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The crystal structure of the title compound has been determined from three-dimensional X-ray diffraction data. The compound crystallises in space group P, with a= 15.570(7), b= 13.727(5), c= 9.082(4)A, α= 94.8(1), β= 104.9(1), γ= 99.6(1)°, and Z= 2. The structure was solved by Patterson and Fourier methods; full-matrix least-squares refinement based on 3 584 reflections gave a final R value of 0.053. The co-ordination about the uranium atom in the anion [U(cp)3(NCS)2]–(cp = cyclopentadienyl) is a trigonal bipyramid with three π-bonded cp rings in the equatorial plane (U–ring centre distances 2.48, 2.49, and 2.50 A) and two nitrogen-bonded thiocyanate groups in the axial positions (U–N 2.46 and 2.50 A). The As–C distances in the cation [AsPh4]+ range from 1.873 to 1.886 A and the C–As–C angles fall in the range 106.5–111.9°. The structure is discussed in conjunction with information available for [U(cp)3(NCS)(NCCH3)] and [U(cp)3(NCCH3)2]2[UO2Cl4]·2L(L = buta-1,3-diene).

Salts of the type [Cp3U(NCR)2][BPh4] (Cp  η5-C5H5), R  CH3, 1: R  C2H5, 2 or R  n-C3H7, 3 Ph  C6H5) can be prepared either from the aqua salts, [Cp3U(OH)2)2][BPh4] · xH2O, and nitrile in n-hexane, or, better, by a one-pot reaction from Cp3UCl and Na[BPh4] in NCR/H2O mixtures. The NIR/VIS and the 1H NMR spectra of 1–3 strongly suggest a trigonal bipyramidal (tbp) configuration for the cation. This prediction has been fully confirmed by a single crystal X-ray study of 1. The UN(acetonitrile) distance in tbp-configurated complexes ranges from 2.57 A (in 1) to 2.66 A in Cp3U(NCS)(NCMe) (4), confirming the previously suggested “trans effect” in tbp-systems. The crystal and molecular structure of 4 has been re-examined for a single crystal obtained from a solution of [N(n-C4H9)4]Cp3U(NCS)(NCBH3)] in NCMe. The salts 1–3 lose readily BPh3 (and NCR) when heated (up to ≥ 60° C) under a high vacuum or when dissolved in common solvents, such as toluene, CH2Cl2, or THF). The 13C NMR shfits of the Cp ring carbon atoms of 1 (δ 145.9 ppm) are another feature of the unusually weakly paramagnetic title compounds.

The title compound crystallizes in the triclinic system, space group P1 with a = 11.512(3), b = 9.387(3), c = 6.757(2) A, α = 105.6(4), β = 96.8(4) and γ = 107.0(4)° and Z = 2. The structure is built up from two distinct coordination polyhedra, one is formed by the uranium which is at a centre of a pentagonal bipyramid, the other by the potassium cations heptacoordinate to oxygen atoms either belonging to the maleic ligands or to the uranyl group. The uranium polyhedra are connected through bridging maleato groups. The maleato-U-maleato chains in the direction of the c axis are held together through the potassium coordination polyhedra.

The crystal structure of the title compound has been determined from single crystal diffractometer data. The crystals are monoclinic, space group P21/c, a = 12.112(3), b = 7.217(2), c = 16.359(4), β = 111.96(10), Z = 4.1845 reflections were refined to a final R = 4.7%. The crystals contain water, NH4+ and [UO2(C3H2O4)2]n2n−1 ions. In the latter, one malonate group is bidentate and the second terdentate, giving chains parallel to b. Both ligands form six-membered rings with uranium. The uranyl UO distance (mean value) is 1.76 A and the geometry around the uranium is approximately pentagonal bipyramidal.

The synthesis, thermal behaviour and crystal structure of lithium glutaratehydrogenglutaratedioxouranate(VI) tetrahydrate is described. The compound crystallizes in the monoclinic system, space group P21/n with a = 9.143(3), b = 26.825(11), c = 7.776(2) A, β = 101.2°(2) and Z = 4. The two glutarato ligands behave differently; one is bridging the uranyl groups in infinite chains running approximately in the a axis direction, the second is bridging the uranyl and the lithium ions. The carboxylic groups are chelated on the uranium and monodentate on the lithium. The structure is linked through a network of hydrogen bonding involving water molecules and oxygen atoms from the carboxylato groups. The geometry around the uranium is approximately hexagonal bipyramidal while the lithium is tetrahedrally coordinated with one glutarate oxygen and 3 water oxygens.

Thorium(IV) and uranium(IV) halide and pseudohalide derivatives form complexes with variable stoichiometry with differently substituted amide and urea ligands. This is related either to the bulk of the anionic or/and of the neutral ligands. The compounds here reported are ThBr4(MeCON(i-Pr)2)2 (I), Th(NCS)4(MeCON(i-Pr)2)4·CH2Cl2 (II), ThBr4((Et)2NCON(Et)2)2 (III), ThCl4(PhMeNCONPhMe)3 (IV) and U(NCS)4(EtCON(i-Pr)2)3 (V). Crystal data show that the coordination geometry around thorium in (I) and (III) is trans octahedral while in (II) it is dodecahedral with the N atoms of the NCS groups occupying the dodecahedral B sites and the neutral ligand O atoms the A sites. The different hindrance of bromine in (I) with respect to isothiocyanate in (II) allows in (II) the coordination of four neutral ligands instead of two as has been found in (I). In (IV) the coordination polyhedron about the seven coordinate thorium ion is a pentagonal bipyramid with two chlorine atoms in the axial positions as in tetrachloro tris(N,N-diethylpropionamide) thorium(IV). A similar coordination geometry around uranium(IV) has been found in (V) where two N atoms from the (NCS) are in the axial positions ligands while in the diisopropylacetamide derivative (dipa) U(NCS)4(dipa)4 the coordination polyhedron is a regular dodecahedron. The hindrance of the additional methyl group present in the diisopropylpropionamide ligand causes a reduction in the coordination number around uranium from eight to seven.

The synthesis of ethyl and methyl esters of 2-substituted 5-cyano-1,6-dihydro-6-oxo-3-pyridinecar☐ylic acids by reaction of ethyl or methyl 2-dimethylaminomethylene-3-oxoalkanoates with sodium cyanoacetamide is described. These esters gave by alkaline hydrolysis the corresponding car☐ylic acids, which were decar☐ylated to 6-substituted 1,2-dihydro-2-oxo-3-pyridinecarbonitriles. As milrinone analogues, nearly all the above compounds were tested on contractile activity and frequency rate of spontaneously beating atria and electrically driven left atria from guinea pigs. Among the esters, ethyl 5-cyano-1,6-dihydro-2-methyl-6-oxo-3-pyridinecar☐ylate induced positive inotropic and chronotropic effects superior to those caused by milrinone. By increasing or branching the 2-substitutent, the activity decreased until faded or even reversed. Car☐ylic acids and nitriles were less active than milrinone. Some aspects of the structure-activity relationship of these compounds are discussed on the basis of X-ray structural analyses of 2-methyl, 2- t -butyl and 2-phenyl esters.

SrUO2(C3H2O4)2 · 3H2O and BaUO2 (C3H2O4) · 3H2O are isostructural. They crystallize in the orthorhombic system space group Pbca with eight molecules in cells of dimensions a = 16.729 (8), b = 23.247 (11) and c = 6.848 (5) A and a = 17.063 (9), b = 23.604 (12) and c = 6.885 (5) A, respectively. The structures were solved by the heavy-atom technique and refined with full-matrix least-squares to the R values of 0.043 and 0.046, respectively. The coordination geometry around the uranium atom is a pentagonal bipyramid with the malonates behaving as bidentate or terdentate ligands to the uranium atoms forming polymeric chains [UO2(C3H2O4)2]n2n− parallel to c. The space between the uranyl dimalonate chains is occupied by the oxygen atoms belonging either to the water molecules or to the carboxylic groups. Each polyhedron shares two edges forming columns running in the same direction as the uranyl chains and connecting them four by four.

Thorium tetrachloride forms a 1:3 complex, ThCl 4 ·3L, with N,N -diethyl N ′, N ′-dimethylurea (dedmu); and 1:2 complexes with dedmu, N,N -diisopropyl N ′, N ′-dimethyl (dibdmu), N,N -diisobutyl- N ′, N ′-dimethyl (dibdmu), N,N -diisopropyl N ′, N ′-diphenyl (dipdpu), N,N,N ′, N ′-tetramethyl (tmu) and N,N,N ′, N ′-tetraethylurea (teu) have been obtained. A dichloromethane solvate, ThCl 4 ·3L·CH 2 Cl 2 , where L= N,N ′-dimethyl- N ′, N -diphenylurea (dmdpu), has also been obtained. The crystal and molecular structure of ThCl 4 (dmdpu) 3 ·n-pentane has been determined from three dimensional X-ray diffraction data. The cell is triclinic, space group P 1 , with a =16.826(3), b =16.019(3), c =12.131(2) A, α=11O.4(1), β=106.6(1) and γ=59.4(1)° and Z =2. Full matrix least-squares refinement with 7963 intensity observations reached convergency with R =0.053 and R w =0.058. The coordination polyhedron about the seven-coordinate thorium atom is a pentagonal bipyramid with two chlorine atoms in apical positions. The average bonding distances are ThO=2.392(5), ThCl eq =2.743(3) and ThCl ax =2.696(3) A. The IR spectra of the complexes are also reported.

The crystal structures of the titlke compounds have been determined by X-ray diffraction. Urea, I crystallizes in the triclinic PI space group with cell dimensions a = 8.336(2), b = 11.009(2), c = 13.313(2) A, α = 105.55(3), β = 103.62(3), γ = 104.63(3)° and Z = 2 final R value 0.072 for 2105 observations. Urea, II crystallizes in the orthorhombic P212121 space group with cell dimensions a = 8.750(2), b = 10.844(3) and c = 21.215(3) A and Z = 4, final R value 0.083 for 599 observations. All the hydrogen atoms were located in the complex urea, I; urea molecules form hydrogen bonded dimers about centers of symmetry, these dimers are sandwiched between macrocyclic rings forming one simple and one bifurcated hydrogen bond from the “endo” hydrogen atoms to the ether oxygen atoms. These units are held by hydrogen bonding between the urea molecules and carboxylic acids in two other units; these hydrogen bonds are cyclic involving eight atoms -(N-H(exo)…O(keto)-C-O-H…O(urea)-C)-. Only one carboxylic acid group per molecule takes part in these hydrogen bonds, the other forms a short, 2.490(7) A, internal bond to the acceptor keto oxygen atom. N(H)…O bonds range from 2.930(7) to 3.206(7) A, O(H)…O is 2.475(6) A. In the complex urea, II each urea is hydrogen bonded to three different host molecules and vice versa; the urea “endo” hydrogen atoms bond to the ether oxygen atoms, while both “exo” hydrogen atoms take part in cyclic hydrogen bonds to carboxylic acids. There is not internal hydrogen bond. N(H)…O bonds range from 2.83 to 3.26(2) A and the O-…O bonds are 2.55 and 2.56(2) A.

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 1 with a = 14.870(2) A, b = 13.261(2) A, c = 8.832(1) A, α = 91.2(1)°, β = 93.4(1)°, γ = 87.6(1)°, Z = 2 and U = 1736.6 A3. 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 4F3/2 → 4I9/2 and 4F3/2 → 4I11/2 analyzed.

Treatment of a solution of [UIV(cp)3Cl](cp =η5-C5H5) in CH3CN with gaseous butadiene containing traces of O2 initiates the formation of a crystalline green product composed of the novel cationic complex [UIV(cp)3(NCMe)2]+, the anion [UVIO2Cl4]2–, and two non-co-ordinated butadiene molecules. This salt contains the first example of a well defined cationic organo-f-element complex, and provides at the same time a new example of a crystallographically confirmed [U(cp)3XY](X, Y = neutral and/or anionic ligand) system of trigonal bipyramidal co-ordination. The results are discussed in relation to the as yet unsubstantiated access to organometallic compounds of UV and UVI with the cp ligand.

Systematic studies to arrive at some first examples of the sterically congested complex type Cp3Ln(NCR)2 (Cp = η5-C5H5, Ln = lanthanoid element) resulted in the preparation and detailed spectroscopic characterization of analytically pure representatives of this type with Ln = La, Ce and Pr, but not with Nd (R = CH3, and C2H5 for Ln = La only). The crystal and molecular structures of representatives of the isomorphous series Cp3Ln(NCCH3)2, (Ln = La, Ce, Pr) were determined from three-dimensional X-ray diffraction data. The compounds crystallize in the orthorhombic space group Pnca (standard group Pbcn) with: a = 14.940(3), b = 14.074(3), c = 8.596(2)A, Z = 4, R = 0.070, Rw = 0.079 for 1633 intensity data (La derivative, I); a = 14.906(3), b = 13.974(3), c = 8.502(2)A, R = 0.041, Rw = 0.047 for 1378 intensity data (Ce derivative, VII); a = 14.936(3), b = 13.986(3), c = 8.498(2)A, R = 0.031 for 1372 intensity data (Pr derivative, IX). According to the X-ray crystallographic results, the novel complexes are trigonal bipyramidally coordinated with three η5-bonded Cp rings in the equatorial plane (Ln—ring centre distances 2.62, 2.64 for La, 2.58, 2.59Afor Ce and 2.57, 2.57Afor Pr and two acetonitrile groups in the axial positions (Ln N 2.785 for La, 2.749 for Ce, 2.752 for Pr). The range of the distances in the three derivatives is in agreement with the trend in the crystal radii along the lanthanoid series. Pure 1:2 adducts involving any alkyl group larger than R = C2H5 could not be isolated. The relative stabilities of the novel Cp3Ln(NCR)2 systems, with respect to the decreasing ionic radius (i.e. from La to Nd) and to the variable space demanded by the group R, are in excellent accord with independent expectations based on the recently developed cone packing model (‘SAS-rule’) for f-element organometallics.

Reactions of aliphatic branched aldehydes with proline in dimethyl sulfoxide or acetonitrile solution afford oxazolidin-5-ones with high diastereoselection. Linear aldehydes afford aldolic/crotonic condensation products; with short reaction times, the presence of Oxazolidinones can be detected in the pmr spectra. Acyclic aminoacids and branched aldehydes yield a reaction mixture the pmr and ir spectra of which give evidence for iminic-oxazolidinone equilibria. The structure of (2R,5S)-2-trichloromethyl-1-aza-3-oxabiciclo-[3.3.0]octan-4-one has been confirmed by X-ray diffraction analysis.

Nd(NO3)3. 18-Crown-6 crystallizes in the orthorhombic system, space group Pbca with eight molecules in a cell of dimensions a = 15.512(9), b = 21.662(1), c = 12.141(6) A. The structure has been determined by Patterson heavy -atom methods and refined by full-matrix least squares to R = 0.038. The neodymium atom is coordinated by 6 oxygen atoms of the 18-crown-6 unit and by three bidentate nitrate groups; one of the more hindered side of the ring and two on the opposite side.

The compounds of the formula CuCl2(4-aminobenzophenone) (hereinafter L) 0.5S (S = ethanol or methanol) were synthesized and characterized by means of thermogravimetric electronic, IR spectra and magnetic susceptibility measurements. For the ethanol derivative, the structure was determined by a single crystal X-ray diffraction analysis. It crystallizes in the monoclinic system, space group P21/awith Z = 4 in a unit cell having a = 29.903(4), b = 6.202(2), c = 8.195(2) A, β = 92.88(4)°. The structure is polymeric and consists of infinite chains of chlorine bridged copper(II) ions along the b axis: the repeating unit is (LCuCl2EtOHCuCl2L)n. Although the two coppers are related through crystallographic inversion centres, they have different coordination geometries owing to the statistical positioning of the ethanol molecule. One is octahedrally coordinated to three chlorines in the square plane and to the nitrogen of L, while in the apical positions are the ethanol oxygen and a fourth chlorine atom; the second has a pyramidal coordination geometry, because of the missing ethanol oxygen in one apical position. (The same structure has been deduced for the methanol derivative.) Relevant bond distances are CuCl(1), 2.593(5); CuCl(1)′, 2.294(4); CuCl(2)″, 2.450(4); CuN, 2.03(1); CuO, 2.06(2) A.

The title compound (UO 2 -saloden·CHCl 3 ) crystallizes in an orthorhombic system, space group Cmc 2 1 with a = 16.938(6), b = 12.440(5) and c = 10.662(4) A , Z = 4 . The coordination geometry of the uranium atom is bipyramidal pentagonal with the ligand pentadentate in the equatorial plane of the uranyl ion. The chloroform molecule does not interact directly with the ligand. The IR spectral data are also discussed.

The synthesis, thermal behaviour and crystal structure of fumarate dioxouranium(VI) dihydrate are described. The compound crystallizes in the monoclinic system, space group P 2 1 /n with a = 9.952(3), b = 7.502(2), c = 5.571(2) A, β = 98.6(3)° and Z = 2.555 observed reflections (I > 3σ( I )) were refined to a final R = 0.0235. The fumarate ligands bridge the uranyl groups in chains. The geometry around the uranium is approximately hexagonalbipyramidal, with the two water molecules coordinated to the uranyl group.

C13H10ClO2NS, Mr = 279.75, monoclinic, P2(1)/a, a = 14.490 (3), b = 22.598 (5), c = 7.336 (2) A, beta = 92.4 (1) degree, U = 2400 (1) A3, Z = 8, D chi = 1.548 g cm-3, lambda(Mo K alpha) = 0.71069 A, mu = 2.07 cm-1, F(000) = 1152, room temperature, R = 0.037 for 2423 independent reflections with I greater than or equal to 3 sigma(I). Each unit cell contains two independent molecules which differ mainly in the orientation of their N(CH3)2 groups. The two tricyclic moieties of each molecule are not coplanar, the pyran ring being tilted by 7.9 (1) degree with respect to the benzene ring in molecule 1 and by 8.7 (1) degree in molecule 2. There are weak interactions between the molecules involving the carboxylic O atoms and the H atoms of the phenyl moieties.

The structure of the title compound has been determined from single-crystal X-ray analysis. The triclinic cell has dimensions a = 13.225(3), b = 10.246(2), c = 8.283(2) A, α = 112.1(1), β = 101.9(1) and γ = 85.0(1)°, space group P 1 , Z = 2. The structure was refined by least square methods to the conventional R value 0.032 for 2791 observed reflections. The molecule is formed by [GdCl2EtOH(18-crown-6)]+ cations and Cl− anions. In the cation the crown ether ligand, which includes the Gd ion, is folded away from the side where a chlorine and the ethanolic oxygen are coordinated to the metal ion; a second chloride ion is coordinated on the opposite side.

Le compose du titre cristallise dans le systeme monoclinique avec le groupe d'espace P2 1 /a. Affinement de la structure jusqu'a 0,064. La geometrie de coordination du complexe cationique [Co(picdien)(H 2 O] 3+ est pratiquement octaedrique

Le complexe du titre cristallise dans le systeme monoclinique, groupe P2 1 /n et sa structure est affinee jusqu'a R=0,096. La molecule presente une libration elevee, particulierement au niveau des coordinats Cp. Nature electrostatique de la liaison entre l'ion metallique et les coordinats Cp

The crystal and molecular structures of ThCl 4 (depa) 3 (1) (depa = N,N-diethylpropionamide) and Th(NCS) 4 (dmpa) 4 (2) (dmpa = N,N-dimethylpropionamide) have been determined from three-dimensional X-ray diffraction data. The compounds crystallize in space group P2 1 /n (1) and P2 1 /a (2), with a = 18.107(5), b = 10.347(3), c = 17.867(5) A , β = 108.5(1)°, Z = 4 (1) and a = 22.759(6), b = 13.763(4), c = 11.910(3) A , β = 91.4(1)° and Z = 4 (2). Full matrix least-squares refinement of both structures gave for (1) with 3126 intensity data R = 0.046 and Rw 0.046 and for (2) with 3480 intensity data R = 0.050, Rw 0.054. The different steric constraints imposed by the ligand give rise to different coordination numbers. In (1) the coordination polyhedron about the seven co-ordinate thorium atom is a pentagonal bipyramid with two chlorine atoms in the axial positions, an unusual geometry for Th(IV) species. The average bonding distances are ThO = 2.340(9), ThCl eq = 2.754(3) and ThCl ax = 2.692(3) A . In (2) the less hindering dmpa ligand favours the presence of four of them in the metal coordination sphere in a distorted square antiprismatic coordination geometry. ThO and ThN average 2.37(1) and 2.49(2) A respectively.

1,4-Cycloaddition of phenylchloroketene to N,N-disubstituted 5-aminomethylene-6,7-dihydrobenzo[b]- furan-4(5H)-ones gave the corresponding adducts, namely N,N-disubstituted 4-amino-3-chloro-3,4,5,6-tetra- hydro-3-phenyl-2H-furo[2,3-h]-l-benzopyran-2-ones II, which were dehydrochlorinated with DBN to N,N-disubstituted 4-amino-5,6-dihydro-3-phenyl-2H-furo[2,3-h]-1-benzopyran-2-ones III. Compounds III afforded the title compounds IV by dehydrogenation with DDQ. In the cycloaddition step, 3-phenylangelicin V, whose structure was confirmed by 1H-nmr shift reagents data and by X-ray crystal structure determination, was almost always formed, probably starting from II by dehydrochlorination, dehydrogenation and hydrogenolysis of the disubstituted amino group. Separation of V was achieved by alumina chromatography either in the cycloaddition step or, in most cases, in the dehydrochlorination step. 3-Phenylangelicin crystallizes in the trigonal system, space group R3, with cell parameters (hexagonal axes) a = b = 41.021(10), c = 3.888(2) A. The angelicin moiety forms a dihedral angle of 42.1(1)° with the phenyl substituent. Disordered solvent molecules of ethyl acetate are clathrated in channels in the direction of the crystallographic axis c.

Tris-isothiocyanato complexes of the general formula [M(NCS)3L] have been synthesized and characterized, in which M is yttrium(III) or europium(III) and L is an 18-member macrocyclic ligand with a six-nitrogen-donor cavity (LI = C22H26N6, LII = C18H18N6). X-ray analysis of the yttrium(III) and europium(III) complexes of ligand LI showed the coexistence in the same crystal of two kinds of nine-coordinate molecules with different macrocycle conformations. The two complexes were isostructural and crystallized in the monoclinic Cc space group, with cell parameters a = 33.244(3), b = 11.976(2), c = 14.164(2) A, β = 92.72(5)° for europium and a = 33.226(3), b = 11.986(2), c = 14.102(2) A, β = 92.84(5)° for yttrium. The structure of the europium(III) complex, refined by block matrix least-squares, gave the final values R = 0.0236 and Rw = 0.0244; the structure of the yttrium(III) complex, refined by full matrix, resulted in R = 0.042 and Rw = 0.039.

The crystal and molecular structures of [U(cp)Cl3(PPh3O)2]·thf (thf = tetrahydrofuran)(1) and [U(cp)Cl3{P(NMe2)3O}2](cp =η5-cyclopentadienyl)(2) have been determined from three-dimensional X-ray diffraction data. The compounds crystallize in space groups P21/c(1) and P21/n(2), with a= 21.725(5), b= 11.699(2), c= 17.269(4)A, β= 97.9(2)°, and Z= 4 for (1), and a= 9.942(6), b= 32.005(15), c= 9.576(6)A, β= 106.3(1)°, and Z= 4 for (2). The structures were solved by Patterson and Fourier methods and refined by least squares to final R values of 0.054 for 3 888 independent reflections for (1) and 0.032 for 3 777 independent reflections for (2). In both compounds the uranium atom is octahedrally co-ordinated with the two neutral ligands [PPh3O and P(NMe2)3O] in cis positions; the chlorine atoms are in the mer arrangement and the cyclopentadienyl group is trans to one neutral ligand. The appearance of cis octahedral geometry in complexes of the type [U(cp)Cl3L2] is discussed in terms of the operation of a possible trans effect.

Preparation et etude structurale de Lu(C 22 H 26 N 6 )(CH 3 COO)(ClO 4 )(CH 3 OH)(H 2 O) 0,5 . Cristallisation dans le systeme triclinique, groupe P1. Coordinence 9 de Lu

U(cp)3Me(cp =η5-cyclopentadienyl) reacts at room temperature with CNC6H11 to give quantitatively the insertion product U(cp)3[η2-CmeN(C6H11)], the 1H n.m.r. data and the X-ray crystal structure of which show that the imine ligand is η2-co-ordinated; the cyclohexyl group is equatorially substituted by the N atom and experiences notable steric congestion.

Le compose du titre cristallise dans le systeme monoclinique avec le groupe d'espace P2 1/c . Affinement de la structure jusqu'a 0,041. Deformation angulaire du cycle phenyle de l'anion. Dans le cation, les groupes methyle se trouvent de part et d'autre du plan central N-C-N

Macrobicyclic polyether ligands I, II, III and IV have been shown [1] to form complexes with alkali salts having high formation constants even in water (105 l mol−1). Ln/Ligand La Nd Sm Gd I LaCl3·I·2H2O NdCl3·I·H2O GdCl3·I·2H2O II LaCl3·II·2H2O SmCl3·II·H2O GdCl3·II·H2O III LaCl3·III·1.5H2O NdCl3·III·1.5H2O SmCl3·III· 1 2 H2O GdCl3·III·H2O IV LaCl3·IV·H2O NdCl3·IV·0.3H2O GdCl3·IV·H2O These ligands provide potentially 7, 8, 8 and 9 oxygen atoms for coordination with a cation. We investigated the reaction between LaCl3, NdCl3, SmCl3 and GdCl3 and four ligands. Crystalline compounds were obtained all of stoichiometry LnCl3:ligand = 1:1, as deduced from elemental analysis. The existence of crystals depends upon the presence of water, evidence of this was obtained from infra red spectra particularly in the 3000—3500 cm−1 region and from analysis. Preliminary X-ray diffraction measurements and the densities of laCl3· II·xH2O and LaCl3·III·yH2O gave values of x and y which are independent of elemental analysis. Summary of the compounds obtained. (see Table) A complete single crystal structure analysis of LaCl3·II·H2O has shown the crystals to contain (LaCl2·II)+ cations with the third chlorine ion and the water molecules occupying disordered sites in channels, similar to those in KCl·III·5H2O[2].

Interest in urea inclusion compounds has changed in three decades from its properties as a host to its potential as a guest, more or less directly in the hope that improvement in artificial kidneys can be achieved. There is a fine balance between the tendency of urea molecules to hydrogen bond to each other and to form external bonds, as required for encapsulation. Further, it may form uronium salts with strong acids.

The crystal structure of the title compound has been determined from three-dimensional X-ray diffraction data. The compound crystallises in space group P21 with a= 12.073(6), b= 15.824(7), c= 10.162(5)A, β= 100.3(1)°, and Z= 2. The structure was solved by Patterson and Fourier methods; full-matrix least-squares refinement based on 1 836 observed reflections gave a final R value of 0.054 (R′= 0.048). There is a distorted octahedral array of ligands around the uranium atom with the triphenylphosphine oxide (tppo) molecules co-ordinated in trans positions. The U–O distances are 2.21(3) and 2.24(2)A, and the U–Br distances range from 2.758(5) to 2.800(5)A. A new crystal modification of tetrachlorobis(triphenylphosphine oxide)uranium (IV), β-UCl4·2tppo, is reported. The structural data are discussed in conjunction with i.r. results for this metastable phase, for α-UCl4·2tppo, and for other actinide complexes of the type MX4·2tppo (M = Th–Pu inclusive; X = Cl or Br). It is concluded that the β-phase is the trans isomer. Solid-state electronic spectra are reported for α- and β-UCl4·2tppo and UBr4·2tppo.

The crystal and molecular structures of Th(oda)2(H2O)4·6H2O (1) and Na2[Th(oda)3]·2NaNO3 (2) (oda = oxydiacetate) have been determined from three-dimensional X-ray diffraction data and refined by least squares to R = 0.049 and Rw = 0.049 for 2265 independent reflections for (1) and to R = 0.024 and Rw = 0.023 for 2196 independent reflections for (2). Crystal parameters are as follows: (1), tetragonal, space group P41212, a = 10.335(2), c = 20.709(5) A and Z = 4; (2), monoclinic, space group C2/c, a = 17.096(5), b = 9.451(2), c = 16.245(4) A, β = 107.8(1) and Z = 4. In both compounds the thorium atom lies on a crystallographic two-fold axis. The co-ordination number for thorium in (1) is 10 (bicapped square antiprism geometry), the compound is monomeric, the two oda ligands are tridentate to the metal, and four water molecules complete the coordination sphere; in thorium (2) the coordination number is 9 (tricapped trigonal prism geometry) with three oda ligands tridentate to the metal, the [Th(oda)3]2− and NO3− anions are held together through the sodium ions which are coordinated both to the oda carboxylic oxygens and to the nitrate oxygens. The ThO coordination distances are: in (1) 2.411(8), 2.414(9) for the carboxylic oxygens, 2.479(10) and 2.486(8) for water molecules and 2.697(9) for the etheric oxygen and in (2) 2.384(3), 2.402(4) and 2.402(4) for the carboxylic oxygens, 2.559(5) and 2.562(4) A for the etheric oxygens.

The Schiff-base condensation of 2,6-diacetylpyridine and 1,2-diaminobenzene in the presence of uranyl salts produced complexes of the general formula (UP{sub 2}(C{sub 30}H{sub 26}N{sub 6}))X{sub 2}, with X = ClO{sub 4}{sup {minus}}, NO{sub 3}{sup {minus}}, and CH{sub 3}COO{sup {minus}}. A related complex, (Pr(NO{sub 3}){sub 2}(CH{sub 3}OH)(C{sub 30}H{sub 26}N{sub 6}))(ClO{sub 4}){center dot}0.5CH{sub 3}OH{center dot}0.5H{sub 2}O, was obtained from a similar metal-templated reaction followed by partial anion metathesis. The Pr(III) complex crystallized in the monoclinic space group P2{sub 1}/c with Z = 4 in a cell having a = 20.198 (3) {angstrom}, b = 14.208 (2) {angstrom}, c = 12.727 (2) {angstrom}, and {beta} = 104.25 (4){degree}. In this complex the Pr(III) ion was 11-coordinated, being linked to the six nitrogen atoms of an 18-membered macrocyclic ligand, to two bidentate nitrates situated on opposite sides of the macrocycle, and to one molecule of methanol. A noncoordinated ClO{sub 4}{sup {minus}} ion balanced the cationic charge of the complex cation; clathrated water and methanol were also present. The macrocyclic cations existing in these uranyl and praseodynium(III) complexes retained their identity in solution and were moderately inert to metal release in the present of acids or bases. 15 refs., 3 figs., 5 tabs.

The holmium and europium complexes of the tetraanion of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (H4DOTA), namely, sodium aqua(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetato)-holmium(III) tetrahydrate, Na[Ho(C 16 H 24 N 4 O 8 )(H 2 O)].4H 2 O, and sodium aqua(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetato)europium(III) tetrahydrate, Na[Eu(C 16 H 24 N 4 O 8 )(H 2 O)].4H 2 O, show nine-coordination around the metal ion, with a square antiprismatic coordination geometry involving four N- and four O-donor atoms of the DOTA ligand, and a coordinated water molecule in a capping position.

Treatment of [Pt(CH2CH2)(PPh3)2] with NNCHCO2Et (ethyldiazoacetate) or with trans-CH(CO2Et) CH(CO2Et) (diethyl fumarate) affords [Pt{trans-CH(CO2Et)CH(CO2Et)}(PPh3)2] (1), whereas [Pt{cis-CH(CO2Et)CH(CO2Et)}(PPh3)2] (2) is obtained from the reaction with cis-CH(CO2Et)CH(CO2Et) (diethyl maleate). The molecular structure of 1 has been confirmed by X-ray diffraction analysis which indicates that the diethyl fumarate ligand binds to platinum via the olefinic bond, a weak metal-α-C(olefin)-H interaction also having been detected; the corresponding PtC distance is 2.110(3) A, and the olefinic CC bond length is 1.466(6) A. The redox properties of these complexes, as studied by cyclic voltammetry and controlled potential electrolysis, are also described.

The reaction of the oxocumulene ylide ketenylidenetriphenylphosphorane, Ph3PCCO (1), with an excess of water in THF yields a white microcrystalline solid, methyltriphenylphosphonium hydrogencarbonate, which contains one molecule of crystallization water, [Ph3MeP]CO3H·H2O (2). Compound 2 was characterized by IR, multinuclear NMR and ESI mass spectra. The chemical constitution was confirmed by X-ray crystal analysis. On heating, compound 2 decomposes giving CO2, H2O, C6H6 and Ph2MePO.