁺ + X where X = H₂, CH₄, CO, N₂, CO₂ and N₂O and the type H₂O + X^? → XH + OH^? where X = H, NH₂ and C₂H₅NH have been measured at 297 K using the flowing afterglow technique. The results compare favourably with the predictions of the average-dipole-orientation theory. A trend is observed with exothermicity on a plot of (k_exp/k_ADO)_{298 K} versus ?ΔH_{298 K}⁰. The question is raised whether the relatively low probability observed for slightly exothermic proton transfer reactions is a consequence of reaction mechanism or results from the presence of a small activation energy barrier.     

Bildung und Verhalten von Chlorozinksäuren in äthanolischer Lösung

Formation and Behaviour of Chlorozinc Acids in Ethanolic Solution The reaction between ZnCl₂ and HCl in ethanol leads to H₂ZnCl₄ only. The behaviour of H₂ZnCl₄ · 3 (C₂H₅)₂O, (NH₄)₂[ZnCl₄] and HCl in ethanolic solutions has been investigated by means of conductivity measurements at ?10 and ?20°C. The equivalent conductivities have been determined. The Stokes radii of [ZnCl₄]^2?, H⁺, and [(C₂H₅)₂OH]⁺ are calculated.     

Propionyl complexes of ruthenium derived from the reaction of ethylene with RuHCl(CO)2(PPh3)2

RuHCl(CO)₂(PPh₃)₂ reacts with ethylene under mild conditions (25 psi, 80°C) to yield a propionyl derivative RuCl(C[O]C₂H₅)(CO)(PPh₃)₂ which is believed to be coordinatively unsaturated. Unlike the acetyl analogue, RuCl[C[O]C₂H₅(CO)-(PPh₃)₂ does not isomerize to RuCl(C₂H₅)(CO)₂(PPh₃)₂ in solution. Under one atmosphere of carbon monoxide, RuCl(C[O]C₂H₅(CO)(PPh₃)₂ exists in equilibrium with two species believed to be RuCl(C[O]C₂H₅)(CO)₂(PPh₃)₂ and [Ru(C[O]C₂H₅)(CO)₃(PPh₃)₂]Cl. RuCl(C[O]C₂H₅)(CO)(PPh₃)₂ reacts with CO/ AgClO₄ to give mer-[Ru(C[O]C₂H₅)(CO)₃(PPh₃)₂]ClO₄, p-tolylisocyanide (RNC) and NaClO₄ to give cis-[Ru(C[O]C₂H₅)(CO)(CNR)₂(PPh₃)₂ClO₄, and hydrochloric acid to yield the hydroxycarbene complex, RuCl₂(CO)(C[OH]C₂H₅)(PPh₃)₂.     

Vinyliden-Übergangsmetallkomplexe: II. Die Protonierung der Vinyliden-Komplexe C5H5Rh(CCHR)(PPri3) und ihre stufenweise Umwandlung in Vinyl- und α-Halogenalkyl-Rhodiumverbindungen

The protonation ofC₅H₅Rh(CCH₂)(PPrⁱ₃) (I) by CF₃CO₂H, HCl and HI gives the vinylrhodium compounds C₅H₅Rh(CHCH₂)(PPrⁱ₃)X (II-IV). The reaction of III (X = Cl) and IV (X = I) with a second molecule of HCl leads to the formation of the α-chloroethyl complexes C₅H₅Rh(CHClCH₃)(PPrⁱ₃)X (VII, VIII). The stereochemistry of these products allows us to propose a mechanism for HCl addition to the CC double bond of the vinyl ligand. C₅H₅Rh(CCHPh)(PPrⁱ₃) (XII) reacts with CF₃CO₂H and HI to give the kinetically preferred compounds C₅H₅Rh(Z-CHCHPh)(PPrⁱ₃)X (XIVa, XVa) of which XIVa (X = CF₃CO₂) in4bpolar solvents rearranges smoothly to form the thermodynamically more stable E isomer C₅H₅Rh(E-CHCHPh)(PPrⁱ₃)OCOCF₃ (XIVb). C₅H₅Rh(E-CHCHPh)(PPrⁱ₃)I (XVb) is obtained from XIVb and NaI. The protonation reactions of C₅H₅Rh(CCHMe)(PPrⁱ₃) (XIII) with CF₃CO₂H, HCl and HI always produce mixtures of isomers of the complexes C₅H₅Rh(CHCHMe)(PPrⁱ₃)X (XVI-XVIII). The ratio of Z to E isomers (≈ 62/38) is not dependent on the anion X and is also not influenced by the polarity of the solvent.     

Coordination Properties of Perfluoroethyl‐ and Perfluorophenyl‐Substituted Phosphonous acids,RfP(OH)2

Phosphinic acids, R^fP(O)(OH)H (R^f=CF₃, C₂F₅, C₆F₅), turned out to be excellent preligands for the coordination of phosphonous acids, R^fP(OH)₂. Addition of C₂F₅P(O)(OH)H to solid PtCl₂ under different reaction conditions allows the isolation and full characterization of the mononuclear complexes [ClPt{P(C₂F₅)(OH)O}{P(C₂F₅)(OH)₂}₂] and [Pt{P(C₂F₅)(OH)O}₂{P(C₂F₅)(OH)₂}] containing hydrogen‐bridged [R^fP(OH)O]^? and R^fP(OH)₂ units. Further deprotonation of [Pt{P(C₂F₅)(OH)O}₂{P(C₂F₅)(OH)₂}₂] leads to the formation of the dianionic platinate, [Pt{P(C₂F₅)(OH)O}₄]^2?, revealing four intramolecular hydrogen bridges. With PdCl₂ the dinuclear complex [Pd₂(μ‐Cl)₂{[P(C₂F₅)(OH)O]₂H}₂] was isolated and characterized. The Cl^? free complex [Pd{P(C₂F₅)(OH)O}₂{P(C₂F₅)(OH)₂}₂] was also prepared and deprotonated to the dianionic palladate, [Pd{P(C₂F₅)(OH)O}₄]^2?. Both compounds were characterized by NMR spectroscopy, IR spectroscopy, and X‐ray analyses. In addition, the C₆F₅ derivatives [ClPt{P(C₆F₅)(OH)O}{P(C₆F₅)(OH)₂}₂] and [Pd₂(μ‐Cl)₂{[P(C₆F₅)(OH)O]₂H}₂] as well as the CF₃ derivative [Pd₂(μ‐Cl)₂{[P(CF₃)(OH)O]₂H}₂] were synthesized and fully characterized. Phosphonous acid complexes are inert towards air and moisture and can be stored for several months without decomposition. The catalytic activity of the palladium complexes in the Suzuki cross‐coupling reaction between 1‐bromo‐3‐fluorobenzene and phenyl boronic acid was demonstrated.     

Ruthenium bidentate phosphine complexes for the coordination and catalytic dehydrogenation of amine- and phosphine-boranes

Addition of the amine–boranes H₃B ? NH₂tBu, H₃B ? NHMe₂ and H₃B ? NH₃ to the cationic ruthenium fragment [Ru(xantphos)(PPh₃)(OH₂)H][BAr^F₄] ( 2 ; xantphos=4,5‐bis(diphenylphosphino)‐9,9‐dimethylxanthene; BAr^F₄=[B{3,5‐(CF₃)₂C₆H₃}₄]^?) affords the η¹‐B? H bound amine–borane complexes [Ru(xantphos)(PPh₃)(H₃B ? NH₂tBu)H][BAr^F₄] ( 5 ), [Ru(xantphos)(PPh₃)(H₃B ? NHMe₂)H][BAr^F₄] ( 6 ) and [Ru(xantphos)(PPh₃)(H₃B ? NH₃)H][BAr^F₄] ( 7 ). The X‐ray crystal structures of 5 and 7 have been determined with [BAr^F₄] and [BPh₄] anions, respectively. Treatment of 2 with H₃B ? PHPh₂ resulted in quite different behaviour, with cleavage of the B? P interaction taking place to generate the structurally characterised bis‐secondary phosphine complex [Ru(xantphos)(PHPh₂)₂H][BPh₄] ( 9 ). The xantphos complexes 2 , 5 and 9 proved to be poor precursors for the catalytic dehydrogenation of H₃B ? NHMe₂. While the dppf species (dppf=1,1′‐bis(diphenylphosphino)ferrocene) [Ru(dppf)(PPh₃)HCl] ( 3 ) and [Ru(dppf)(η⁶‐C₆H₅PPh₂)H][BAr^F₄] ( 4 ) showed better, but still moderate activity, the agostic‐stabilised N‐heterocyclic carbene derivative [Ru(dppf)(ICy)HCl] ( 12 ; ICy=1,3‐dicyclohexylimidazol‐2‐ylidene) proved to be the most efficient catalyst with a turnover number of 76 h^?1 at room temperature.     

Group 12 metal complexes of tetradentate N2O2–Schiff-base ligands incorporating pyrazole: Synthesis,characterisation and reactivity toward S-donors,N-donors,copper and tin acceptors

New [M(Q)₂(X)] derivatives (where M=Zn, Cd or Hg; Q=1-phenyl-3-methyl-4-R(C=O)-pyrazolon-5-ato; in detail: Q_L, R=C₆H₅; Q_B, R=CH₂C(CH₃)₃; Q_S, R=CH(C₆H₅)₂; X=EtOH or H₂O) have been synthesised and characterised. These compounds undergo a condensation reaction with the appropriate diamine in ethanol, affording novel Schiff-base metal derivatives [M(diaquo)bis(1-phenyl-3methyl-4-R(C=N)-pyrazolone)(CH₂)_ndiimmine] (LⁿH₂, R=C₆H₅, n=2, 3 or 4; BⁿH₂, R=CH₂C(CH₃)₃, n=2, 3 or 4; SⁿH₂, R=CH(C₆H₅)₂, n=2 or 3; M=Zn, Cd or Hg). These compounds possess a six-coordinate metal environment. A ¹¹³Cd NMR study has been carried out on cadmium derivatives. The derivative [Zn(L²)(H₂O)₂] reacted with CuCl₂ and with Cu(ClO₄)₂ affording [Cu(Q_L)₂] and [Cu(en)₂](ClO₄)₂ (en=ethylendiamine), respectively, upon breaking of the C=N bond in the Schiff-base donor. In addition [Zn(L²)(H₂O)₂] reacted with 1,10-phenanthroline (phen), yielding the derivative [Zn(Q_L)₂(phen)]. Whereas when [Zn(L²)(H₂O)₂] reacted with CdCl₂, formation of [Cd(L²)(H₂O)₂] due to exchange of the metal centre was observed. Finally the derivative [Zn(L²)(Hmimt)], likely containing a five-coordinate ZnN₂O₂S central core, has been obtained from the exchange reaction between [Zn(L²)(H₂O)₂] and 1-methylimidazolin-2-thione (Hmimt).     

New η-allyl η-cyclopentadienylcobalt cations

[Co(R-η-C₃H₄)(η-C₅H₅)I] is a good precursor for the preparation of some new cationic complexes as the iodide can easily be replaced; thus addition of PEt₃ to the iodo-complex (R  H) gives [Co(η-C₃H₅)(η-C₅H₅)(PEt₃)]⁺. The reactions of [Co(R-η-C₃H₄)(η-C₅H₅))I] (R  H or 2-Me) with AgBF₄ give solutions containing the coordinatively unsaturated species [Co(R-η-C₃H₄)(η-C₅H₅)⁺. The presence of traces of water leads to the formation of [Co(R-ηC₃H₄)-(η-C₅H₅)(H₂O)]⁺. The addition of monodentate ligands L  PEt₃ PPh₃, AsPh₃, SbPh₃, CNCH₃ and bidentate ligands LL  Ph₂PCH₂CH₂PPh₂(dppe) and o-C₆H₄(AsMe₂)₂(diars), gives, respectively mononuclear [Co(2-Me-ηC₃H₄)-(η-C₅H₅)L]⁺ and binuclear ligand-bridged [(2-Me-ηC₃H₄)(η-C₅H₅)CoLLCo(2-Me-ηC₃H₄)(η-C₅H₅))]²⁺ complexes. Crystals of [Co(2-Me-ηC₃H₄)(η-C₅H₅)-(H₂O)]⁺[BF₄]^- are monoclinic, space group P2₁/c, with a 7.858(3), b 10.262(4), c 15.078(4) Å, β 98.36(1)°. The molecular structure contains the cobalt atom bonded to planar 2-Me-allyl and cyclopentadienyl substituents, which are almost parallel with the H₂O molecule in a staggered conformation with respect to the 2-Me group.     

Hydroxyl Ammonium and Diethyl Ammonium Glutaratouranylates: Synthesis and Structure

The structures of two new coordination polymers, namely, hydroxyl ammonium glutaratouranylate NH₃OH[UO₂(C₅H₆O₄)(C₅H₇O₄)] · H₂O (I) and diethyl ammonium glutaratouranylate NH₂(C₂H₅)₂[UO₂(C₅H₆O₄) (C₅H₇O₄)] · 2H₂O (II), have been characterized by single-crystal X-ray diffraction. It has been established that the structures of complexes I and II contain [UO₂(C₅H₆O₄)(C₅H₇O₄)]–infinite chains with the crystallochemical formula AQ⁰²B⁰¹ (\(\rm{A = UO_2^{2+}}, Q^{02} = C_5H_6O_4^{2-}, B^{01} = C_5H_7O_4^{-}\)). Despite the identical compositions, uranyl glutarate chains in the studied structures appreciably differ from each other by their geometry and linking. The specific features of nonbonded interactions in the structures of complexes I and II have been characterized by the Voronoi–Dirichlet method of molecular polyhedra.     

The Nitrogen‐Assisted Triphenylphosphine Displacement of 3‐Hydroxypyridine and 3‐Aminopyridine Ligands in Palladium(II) Complexes: Crystal Structures of [Pd(PPh3)Br]2{μ,η2‐C5H3N(OH)}2 and [Pd(PPh3)Br]2{μ,η2‐C5H3N(NH2)}2

Treatment of Pd(PPh₃₎₄ with 2‐bromo‐3‐hydroxypyridine [C₅H₃N(OH)Br] and 3‐amino‐2‐bromopyridine [C₅H₃N(NH₂)Br] in dichloromethane at ambient temperature cause the oxidative addition reaction to produce the palladium complex [Pd(PPh₃₎₂{η¹‐C₅H₃N(OH)}(Br)], 2 and [Pd(PPh₃₎₂{η¹‐C₅H₃N(NH₂)}(Br)], 3 , by substituting two triphenylphosphine ligands, respectively. In dichloromethane solution of complexes 2 and 3 at ambient temperature for 3 days, it undergo displacement of the triphenylphosphine ligand to form the dipalladium complexes [Pd(PPh₃)Br]₂{μ,η²‐C₅H₃N(OH)}₂, 4 and [Pd(PPh₃)Br]₂{μ,η²‐C₅H₃N(NH₂)}₂, 5 , in which the two 3‐hydroxypyridine and 3‐aminopyridine ligands coordinated through carbon to one metal center and bridging the other metal through nitrogen atom, respectively. Complexes 4 and 5 are characterized by X‐ray diffraction analyses.