Reactions of Nb2Cl6(SMe2)3 and Ta2Cl6(SMe2)3 with compounds containing NN single bonds

Ta₂Cl₆(SMe₂)₃ reacts with PhHNNHPh to afford Ta₂Cl₄(μ-Cl)₂(μ-PhN)(PhNH₂)₃ (1) a compound with a Ta^IVTa^IV single bond, with a length of 2.644(1) Å. The compound crystallizes in space group Pnma with unit cell dimensions a = 22.960(8), b = 16.875(4), c = 6.367(3) Å, V = 2467(1) ų, and Z = 4. The reaction of Nb₂Cl₆(SMe₂)₃ with PhHCNNCHPh, merely on mixing at room temperature produced Nb₂Cl₆(SMe₂) [PhHC(N)PhHCNHNCHPh]·C₇H₈ (2) as large red crystals in ca. 50% yield. The molecule consists of two Nb^IV atoms, one six-coordinate and the other seven-coordinate, united by three bridging atoms (Cl, Cl, N) and a NbNb bond of length 2.681(1) Å. The way in which the tridentate triazo ligand is generated is completely obscure. Crystallographic data for 2: space group P2₁/n with a = 11.393(3), b = 11.988(3), c = 27.233(7) Å, β = 100.75(2)°, V = 3654(3) Å, and Z = 4.     

Coordination modes of polydentate ligands. 4. The crystal and molecular structure of an oxo-bridged iron(III) complex containing a pentadentate imino-alkoxy ligand

In the presence of Fe³⁺, template condensation of the fluorinated keto-alcohol CH₃C(O)CH₂C- (CF₃)₂OH with the triamine CH₃C(CH₂NH₂)₃ leads to two products: a fully condensed, imino-alkoxy, iron(III) complex, Fe{CH₃C[CH₂NC(CH₃)CH₂C(CF₃)₂O]₃}, and a partially condensed iron(III) complex, O{FeCH₃C[CH₂NC(CH₃)CH₂C(CF₃)₂O]₂(CH₂NH₂)}₂, in which two six-coordinate iron(III) centers are linked by an oxide ion. A complete crystal and molecular structure determination of the latter has been made.Crystals are monoclinic, space group C2/c, a= 13.886(4); b=23.206(5); c=15.241(4) Å; β= 106.55(2)°; V=4708 ų; Z=4. Least-squares refinement on F of 322 variables using 2627 observations converged at a conventional agreement factor of 3.8%. The Fe to bridging oxide distance is 1.811(1) Å, the FeFe distance 3.468 Å, and the FeOFe angle 146.6(2)°. A comparison is made between this structure and those of natural hemerythrin systems.     

Binuclear copper(II) complexes of tetradentate (Ne) diazine ligands. Crystal structures of [μ-1,4-Bis(4,6-dimethyl-2-pyridylamino)phthalazine-N,μ-N3,μN3,N]-(μ-Dichloro)dichlorodicopper(II), [μ-3,6-Bis(2-pyridylthio)pyridazine-N,μ-N1,μ-N2,N] (μ-dichloro)dichlorodicopper(II) ethanol,and 3,6-Bis(2-pyridylthio)-pyridazine

The X-ray structures of two binuclear copper(II) chloride complexes of the tetradentate ligands 1,4- bis(4,6-dimethyl-2-pyridylamino)phthalazine (PAP46Me) and 3,6-bis(2-pyridylthio)pyridazine are reported. [Cu₂(PAP46Me)Cl₄] (1) and [Cu₂(PTP)Cl₄]· CH₃CH₂OH (2) contain triply bridged binuclear centres involving a diazine (NN) and two chlorobridges with copper-copper separations in the fange 3.19–3.25 Å and distorted square pyramidal copper stereochemistry. The reduced room temperature magnetic moments indicate antiferromagnetically coupled binuclear copper(II) centres.Complex 1 forms green crystals with a= 15.795(3), b=10.661(3), c=16.155(4) Å, β= 113.82(3)°, C2/c, Z = 4, R_f=0.031. Complex (2) forms green crystals with a=33.9022(8), b= 9.1626(5), c= 15.7885(5) Å,β= 114.853(2)°, C2/c, Z=8, R_f=0.047. The structure of the ligand PTP is also reported and compared with that of 2.     

Iron(III) nitrate complexes with linear pentacoordinate ligands and their base hydrolysis products

The complexes, Fe(saldpt)NO₃, [Fe(salmedpt)]₂(NO₃)(OH), Fe(saldien)NO₃, and Fe(salmedien)NO₃·CH₂Cl₂, have been prepared. Solid state properties (IR spectra, Mössbauer spectra and magnetic moments) and solution properties (electronic spectra, PMR spectra, conductivities and cyclic voltammograms) have been measured. The saldpt and saldien compounds when reacted with aqueous KOH formed Fe(saldpt)sal and Fe(saldien)OC₂H₅·H₂O. Single crystals of Fe(saldpt)sal were prepared and examined. Crystal data: Fe(saldpt)sal: monoclinic, space group P2₁/c(#14), a=12.486(5), b=18.502(8), c=10.870(5) Å, β=104.23(3)°, V=2434(2) ų, Z=4, D_c=1.40 g cm⁻³, R=0.0473 (R_w=0.0681) for 317 parameters and 2107 data with F_o² > 3σ(F_o²).     

Oxo-bridged Ta(+3) dimers, (TaCl2L2)2(μ-O)(μ-SR2), revisited. Structural differences between isoelectronic μ-O and μ-OH complexes

The compounds Ta₂Cl₄(dmpe)₂(μ-Me₂S)(μ-O) (1) and Ta₂Cl₄(py)₄(μ-THT)(μ-O) (2) where dmpe = Me₂PCH₂CH₂PMe₂ and THT = tetrahydrothiophene, have been prepared and structurally characterized. They are authentic examples of μ-O bridged Ta^IIITa^III edge-sharing bioctahedral complexes. Their structures are virtually identical with respect to all of the bonds that they have in common. However, the structure of 1 differs significantly in its TaTa, TaO and one type of TaCl distance from the previously reported Ta₂Cl₄(dmpe)₂(μ-Me₂S)(μ-O)·HCl (3). These differences show that in 3 there is a μ-OH group hydrogen bonded to a Cl⁻ ion. The structural differences attendant upon the μ-OH ⇌ μ-O change are of general interest and are discussed. The crystallographic data for the new compounds are as follows: 1: monoclinic (P2₁/c) with a = 10.412(2), b = 14.749(2), c = 22.177(3) Å, β = 99.25(1)°, V = 3361(1) ų and Z = 4. 2: monoclinic (P2₁/a) with a = 18.238(4), b = 10.402(3), c = 19.070(2) Å, β = 95.37(2), V = 3602(2) ų and Z = 4.     

Solvent-extraction complex of uranium(VI) with cis,syn, cis-dicyclohexano-18-crown-6

The extraction of U(VI)with dicyclohexano-18-crown-6 (mixed isomers or isomer A) from HCl medium is effective and selective, and can be used for separating and analysing uranium and thorium. However, little is known of the properties of the extraction complex of uranium with crown-ether in organic phase. In this paper we report the preparation, characteristic and structure of the crystalline extraction complex IaUO₂Cl₂HClH₂O, Iabeing isomer A of dicyclohexano-18-crown-6.After extracting uranium(VI) from aqueous hydrochloric acid solution with Ia in 1,2-dichloroethane, the crystalline product of the extraction complex was prepared from the organic phase by diluting with a non-polar solvent at 25 °C. The content of uranium, crown-ether and HCl was determined. The IR spectrum of the crystals shows that the strong hydronium-crown ether/oxygen hydrogen bond absorption is found in the region 2300–2400 cm⁻¹. The chemical shift in the range 9–12 ppm was observed. The ¹H NMR signal of hydronium protons appears at 9.890 ppm. The results of assay correspond to the formula Ia₂·(H₃O⁺)₂·UO₂Cl₄²⁻.Crystal structure of the extraction complex has been determined by X-ray crystallography. Crystals are monoclinic, space group C_2/c (No. 15) a=32.464, b=10.203, c=21.616 Å, β=119.73° and Z=4. In the complex each of the two H₃O⁺ cations is anchored in the crown-ether cavity by three stronger hydrogen bonds (distances approximately 2.65 Å), whereas uranium forms UO₂Cl₄²⁻ with Cl⁻ as counterion about 8 Å away from the H₃O⁺.     

Platinum(II) complexes of methyl-substituted xanthines: crystal structures of K[Pt(theobromine)Cl3]·H2O,trans-[ Pt(isocaffeine)2Cl2]·H2O and K(isocaffeinium)[PtCl4]·H2O

The preparations of Pt(theophylline)₂Cl₂, K[Pt- (theophylline)Cl₃], K[Pt(theobromine)Cl₃]·H₂O (1), trans-[Pt(isocaffeine)₂Cl₂]·H₂O (2), and K(isocaffeinium)[PtCl₄]·H₂O (3) are reported.Crystals of 1 are monoclinic P2₁/n with a=7.641- (2), b=11.873(3), c=15.868(4) Å, β=90.80(2)°, Z=4. The structure was refined on 1443 reflections to R=0.028. In the planar [Pt(theobromine)Cl₃]⁻ anion Pt-N(9)=2.016(6) Å, Pt-Cl=2.299(2), 2.289(2), and 2.303(2) Å. The imidazole ring is rotated away from the coordination plane by 79.8°. Symmetry related theobromine units pack parallel to each other with a mean inter-ring separation of 3.27 Å.Crystals of 2 are monoclinic P2₁/a with a=7.345- (2), b=20.021(5), c=8.031(2) Å, β=104.18(2)°, Z=2. The structure was refined on 1132 reflections to R=0.029. The Pt-N(7) distance is 2.003(3) Å and Pt-Cl=2.298(1) Å. The imidazole ring is rotated away from the PtCl₂N₂ plane by 76.8°. In this compound, the isocaffeine units do not stack, but form a staggered arrangement within the unit cell.Crystals of 3 are monoclinic P₁/c with a= 7.382- (1), b=14.014(4), c=15.757(4) », β=92.30(2)°, Z=4. The structure was refined on 2057 reflections to R=0.032. The isocaffeine is protonated at N(7). The Pt-Cl distances in the PtCl₄²⁻ anion range between 2.29–2.31 Å. The protonated isocaffeine cations and the PtCl₄²⁻ anions form a very nearly parallel infinitely stacked arrangement with minimum interlayer atomic separations of 3.37 and 3.44 Å.     

Metal-penicillamine interactions. Part 1. Preparation and crystal structure of a 1:1 complex of mercuric chloride with d-penicillamine, 2[μ3-Cl){HgSC(CH3)2CH(NH3)COO}3·3(μ2-Cl)· 2(H3O)·(H2O·Cl)3

A 1:1 complex of mercuric chloride with D-peniccillamine has been isolated and characterised as 2[(μ₃-Cl){HgSC(CH₃)₂CH(NH₃)COO}3]·3(μ₂-Cl)·2(H₃O)·(H₂O·Cl)₃. The compound crystallises in cubic space group P4₁32, with a = 18.679(5) Å and Z = 4. The structure, refined to R_F = 0.086 for 443 observed Mo-Kα diffractometer data, features a triply bridging chloride ion linking three equivalent [HgSC(CH₃)₂CH(NH₃)COO]⁺ units [Hg-Cl = 2.37(1) Å, Hg-Cl-Hg′ = 98.5(9)°]. The carboxylate groups of a pair of adjacent penicillamine ligands are strongly linked via a symmetrical O?H?O hydrogen bond of length 2.24(8) Å, and neighboring pyramidal trinuclear [μ₃-Cl){HgSC(CH₃)₂CH(NH₃)-COO}₃]²⁺ moieties are further connected by symmetrical chloride bridges [Hg-Cl = 3.06(2) Å; HgClHg′' = 79.6(7)°] to form a three-dimensional network. The voids in the lattice are filled by hydronium ions and novel planar cyclic hydrogen-bonded (H₂O·Cl^?)₃ rings of edge O-H?Cl = 2.46(4) Å.     

A versatile entry into aqueous niobium chemistry: isolation and structure of the intermediate Nb4(μ2-O)2(μ2-OC2H5)4Cl4(OC2H5)4(HOC2H5)4

The reduction of ethanolic solutions of niobium pentachloride with zinc, followed by treatment with aqueous acids serves as a versatile entry into the aqueous solution chemistry of niobium. From the zinc-reduced solution, the major intermediate, Nb₄(μ₂-O)₂(μ₂-OC₂H₅)₄Cl₄(OC₂H₅)₄(HOC₂H₅)₄, was isolated and the crystal structure determined by X-ray crystallography. The complex crystallizes in the orthorhombic space group Pccn, with Z=4, a=21.0105(9), b=11.0387(5), c=19.1389(8), V=4438.9(3) ų, M_r=1090.19,R₁=0.0327 and wR₂=0.0876. The structure revealed a centrosymmetric tetrameric Nb(IV) complex, consisting of a pair of edge-sharing bi-octahedral Nb₂(μ₂-OC₂H₅)₄Cl₂(OC₂H₅)₂(HOC₂H₅)₂ units that are joined by two axial oxo ligands. The Nb-Nb distance of 2.7458(3) Å is consistent with a single metal-metal bond.     

Comparative structural studies of the first row early transition metal(III) chloride tetrahydrofuran solvates

Two compounds of empirical formula MCl₃- (THF)₃, M = V and Cr, have been characterized by single crystal X-ray studies. The VCl₃(THF)₃ molecule, which has a mer octahedral stereochemistry, crystallizes in the monoclinic space group P2₁/c with a= 8.847(2),b= 12.861(5),c= 15.134(3) Å, β = 91.94(2)°, V = 1721(1) ų and Z = 4. The V-Ci(1) and V-CI(2) distances have a mean value of 2.330 [3] Å while V-CI(3) = 2.297(2) Å, The VO(1) and VO(2) distances have a mean value of 2.061[8] Å while V-O(3) = 2.102(3) Å cis ClVCl angles average 92.0[5]° and cis OVO angles average 86.2[2]° . The isostmctural complex, CrCl₃(THF)₃, has a crystal structure made up of discrete octahedral mer-CrCl₃(THF)₃ molecules with the following unit cell dimensions (space group P2₁/c): a = 8.715(1), b= 12.786(3), c = 15.122(3) Å, β = 92.15(1)°, V = 1684(1) ų and Z = 4. The CrCl(1) and CrCl(2) distances have a mean value of 2.310131 Å while CrCl(3) = 2.283(2) Å. The CrO(1) and CrO(2) distances have a mean value of 2.0101171 Å while CrO(3) = 2.077(4) Å. cis ClCrCl angles average 90.9[4]° and cis OCrO angles average 86.1 [2]°. The structures of these two octahedral complexes and those previously reported for ScCl₃(THF)₃ and TiCl₃(THF)₃ are compared and certain general trends are discussed.     

f-Element/crown ether complexes. 16. Synthesis,crystallization and crystal structure of [Dy(OH2)8]Cl3·18-crown-6·4H2O

When crystals of [Dy(OH₂)₇(OHMe)] [DyCl(OH₂)₂(18- crown-6)]₂Cl₇·2H₂O [1] are allowed to warm from 5 °C to ambient temperature (22 °C) under the original solvent mixture (1:3 CH₃OH: CH₃CN), they redissolve and the title complex can be isolated by slow evaporation of the resulting solution. The crystal structure of this complex, [Dy(OH₂)₈]Cl₃·18-crown-₆·4H₂O, has been determined. It crystallizes in the monoclinic space group, P2₁/c, with a = 10.395(1), b = 18.684(1), c = 16.259- (3) Å, β= 102.56(1)°, and D_calc = 1.61 g cm⁻³ for Z = 4. A final conventional R value of 0.041 was obtained by least-squares refinement using 3453 independent observed [F_o⩾5σ(F_o)] reflections. The [Dy(OH₂)₈]³⁺ cations and crown ether molecules are hydrogen bonded in a polymeric chain with the crown molecules separating the cations and a total of seven DyOH₂···O(crown ether) hydrogen bonds. The chains are connected by a hydrogen bonding network consisting of the cations, chloride ions, and uncoordinated water molecules. The geometry of the cation is best described as a bicapped trigonal prism with distortions on the reaction pathway toward dodecahedral symmetry. The two capping atoms average 2.41(1) Å from Dy, the remaining DyO distances average 2.38(2) Å. The 18-crown-6 molecule has the D_3d conformation normally observed except for a distortion of one OCCO unit containing the oxygen atom accepting two hydrogen bonds.     

Synthesis,characterization and crystal structure of 2-dimethylacetal-4-chloro-6-formylphenol and aquabis(2-dimethylacetal-4-chloro-6-formylphenolato)dioxouranium(VI)

The ligand 2-dimethylacetal-4-chloro-6-formylphenol, H(ALAC), prepared by boiling 2,6-diformyl-4-chlorophenol, H(DIAL), in methanol, was reacted with uranyl acetate to obtain the complex [UO₂(ALAC)₂(H₂O)]. The ligand and the uranyl complex were characterized by X-ray crystallography, infrared, ¹H NMR and electronic spectroscopy. Thermogravimetric and mass spectrometry data are also reported. In acid media H(ALAC) transforms easily into H(DIAL). H(ALAC) is monoclinic, P2₁/n, with a=13.951(5), b=7.902(5), c=9.465(5) Å, β= 91.33(3)°. The structure was refined to R=3.9%, based on 1657 observed reflexions. [UO₂(ALAC)₂(H₂O)] is tetragonal, P4₃2₁2, with a=11.147(5) and c=19.150(4) Å. The structure was refined to R=4.0%, based on 2938 observed reflexions. Four ligand oxygens and one water molecule are equatorially bonded to the uranyl group in this compound. Uranium and water oxygen lie in special positions on a crystallographic twofold axis so that the two halves of this molecule are symmetrically related. Selected bond distances for [UO₂(ALAC)₂(H₂O)] are: UO (charged) 2.28(2) Å, UO (neutral) 2.45(2) Å, UO (uranyl) 1.77(2) Å, UO (water) 2.44(4) Å.     

Structural models for [M(CO)3(H2O)3]+ (M=Tc,Re): fully aqueous synthesis of technetium and rhenium tricarbonyl complexes of tripodal oxygen donor ligands

The reaction of [M(H₂O)₃(CO)₃]⁺ (M=Tc, Re) with Na[CpCo[PO(OR)₂]₃] (NaL_OR; R=Me, Et) in water produced the compounds M(CO)₃(L_OR), all of which were yellow solids, in yields varying from 55 to 89%. The two compounds M(CO)₃(L_OEt) were structurally characterized by single crystal X-ray crystallography. In both cases, the ligand L_OEt was bound to the metal center in a tridentate fashion utilizing an {OOO} donor set. The ligands L_OR can be used as models for facially coordinated triaqua groups owing to their position in the spectrochemical series. Therefore, these four compounds, M(CO)₃(L_OR), can be considered structural models for [M(H₂O)₃(CO)₃]⁺. Crystal data for Tc(CO)₃(L_OEt) are as follows: molecular formula C₂₀H₃₅CoO₁₂P₃Tc, MW=717.32, monoclinic, a=11.5661(11) Å, b=18.671(2) Å, c=13.7852(13) Å, β=92.770(2)°, V=2973.5(5) Å³, space group P2₁/n, Z=4, final R₁=0.0669, wR₂=0.1361. Crystal data for Re(CO)₃(L_OEt) are as follows: molecular formula C₂₀H₃₅CoO₁₂P₃Re, MW=805.52, monoclinic, a=11.5113(7) Å, b=18.6022(12) Å, c=13.7397(8) Å, β=92.7580(10)°, V=2938.7(3) Å³, space group P2₁/n, Z=4, final R₁=0.0384, wR₂=0.0760.     

N,N-diisopropylcarboxylic acid amide complexes of thorium(IV) and uranium(IV) N-thiocyanates; the crystal structure of tetraisothiocyanato tetrakis(N,N-diisopropylacetamide-O)uranium(IV)

The complexes M(NCS)₄·xL (x = 2, M = U, L = Me₃CCON(Prⁱ)₂(dippva); x = 3, M = Th, L = Me₂CHCON(Prⁱ)₂(dipiba) and dippva, M = U, L = EtCON(Pr¹)₂(dippa), dipiba and dippva; x = 4, M = Th, L = MeCON(Prⁱ)₂(dipa), dippa and dipiba, M = U, L = dipa, dippa) and the solvates M(NCS)₄·4dipa·CH₂Cl₂ (M = Th, U) have been prepared. Their i.r. and u.v.-visible (M = U only) spectra are reported. The crystal and molecular structure of U(NCS)₄(dipa)₄· CH₂Cl₂ has been determined by the heavy-atom method from X-ray diffractometer data and refined by least squares to R 0.029 for 1135 independent reflections. The crystal is tetragonal, space group P$\text{4}$2₁c, with Z = 2, a = 15.663(4) and c = 10.512(3) Å. The coordination geometry about the 8-coordinate uranium atom is dodecahedral with the N atoms of the NCS groups occupying the dodecahedral A sites and the ‘dipa’ O atoms the B sites. The bonding distances of UO and UN are 2.363(8), and 2.444(11) Å respectively.     

Metal-phenoxyalkanoic acid interactions. Part 15. The crystal structures of diaquabis(phenoxyacetato)cadmium(II) and catena-μ-[aquabis(phenoxyacetato-O)lead(II)-bis(phenoxyacetato)lead(II)]

The crystal structures of the cadmium(II) and lead(II) complexes of phenoxyacetic acid (PAH) have been determined by single crystal X-ray diffraction techniques. The cadmium complex, [Cd(PA)₂(H₂O)₂] (1), space group C2, with Z = 2 in a cell of dimensions, a = 11.801(2), b = 5.484(1), c = 13.431(3) Å, β = 100.87(2)°, possesses a distorted trapezoidal bipyramidal coordination around the metal atom, involving two water oxygens [2.210(5) Å] and four carboxyl oxygens from two symmetrical bidentate phenoxyacetate ligands [2.363(4), 2.365(4) Å] with Cd lying on the crystallographic two- fold axis. The lead complex, [Pb₂(PA)₄(H₂O)]_n(2) is triclinic, space group P$\text{1}$, Z = 2, with a cell of dimensions, a = 10.135(4), b = 10.675(3), c = 19.285(9) Å, α = 114.66(3), β = 91.94(3) and γ = 114.99(3)°. (2) is a two-dimensional polymer with a repeating dimer sub-unit. The first lead [Pb(1)] has an irregular MO₈ coordination [2.34?2.96(2) Å: mean, 2.63(2) Å] involving the water molecule, two oxygens from an asymmetric bidentate carboxylate group, two from a bidentate chelate [O(ether), O(carboxylate)] group and three from bridging oxygens, one of which also provides a polymer link to another symmetry generated lead. The second lead [Pb(2)] is irregular seven-coordinate [PbO, 2.48?2.73(2) Å: mean, 2.61(2) Å] with three bonds from the bridging groups, two from an unsymmetrical bidentate carboxylate (O, O′) group and one from a second carboxyl group which also bridges two Pb(2) centres in the polymer.     

Complexes of hybrid ligands. Synthesis of mixed-ligand,phosphino-alkoxide complexes of Pd2+: the crystal and molecular structure of the complex Ph2 PCH2C(CF3 )2OPdCl(PPh2Me)

The hybrid, bidentate, diarylphosphino-alkoxide ligand PPh₂CH₂C(CF₃)₂O⁻, L¹, gives the Pd²⁺ bis- complex Pd(L¹)₂, from which the chloride-bridged dinuclear complex [(L¹)Pd(μ-Cl)₂Pd(L¹)] is made by reaction with PdCl₂(PhCN)₂. Cleavage of the dinuclear complex with monodentate ligands L² then gives Pd(L¹)Cl(L²) (L² =PPh₃, PPh₂Me, PPhMe₂, PMe₃, SMe₂, or pyridine); NMR data show that PR₃ is cis to the phosphine site in L¹ in these complexes, but SMe₂ or pyridine are probably trans.A complete crystal and molecular structural determination has been made for cis-Pd(L¹)Cl(PPh₂Me). Crystals are monoclinic, space group P2₁/c, a = 10.821(1), b = 14.600(1), c = 18.674(2) Å, β = 101.25(1)°, V = 2893 ų, Z = 4. Least-squares refinement on F of 361 variables using 3977 observations converged at a conventional agreement factor R = 0.025. The complex is square-planar, with the two phosphines cis; the 5-membered chelate ring is in a dissymmetric envelope conformation. The PdP bonds differ in length, with that to the unidentate phosphine, 2.259(1) Å, being significantly longer than that to the phosphine on the chelating ligand, 2.231(1) Å.     

Synthesis and coordination chemistry of tripodal dialkyl[1,2-bis(diethylcarbamoyl)ethyl]phosphonates with lanthanide nitrates

Trifunctional dialkyl [1,2-bis(diethylcarbamoyl)- ethyl] phosphonates, (RO)₂P(O)CH[C(O)N(C₂H₅)₂]- [CH₂C(O)N(C₂H₅)₂] R  CH₃, C₂H₅, i-C₃H₇, n-C₆H₁₃ were prepared from the respective sodium salts, Na[(RO)₂P(O)CHC(O)N(C₂H₅)₂] and N,N- diethylchloroacetamide, and they were characterized by elemental analysis, mass, infrared and NMR spectroscopy. The molecular structure of (i-C₃H₇O)₂- P(O)CH[C(O)N(C₂H₅)₂][CH₂C(O)N(C₂H₅)₂] was determined by single crystal X-ray diffraction analysis and found to crystallize in the monoclinic space group P2₁/c with a=15.589(6), b=9.783(4), c= 16.283(7) Å, β = 110.90(3)°, Z = 4 and V= 2320(2) ų. The structure was solved by direct methods and blocked least-squares refinement converged with Rf = 5.7% and R_wF= 4.4% on 2266 unique data with F>4σ(F). Important bond distances include PO 1.459(3) Å, CHCO 1.228(3) Å and CHCH₂CO 1.223(3) Å. The coordination chemistry of the ligand with several lanthanides was examined, and the structure of the complex Gd(NO₃)₃{[(i-C₃H₇O)₂P(O)CH[C(O)N(C₂H₅)₂][CH₂C(O)N(C₂H₅)₂]}₂·H₂O was determined. The complex crystallized in the monoclinic space group P2₁/n with a = 13.524(5), b = 22.033(4), c = 19.604(4) Å β = 106.22(2)°, Z = 4 and V= 5609(3) ų. The structure was solved by heavy atom techniques and blocked least-squares refinement converged with R_F = 5.9% and R_wF = 4.1% on 5275 reflections with F > 4σ(F). Both trifunctional ligands were found to bond to Gd(III) through only the phosphoryl oxygen atoms. The remainder of the Gd coordination sphere was composed of three bidentate nitrate oxygen atoms and an oxygen bonded water molecule. Several important bond distances include GdO(phosphoryl)_av = 2.343(5) Å, GdO(nitrate)_av = 2.475(7) Å, GdO(water) = 2.354(5) Å, PO(phosphoryl)_av = 1.467(6) Å, CHCO_av = 1.242(10) Å and CHCH₂CO_av = 1.209(11) Å.     

Binuclear rhodium carbonyl halide complexes containing the 1,1-bis(diphenylphosphino)ethene ligand,and the crystal structure of [Rh2Cl2(μ-CO){Ph2PC(CH2)PPh2}2]

Treatment of [RhCl(CO)₂]₂ with 1,1-bis(diphenylphosphino)ethene (dppee) yields the cationic binuclear rhodium complex [Rh₂(μ-Cl)(CO)₂(μ-CO)(dppee)₂]⁺ which may be isolated as the [RhCl₂(CO)₂]⁻ salt at low temperature (230 K) but which readily forms the Cl⁻ salt on allowing the solution to warm to room temperature. On bubbling nitrogen through a solution of this cationic complex at room temperature, the monocarbonyl species, [Rh₂Cl₂(μ-CO)(dppee)₂] is obtained. The crystal structure of this complex has been determined. The crystals are orthorhombic, space group Pnca, a = 29.98(3), b = 23.70(2), c = 14.78(3) Å, Z = 8. Using 3019 unique reflections the structure was refined to R = 0.091. The rhodium-rhodium distance is 2.650(14) Å. Direct rhodium NMR data are reported for these complexes.