Transition metal(II) complexes of a biological buffer. Structural and spectroscopic study on Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) complexes of N-[2-hydroxy-1,1-bis-(hydroxymethyl)ethyl]glycine

The structural and spectroscopic properties of complexes of N-[2-hydroxy-1,1-bis-(hydroxymethyl)ethyl]glycine (thmmg) with Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) were investigated. The complex [Zn(thmmg)₂] crystallizes in the space groupP2₁/n, witha=8.796(2),b=9.050(3),c=9.926(2) Å,=97.35(1)° andZ=2; the copper(II) homolog is isomorphous. The complex [Ni(thmmg)₂]·6H₂O crystallizes in the space groupP2₁/n witha=8.432(8),b=8.495(2),c=15.967(1) Å,=95.57(2)° andZ=2; the cobalt(II) homolog is isomorphous. Ni(II) and Zn(II) complexes show an elongated octahedral coordination arising from two symmetry related amino acid molecules acting as a tridentate chelate through the amino nitrogen, one carboxylate oxygen, and one hydroxyl oxygen; the water molecules in the Ni(II) complex are not involved in metal coordination. The same ligand bonding mode may be suggested also for the Cu(II) and Co(II) complexes, while for Cd(II) only the nitrogen atom and the carboxylate oxygens seem to be involved in metal coordination.     

Cobalt(II) and nickel(II) complexes ofN-protected amino acids. Crystal and molecular structure of bis (N-acetylglycinato)tetraaquocobalt(II)

Binary complexes of formula [M(II)(acgly)₂(H₂O)₄] (M(II)=Co(II), Ni(II), acgly=N-acetylglycinate ion) were synthesized, and for the Co(II) complex the crystal and molecular structure was determined. The crystals are monoclinic, space groupP2₁/c,a=4.838(1),b=10.785(2),c=14.340(6) Å,=96.96(2)°,Z=2. The structure was solved by the heavy-atom method and refined through full-matrix least-squares calculations toR=0.0394 for 1069 observed reflections. The coordination around the cobalt atom is slightly elongated octahedral arising from one carboxylate oxygen of each of the two centrosymmetrically related monodentateN-acetylglycinate anions and four water molecules.     

Synthesis,spectroscopic characterization of thiosemicarbazone complexes of nickel(II) and X-ray structures of anisaldehyde thiosemicarbazone (ATSZH) and bis(tolualdehyde thiosemicarbazonato)nickel(II)

Complexes of nickel(II) with anisaldehyde (ATSZH), tolualdehyde (TTSZH), and vanillin (VTSZH) thiosemicarbazones have been synthesized and characterized by means of UV-Visible, I.R., Raman,¹H and¹³C NMR spectroscopy. The thiosemicarbazones have been found to exist in the thione form.¹H and¹³C NMR as well as electronic spectral data support a square planar structure for Ni(ATSZ)₂ and Ni(TTSZ)₂ complexes.¹H and¹³C NMR spectra indicate that the structure of Ni(VTSZ)₂ complex differs from the other two nickel(II) complexes and it may possibly consist of mixtures of isomers. The X-ray structures of Ni(TTSZ)₂ and ATSZH were determined: the nickel complex is monoclinic witha=26.412(6),b=12.135(3),c=6.888(1)Å,=95.41(5)°,Z=4,R=0.0647, space groupC2/c. The structure consists of discrete Ni(TTSZ)₂ molecules in which the metal, located on a symmetry centre, is N,S-chelated by two ligands forming two five-term chelate rings. The structure of ATSZH is also monoclinic:a=7.859(1),b=13.481(3),c=10.028(3) Å,=106.32(4)°,Z=4,R=0.0412, space groupP2₁/c. The molecules, connected by NO hydrogen bonds, reveal a considerable tilting of the aromatic ring in respect to the thiourea moiety if compared with the nickel structure.     

The crystal structure of a N-(2-thiophenyl)-salicylaldiminopiperidino nickel(II) complex

The crystal and molecular structure of the title complex, C₁₈H₁₉N₂OSNi, has been determined by direct methods. The compound crystallizes in monoclinic crystal system witha=11.968(1),b=12.182(1),c=12.399(1) Å, =115.23(1)°, space group P2₁/n. Nickel is in a slightly distorted square-planar environment of two nitrogens [1.881(2) and 1.952(2) Å] and one oxygen [1.856(3) Å] and one sulphur [2.138(2) Å] atom. Ni is 0.005 Å out of the plane of its ligands.     

[N(2-ammoniumethyl)piperazinium]tetrachloromono-bromocuprate(II) monohydrate: A compound containing a discrete square-pyramidal unit

The crystal and molecular structure of the [N(2-ammoniumethyl)piperazinium]tetra-chloromonobromocuprate(II) monohydrate is reported. The crystals are monoclinic, space groupP2₁/c,Z=4, witha=9.560(2),b=9.240(3),c=18.270(7)Å,=99.20(2)°. The structure consists of discrete N(2-ammoniumethyl)piperazinium cations, uncoordinated water molecules and [CuCl₄Br]^3– anions, in which four coplanar chlorine atoms occupy the square-basal plane and one bromine atom the axial position, giving the copper(II) ion a moderately elongated square-pyramidal geometry. The structure was refined to a finalR index of 0.0765.     

Preparation and crystal structure of diaquabis(1,8-naphthyridine-N-monoxide)nickel(II)nitrate

The title compound [Ni(napyo)₂(H₂O)₂](NO₃)₂ was formed by the reaction of nickel(II) nitrate with 1,8-naphthyridine-N-monoxide (napyo) in ethanol medium. The complex crystallizes in the monoclinic, space groupP2₁/n withZ=2. Lattice parameters are:a=7.160(2),b=11.713(3),c=11.830(2) Å,=95.11(3)°. The structure was determined from 1399 observed reflections and refined toR=0.061. The Ni atom shows a slightly distorted octahedral coordination, being bonded to two oxygen atoms and two nitrogen atoms of two napyo ligands and to two oxygen atoms of two water molecules.     

Structure of hexakis(imidazole)nickel(II) disalicylate, [Ni(Im)6](Sal)2

The crystal and molecular structures of [Ni(Im)₆](Sal)₂ (Im = imidazole, Sal = salicylate) have been determined by X-ray crystallography. It crystallizes in the triclinic system, space group P1¯, with lattice parameters a = 8.3125(2), b = 8.7168(1), c = 12.3262(3) Å, = 90.341(1), = 96.33(1), = 101.544(1)°, and Z = 1. The crystal structure of the title compound is built up of discrete monomeric molecules of [Ni(Im)₆](Sal)₂. The nickel(II) ions have an octahedral geometry with the NiN₆ chromophore. In the solid state, the title compound forms a network through N—H···O hydrogen bonds, the intermolecular hydrogen bonds connect the Ni(Im)²⁺ ₆ moieties and salicylate molecules.     

Crystal and molecular structure of bis(tetrathiafulvalene) bis(maleonitrile-1,2-dithiolato)nickelate(II)

The crystal and molecular structure of the title compound, C₂₀H₈N₄S₁₂Ni, is reported. Crystals are triclinic, space groupP¯1 (No. 2) withz=1 in a cell of dimensionsa=8;482(2),b=7.950(2),c=9.976(2) Å,=95.64(2),=98.60(2), and =87.65(2)°. The structure was solved by Fourier methods and refined by the method of least squares toR=0.033 for 2027 unique reflections. The Ni atom has an approximate square-planar configuration with Ni-S(1)=2.179(1), Ni-S(2)=2.175(1) Å, and the S(1)-Ni-S(2) bite angle of 91.89(4)°. The anions and the cations form a mixed stack (DAD-DAD-) along the diagonal of theab plane, showing the possibility of unusual electrical behavior.     

Coordination of Schiff bases derived from pyrrole-2-carboxaldehyde and triamines to copper(II) and nickel(II) ions. Crystal structures of [Cu(C15H20N5)]NO3 and [Ni(C15H20N5)]ClO4

The Schiffbases 1,9-bis(2-pyrrolyl)-2,5,8-triazanona-1,8-diene (H₂L¹), 1,10-bis(2-pyrrolyl)-2,5,9-triazaundeca-l,9-diene (H₂L²), and 1,11-bis(2-pyrrolyl)-6-methyl-2,6,10-triazaundeca-l,10-diene (H₂L⁴) react with copper(II) nitrate or nickel(II) perchlorate in the presence of triethylamine to give new complexes [Cu(HL^1,2,4)]NO₃ and [Ni(HL^1,2,4)]ClO₄. The crystal structures of [Cu(HL²)]NO₃ and [Ni(HL²)]CIO₄ have been determined from single crystal diffractometer data and refined to finalR factors of 5.09 and 5.3%, respectively. Crystallographic data: [Cu(HL²)]NO₃: monoclinic,P2₁/c,a=10.036(2),b=14.500(2),c=13.317(2) Å,=108.14(1)°,Z=4, andd _c =11.427 Mg m^–3; [Ni(HL²)]ClO₄: monoclinic,P2₁/n,a=10.578(3),b=13.953(3),c=12.394(4) Å,=93.78(2)°,Z=4, andd _c =1.549 Mg m^–3. In both the structures the potentially pentadentate ligand (HL²)^– acts as a tetradentate one leaving one pyrrole group uncoordinated. Interesting is the metal dependent sequence of the three chelate rings. While the Ni (II) ion coordinates the (HL²)^– ligand to form a 5-5-6-membered ring system, the ring arrangement in the copper complex is of the 5-6-5 type.     

Crystal and molecular structure of [CpRu(PPh3)2(t-C4H9SH)]BF4

The structure of the [CpRu(PPh₃)₂(t-C₄H₉SH)]BF₄ complex was determined by X-ray diffraction techniques: monoclinic space groupP2₁/c,a=14.662(9),b=18.515(7),c=15.368(6)Å,=101.88(5)°,V=4082(6)ų,Z=4,R=0.049,R _w=0.057. The Ru is attached to two triphenylphosphine ligands, a cyclopentadienyl and thet-butylmercaptan. The Ru-S distance is 2.396(2)Å and the S-H distance is 1.289(2)Å.     

Gold(I)-selenium bond: synthesis and x-ray structure of chloro(triphenylphosphine selenide)gold(I)

The crystal and molecular structures of chloro(triphenylphosphineselenide)gold(I), [(C₆H₅)₃PSe]AuCl, have been determined from three-dimensional X-ray intensity data collected on a CAD4 diffractometer. The compound crystallizes in the triclinic space groupPl witha=9.322(3),b=10.639(5),c=9.252(3) Å, =104.74(4), =99.52(3), =76.97(3)°, andZ=2. Atomic parameters were refined by full-matrix least-squares to anR value of 5.7% for 2591 observed reflections. This is one of the few known examples of linear gold(I) complexes having an Au-Se linkage. The Se-Au-Cl angle is 178.6(1)°, and the Au-Se and Au-Cl distances are 2.371(2) and 2.277(6) Å, respectively. As expected, the Au-Se bond length is 0.10–0.18 Å longer than the Au-S bond length observed in similar two-coordinate linear gold(I) complexes.     

Crystal structure ofcis-diaqua bis(2,2′-bipyridyl)chromium(III) nitrate, [Cr(bipy)2(H2O)2] (NO3)3

cis-Diaquabis(2,2-bipyridyl)chromium(III) nitrate crystallizes in the mono-clinic system, space groupP2₁/c, witha=16.102(6),b=10.792(5),c=15.076(6) Å,=112.90(5)°, andZ=4. The saltlike structure was determined from X-ray crystallography and refined toR=7.5% for 3342 observed reflections. The Cr atom is octahedrally surrounded by twocis water molecules and by two chelated 2,2-bypiridyl ligands forming two nearly orthogonal planes. Selected bond distances are: Cr-O, 2.00(1) and 1.98(1) Å, Cr-N, 2.04 Å (mean).     

Structures of three halo(tetramethylethylenediamine)copper(I) complexes

The X-ray crystal structures of three halo(tetramethylethylenediamine)copper(I) complexes have been determined. (TMED)₂Cu⁺CuCl ₂ ^– (I) crystallizes in monoclinic space groupP2₁/n with lattice constantsa=9.332(9),b=15.126(7),c=14.49(1) Å,=96.95(7)°. (TMEDCuBr)₂ (II) crystallizes in monoclinic space groupP2₁/c with lattice constantsa=12.064(5),b=11.888(6),c=15.841(6) Å,=113.97(3)°. (TMED CuI)₂ (III) crystallizes in monoclinic space groupP2₁/c with lattice constantsa=12.401(6),b=12.159(6),c=15.412(9) Å,=109.12(4)°. Compound (I) is a molecule exhibiting two discrete environments for copper(I). The cation is a pseudotetrahedral monomer and the anion a linear monomer. Both (II) and (III) are dimers with asymmetrically bridging bromine and iodine atoms, respectively. Distortions from tetrahedral geometry are observed about the copper atoms in (II) and (III).     

Crystal structure of the addition compound of [Ni(meso-cth)][Cr(ox)2(bpy)](H2O)(ClO4) with weak coordination bonds and hydrogen bonds

A new ionic complex [Ni(meso-cth)][Cr(ox)₂(bpy)](H₂O)(ClO₄) [meso-cth = meso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, ox = oxalato ainon, bpy = 2,2-bipyridine] was prepared and its structure was determined. The complex was found to crystallized in monoclinic space group P2(1)/n, with a = 13.6000(4) Å, b = 18.763(5) Å, c = 14.995(4) Å, =106.958(5)°, V = 3659.9(17) ų, and Z = 4. The structure consisted of cationic [Ni(meso-cth)]²⁺, anionic [Cr(ox)₂(bpy)]^–, and perchlorate anions; the cationic [Ni(meso-cth)]²⁺ and anionic [Cr(ox)₂(bpy)]^– units were related by weak coordination bonds and hydrogen bonds.     

Crystal and molecular structure of palladium(II), copper(II) and zinc(II) complexes of 1-methyl-3-(4-methyl)phenyltriazen-1-oxide

The structures of palladium(II), copper(II) and zinc(II) bis(chelates) of 1-methyl-3-(4-methyl)phenyltriazen-1-oxide have been determined by single-crystal X-ray methods. The crystals of [Pd(OMeN₃C₆H₄Me-4)₂] (I) are triclinic witha=7.410(3),b=7.806(3),c=8.371(2) Å, =65.80(2), =88.73(3), =81.04(3)°,Z=1, space group . The crystals of [Cu(OMeN₃C₆H₄Me-4)₂] (II) are monoclinic,a=14.934(5),b=10.111(4),c=11.762(3) Å, =96.00(2)°,Z=4, space group P2₁/c. The crystals of [Zn(OMeN₃C₆H₄Me-4)₂] (III) are triclinic witha=7.912(2),b=10.056(2),c=11.600(2) Å, =87.31(3), =74.96(3), =74.02(3)°,Z=2, space group . The structures of (I), (II), and (III) were solved to final values ofR=0.029, 0.043 and 0.034, respectively. A planar structure has been found for (I), (II) exhibits a tetrahedrally distorted square planar structure, whereas (III) is tetrahedral. The crystals of all three complexes are held by networks of stacking interactions.     

Isolation and crystal structures of triethylenediamine-hydroquinone (1/1) and triethylenediamine-phenol (1/2)

Two crystalline adducts of triethylenediamine with hydroquinone [N(CH₂CH₂)₃N·C₆H₄(OH)₂,I] and phenol [N(CH₂CH₂)₃N·2C₆H₅OH,II] have been isolated and characterized by X-ray analysis. ComplexI crystallizes in the monoclinic space groupC2/c, witha=11.944(2),b=9.491(2),c=11.986(2) Å,=121.70(1)°, andZ=4. Both molecular components occupy sites of symmetry 2, and are linked alternately by N H-O hydrogen bonds to form infinite zigzag chains. Crystals ofII are also monoclinic, with space groupP2₁/c,a=12.987(2),b=6.376(1),c=21.350(3) Å,=106.94(1)°, andZ=4. The structure is composed of discrete hydrogen-bonded molecular aggregates corresponding to the stoichiometric formula. The triethylenediamine moieties in both adducts closely approximate to the idealizedD ₃ h conformation. The structures have been refined toR values of 0.097 (I) and 0.092 (II) using, respectively, 479 and 1580 observed MoK data.     

Structures of bis(salicylaldoximato)- and bis(5-chlorosalicylaldoximato)nitrosylcobalt,examples of nitrosyls containing a bent Co-N-O group

The crystal and molecular structures of [Co(NO)(salox)₂] and [Co(NO)(5-Clsalox)₂], where saloxH is salicylaldoxime and 5-ClsaloxH is its 5-chloro derivative, have been determined. The unsubstituted nitrosyl crystallizes in the orthorhombic system,a=11.557,b=15.333,c=8.245 Å,Z=4, space groupPna2₁. The structure was determined by theDIRDIF difference structure factors method, using MoK diffractometer data, and refined by full-matrix least squares toR=0.055 for 685 observed reflexions. The 5-chloro analogue crystallizes in the monoclinic system,a=8.553,b=12.510,c=15.702 Å, =102.84°,Z=4, space groupP2₁/c. This structure was determined by the heavy-atom method, using MoK diffractometer data, and refined by full-matrix least squares toR=0.043 for 2107 observed reflections. In both compounds, the molecule excluding the nitrosyl group is approximately planar. The cobalt atom is 5-coordinate in an essentially square pyramidal arrangement with the basal plane defined bytrans bidentate oximato ligands between which are strong hydrogen bonds. The nitrosyl group occupies the apical position, and the Co-N-O angles and the N-O bond lengths are 116(2)° and 1.48(3) Å ([Co(NO)(salox)₂]), and 123.4(3)° and 1.070(5) Å ([Co(NO)(5-Clsalox)₂]). The more acute angle and unusually long N-O bond of [Co(NO)(salox)₂] may be due to disorder and/or an interaction between the NO oxygen atom and one of the oxime groups.     

The molecular structure of dibutylbis(2-pyridinethiolato-5-ethyl ester)tin(IV), [SnBu2(TNEE)2]

The crystal structure of [SnBu₂(TNEE)₂], (HTNEE=5-ethyl ester of 2-mercaptopyridine-5-carboxylic acid) has been determined by X-ray single crystal diffraction study. The crystal is triclinic, space groupP,a=10.042(1),b=18.421(2),c=7.979(1) Å, =98.7(1), =107.3(1), =87.7(1)^o,V=1393(1) ų, and Z=2 The tin center is coordinated to two butyl groups and to the nitrogen and the sulfur atoms of two ligand molecules in a very distorted trapezoidal bipyramid.     

Reaction of 5,5-diphenyl-2-thiohydantoin with ethyl-2,3-dibromopropionate. Crystal and molecular structure of ethyl-2-{2,3-dihydro-6,6-diphenylimidazo-[2,1-b]-thiazol-5(6H)-one} formate

The crystal and molecular structure of the title compound, obtained by intramolecularN,S-dialkylation of 5,5-diphenyl-2-thiohydantoin with ethyl-2,3-di-bromopropionate, has been determined from X-ray diffractometer data. Ethyl-2-{2,3-dihydro-6,6-diphenylimidazo-[2,1-b]-thiazol-5(6H)-one}formate crystallizes in space groupP2₁/c witha=12.166(4),b=10.689(2),c=15.021(6) Å,=113.63(4)°, andZ=4. The molecular structure was found with nonplanar thiazole ring. The structure was solved withR=0.051.     

Heptacoordination in MnII,NiII, and CuII complexes of 2,6-diacetylpyridine bis (acetylhydrazone)

Manganese(II), nickel(II), and copper(II) complexes of 2,6-diacetylpyridine bis (acetylhydrazone) (H₂dapac) have been synthesized and structurally characterized by X-ray diffraction methods. [Mn(H₂dapac) (OH₂)₂](NO₃)₂ crystallizes in the monoclinic space groupP2₁/c witha=11.145(3),b=10.723(4),c=17.189(2) Å, =92.81(2)° andZ=4; [Ni(H₂dapac)(OH₂)₂] (NO₃)₂·H₂O crystallizes in the monoclinic space groupP2₁ witha=9.994(3),b=14.423(4),c=7.697(2)Å, =100.37(2)°, andZ=2; [Cu(H₂dapac)(OH₂)₂](NO₃)₂·H₂O crystallizes in the orthorhombic space groupPbcn witha=20.986(5),b=14.552(3),c=6.905(1)Å andZ=4. In each case the metal atom has a slightly distorted pentagonal bipyramidal environment, the equatorial positions being occupied by three nitrogen and two oxygen atoms from the hydrazone ligand and the apices by two water molecules. The crystalline cohesion in ensured by a three-dimensional network of hydrogen bonds involving the complex cations, the nitrate anions, and, where present, the uncoordinate water molecules.