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In a template synthesis from copper(II) acetate, 2,6-diacetylpyridine, and semioxamazide (NH2CO CONHNH2), two copper(II) complexes, [Cu(dapsox)(H2O)]·H2O and [Cu(Hdapsox)](H2O)]ClO4, (where H2dapsox = 2′,2‴-(2,6-pyridindiyldiethylidene)dioxamohydrazide) were obtained and characterized. The structure of the former complex was determined by a single-crystal X-ray analysis. CuII is located in a square pyramidal environment. The polydentate ligand, dapsox2− is coordinated in dianionic form, as an unsymmetrical quadridentate planar system forming one-membered and two-five-membered metal-chelate rings. The fifth coordination site is occupied by a water molecule.

Conformational and vicinal optical activities of four classes of mixed mono( S -aminocarboxylato)cobalt(III) complexes, lacking configurational dissymetry, were studied. The efrect of conformational changes of aminocarboxylato chelate ligands containing various ring side alkyl groups, caused by the replacement of a relatively small ammine by a bulky nitro ligand, were followed. Solution CD spectra supported the earlier conclusion that the more axially oriented chelate ring side group of an S -aminocarboxylato ligand produces a larger negative dichroism in the region of the first, spin allowed, d-d electronic transition. Solid-state CD spectra enabled the application of the theoretically based sector rules for optical activity in cobalt(III) complexes to the four investigated complexes, for which crystal structures have been determined. It emerged that an axial orientation of the aminocarboxylato chelate ring side alkyl is very effective, not only due to the displacement of this alkyl from an equatorial position, nodal plane of the Sector rule, but also due to the proximity of the oriented group to the metal centre.

The preparation of the trans(NO2) and cis (NO2),trans(NH2) isomers of the (1,4- diaminobutane)(glycinato)dinitrocobalt(III) complex, as well as trans(NO2), δ-(—)589-cis (NO2),trans(NH2) and λ-(+)589-cis (NO2),trans(NH2) isomers of the (R-alaninato) (1,4-di- aminobutane)dinitrocobalt(III) complex, is described. These substances were obtained in the reaction of sodium hexanitrocobaltate(III) with 1,4-diaminobutane and the corresponding amino acid. The separation of the isomers was performed on an anionic Dowex 1-X4 column. The composition of the isolated substances was determined by elemental microanalysis. The position of the nitro groups in the substances obtained was determined from their electronic absorption spectra in the UV region and by paper chromatography. The X-ray crystal structure of the δ-(—)589-cis(NO2),trans(NH2)-(R-alaninato)(1,4-diamino-butane) dinitrocobalt(III) diastereomer was established and the arrangement of ligands in other isomers prepared was established by comparing their electronic absorption spectra with the alaninato diastereomer.

X-ray powder diffraction data for Hf 2 Fe were collected at room temperature and refined according to the Rietveld profile method. In the space group Fd 3 m , the hafnium atoms occupy 16c and 48f positions and the iron atoms occupy the 32e position. The coordination numbers of the three coordination polyhedra are 16c-12, 48f-14 and 32e-12. These results are the correction of a previously reported structure of prototypic Ti 2 Ni.

Reaction of S-methylisothiosemicarbazide hydroiodide, pentane-2,4-dione and sodium carbonate with iron(III) nitrate in ethanol yielded paramagnetic (µeff= 3.00)[FeL(I)][L = pentane-2,4-dione bis(S-methylisothiosemicarbazonato)(3–)]. When treated with ammonia a methanolic solution of [FeL(I)] yielded the diamagnetic complex [(FeL)2O]. Its structure has been determined by X-ray crystallography, and characterized by spectroscopic measurements. The complex crystallizes in the monoclinic space group P21/c with a= 11.542(1), b= 20.710(4), c= 13.232(2)A, β= 113.12(1)° and Z= 4. The structure was solved by application of the heavy-atom method on the basis of 3362 reflections [I > 3σ(I)] and refined by full-matrix least squares to R 0.025. It consists of a binuclear complex molecule in which two iron atoms are bridged by oxygen. Both Fe atoms have approximate square-pyramidal co-ordination with the quadridentate ligand lying in the basal plane and the bridging oxygen occupying the apical position. The ligands in both halves of the molecule are saddle shaped, bent away from the apical oxygen atom and twisted around the Fe–O–Fe bridge. The Fe–O distances are 1.736(2) and 1.745(2)A, Fe–N in the range 1.893(3)–1.917(2)A. On the basis of the stoichiometry, crystal structure, electronic and NMR spectra, and magnetic measurements the formal oxidation state of +4 was assigned to iron in [(FeL)2O].

C 18 H 16 CuN 2 O 6 cristallise dans P2 1 /n avec a=15,685, b=12,900, c=8,825 A, β=100,45°, Z=4; affinement jusqu'a R=0,057. Dans chaque monomere la coordination autour du cuivre est de forme pyramidale carree, constituee par les azotes de la bipyridine, deux des carboxylates dans le plan de base et un O d'un carboxylate de l'autre monomere, en position axiale

[Ni(C 8 H 4 O 4 )(C 12 H 8 N 2 )(H 2 O) 3 ]•(H 2 O) cristallise dans P2 1 /n avec a=20,157, b=13,632, c=7,529 A, β=97,36 o , z=4; affinement jusqu'a R=0,062. [Ni(C 8 H 4 O 4 )(C 10 H 9 N 3 )(H 2 O) 3 ]•2H 2 O cristallise dans P2 1 /n avec a=8,026, b=19,901, c=13,235 A, β=99,61 o , z=4; affinement jusqu'a R=0,037. Dans les deux composes etudies, les complexes discrets ont des configurations similaires. Les atomes de nickel sont dans un environnement octaedrique deforme, les trois molecules d'eau etant en position meridionale. Les anions benzenedicarboxylate-1,2 se comportent en coordinats monodentes, tandis que les autres atomes d'oxygene carboxylate, avec l'eau de cristallisation, forment un systeme de liaisons hydrogene intramoleculaires. Ceci diminue notablement la capacite de l'ion phtalate a agir comme chelate ou coordinat pontant

In the crystal structure of Δ-cis(NO2),trans(NH2)-silver(I)-dinitrobis(S-valinato) cobaltate(III) the S-valinato ligand is found to form the chelate ring of a strained envelope conformation with one methyl group of the ring side chain completely axially oriented and in the proximity of the cobalt atom. The conformation supports the basic idea that an axial positioning of an aminocarboxylato chelate ring side chain induces a large contribution to the optical activity of a complex.

In the molecule of the title compound, [MoO2(L)(CH3-OH)] [L is the dianion of 2'-(2-benzoyl-1-methylethylidene)-1-naphthohydrazide, C21H16N2O2], the Mo atom displays distorted octahedral coordination geometry, being coordinated by two mutually cis oxo ligands, the methanol O atom and the tridentate ligand L bonded through the azomethine N atom, the enolic O atom and the oxazine O atom (equatorially disposed). The packing in the crystal structure involves a hydrogen bond from the methanol OH as donor to an oxo ligand as acceptor.

[Co(C 3 H 6 NO 2 )(NH 3 ) 4 ]SO 4 cristallise dans P2 1 avec a = 9,769, b = 9,080 et c = 12,474 A, β = 100,98°, Z = 4; affinement jusqu'a R = 0,035. La structure contient deux cations complexes independants et deux anions independants lies par des forces coulombiennes et des liaison hydrogene. Coordination octaedrique deformee autour de Co dans les deux cations. Les coordinats alaninato sont bidentes.

The title compound, [Ni(C 30 H 28 N 3 O 2 PS)], is the first example of a transition metal complex involving a thiosemicarbazide-based tetradentate ligand with a P atom in its coordination sphere. The Ni atom in the complex has a distorted square-planar configuration formed by N 2 OP donor atoms. It can be concluded from the structure that the formation of the complex involved addition across the azomethine group, which is the first time this has been observed for this class of ligands.

The complex [Co(H 2 L)(H 2 O)(MeOH)](ClO 4 ) 2 [H 2 L] = 2′,2‴-(2,6-pyridindiyl-diethylidene)-dioxamohydrazide] has been prepared by direct and template syntheses and characterized by elemental analysis, IR spectroscopy, and magnetic susceptibility measurements. The crystal structure of the complex has also been determined. The cobalt atom is seven coordinated with approximately pentagonal-bipyramidal geometry. The H 2 O and methanol are axial with the planar pentadentate H 2 L ligand forming the equatorial plane. The possible reaction mechanism has been proposed.

The crystals of K[CoNH3gly(NO2)3] · H2O belong to monoclinic system, space group P21/c, a = 9.985(4), b = 9.384(3), c = 12.136(7) A, β = 107.14(3)°, Z = 4. The structure was solved by the heavy atom method and refined by full-matrix least squares calculations to R = 0.048 and Rw = 0.044 for 897 independent nonzero reflexions, measured on a Syntex P&1macr; diffractometer. The crystal structure is built of K catione, complex anions and water molecules. The coordination around the cobalt atom is slightly distorted octahedral, with nitro groups in meridional arrangement. The nitrogen atoms from the glycine ligand and from ammonia are in the trans position. The metal—glycine five-membered ring has the conformation of an asymmetric envelope. Die Kristallstruktur des K[CoNH3gly(NO2)3] · H2O Inhaltsubersicht. Die Kristalle des K[CoNH3gly(NO2)3] · H2O gehoren zum monoklinen System, Raumgruppe P21/c, a = 9,985(4), b = 9,384(3), c = 12,136(7) A, β = 107,14(3), Z = 4. Die Struktur wurde durch die Schweratom-Methode bestimmt und verfeinert mit dem “full-matrix least squares”-Programm, R = 0,048 und Rw = 0,044 fur 897 unabhangige Nicht-Null-Reflexe. Die Kristallstruktur wird aus K-Kationen, Komplex-Anionen und Wassermolekeln aufgebaut. Die oktaedrische Koordination um das Kobaltatom ist leicht gestort, mit Nitrogruppen in meridionaler Anordnung. Die Stickstoffatome des Glycons und Ammoniaks sind in trans-Stellung. Der funfglied rige Metall-Glycin-Ring hat die Konformation einer asymmetrischen Hulle. It is a pleasure to thank Professor M. B. Celap nnd Mr. M. J. Malinar for providing the crystal and for many helpful discussions and to Professor I. Krstanovic and Mr. S. Djuric for the collection of the data on Syntex diffractometer.

The crystal structure of Sn[H2PO4]2 has been determined from X-ray diffractometer data by Patterson and Fourier methods. Crystals are monoclinic, space group C2/c, with Z= 4 in a unit cell of dimensions a= 16.561 (9), b= 6.896(2), c= 5.939(2)A, and β= 91.35(4)°. The structure has been refined by least-squares methods to R 0.039 for 1 429 reflections. It consists of [H2PO4]– tetrahedra and Sn2+ ions. Each Sn atom has four O neighbours all lying on one side. Two of the Sn–O bonds are short (2.209 A) and two are longer (2.466 A). Such a co-ordin-ation of Sn is usually described as distorted square pyramidal, with four basal oxygens and the apex occupied by a stereochemically active lone pair of electrons from Sn. The [H2PO4]– groups are linked by strong hydrogen bonds (2.545 and 2.627 A).

The electric quadrupole interactions at181Ta probe nuclei in a cubic Hf2Fe lattice were studied by the TDPAC method. In addition, the crystalline structure study of the Hf2Fe compound was performed. The results of the EQI measurement show the presence of two independent interactions, one at low frequency, characterized by ωQ(1)=33 Mrad/s and δ=30%, and the other at high frequency described by ωQ(2)=207 ± 2 Mrad/s and δ=4%. Both interactions are found to be compatible with the crystalline structure established in this investigation. The large temperature dependence of the electric field gradient of the second interaction in the range from 78K to 1183K was determined. The change in the EFG follows the empiricalT3/2-relation.

The crystals of racemic cis-dinitrobis(1,3-diaminopropane)cobalt(III) chloride monohydrate are monoclinic: a = 24.918(8), b = 8.867(4), c = 15.542(4) A, β = 122.60(2)°, V = 2876 A3. Space groupy C2/c, Z = 8. The structure was solved by heavy atom method on the basis of 1987 intensities, measured on the Nonius CAD-4 four-circle diffractometer. The full-matrix least-squares refinement of positional and anistropic temperature factors gave R = 0.027, Rw = 0.029. The crystal structure consists of enantiomer pairs of the complex cations, chloride anions and molecules of water. The cobalt(III) ion is surrounded by two nitrogen atoms of nitro groups and four nitrogen atoms of 1,3-diaminopropane molecules in distorted octahedral arrangement. The nitro groups are in the cis-position. The two 1,3-diaminopropane ligands are didentately bonded to the cobalt forming six membered chelate rings. Both rings have chair conformation in (C1)-constellation.

Co(H2PO4)2 · 2H3PO4, triclinic, P[unk], a = 8.121(4), b = 5.286(2), c = 7.195(4) Å, α = 92.97(3), β = 101.10(4), γ = 96.72(3)°, V = 300.1(2) Å3, Dx = 2.48 g cm−3 (calculated for Z = 1), μ(MoKα) = 2.11 mm−1, final R = 0.030. The structure consists of Co2+ and H2PO4 − ions and H3PO4 molecules. The coordination around cobalt is octahedral. Phosphate tetrahedra form layers parallel to y-z plane. Two neighbouring layers are linked by hydrogen bonds and Co2+ ions in sheets. No hydrogen bonds exist between the sheets.

N–N′-dibenzylidene-1,2-diphenylethylenediamine, C28H24N2 crystallizes in the monoclinic space group P21/c with cell dimensions a = 17.645 ± 0.003, b = 5.574 ± 0.002, c = 23.049 ± 0.003 Å and β = 101.12 ± 0.01° and four molecules in the unit cell. The structure was solved by direct methods, using the tangent multisolution technique, and refined to a final R value of 0.063 for 2418 observed and independent reflections. The crystal structure consists of d- and l-molecules of C28H24N2 bonded with relatively weak van der Waals forces. The average value of the interatomic distances for different types of bonds have been calculated as 1.383, 1.465, 1.512 and 1.266 Å for aromatic, ethylenic, exocyclic and double C = N bond lengths respectively. The conformation of the four groups in the molecule is essentially planar.

2,6-Dichloro-9-thiabicyclo-[3.3.1]-3,7-nonadien, C8H8Cl2S crystallizes in the orthorhombic space group Cmcm with cell dimensions a = 13.24 ± 0.01, b = 9.32 ± 0.01, c = 7,34 ± 0.01 Å and four molecules in the unit cell. The structure was solved by the interpretation of its three-dimensional Patterson function, and refined by least squares to a final value of R = 0.116 for 460 observed reflections. The crystal structure consists of statistically distributed enantiomers of C8H8Cl2S molecules. The molecule itself can be described as a distorted adamantane structure, opened on one side. The bond lengths C–S and C–Cl are 1.80 and 1.81 Å respectively; the bond angle C–S–C is 94.2°. The average C–C bond in the molecule is 1.50 Å and the average bond angle around the carbon atoms 114.0°. Each molecule in the crystal structure is bonded to adjacent ones solely by van der Waals forces.

The crystal structure of ammonium oxobisoxalatobisaquoniobate(V) trihydrate NH 4 [NbO(C 2 O 4 ) 2 (H 2 O) 2 ] · 3H 2 O has been determined from three-dimensional X-ray data and re-investigated by neutron diffraction, to obtain information concerning the correct formulation of the compound and the hydrogen-bond system. The crystals are monoclinic, space group P2 1 n , with a = 12.308(3), b = 16.368(3), c = 6.578(2) A , β = 92.63(2)° and Z = 4. All atoms were refined with anisotropic thermal parameters. The structure consists of a three-dimensional packing of ammonium cations and complex anions, described by the formula [NbO(C 2 O 4 ) 2 (H 2 O) 2 ] − and crystalline-water molecules. The niobium atom has a pentagonal bipyramidal environment. The shortest and the longest niobium-oxygen bond distances (Nb = O and Nb-OH 2 at 1.706(6) and 2.299(6) A, respectively) are axial and nearly perpendicular to the pentagonal equatorial plane, which consists of four oxygen atoms from two oxalato groups and one water molecule (with the niobium-oxygen distances in the range 2.105–2.135 A). Bond lengths, especially of hydrogen atoms, together with IR spectra are discussed in terms of the structure refined by neutron data.

The crystal structure of trans, trans, trans - pottasium dinitrobis(β-alaninato)cobaltate(III), K[Co(NH2CH2CH2COO)2(NO2)2] was determined by X-ray diffraction technique. The crystals belong to the monoclinic system, a = 12.38(1), b = 13.12(1), c = 8.27(1), β = 115.2(2), z = 4, Dm = 2.03(2)gcm−3, Dx = 2.00 gcm−3, space group C2/c. A total of 1008 independent nonzero reflexions was collected by multiple film Weissenberg technique and the model was refined by least squares method to a conventional R-factor of 11.8%. The coordination around the CoIII atom is octahedral, with two nitro groups in a trans arrangement. The β-alaninato ligands form six-membered chelate rings through the use of the amino nitrogen and the carboxylate oxygen atoms, both in the trans position too.

Neutron diffraction on a single crystal of partly deuterated 4-nitroaniline C6H2D2NO2ND2 yielded the integrated intensities of 145 independenth0l reflections. The positional and thermal vibration parameters were refined by the least squares procedure, a finalR-index of 0·135 was achieved. TheX andZ fractional coordinates of the carbon atoms of the benzene ring and the nitrogen atoms were found to be the same as those in Trueblood's three-dimensional X-ray analysis, but the coordinates of “outer” oxygen and hydrogen atoms were shifted. The positions of two oxygen atoms in the nitrogroup and two deuterium atoms in the aminogroup indicate the shorter hydrogen bridges between neighbouring molecules. The bonds between two hydrogen and two deuterium atoms and corresponding carbon atoms of the benzene ring appeared to be longer than the bonds resulting from X-ray data.

A preliminary X-ray single crystal analysis shows that [Cu(phthalate)(2,2′-bipyridine)] · 2H2O is dimeric in structure, which is usually not encountered in Cu-phthalate complexes.

0.099. The seven shortest P b O distances are in the range 2 .44-2 .88 A. Hydrogen-bonded dimers form a three-dimensional network. I n t r o d u c t i o n . The investigation of the crystal structure of Pb(H2PO4)2 was performed as part of a study of acidic phosphates. To obtain crystals of Pb(H2PO4) 2, first Pb(HPO4) was prepared. PbCO3 was added to 50% H3PO 4 and heated at 353 K until a precipitate began to appear. The solution was then heated at 373 K to dissolve all PbCO3. On cooling, tiny plates of Pb(HPO4) crystallized. The precipitate was washed with water, dried and dissolved in 96% H3PO 4 at 453 K. By cooling slowly, prismatic needles of Pb(H2PO4)2 were obtained. The crystals are sensitive to moisture. The excess of H3PO 4 is difficult to wash out. Treatment with ether, as recommended by Mellor (1947), has no appreciable effect on the stability of the crystals. For all crystallographic measurements, crystals sealed in Lindemann-glass capillaries were used. Preliminary Weissenberg photographs indicated triclinic symmetry. A crystal of dimensions 0.09 x 0.14 x 0.28 mm was mounted on a Syntex P i diffractometer. Cell parameters were determined by least squares from 20 values for 14 strong general reflexions. The intensity measurements were made by the m-scan technique, using graphite-monochromated Mo K a radiation. Intensities of 1730 reflexions in the sphere 0 3o(1) were used in the subsequent analyses. In the absence of a suitable program no absorption correction was applied. The structure was solved by the heavy-atom method. Isotropic refinement of the nonhydrogen atoms terminated at R = 0.136. Refinement with anisotropic thermal parameters for Pb led to a non-definite value for the vibrational tensor. The least-squares refinement in space group P1 was unsuccessful. At that stage of 0567-7408/81/030660-03501.00 Table 1. Fractional coordinates (x 105 for Pb, x 104 for P, O) and thermal parameters

A preliminary X-ray single crystal analysis shows that [Cu(phthalate)(2,2′-bipyridine)] · 2H2O is dimeric in structure, which is usually not encountered in Cu-phthalate complexes.

The crystal structure of Sn[H2PO4]2 has been determined from X-ray diffractometer data by Patterson and Fourier methods. Crystals are monoclinic, space group C2/c, with Z= 4 in a unit cell of dimensions a= 16.561 (9), b= 6.896(2), c= 5.939(2)A, and β= 91.35(4)°. The structure has been refined by least-squares methods to R 0.039 for 1 429 reflections. It consists of [H2PO4]– tetrahedra and Sn2+ ions. Each Sn atom has four O neighbours all lying on one side. Two of the Sn–O bonds are short (2.209 A) and two are longer (2.466 A). Such a co-ordin-ation of Sn is usually described as distorted square pyramidal, with four basal oxygens and the apex occupied by a stereochemically active lone pair of electrons from Sn. The [H2PO4]– groups are linked by strong hydrogen bonds (2.545 and 2.627 A).

Three new compounds result from the reaction of mer-[Co(NH2CH2CONCH2CO2)NO 2(en)] with formaldehyde in alkaline aqueous solution: mer-(ethylenediamine)[N-((5,6-dihydro-5,5-bis(hydroxymethyl)-1,3-oxazin-4-yl) carbonyl)glycinato]nitrocobalt(III) trihydrate (mer-[Co{(CH2OH)2CCH2OCH 2N=CCONCH2CO2}NO 2(en)]·3H2O), mer-(ethylenediamine)[N-(((methylimino)methyl)carbonyl)glycinato] nitrocobalt(III) (mer-[Co(CH3N=CHCONCH2CO2)NO2(en)]), and mer-(ethylenediamine)(N-methylideneglycylglycinato)nitrocobalt(III) (mer-[Co(CH2=NCH2CONCH2CO2)NO 2(en)]). They were separated by adsorption chromatography on a cationic exchanger, in the hydrogen form, and characterized by elemental analysis, electronic spectroscopy, and 1H and 13C NMR spectroscopy. The structure of mer-[Co{(CH2OH)2CCH2OCH 2N=CCONCH2CO2)-NO 2(en)]·3H2O was determined by X-ray crystallography. It crystallizes in the monoclinic space group P21/n in a unit cell of dimensions a = 8.843(1) Å, b = 26.809 (2) Å, c = 8.910 (1) Å, β = 115.91 (2)°, V = 1899.9 Å3, and ρcalcd = 1.62 g cm-3, with Z = 4. Refinement converged to R = 0.031 for 3260 independent observed (I/σ(I) > 3) reflections. The 1,3-oxazine derivative is tridentate, coordinated through carboxylato oxygen, peptide nitrogen, and imino nitrogen atoms. The equatorially disposed ligand forms with cobalt three fused rings, two five-membered chelates, and one six-membered heterocyclic ring. © 1990 American Chemical Society.

The synthesis and crystal structure of the title compound, K + .C 5 H 9 N 2 O 2 S 2 - .2H 2 O, are described. The structure consists of potassium cations, 3-dithiocarboxy-3-aza-5-aminopentanoate anions and molecules of water. The anion exists in two tautomeric forms, each described by two resonance structures.

This paper reports the first Co(II) complexes with a singly- and doubly-deprotonated H2L ligand (H2L = 2′,2″-(2,6-pyridindiyldiethylidene)dioxamohydrazide belonging to the planar pentadentate class. The complexes were characterized by elemental analysis, thermal analysis, IR spectroscopy, molar conductivity and magnetic susceptibility measurements. The crystal structure of [Co(L)(H2O)2] 6H2O complex has been determined. The pentagonal bipyramidal geometry present in the previously synthesized complex [Co(H2L)(H2O)(MeOH)](ClO4)2, wherein the ligand is present in a neutral form, has been preserved around Co(II).