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.     

Crystal and molecular structure of aquabis(2,2′-bipyridine)nitratomanganese(II) nitrate monohydrate

A new monomeric manganese(II) nitrate complex with 2,2-bipyridine (bpy), [Mn(bpy)₂(NO₃)(H₂O)](NO₃)·H₂O, has been prepared and characterized by X-ray crystallography. The complex crystallizes in the triclinic space group witha=9.721(3),b=14.691(5),c=8.578(3) Å, =106.79(3), =96.05(3), =82.55(3)°,V=1159.9 ų andZ=2. The structure comprises discrete cation [Mn(bpy)₂(NO₃)(H₂O)]⁺ in which the metal atom is coordinated by a pair of bidentate bpy ligands [Mn–N=2.261(4)–2.299(4) Å], a unidentate nitrato [Mn–O=2.284(4) Å] and aqua [Mn–O=2.160(3) Å] ligands in a highly distorted octahedral arrangement.     

Crystal structure of [Co(bipy)(maleato) (H2O)3]·H2O (bipy = 2,2′-bipyridine)

Preparation of the mononuclear cobalt(II) complex, [Co(bipy)(maleato) (H₂O)₃]·H₂O (1) where bipy = 2,2-bipyridine, were accomplished by reaction of an aqueous solution containing sodium maleate and an ethanolic solution of Co(NO₃)₂·6H₂O and bipy. The crystal structure of complex (1) was determined by X-ray crystallography. The complex crystallizes in the monoclinic space group P2₁/n with a = 9.477(3), b = 7.660(2), c =23.526 (3) Å, = 97.64(2)°, V = 1692.6(6) ų, and Z = 4. The structure consists of discrete mononuclear cobalt molecules. The cobalt atom is six-coordinate and presents a slightly distorted octahedral geometry, which consists of the two imine N atoms of bipy, a terminal carboxylate O atom from maleato ligand, and a water O atom in the basal plane with Co—N bond distances of 2.116(2) and 2.124(3) Å and Co—O distances of 2.075(2) and 2.088(2) Å, respectively. The relatively shorter Co—O distances are due to the trans effect of the bipy ligand. The octahedral coordination is completed the other two water molecules. The coordinate and the lattice water molecules were identified by TG study.     

Synthesis and crystal structure of [Co(phen)(H2O)4](SO4)⋅2(H2O)

The title complex, [Co(phen)(H₂O)₄](SO₄)2(H₂O) (phen = 1,10-phenanthroline) was prepared in aqua tert-butylperoxohydrogen solution. X-ray single crystal structure determination reveals that the complex consists of a phenanthrolinatocobalt(II)tetrahydrate dication, two uncoordinated water molecules and a sulfate anion. It crystallizes in the orthorhombic space group Pbca with a = 8.856(1), b = 18.318(3), c =21.918(5) Å, V = 3555.6(11) ų. The coordination geometry at each cobalt(II) atom is a slightly distorted octahedron.     

Influence of the spectator cation on the structure of anionic pyridine-2,6-dicarboxylato complexes of cobalt(II), nickel(II), and copper(II)

The structures of anionic pyridine-2,6-dicarboxylato (pdc^2–) complexes of cobalt, nickel, and copper have been studied. The stoichiometries and structures are very much dependent on whether KOH, Et₄NOH, or NaOH is used in the synthesis to deprotonate the H₂pdc ligand. Crystallographic results are: (1) K₂[Co(pdc)₂] · 7H₂O, orthorhombic, Pnna, Z = 4, a = 20.637(2)Å, b = 13.480(1)Å, c = 8.200(1)Å (2) K₂[Ni(pdc)₂] · 7H₂O, orthorhombic, Pnna, Z = 4, a = 20.648(1)Å, b = 13.375(1)Å, c = 8.2393(8)Å (3) [Co₂(H₂O)₅(pdc)₂] · 2H₂O, monoclinic, P2₁/c, Z = 4, a = 8.3880(6)Å, b = 27.384(2)Å, c = 9.6110(8)Å, = 98.271(6)° (4) [Ni(Hpdc)₂] · 3H₂O, monoclinic, P2₁/c, Z = 4, a = 13.679(1)Å, b = 10.0450(9)Å, c = 13.767(2)Å, = 115.184(7)° (5) Na₆[Co(H₂O)₆][Co(pdc)₂]₄ · 28H₂O, monoclinic, P2₁/n, Z = 2, a = 13.363(1)Å, b = 8.437(1)Å, c = 40.689(3)Å, = 91.288(5)° (6) Na[Ni(Hpdc)(pdc)] · 11.5H₂O, monoclinic, C2/m, Z = 4, a = 15.200(2)Å, b = 22.299(2)Å, c = 8.3596(7)Å, = 118.894(7)° (7) Na[Cu(Hpdc)(pdc)] · 3H₂O, monoclinic, P2₁/n, Z = 4, a = 9.516(4)Å, b = 14.917(6)Å, c = 12.247(5)Å, = 92.00(5)°. The potassium and sodium complexes have extensive K⁺—H₂O and Na⁺—H₂O networks. The fact the Et₄N⁺ ion does not appear in any of the complexes is likely due to the fact that it is incapable of forming the intricate cation—water and hydrogen-bonding networks observed in all of the other structures.     

Synthesis and crystal structure of [Y(NO3)3(OH2)3]·(Me2-16-crown-5)·H2O

The complex [Y(NO₃)₃(OH₂)₃]·(Me₂-16-crown-5)·H₂O has been prepared and its crystal and molecular structure determined using single crystal X-ray diffraction. The colorless crystals belong to the monoclinic space group P2₁/n with Z = 4. Lattice parameters are a = 10.420(1), b = 17.257(3), c = 14.646(2) Å, = 96.79(1)°, V = 2615.1(6) ų. The yttrium(III) ion is nine-coordinate, bonded to three bidentate nitrate groups and three water molecules. The average Y–O(nitrate) and Y–O(water) distances are 2.42(3) and 2.33(1) Å, respectively. The average HO–H···O hydrogen bonded separation is 2.767Å.     

Crystal and molecular structure of 1-amino-1-methylethylphosphonic acid monohydrate

The crystal and molecular structure of 1-amino-1-methylethylphosphonic acid monohydrate (C₃H₁₀NO₃P·H₂O) has been determined by single-crystal X-ray diffraction methods. The crystals are orthorhombic:Pna2₁,a=11.665(2),b=9.415(1),c=6.386(1) Å,Z=4. The structure was solved by the heavy-atom method and refined to a finalR=0.028. The molecule exists as a zwitterion, H ₃ ⁺ N-C-(CH₃)₂-PO₃₄H^–. There are six independent hydrogen bonds in the structure, three of the type N-HO with lengths 2.904(5), 2.745(6), and 2.765(5) Å and three of the type O-HO with lengths 2.754(4), 2.833 (7), and 2.548(5) Å.     

Synthesis and structure of bis(2,6-dimethylpyrazine)(THF)copper(II) nitrate

Attempts to crystallize Cu(2,6-dmpz)(NO₃)₂ (2,6-dmpz = 2,6-dimethylpyrazine) by reaction of 2,6-dmpz with Cu(NO₃)₂·3H₂O in THF resulted in the synthesis of Cu(2,6-dmpz)₂(NO₃)₂·THF. The compound crystallized in the monoclinic space group C2/c and exists as isolated molecules with distorted square pyramidal geometry: a = 11.609(4) Å, b = 10.415(3) Å, c = 18.256(6) Å, = 108.332(4)°. The 2,6-dmpz molecules coordinate to the Cu ions through the distal (remote from the methyl) nitrogens. The molecules are arrayed in stacks parallel to the b-axis.     

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.     

Crystal and molecular structures of 5,7-dimethyl-1,8-naphthyridine-2-ol (=LH) and of its mercury (II) complex HgL2 and synthesis of some lanthanide/HgL2 heterometallic complexes

The crystal structures of the title compounds have been determined by single crystal diffraction methods. Crystals of 5,7-dimethyl-1,8-naphthyridine-2-ol (1) are monoclinic, space groupP2₁/n witha=7.336(2),b=8.989(2),c=13.125(3)Å,=95.72(3)°,V=861.2(4)ų,Z=4,D _c =1.34 g cm^–3, finalR=0.052. The molecules are linked in pairs by two N-HO hydrogen bonds, and these dimers are stacked in a discontinuous, stepped fashion. Crystals of HgL₂ (2) are monoclinic space groupP2₁,/c witha=4.044(2),b=12.147(2),c=18.093(5)Å,=93.32(2)°,V=887.3(4)ų,Z=2,D _c =2.05 g cm^–3, finalR=0.051. In2 the mercury binds to N(1) to form a linear N-Hg-N coordination geometry, and the HgL₂ molecules form a continuous stacked structure. The syntheses of the compounds ML₄(NO₃)₃·H₂O (M=Nd, Gd, and Er), PrHg₂L₄(NO₃)₃, andM ₂Hg₃L₆(NO₃)₆ (M=Gd, Er) are also reported.     

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.     

Crystal structure of two lipophilic antifolates: 2,4-diamino-5-(n-hexyl)-6-methylpyrimidine and 2,4-diamino-5-(n-heptyl)-6-methylpyrimidine ethanesulfonate

The 5-hexyl (I) and the 5-heptyl (II) analogs of 2,4-diamino-6-methylpyrimidine both crystallize in the space groupP2₁/c withZ=4. Unit cell parameters of I are C₁₁H₂₀N₄·H₂O,a=17.204(3),b=4.609(9),c=16.765(2)Å,= 91.53(2)°; those of II are C₁₂H₂₃N₄ ⁺·C₂H₅SO₃ ^–,a=12.489(1),b=16.702(2),c=8.9558(7)Å,=99.208(8)°. The molecular packing of I contains one water, while II forms a salt with ethanesulfonic acid. The alkyl chain of I adopts an alltrans conformation; in contrast, II has onegauche orientation between carbons 2 and 3 of heptyl. These are the first structural data on two alkyl lipophilic antifolates with antineoplastic activity.     

The crystal and molecular structure of [K·DB-18-C-6][AlMe3NO3]·0.5C6H6

The use of dibenzo-18-crown-6 in the synthesis of trimethylaluminum adducts of KNO₃ results in the formation of a 1/1 adduct, [K·DB-18-C-6]-[AIMe₃NO₃]. The crystal structure of [K·DB-18-C-6][AlMe₃NO₃]-has been determined from single-crystal X-ray diffraction data collected by counter methods. The title compound crystallizes in the monoclinic space groupP2₁/c (No. 14) with unit cell parametersa=11.804(3),b=28.828(4),c=9.118(3) Å, =96.61(3)°, andD _calc=1.23 forZ=4. Least-squares refinement gave a final conventionalR value of 0.045 for 983 independent observed reflactions. The potassium atom is centered among the six oxygen atoms of the crown at an average KO contact of 2.74(2) Å. Its environment is completed by an oxygen atom of a nitrate anion (2.88 Å) and a benzo group (>3.44 Å) of a neighboring crown ether. The trimethylaluminum moeity is coordinated to the nitrate anion by an oxygen atom at an Al-O bond distance of 1.92(1) Å.     

Structure of 2-{2-[3-methyl-3-(2,4,6-trimethylphenyl) cyclobutyl]-2-oxoethyl}isoindole-1,3-dione

2-{2-[3-Methyl-3-(2,4,6-trimethylphenyl)cyclobutyl]-2-oxoethyl}isoindole-1,3-dione (C₂₄ H₂₅NO₃) was synthesized, and its crystal structure was determined by X-ray crystallographic techniques. The compound crystallizes in the triclinic space group P-1, with unit cell parameters: a = 14.109(9) Å, b = 14.130(8) Å, c = 12.152(6) Å, = 105.62(5)°, = 113.75(4)°, = 98.78(5)°, V = 2039.8(19) ų, D _c= 1.223 g/cm³, and Z = 4. The crystal structure has two crystallographically independent molecules, I and II. These molecules are held together by weak intermolecular C—H···O interactions, forming a continuous chain. The dihedral angles between the N-substituted phthalimide moiety and cyclobutane ring in molecules I and II are 60.37(14) and 68.18(18)°, respectively.     

Crystal and molecular structure of aqua(2,2′-bipyridine)bis(betaine)copper(II) perchlorate monohydrate

A new monomeric copper(II) complex with 2,2-bipyridine (bpy) and betaine (bet), [Cu(byy)(bet)₂(H₂O)](ClO₄)₂ · H₂O, has been prepared and characterized by X-ray crystallography. The complex crystallizes in the triclinic space groupP-1 witha=8.859(2),b=11.191(2),c=14.850(3) Å, =91.41(1), =97.19(1), =91.97(1)°,V=1459.2(7) ų, andZ=2. The structure comprises discrete cations [Cu(bpy)(bet)₂(H₂O)]²⁺ in which the metal atom is coordinated in a distorted square-pyramidal environment by two oxygen atoms from a pair of monodentate carboxylato ligands [Cu–O=1.950(2) Å] and two nitrogen atoms of a bidentate bpy ligand [Cu–N=1.997(3)–2.005(3) Å] on the basal plane, and one aqua [Cu–O=2.267(3) Å] ligand at the apical position.     

Structures and crystallization behavior of cis-α-[Co(trien)(NO2)2]·ClO4 (I), cis-β-[Co(trien)(NO2)2]Br·2H2O (II), and cis-β-[Co(trien)(NO2)2]·ClO3 (III)

Structures, conformations, and crystallization behavior of compounds cis--[Co(trien)(NO₂)₂]·ClO₄ (I), cis--[Co(trien)(NO₂)₂]Br·2H₂O (II), and cis--[Co(trien)(NO₂)₂]·ClO₃ (III) are reported. Compound (I) crystallized in space group Pbca, with a = 12.3323(9), b = 13.0265(9) and c = 18.1597(13) Å; compound (II) crystallized in space group Pca2₁, with a = 8.1844(7), b = 14.7011(14) and c = 12.4875(12) Å, while compound (III) also crystallized in space group Pca2₁, with a = 12.4897(8), b = 8.8499(6) and c = 12.6500(8) Å. In all three cases, the Co(III) ions were six-coordinated with nitrogens from trien and two nitrates. Inter- and intramolecular hydrogen bonding interactions are discussed to explain the conglomerate versus racemate crystallization behavior adopted by these three compounds, with comparison of their known analogue compounds of cis-/-[Co(trien)(NO₂)₂]X, where X = halide and NO^– ₃. For the cis--[Co(trien)(NO₂)₂]⁺ cation, the conformation of the cation itself determines the intramolecular hydrogen bonding pattern, and the interaction of counteranions can be ignored, while in cis--[Co(trien)(NO₂)₂]·ClO₄, the perchlorate interrupts the intramolecular hydrogen bonding pattern observed in the halide analog.     

Structure of a Cu(II)-containing peptide,diaquo-gly-l-tyr Cu(II) dihydrate, [Cu(C11N2O4H13)(H2O)2·2H2O

The structure of the Cu(II) complex of gly-l-tyr [Cu(C₁₁N₂O₄H₁₃) (H₂O)₂]·2H₂O has been solved by X-ray diffraction methods. The compound crystallizes in the orthorhombic space groupP2₁2₁2₁ witha=11.970(2) Å,b=12.485(2) Å andc=10.418(3) Å, respectively, (MoK)=0.710 Å,D _c =1.59 Mgm^–3,D _m =1.59 Mgm^–3, finalR=0.04. The structure was solved by heavy atom (Cu) phased Fourier and refined by full-matrix least squares methods. The coordination geometry of the ligand around the Cu(II) ion has been established as a distorted tetragonal pyramid. The peptide molecule behaves as a tridentate ligand via its amino (N2), amido (N1) nitrogens and carboxyl (O2) oxygens. The peptide nitrogen is found to be deprotonated.     

Synthesis and crystal structure of a novel tetraiminediphenolate iron(II) macrocyclic complex: A six-coordinate iron–protein model

A novel tetraiminediphenolate iron(II) macrocyclic complex [Fe(tidf)(CH₃OH)₂](NO₃)₂ (1) has been prepared and characterized by microanalysis, X-ray crystallography, FTIR spectroscopy, and mass spectrometry. The crystal structure (monoclinic, space group C2/c, Z=8, a = 26.8573(6) Å, b = 10.6551(4) Å, c = 23.5371(7) Å, = 107.450(2)°) shows that the iron(II) occupies a distorted octahedral geometry with two methanol molecules bound axially. The macrocyclic ligand is very flexible and adopts a butterfly conformation with a dihedral angle of 112°.     

Structures of 1,2,3,4-tetrahydro-6H-pyrimido[2,1-b]-quinazolin-6-one and its hydrochloride

C₁₁H₁₁N₃O, m.p. 243°C, P2/n,Z=4,a=5.843(2),b=14.241(3),c=11.102(1) Å, =93.30(2)°,R=0.046; C₁₁H₁₁N₃O·HCl·H₂O, Pca2₁,Z=8,a=18.640(2),b=8.894(2),c=14.404(2)Å,R=0.062. The molecules of the free base are in 1H-tautomeric form. N(1)-H...N(11) hydrogen bonds join molecules of the free base into dimers, which enable tautomeric rearrangement (not observed in this study) also in the solid state without any changes in molecular packing. The quinazoline system deviates slightly from planarity and benzene electrons are partially localized at C(7)–C(8) and C(9)–C(10) bonds as seen from their lengths of about 1.375 Å, while other bonds in the benzene ring are at least 0.02 Å longer.     

Crystal structure of triaquamaleatostrontium(II) monohydrate, [Sr(C4H2O4)(OH2)3]·H2O

[Sr(C₄H₂O₄)(OH₂)₃]·H₂O is monoclinic, P2₁/n, witha=11.476(2),b=7.027(1),c=12.344(2) Å, =115.74(3)°,V=896.67 ų,Z=4. The Sr atom is surrounded by nine oxygen atoms which come from four different maleate anions and three water molecules. The Sr–O distances range from 2.546(2) to 2.808(2) Å. The C–O distances are equal within the standard deviation 1.263(3) to 1.258(3) Å). In the maleate anion, the planes that contain the carboxylate groups form an angle of 74.44(9)°. Both carboxylate groups deviate significantly from planarity. The different coordination modes of the carboxylate group and the extensive hydrogen bonding present are responsible for the polymeric nature of the structure.