Chloro Species Research Articles

Solvation of uranyl(II), europium(III) and europium(II) cations in "basic" room-temperature ionic liquids: a theoretical study.

We report a molecular dynamics study of the solvation of UO2(2+), Eu3+ and Eu2+ ions in two "basic" (Lewis acidity) room-temperature ionic liquids (IL) composed of the 1-ethyl-3-methylimidazolium cation (EMI+) and a mixture of AlCl4- and Cl- anions, in which the Cl-/AlCl4- ratio is about 1 and 3, respectively. The study reveals the importance of the [UO2Cl4]2- species, which spontaneously form during most simulations, and that the first solvation shell of europium is filled with Cl- and AlCl4- ions embedded in a cationic EMI+ shell. The stability of the [UO2Cl4]2- and [Eu(III)Cl6]3- complexes is supported by quantum mechanical calculations, according to which the uranyl and europium cations intrinsically prefer Cl- to the AlCl4- ion. In the gas phase, however, [Eu(III)Cl6]3- and [Eu(II)Cl6]4- complexes are predicted to be metastable and to lose two to three Cl- ions. This contrasts with the results of simulations of complexes in ILs, in which the "solvation" of the europium complexes increases with the number of coordinated chlorides, leading to an equilibrium between different chloro species. The behavior of the hydrated [Eu(OH2)8]3+ complex is considered in the basic liquids; the complex exchanges H2O molecules with Cl- ions to form mixed [EuCl3(OH2)4] and [EuCl4(OH2)3]- complexes. The results of the simulations allow us to better understand the microscopic nature and solvation of lanthanide and actinide complexes in "basic" ionic liquids.

Thermodynamic Model for the Solubility of TcO2· xH2O(am) in the Aqueous Tc(IV) – Na+– Cl-– H+– OH-– H2O System

Solubility studies of TcO2· xH2O(am) have been conducted as a function of H+ concentration from 1 × 10− 5 to 6 M HCl and as a function of chloride concentration from 1 × 10− 3 to 5 M NaCl. These experiments were conducted under carefully controlled reducing conditions such that the preponderance of Tc present in solution is in the reduced oxidation state and was determined to be Tc(IV) by XANES analysis. The aqueous species and solid phases were characterized using a combination of techniques including thermodynamic analyses of solubility data, XRD, and XANES, EXAFS, and UV-vis spectroscopies. Chloride was found to significantly affect Tc(IV) concentrations through (1) the formation of Tc(IV) chloro complexes [i.e., TcCl4(aq) and TcCl6 2 −] and a stable compound [data suggests this compound to be TcCl4(am)] in highly acidic and relatively concentrated chloride solutions, and (2) its interactions with the positively charged hydrolyzed Tc(IV) species in solutions of relatively low acidity and high chloride concentrations. A thermodynamic model was developed that included hitherto unavailable chemical potentials of the Tc(IV)–chloro species and Pitzer ion-interaction parameters for Tc(IV) hydrolyzed species with bulk electrolyte ions used in this study. The thermodynamic model presented in this paper is consistent with the extensive data reported in this study and with the reliable literature data and is applicable to a wide range of H+ and Cl− concentrations and ionic strengths.

OH-exchange by hydroxo complexes of platinum(II)

The improved preparation and the new synthesis of the hydroxo complexes [Pt(Me)(OH)(PP)] (PPPh 2PCH 2CH 2PPh 2 ( 1), Ph 2PCHCHPPh 2 ( 2)), abbreviated as [Pt]OH, is reported. The chemical behavior of 1 towards bases, organic and organometallic halides has been tested. There was no NMR spectroscopic evidence for the formation of a reactive oxo intermediate [Pt]O − upon reaction with a strong base. In the presence of an electrophilic organic reagent such as an alkyl halide RX (R=Me, CH 2Ph, Et, t-Bu; X=Cl, Br, I), the OH for X exchange process takes place with the formation of the organometallic derivative [Pt(Me)(X)(PP)] and the corresponding alcohols ROH. Similar reactions carried out in the presence of an electrophilic organometallic species such as the neutral complexes [PtCl 2(CNC 6H 4 p-OMe)(PPh 3)] and [PtCl 2(COD)] or the cationic derivative trans-[PtCl(CNMe)(PPh 3) 2][BF 4] indicate primarily OH for Cl exchange with formation of the chloro species [Pt(Me)(Cl)(PP)] and unstable hydroxo complexes, which decompose under the experimental conditions. In the case of the cationic complex also OH for PPh 3 exchange is observed. A possible mechanism for the observed reactivity is described.

Halogenation of Alkenes in Five-Coordinate Platinum(II) Complexes – A Route to Stable (β-Haloalkyl)platinum(IV) Species

Five-coordinate complexes [PtX2(olefin)(2,9-Me2-phen)] (1; 2,9-Me2-phen = 2,9-dimethyl-1,10-phenanthroline; olefin = ethene denoted by a, propene by b, 1-butene by c; × = Cl denoted by x, Br by y) undergo photoactivated reactions with Cl2 and Br2 to give the (β-haloalkyl)platinum(IV) complexes [Pt(CH2CHRX)(2,9-Me2-phen)X3] (2). Bromination of the chloro species 1ax leads to the formation of the PtIV species 2axy containing the bromide, the bromoalkyl, and the phenanthroline ligands in the equatorial plane and two chloride ions in axial positions. The iodo complexes 1(a–c)z are not oxidized by iodine even under UV irradiation but react readily with Cl2 or Br2 to give 2(a–c)x and 2(a–c)y. The structure of 2ay, the first structurally characterized (β-haloalkyl)platinum complex, has been determined by X-ray diffraction methods. The stereochemistry of the (β-haloalkyl)platinum(IV) complexes is in accord with a simultaneous addition of two halogen atoms to the coordinated olefin and to the metal center.

Reactivity of an extremely sterically crowded monofunctional Pt complex, [Pt(1-MeC-N3)3(H2O)]2+ (1-MeC = 1-methylcytosine), toward model nucleobases and selectivity toward guanine in single- and double-stranded deoxyoligonucleotides.

Reactions of [Pt(1-MeC-N3)3Cl]NO3 (1-MeC-N3 = 1-methylcytosine, bound to Pt via N3) and the respective aqua species [Pt(1-MeC-N3)3(H2O)]2+ with the model nucleobases 9-ethylguanine (9-EtGH), 9-methyladenine (9-MeA), single-stranded 5'd(T3GT3), and double-stranded [5'd(GA-GA2GCT2CTC)]2 have been studied in solution by means of 1H NMR spectroscopy, HPLC, and electrospray ionization mass spectrometry. Reactions are generally slow, in particular with the chloro species, and guanine is the only reactive base in the oligonucleotides. However, unlike (dien)PtII, which binds randomly to the guanines in the ds dodecamer, (1-MeC-N3)3PtII binds selectively to the terminal guanine only, probably because base fraying takes place at the duplex ends. The X-ray crystal structures of [Pt(1-MeC-N3)3(9-EtG-N7)]ClO4.8H2O (1b) and of [Pt(1-MeC-N3)3(9-MeA-N7)](ClO4)2.0.5H2O as well as NMR spectroscopic studies of [Pt(1-MeC-N3)3(9-EtGH-N7)] (NO3)2.H2O (1a) are reported. The tetrakis(nucleobase) complexes adopt a head-tail-head orientation of the three 1-MeC bases and an orientation of the fourth base (purine) that permits a maximum of intracomplex H bonds between exocyclic groups. As far as the guanine adduct (1a, 1b) is concerned, relative orientations of the four bases are identical in the model and in the oligonucleotide adduct.

Specific displacement of glutathione from the Pt(II)–glutathione adduct by Cu(II) in neutral phosphate buffer

The Pt–S bond of Pt(II)–glutathione (GS–Pt) complex was dissociable in neutral phosphate buffer at room temperature in the presence of Cu(II) ion. In addition, the chloro species, Pt(terpy)Cl +, was isolated and identified as the major cleavage product of Pt(terpy)(GS) 2+ complex when CuCl 2 was used. The Pt–S bond dissociation of Pt(terpy)(GS) 2+ mediated by Cu(II) ion was shown to be a pH dependent process in the range of 4.5–8.0. At pH <7, NMR evidence was obtained for a S-bridged heterodinuclear unit formed between Pt(terpy)(GS) 2+ and the Cu(II) ion; however, no Pt–S bond dissociation was observed up to 24 h. At pH ⩾ 7, NMR data suggested coordination of the amide nitrogen of GSH of Pt(terpy)(GS) 2+ to the Cu(II) ion. We propose that the coordination of the amide nitrogen to the Cu(II) ion, together with the formation of the S-bridged heterodinuclear unit, induce the Pt–S bond dissociation in Pt(terpy)(GS) 2+. These results may be exploited to develop a molecular activator to regenerate the anticancer activity in cisplatin pro-drugs.

Cis-Dichloro(alpha,omega-diamino carboxylate ethyl ester)palladium(II) as Palladium(II) versus Platinum(II) Model Anticancer Drugs: Synthesis, Solution Equilibria of Their Aqua, Hydroxo, and/or Chloro Species, and in Vitro/in Vivo DNA-Binding Properties.

cis-Dichloro(d,l-2,3-diaminopropionate ethyl ester)palladium(II), cis-[Pd(Etdap)Cl(2)] (I), and cis-dichloro(d,l-2,4-diaminobutyrate ethyl ester)palladium(II), cis-[Pd(Etdab)Cl(2)] (II), were synthesized and characterized by elemental analysis, IR spectroscopy, and TG-DTA thermal analysis. The equilibrium model and log beta(pqr) constants of hydrolytic species of I and II were also investigated by potentiometric methods (I = 0.15 M (NaClO(4)) and 37 degrees C). Aqueous solutions of cis-[Pd(Etdaa)(H(2)O)(2)](ClO(4))(2) (Etdaa = Etdap (III) or Etdab (IV)) were prepared by stoichiometric reaction of I or II with AgClO(4). Thus, log beta(pqr) of the corresponding cis-aquahydroxo (pqr = 1,0,-1) and di(&mgr;-hydroxo) (pqr = 2,0,-2) species were obtained from E(H(+)) data of alkalimetric titrations of solutions of III or IV. Such constants were then used as fixed values to obtain log beta(pqr)() of chloro-containing species (cis-dichloro (1,2,0), cis-chloroaqua (1,1,0), and cis-chlorohydroxo (1,1,-1)) from E(H(+)) and E(Cl(-)) data pairs simultaneously obtained by titration of solutions of III or IV with NaOH and NaCl. All log beta(pqr) were fitted by the SUPERQUAD program. Appropriate log beta(pqr)() sets give good simulations of experimental titration curves and several species distribution diagrams. In addition the interaction of I and/or II with DNA in vitro and in vivo was studied by various methods. UV spectral data and melting and renaturation curves indicate that both compounds destabilize the DNA helicoidal structure. Compound II disrupts in vivo the structure and transcription process of polytene chromosomes of Drosophila hydei.

高分子量第四アンモニウム塩による塩酸溶液からのロジウム（ＩＩＩ）の抽出

The extraction of rhodium (III) from hydrochloric acid solutions has been investigated by using a trioctylmethylammonium chloride (TOMAC; R3R'NCl) under various conditions.The extraction curve shows a minimum value at about 4 mol dm-3 in initial aqueous hydrochloric acid solution. The extraction efficiency is promoted in chlorobenzene, nitrobenzene and 1, 2-dichloroethane as diluent and suppressed in carbon tetrachloride and chloroform. At low acidity (≤4 mol dm-3HCl) both origomer bridged by hydroxyl group and chloro species are extracted, while at higher acidity (≥4 mol dm-3HCl) the origomer species is principally extracted. The stoichiometric composition of the origomer complex formed in the organic phase was found to be (R3R'N) 2Rh3 (OH) 4Cl7 (H20) 3.The distribution ratio increases with increasing temperature.In the examination of separation between rhodium (III) and ruthenium (III), the separation factor in the extraction of rhodium chloro species becomes about sixteen times greater than that from the solution containing origomer and chloro species.

塩化トリオクチルメチルアンモニウムによるロジウム（ＩＩＩ）クロロ化学種の抽出

The extraction of rhodium (III) chloro species has been investigated by using a trioctylmethylammonium chloride (R3R'NCl) in various diluents. The extraction isotherm decreasesThe extraction isotherm decreases with increasing the acid concentration. The stoichiometric composition of the complex formed in the organic phase deduced to be (R3R'N) RhCl4(H2O)2. Therefore, the following mechanism is proposed for the extraction of rhodium (III) chloro species.R3R'NCl (org) +RhCl4(H2O)2-(aq)⇔(R3R'N) RhCl4(H2O)2 (org)+Cl-(aq).These results are also confirmed by visible and infrared spectral measurements.In the examination of diluents effects, nitrobenzene and benzene most promoted the extraction of Rh (III) at 0.1 and 7 mol dm-3 hydrochloric acids, respectively.The distribution ratio increases with increasing temperature.

Lewis Base Adduct Stabilized Organogallium Azides: Synthesis and Dynamic NMR Spectroscopic Studies of Novel Precursors to Gallium Nitride and Role of Ammonia as Reactive Carrier Gas

The organogallium azides (N3)2-a(R)aGa[(CH2)3NMe2]1-a (1a-c: R = CH3, tBu; a = 0, 1), (Et)(N3)2Ga (2a), and (Et)(N3)2Ga·L (2b−d: L = thf, H2NtBu, py, NC7H13) are quantitatively synthesized by salt metathesis from the chloro species (Cl)2-a(R)aGa[(CH2)3NMe2]1-a (a = 0, 1) or EtGaCl2 and sodium azide. The preferential ammonolysis of Ga−N3 bonds for [Et2Ga(N3)]3 (4) and 1 and 2 is demonstrated; e.g. the dimer Et2Ga(μ-NH2)(μ-N3)GaEt2 (3) was obtained. The characterization of these compounds by means of elemental analysis, 1H-, 13C-, 14N-, and 15N-NMR, MS, and infrared ν(N3) data is reported. The dynamics of the intramolecular Ga−N donor−acceptor bonded heterocycle and the azide group is discussed on the basis of variable-temperature NMR data. The barrier of activation of the bimolecular azide exchange process for (N3)2Ga[(CH2)3NMe2] (1c) amounts about 50 kJ·mol-1. The role of ammonia as reactive carrier gas for low-pressure metal organic chemical vapor deposition (MOCVD) of GaN with 1c as precursor is discu...

Steric constraints and addition reactions in platinum(II) complexes containing 2,9-dimethyl-1,10-phenanthroline (Me 2-phen). X-ray crystal structures of [PtBr 2(Me 2-phen)] and [PtI 2(Me 2-phen)

[PtX 2(Me 2-phen)] complexes (X  Cl ( 1), Br ( 2), I ( 3); Me 2-phen=2,9-dimethyl1,10-penanthroline) react with dimethylsulfoxide, dimethylsulfide and nitrosobenzene to give the addition products [PtX 2(Me 2-phen)(L)] (L  DMS, 1–3a; DMSO, 1–3b; PhNO, 1–3c) containing mono-coordinated Me 2-phen. The equilibrium constants for the addition reactions ( K f) have been determined by 1H NMR spectroscopy and found to be strongly dependent upon the bulkiness of the halogen atoms; log K f increases linearly with the van der Waals radius of the halogens. The crystal structures of the complexes [PtBr 2(Me 2-phen ( 2) and [PtI 2(Me 2-phen)] ( 3) have been determined by X-ray diffraction methods. Crystal data for 2: monoclinic, space group P2 1/ n, a = 12.155(4), b = 7.933(2), c = 14.522(2) A ̊ , β = 93.74(2)°, Z = 4, R = 0.046 . Crystal data for 3: monoclinic, space group P2 1/ n, a = 12.542(2), b = 7.957(1), c = 14.976(3) A ̊ , β = 94.49(3)°, Z = 4, R = 0.036 . The distortions in the square-planar coordination geometry are compared to those found for the analogous chloro species and correlated to differences in reactivity.

Synthesis and crystal structure of nickel(II) complexes of macrobicyclic ligands: identification and electron-transfer reactions of the corresponding nickel(III) complexes in solution

The macrobicyclic complex [NiL1(ClO4)]ClO4(L1= 15-oxa-1,5,8,12-tetraazabicyclo[10.5.2]nonadecane) and the monocyclic precursor [NiL2(NCMe)][ClO4]2, [L2=N,N′-bis(3-aminopropyl)-1-oxa-4,7-diazacyclononane] have been prepared and their crystal structures determined: [NiL1(ClO4)]ClO4, space group P21/n, a= 13.580(6), b= 15.400(8), c= 10.418(4)Å, β= 97.91(2)°, Z= 4, R= 0.067, R′= 0.069; [NiL2(NCMe)][ClO4]2, monoclinic, space group Cc, a= 9.182(1), b= 19.859(3), c= 12.903(2)Å, β= 100.99(1)°, Z= 4, R= 0.063, R′= 0.065. In each of these species the complexed cation is six-co-ordinate with the ether oxygen co-ordinated ‘axially’ at distances of 2.109(6) and 2.189(12)Å, respectively. However, the equatorial co-ordination is significantly different. In [NiL1(ClO4)]+ the nickel arm is coplanar with the four nitrogen donors of the 14-membered macrocyclic ring. In [NiL2(NCMe)]2+ one pendant arm is axial (trans to the ether oxygen) with an acetonitrile molecule in the equatorial plane. Coplanarity of the equatorial donor set is not realized in this cation. The sixth position in [NiL1(ClO4)]+ is occupied by a weakly bound perchlorate ion [Ni–O 2.373(7)Å]. The corresponding nickel(III) complexes may be generated by Co3+(aq) oxidation in aqueous media or NO+ in non-aqueous media. Electron spin resonance measurements are consistent with an octahedral d7 on with the spectra obtained being sensitive to the nature of the nuclei in the sixth site. The kinetics of reduction of the nickel(III) macrobicyclic ligand complex and its thiatetraaza and pentaaza analogues with two outer-sphere electron-transfer reagents has been studied. Rapid electron self-exchange rate constants have been evaluated for both the aqua and chloro species [NiL(X)]n+(X = H2O, n= 3; X = Cl, n= 2), with a sensitivity to the nature of the axial ligands being observed.

Microwave spectral study of 3-chloropropionitrile and 3-bromoproprionitrile

The microwave spectra of the anti conformers of 3-chloropropionitrile and 3-bromopropionitrile have been assigned and analyzed. Rotational constants for the 35Cl isotopomer (in MHz) are A = 26818.74(35.13), B = 1508.89(0.01), C = 1454.62(0.01) and for the 79Br isotopomer are A = 26251.22(77.73), B = 1033.69(0.01), C = 1007.76(0.01). Structural computations with a consistent set of constraints have led to a reasonable set of structural parameters for the two molecules. For the chloro species (in Å) CC = 1.544, CC(N) = 1.468 and CCl = 1.789, while for the bromo species the values are CC = 1.544, CC(N) = 1.469 and CBr = 1.969. Hyperfine structure arising from the halogens has been partially resolved and analyzed. The experimental values of χ aa have been discussed in terms of the axial symmetry of the CX bonds.

195Pt and1H NMR study of the products of hydrolysis of Pt(L)X2, where L is an ethylenediamine derivative, and the crystal structure of [Pt(N,N-dimethylethylenediamine) (μ-OH)]2 (NO3)2

The hydrolysis reactions of complexes of the type Pt(L)X2 where L is ethylenediamine (en), N,N- dimethylenediamine (N,N-Me2en), N,N-dimethylenediamine (N,N′-Me2en) and N,N,N′, N′-tetramethylethylenediamine (Me4en) were studied. The halo ligands were removed by precipitation with AgNO3 and the pH of the resulting filtrate, which was about 2, was adjusted to 5.8 (pD = 6.2). The study of the products formed was carried out by multinuclear NMR spectroscopy. The 195Pt NMR spectra showed the presence of several hydrolysed products, especially with en. The hydroxo-bridged dimer can be synthesized in a pure state with all the ligands except en. The results on the latter ligand contradict the published results on the synthesis of the en hydroxo-bridged dimer whose biological properties were studied. When Pt(L)I2 is used as starting material a small quantity of chloro species was always observed, indicating that the reactant contained a small quantity of Pt(L)ICI. The crystal structure of the [Pt(N,N-Me2en)(μ-OH)]2(NO3)2 dimer was determined. The compound belongs to the P21/c space group, with a = 8.262(5), b = 10.960(8), c = 11.405(8), β = 121.07(5)°, Z = 2 and ρcalc = 2.720 mg m−3. The results showed that this is the trans isomer with an inversion centre between the two Pt atoms. There is a considerable strain inside the four-membered ring, as shown by the reduced internal angles OPtO′ = 79.1(6)0 and PtOPt′ = 101.0(6)°.

Preparation and characterisation of [PPh4][fac-PtX3(S4N4)](X = Cl, Br or I)

Reaction of [PPh4]X (X = Cl or Br) with K2[PtX4] in water leads to either [PPh4]2[PtCl4] or a mixture of [PPh4]2[PtBr4] and [PPh4]2[Pt2Br6], depending upon the halogen present; reaction of PtI2 with KI and [PPh4]I leads to [PPh4]2[Pt2I6] as the sole product. All of these compounds react with S4N4 in CH2Cl2 to give the platinum(IV) species [PPh4][PtX3(S4N4)] which contain the S4N42– ligand. The chloro species may also be obtained by metathesis from K[PtCl3(S4N4)] which is itself prepared by reaction of S4N4 with Zeise's salt, K[PtCl3(C2H4)], in tetrahydrofuran. Comparison of the 15N NMR spectra of labelled complexes with that of [Ir(CO)Cl(S415N4)(PPh3)] indicates that in all cases this ligand adopts a facial co-ordination mode, bound by two sulfurs and one nitrogen. Two 2J(15N–15N) interactions of magnitude 3 and 5.5 Hz are observed within the ligand.

Synthesis and characterization of square-planar platinum(II) and palladium(II) complexes with pyridine-2,6-dicarboxylic acid (H 2dipic). X-ray crystal structure of trans-Na 2[Pt(dipic) 2]·6H 2O and K[Pt(dipic)I]·1/2H 2O

The tetra-coordinate complexes trans-[Pt(Hdipic) 2]·2H 2O ( 1) and trans-[Pd(Hdipic) 2]·2H 2O ( 2) as well as their potassium and sodium derivatives trans-K 2[Pt(dipic) 2] ( 3), trans-Na 2[Pt(dipic) 2]·6H 2O ( 4) and trans-Na 2[Pd(dipic) 2]·2H 2O ( 5) have been obtained in high yield by reacting aqueous solutions of K 2[PtCl 4] and K 2[PdCl 4] with pyridine-2,6-dicarboxylic acid (H 2dipic) or its potassium or sodium salts, respectively, in 1:2 molar ratio. 1 and 2 are also formed on reacting equimolar amounts of reagents in water (pH 1.4) leaving in solution unreacted K 2[PtCl 4] and K 2[PdCl 4]. The resulting mixtures brought to pH 5 with KOH undergo a redistribution reaction with formation of the monoanionic species K[Pt(dipic)Cl]·H 2O ( 6) and K[Pd(dipic)Cl]·H 2O ( 7), respectively. The iodo derivative K[Pt(dipic)l]·1/2H 2O ( 8) was obtained from the chloro species by replacement of the coordinated chloride with iodide in aqueous solution. All the complexes have been characterized by a number of physico-chemical measurements including the X-ray analysis of trans-Na 2[Pt(dipic) 2]·6H 2O ( 4) and K[Pt(dipic)I]·1/2H 2O ( 8). Crystals of 4 are monoclinic, space group P2 1/ c, Z=2, with unit-cell dimensions a=11.912(1), b=6.544(1), c=12.699(1) Å, β=91.56(1)°. Crystals of 8 are triclinic, space group P 1 , Z=4, with unit- cell dimensions a=11.018(1), b=11.585(2), c=9.946(1) Å, a=97.99(1), β=115.07(1), γ=73.14(1)°. The structures were solved from three dimensional counter data by Patterson and Fourier methods and refined by full-matrix least-squares to R=0.019 and 0.030 for 1556 and 4118 observed reflections, respectively. The crystal of 4 is built up by centrosymmetric Pt(dipic) 2 2− anions and Na + cations hexacoordinated by four water molecules and two carboxylate oxygens belonging to the ligands. Each dipicolinate ion behaves as a bidentate ligand, and the resulting coordination around the platinum is square planar. The asymmetric unit of compound 8 contains two independent square planar Pt(dipic)l− anions, in each of them the dipicolinate ion acts as a tridentate ligand and the fourth position is occupied by an iodine atom. The planar complex anions Pt(dipic)l− are stacked but not parallel and Pt atoms form infinite zigzag chains.

Synthesis and oxidation reactions of mono- and di-nuclear rhodium carbonyl complexes of (o-diphenylphosphinophenyl)amine, H2L; X-ray structure analysis of a rhodium(II) amido-bridged dimer, [{Rh(µ-HL)(CO)Cl}2]·EtOH

Reaction of cis-[NBun4][Rh(CO)2Cl2] or [{Rh(CO)2Cl}2] with one or two molar equivalents of (o-diphenylphosphinophenyl)amine (H2L) respectively gives the mononuclear halogenocarbonylrhodium(I) complexes [Rh(H2L)(CO)X][X = Cl (2a), Br (2b), or I (2c)]. These new compounds were found to react with air to give the novel amido-bridged rhodium(II) metal–metal bonded dimers [{Rh(µ-HL)(CO)X}2][X = Cl (5a), Br (5b), or I(5c)]. The chloro species (2a) was also shown to react with base in an inert atmosphere to generate the rhodium(I) amido-bridged dimer [{Rh(µ-HL)(CO)}2](4), which reacts with one molar equivalent of halogen to produce (5) or with excess halogen to give the monomeric rhodium(III)mer-trihalogeno complexes [Rh(H2L)(CO)X3][X = Cl (7a), Br (7b), or I (7c)]. The chloro rhodium(II) dimer (5a) has been characterised by X-ray structure analysis. Crystals of (5a)·EtOH are monoclinic, space group P21/c, with a= 14.669(3), b= 14.754(3), c= 18.233(4)Å, β= 92.46(4)°, and Z= 4. Full-matrix refinement of 3 498 unique data with I 3σ(I)(3 < θ < 25°) gave R= 0.045 and R′= 0.042.

Synthesis and structural characterisation of some cyclopentadienyliron–bismuth complexes

Treatment of BiCl3 with 2 equivalents of Na[Fe(CO)2(η-C5H4Me)] in tetrahydrofuran affords the green iron–bismuth complex [{[Fe(CO)2(η-C5H4Me)]2BiCl}3], identified by X-ray crystallography and containing a planar Bi3Cl3 six-membered ring derived from the cyclotrimerisation of Fe(BiCl)(CO)2(η-C5H4Me) units. Similar compounds are formed with C5H5 and C5Me5 ligands although in the latter case significant amounts of the iron chloro species [FeCl(CO)2(η-C5Me5)] are also formed, an X-ray structure of which is reported. Treatment of BiCl3 with 3 equivalents of Na[Fe(CO)2(η-C5H4Me)] affords the tri-iron–bismuth complex [Bi{Fe(CO)2(η-C5H4Me)}3], containing a trigonal-pyramidal bismuth bonded to three Fe(CO)2(η-C5H4Me) fragments. Photolysis of this compound leads to loss of three carbonyl groups and formation of the closo Fe3Bi complex [Fe3(η-C5H4Me)3(µ-CO)3(µ3-Bi)]. Both of the tri-iron–bismuth complexes were characterised by X-ray crystallography.

ChemInform Abstract: Equilibrium and Kinetic Studies of Monoaquo Complexes of Platinum(II). Part 1. Formation from Corresponding Chloro Species by Hydrolysis.

AbstractIn order to discuss the mechanism, the rate and equilibrium constants for the hydrolysis of the complexes (I) are determined.

Equilibrium and kinetic studies of monoaquo complexes of platinum(II). 1. Formation from corresponding chloro species by hydrolysis

Constantes de vitesse et d'equilibre pour l'hydrolyse des complexes cis-Pt (aminoacide) (DMSO)Cl