Structural chemistry of dicyclopentadienidehalides of lanthanides Part 4. Erbiumdicyclopentadienidechloride [Er(C5 H5)2Cl]2

The crystal structure of erbiumdicyclopentadienidechloride [Er(C₅H₅)₂Cl]₂ has been determined from X-ray diffraction data. The compound crystallizes in space group P2₁/c with a=11.056(3), b= 8.015(1), c=12.154(3) Å, β=110.28(2)°, V= 1010.2(7) ų, D_c=2.189 g cm⁻³ and Z=2 dimers. The structure has been refined by full-matrix least- squares techniques to a conventional R factor of 0.027 for 2042 reflections (with I > 2σ(I)). In the unit cell centrosymmetric dimers of orte type exist with bridging chlorine atoms and C₅H₅ groups bonded in η⁵-fashion to the metal (mean ErC 2.59 Å). The [Er(C₅H₅)₂Cl]₂-type is compared to the [Sc(C₅H₅)₂Cl]₂-type structure which is realized in several dicyclopentadienidebromides of the lanthanides.     

Preparation,structure and properties of dicyano silver complexes of the M(en)3Ag2(CN)4 and M(en)2Ag2(CN)4 type

Complexes of the M(en)₃Ag₂(CN)₄ (M = Ni, Zn, Cd) and M(en)₂Ag₂(CN)₄ (M = Ni, Cu, Zn, Cd) type were prepared and identified by elemental analysis, infrared spectroscopy, measurement of magnetic susceptibility, and X-ray powder diffractometry. The crystal structures of Ni(en)₃Ag₂(CN)₄ (I) and Zn(en)₂Ag₂(CN)₄ (II) were determined by the method of monocrystal structure analysis. Complex I crystallizes in the space group C2/c, a = 1.2639(5), b = 1.3739(4), c = 1.2494(4) nm, β = 113.25(4)°, D_m = 1.86(1), D_c = 1.86 gcm⁻³ Z = 4, R = 0.0429. The crystal structure of I consists of complex cations [Ni(en)₃]²⁺ and complex anions [Ag(CN)₂]⁻. Complex II crystallizes in the space group I2/m, a = 0.9150(3), b = 1.3308(4), c = 0.6442(2) nm, β = 95.80(3)°, D_m = 2.14(1), D_c = 2.15 gcm⁻³, Z = 2, R = 0.0334. Its crystal structure consists of infinite, positively charged chains of the [-NCAgCNZn- (en)₂]_nⁿ⁺ type and isolated [Ag(CN)₂]⁻ anions. The atoms of Ag are positioned parallely to the z axis and the AgAg distance is equal to 0.3221(2) nm.     

Crystal structure of [Sm(OPMePh2)4I2]I. A cationic octahedral complex of samarium(III)

The crystal structure of [Sm(OPMePh₂)₄I₂]I, 1, was determined by X-ray diffraction and refined anisotropically to a final R value of 0.067 from 3040 reflections with I>3.0σ(I). The space group was P2/a and Z=2. The unit cell dimensions were: a= 17.777(6), b=13.559(2), c=11.656(4) Å, α=γ= 90.0 and β=97.25(3)°. The cation geometry was octahedral with the Sm(III) bonded to two mutually trans I⁻ ions and four OPMePh₂ groups. A third non-bonded I⁻ was present elsewhere in the cell. The SmI and SmO distances were 3.077(1) and 2.27(1) Å respectively. Two of the SmOP angles were 172.1(6)° and the other two were 162.0(6)°.     

Synthesis, 95Mo NMR spectra and x-ray crystal structure of MoO2(C14H11N2O)2(C2H5H)1 and Mo2O5(C14H11N2O)2(C2H5OH)1(H2O)1

The crystal structures and ⁹⁵Mo NMR spectra of two complexes formed between 2-α-hydroxybenzyl- benzimidazole (C₆H₅·CHOH·C₇H₅N₂=HOBB), as its sodium salt, and MoO₂Cl₂ are reported. [MoO₂- (OBB)₂]·EtOH (OBB=deprotonated HOBB) crystallizes in space group P2₁/n, with a=12.8441(7), b=15.917(3), c=13.314(2) Å, β=97.163(8)° and Z =4. The structure was determined from 3096 observed reflections and refined to a final R value of 0.030. The complex is a six coordinate cis-dioxo species, the ⁹⁵Mo spectrum of which shows a single sharp peak at 56 ppm in dimethylformamide (DMF). The second complex, [Mo₂O₅(OBB)₂]·EtOH·H₂O, crystallizes in space group Pbca, with a=22.482(4), b=16.442(3), c=18.407(3) Å and Z=8. The structure was determined from 2936 observed reflections and refined to a final R value of 0.061. The complex is a binuclear doubly bridged species in which one metal atom is six coordinate while the other is five coordinate. Its ⁹⁵Mo NMR spectrum in DMF shows a sharp peak at 124 ppm and a second broader much weaker peak at 51 ppm.     

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.     

Preparation,properties and crystal structures of nickel(II) complexes with acyclic schiff bases derived from 2,6-diformyl-4-chlorophenol and 1,5-diamino-3-thiapentane or 3,3′-diamino-N-methyl-dipropylamine

Nickel(II) complexes with the compartmental Schiff bases derived from 2,6-diformyl-4-chlorophenol and 1,5-diamino-3-thiapentane (H₂L¹) or 3,3′-diamino-N-methyl-dipropylamine (H₂L²) were synthesized, and the crystal structures of [Ni(L¹)- (py)₂] and [Ni(L²)(dmf)]·H₂0 were determined by X-ray crystallography.Ni(L¹)(py)₂ is monoclinic, space group C2/c, with a= 18.457(6), b = 11.116(7), c= 16.098(6) Å, and β = 115.79(5)°; D_c = 1.49 g cm⁻³ for Z = 4. The structure was refined to the final R of 6.9%. The molecule has C₂ symmetry. The nickel atom is six-coordinated octahedral. Selected bond lengths are: NiO 2.04(1) Å, NiN (L¹) 2.08(1) Å, NiN(py) 2.17(1) Å.[Ni(L²)(dmf)]·H₂O is monoclinic, space group P2₁/n, with a = 17.329(6), b = 13.322(7), c = 12.476(7) Å and β = 95.43(5)°; D_c = 1.45 g cm⁻³ for Z = 4. The structure was refined to the final R of 5.1%. The nickel atom is bonded in the octahedral geometry to the bianionic pentadentate ligand L² and to one molecule of dimethylformamide. Selected bond lengths are: NiO (charged) 2.063(3) Å (mean value), NiO (neutral) 2.120(3) Å, NiN (planar) 2.050(3) Å (mean value), NiN (tetrahedral) 2.177(3) Å.     

Solution and solid state behavior of Co2+, Ni2+ and Zn2+ tosylaminoacidate systems: Crystal and molecular structure of bis(N-tosylglycinato)tetraaquocobalt(II) and bis(N-tosyl-β-alaninato)tetraaquozinc(II) complexes

The interactions between N-tosylamino acids and cobalt(II), nickel(II) and zinc(II) ions in aqueous solution and in the solid state have been investigated. From concentrated aqueous solutions, compounds of general formula [M(II)(N-tosylaminoacidato)₂(H₂O)₄](M = Co(II), Ni(II) and N-tosylaminoacidato = N-tosylglycinate (Tsgly^?), N-tosyl-α- and -β-alaninate (Ts-α- and Ts-β-ala^?); M = Zn(II) and N-tosylaminoacidate = Tsgly^?, Ts-β-ala^?) and [Zn(II)(N- tosylaminoacidato)₂(H₂O)₂] were isolated and characterized by means of thermogravimetric, electronic and infrared spectra. For two of them: [Co(Tsgly)₂(H₂O)₄](I) and [Zn(Ts-β-ala)₂(H₂O)₄](II) the crystal and molecular structures were also determined. Both compounds crystallize in the monoclinic space group P2₁/c, with two formula units in a cell of dimensions: a = 13.007(6), b = 5.036(2), c = 18.925(7) Å, β = 102.33(3)° for (I) and a = 14.173(6), b = 5.469(2), c = 17.701(7) Å, β = 106.63(3)° for (II). The structures were solved by the heavy-atom method and refined by least-squares calculations to R = 0.031 and 0.064 for (I) and (II) respectively. The cobalt and zinc atoms lie in the centers of symmetry, each bonded to two amino- acid molecules through a carboxylic oxygen atom and four water molecules in a slightly tetragonally distorted octahedral geometry. The second carboxylic oxygen atom is not involved in metal coordination. Electronic and X ray-powder spectra suggest that the tetrahydrate complexes of Co²⁺, Ni²⁺ and Zn²⁺ ions of the same amino acids are isomorphous and isostructural. No coordinative interactions between ligand and metal ions were found in aqueous solution on varying the pH values before hydroxide precipitation.     

Intramolecular hydrogen bonding: synthesis and crystal structure of nickel(II) and copper(II) complexes of a tetradentate amine oxime

In the reaction of the tetradentate ligand 3,3′-(1,4- butanediyldiamino) bis (3-methyl-2-butanone)-dioxime (BnAO) with nickel(II) and copper(II), the monomeric [Ni(BnAO-H)]I·H₂O and a mixed monomer/dimer salt [Cu(BnAO-H)H₂O]₂[(Cu(BnAO-H))₂](ClO₄)₄, respectively, are formed, and all complexes have an intramolecular hydrogen bond between cis oxime groups. The OHO bonds give the characteristic infrared absorptions as well as the downfield proton-NMR signal (Ni complex). [Ni(BnAO-H)]I·H₂O crystallizes in space group P2₁/a with a=13.511(2), b=10.599(2), c=14.096(2) Å, β=97.52°, Z=4 and D_c=1.623 g/cm³. The structure was solved by Patterson and Fourier methods and refined by full-matrix least-squares techniques to a final R of 0.021 for 2124 reflections with I 2σ(I). The nickel(II) atom in the complex has slightly distorted square planar geometry with an intramolecular O···O contact of 2.417(7) Å. The copper(II) complex crystallizes in space group P2₁/c with a =13.425(2), b=21.446(3), c=14.349(4) Å, β= 104.4(5)°, Z=8 (monomers) and D_c=1.485 g/cm³. The final R value for this complex was 0.053 for 3033 reflections with I 2σ(I). This structure contains a monomeric [Cu(BnAO-H)H₂O]⁺ ion and a dimeric [(Cu(BnAO-H))₂]²⁺ ion, having intramolecular O···O hydrogen bonds of 2.421(5) and 2.531(5) Å, respectively. The copper(II) ions have square-pyramidal coordination with the axial positions occupied by an oxygen of the water of hydration in the monomer and by an oxime oxygen atom in the dimer. A center of symmetry relates the two halves of the dimer. The copper atom in each case is out of the plane of the four nitrogen atoms toward the axial site. The copper(II) complex is unusual in that the crystal contains both a monomer and a dimer.     

Copper(I)-organophosphine complexes of bis(3,5-dimethylpyrazol-1-yl)dithioacetate ligand

Copper(I) complexes have been synthesized from the reaction of CuCl, monodentate tertiary phosphines PR₃ (PR₃ = P(C₆H₅)₃; P(C₆H₅)₂(4-C₆H₄COOH); P(C₆H₅)₂(2-C₆H₄COOH); PTA, 1,3,5-triaza-7-phosphaadamantane; P(CH₂OH)₃, tris(hydroxymethyl)phosphine) and lithium bis(3,5-dimethylpyrazolyl)dithioacetate, Li[LCS₂]. Mono-nuclear complexes of the type [LCS₂]Cu[PR₃] have been obtained and characterized by elemental analyses, FT-IR, ESI-MS and multinuclear (¹H, ¹³C and ³¹P) NMR spectral data; in these complexes the ligand behaves as a κ³-N,N,S scorpionate system. One exception to this stoichiometry was observed in the complex [LCS₂]Cu[P(CH₂OH)₃]₂, where two phosphine co-ligands are coordinated to the copper(I) centre. The solid-state X-ray crystal structure of [LCS₂]Cu[P(C₆H₅)₃] has been determined. The [LCS₂]Cu[P(C₆H₅)₃] complex has a pseudo tetrahedral copper site where the bis(3,5-dimethylpyrazolyl)dithioacetate ligand acts as a κ³-N,N,S donor.     

Macrocyclic nickel(II) complexes: Spectroscopic studies and crystal structure of bis(difluoroboron-alpha-furilglyoximato)nickel(II)

Bis (difluoroboron - α - furilglyoximato) nickel (II), C₂₀H₁₂O₈N₄B₂F₄Ni, was prepared by cyclization of its hydrogen-bonded precursor with BF₃·OEt₂. The compound crystallizes in the space group P2₁/_c with a = 11.162(2), b = 5.569(2), c = 19.527(3) Å, β = 100.08(1)°, U = 1195.1(3) ų, and Z = 2. The structure was refined to an R value of 0.033 using 2371 unique reflections collected with a CAD4-SDP diffractometer system. Unlike the corresponding planar macrocyclic as well as hydrogen-bonded dimethylglyoximates, the title compound neither dimerizes not exhibits columnar stacked structure. The 14-member macrocycle is planar except the B atoms, and no metal-metal interactions are observed in this compound. The complexation and cyclization reactions were investigated using spectral data. The structure is compared with other macrocyclic complexes.     

The structure of a dinuclear silver(I) complex: Ag2[S2C2(CN)2] [P(C6H5)3]4

The crystal structure of the dimeric Ag maleonitriledithiolate complex, Ag₂[S₂C₂(CN)₂] [P(C₆- H₅)₃]₄ (1), has been performed. Complex 1 crystallizes in the space group P2₁/c with a = 12.2898(77), b = 23.8325(91), c = 23.1790(118) Å, β = 101.315(43)° and Z = 4. Refinement using 3253 reflections with F_o²>3σ(F_o²) yielded R = 0.0662, R_w= 0.0669. The most interesting aspect of the structure is the strong bridging interaction of the chelating maleonitriledithiolate ligand with the second Ag center, where a Ag-S distance of 2.478 Å is observed. The residual bonding capability of the sulfur atoms in the chelating anion [Ag(S₂C₂(CN)₂)(PPh₃)₂]⁻ for [Ag(PPh₃)₂]⁺ is demonstrated.     

Synthesis of dimethylcobalt(III) complexes containing trimethylphosphine and 2-formyl-phenolato- or 2-formyl-enolato(O:O) ligands

Substituted salicylaldehydes [C₆HR¹R²R³(CHO)(OH)] react with CoMe₃(PMe₃)₃ to afford 6-coordinate (cis-dimethyl)(2-formyl-phenolato)trans-bis(trimethylphosphine)cobalt(III) compounds Co[C₆HR¹R²R³(CHO)(O)Me₂](PMe₃)₂ (1: R¹ = H; R² = Me; R³ = tert-Bu; 2: R¹, R² = C₆H₄; R³ = H). Accordingly, substituted enolated malonic dialdehydes (CHO-CR⁴CR⁵-OH) react with CoMe₃(PMe₃)₃ to afford 6-coordinate (cis-dimethyl)(2-formyl-enolato)trans-bis(trimethylphosphine)cobalt(III) compounds Co[(CHO-CR⁴CR⁵-O)(Me)₂](PMe₃)₂ (3: R⁴, R⁵ = (CH₂)₂C₆H₄; 4: R⁴ = R⁵ = C₆H₅). In the molecular structure of 4, the cobalt atom is centred in an octahedral coordination geometry brought about by a six-membered chelate ring (O:O-ligand), cis-dimethyl and trans-trimethylphosphine groups. A reaction mechanism is suggested.     

Structural chemistry of lanthanidedicyclopentadienidehalides. Part 1. Two modifications of gadoliniumdicyclopentadienidebromide, [Gd(C5H5)2Br]2 and 1∞[Gd(C5H5)2Br]

The crystal structures of two modifications of gadoliniumdicyclopentadienidebromide, [Gd(C₅H₅)₂Br]₂ (I) and ¹_∞[Gd(C₅H₅)₂Br] (II) have been determined from X-ray diffraction data. I crystallizes in the [Sc(C₅H₅)₂Cl]₂-type structure, space group P2₁/c, with a=14.110(3), b=16.488(3), c= 13.765(3) Å, β=93.25(2)°, V=3197(2) ų, and D_c= 2.289 g cm⁻³ for Z=6 molecules. II crystallizes in space group P2₁/c with a=5.946(7), b=8.447(5), c=20.239(9) Å, β=90.11(4)°, V=1020(2) ų, D_c=2.392 g cm⁻³ for Z=4 formula units. The structures have been refined by full matrix least-squares techniques to conventional R factors of 0.034 for 3014 (I) and 1964 (II) reflections (with I>2σ(I)). I consists of dimers with two bromine bridges (mean GdBr 2.872 Å). II has a double chain structure with alternating juxtaposition of gadolinium and bromine atoms (GdBr 2.912 Å (once) and 3.133 Å (twice)). The arrangement of the C₅H₅ groups with regard to the metal η⁵ fashion) is nearly identical in I and II (mean GdC 2.63(1) Å (I) and 2.62(1) Å (II)). Single crystals of I and II are obtained by sublimation at different temperatures. The formation of both modifications is discussed as to its dependence on the state of the gaseous phase equilibrium [Gd(C₅H₅)₂Br]₂ ⇄ 2Gd(C₅H₅)₂Br. Obviously, I crystallizes from gaseous phase dimers while II forms from the monomers.     

Photolytic CO-substitution reaction of organoiron thiocarboxylate derivatives CpFe(CO)2SCOR (R=alkyl, aryl) with diphosphines (Ph2P(CH2)nPPh2) (n=1-6): X-ray crystal structure of [CpFe(dppm)SCO(3,5-(NO2)2C6H3)]

The photolytic CO-substitution reaction of the organoiron thiocarboxylate complexes CpFe(CO)₂SCOR (R=CH₃, 2-CH₃C₆H₄, 2-NO₂C₆H₄, 4-NO₂C₆H₄, 3,5-(NO₂)₂C₆H₃) with diphosphines (Ph₂P(CH₂)_nPPh₂) [n=1 (dppm), n=2 (dppe), n=3 (dpppr), n=4 (dppb), n=5 (dppp), n=6 (dpph)] at room temperature using 1:2 (metal-ligand) molar ratio afforded exclusively the disubstituted complexes CpFe(Ph₂P(CH₂)_nPPh₂)SCOR when n=1, 2 and 3 and the monosubstituted analogs CpFe(CO)(Ph₂P(CH₂)_nPPh₂)SCOR when n=4, 5 and 6. This reaction was found to be strongly influenced by the backbone length of the diphosphine ligand, the nature of the R group of the thiocarboxylate moiety and the metal-ligand molar ratios. The crystal structure of CpFe(dppm)SCO(3,5-(NO₂)₂C₆H₃) was determined.     

Crystal structure of bis(N-methylethylenediammonium) hexabromodicuprate(I)

The crystal structure of the title compound (C₃H₁₂N₂)₂Cu₂Br₆, is monoclinic, space group P2₁/n, with lattice constants a=8.222(2), b=11.214(2), c=10.646(2) Å, β=91.97(1)° and V=981.0(3) ų. The structure contains anionic Cu₂Br₆²⁻ dimers and N-methylethylenediammonium (henceforth MEDA²⁺) cations. The centrosymmetric dimer units are composed of two edge-shared CuBr₄ tetrahedra, with bridging Cu-Br distances 0.08 Å longer than the terminal distances. A pair of MEDA²⁺ cations hydrogen bond to each dimer via two of the -NH₃⁺ hydrogen atoms and one of the -NH₂⁺- hydrogen atoms. Additional hydrogen bonding between the cations and anions tie the structure together in a complex supramolecular network.     

Synthesis and characterization of complexes containing the bis(1, 2-diolato)-oxotechnetium(V) core

The complexes (Bu₄N)[TcO(O₂C₆H₄)₂] (1) and Na[TcO(OCH₂CH₂O)₂] (2) have been prepared by reacting TcOCl₄^- with respective diols in methanol. Compound 2 was identified by its elemental analysis and field desorption mass spectrum. Crystals of compound 1 are monoclinic, C2/c, with cell dimensions a = 10.393(3), b = 13.835(3), c = 20.643(5) Å, β = 101.74(3)° and four formula units in the unit cell. The crystal structure was determined by standard methods and refined to R₁ = 0.0694, R₂ = 0.0613, on the basis of 2887 independent reflections. The data were collected with use of Mo Kα radiation and a Syntex P2₁ diffractometer. The anion of 1 is square pyramidal with a short TcO(oxo) bond (1.648(5) Å). TcO distances to the diolate groups are longer (1.956(3), 1.958(3) Å). The technetium atom lies 0.7014(4) Å out of the plane of the four diolate oxygen atoms. Compound 2 is hydrolytically unstable in pure water, but can be stabilized by the addition of a several-fold molar excess of ethylene glycol. Compound 1 decomposes minimally in pure water after 24 h. These complexes are shown to be good structural models for ^99mTc-radiopharmaceuticals containing purely oxygen-donor ligands. Comparison of the physical properties of the structurally characterized members of the series of complexes with core structures TcOS_xO_(4-x) (x = O, 2, 4) shows a shift to low energy in the frequency of the terminal oxygen-technetium band in the IR correlated with increasing softness of the basal plane donor atom set.     

Synthesis and crystal structure of bis(tetramethylammonium) aquotetra-fluorodioxouranate(VI) dihydrate, [(CI3)4 N]2[UO2 F4(H2 O)]·2H2O

The title compound has been synthesized and subjected to crystal structure analysis. M_r = 548.50, m.p. 108.1 °C (decom.), orthorhombic, Im2m,a = 7.006(2), b = 8.938(2), c = 13.619(2) Å V = 852.8(3) ų, Z = 2, D_x = 2.136, D_m, (flotation in CCl₄/CH₂I₂) = 2.128 g cm^?3, λ(Mo-Kα) = 0.71069 Å, μ = 90.79 cm^?1, F(000) = 519.89, T = 295 K, final R_F = 0.036 and R_G = 0.044 for 566 observed reflections. The discrete [UO₂F₄(H₂0)]^2? anion has site symmetry m2m, its virtually linear uranyl moiety being surrounded by fluoro and aquo ligands occupying the vertices of a pentagon in the equatorial plane. Watet molecules serve to link the complex anions by hydrogen bonds into layers, between which the organic cations are accommodated.     

Synthesis and characterization of silver(I) derivatives containing acylpyrazolonate and phosphino ligands: X-ray crystal structures of monomeric [Ag(Q)(PPh3)2] and of dimeric [{Ag(Q)(PiBu3)}2] (Q = 1-phenyl-3-methyl-4-tert-butylacetylpyrazolon-5-ato)

New silver(I) acylpyrazolonate derivatives [Ag(Q)], [Ag(Q)(PR₃)]₂ and [Ag(Q)(PR₃)₂] (HQ = 1-R¹-3-methyl-4-R²(CO)pyrazol-5-one, HQ^Bn = R¹ = C₆H₅, R² = CH₂C₆H₅; HQ^CHPh2 = R¹ = C₆H₅, R² = CH(C₆H₅)₂; HQ^nPe = R¹ = C₆H₅, R² = CH₂C(CH₃)₃; HQ^tBu = R¹ = C₆H₅, R² = C(CH₃)₃; HQ^fMe = R¹ = C₆H₄-p-CF₃, R² = CF₃; HQ^fEt = R¹ = C₆H₅, R² = CF₂CF₃; R = Ph or iBu) have been synthesized and characterized in the solid state and solution. The crystal structure of 1-(4-trifluoromethylphenyl)-3-methyl-5-pyrazolone, the precursor of proligand HQ^fMe and of derivatives [Ag(Q^nPe)(PPh₃)₂] and [Ag(Q^nPe)(PiBu₃)]₂ have been investigated. [Ag(Q^nPe)(PPh₃)₂] is a mononuclear compound with a silver atom in a tetrahedrally distorted AgO₂P₂ environment, whereas [Ag(Q^nPe)(PiBu₃)]₂ is a dinuclear compound with two O₂N-exotridentate bridging acylpyrazolonate ligands connecting both silver atoms, their coordination environment being completed by a phosphine ligand.     

Coordination chemistry of lanthanides with cryptands. An X-ray and spectroscopic study of the complex Nd2(NO3)6 [C18H36O6N2]·H2O

By reacting neodymium nitrate hexahydrate with the cryptand 〈222〉 in methanol, the complex Nd₂-(NO₃)₆[C₁₈H₃₆O₆N₂]·H₂O was obtained and analyzed by single-crystal X-ray diffraction. The cell is triclinic P$\text{1}$ with a = 14.870(2) Å, b = 13.261(2) Å, c = 8.832(1) Å, α = 91.2(1)°, β = 93.4(1)°, γ = 87.6(1)°, Z = 2 and U = 1736.6 ų. The structure was refined by least-squares methods to the conventional R = 0.039 for 6177 observed reflections. The compound contains the cations [Nd〈222〉(NO₃)]²⁺ and the anions [Nd(NO₃)₅·H₂O]^2?, and is isostructural with the samarium analogue. Solid state fluorescence spectra of the title complex were measured at room and liquid nitrogen temperature, and the transitions ⁴F_3/2 → ⁴I_9/2 and ⁴F_3/2 → ⁴I_11/2 analyzed.     

Synthesis,characterization, structure and luminescence studies of dinuclear gold(I) alkynyls of bis(diphenylphosphino)alkyl- and aryl-amines

A series of alkynylgold(I) bis(diphenylphosphino)alkyl- and aryl-amine complexes, [{Ph₂PN(R)PPh₂}Au₂(CCR′)₂] [R = ⁿPr, R′ = Ph (1), C₆H₄OMe-p (2), C₆H₄Me-p (3), C₆H₄Cl-p (4); R = C₆H₄OMe-p, R′ = Ph (5)], has been synthesized. The X-ray crystal structures of 1 and 2 revealed the presence of short intramolecular Au⋯Au contacts with the distances of 2.8404(8) and 3.0708(7) Å. The luminescence behavior of the complexes were studied.