Crystal structures of 2-pyrazinecarboxylato silver(I) and ammine 2,3-pyrazinecarboxylato disilver(I)

X-ray analysis has shown that the complexes of silver(I) with the anionic forms of 2-pyrazinecarboxylic and 2,3-pyrazinedicarboxylic acids are three-dimensional network polymers. Ag(C₅H₃O₂N₂) (1) crystallizes in space groupPna2₁ witha=7.028(2),b=11.510(3),c=6.949(2) Å andZ=4. Silver tetrahedral coordination occurs through three ligands: the first one acts as a bidentate chelator (Ag–O=2.539(4), Ag–N=2.334(4)Å), the second one involves one N pyrazine atom (Ag–N=2.196(4)Å) and the third one bonds through one O-carboxylato atom (Ag–O=2.323(4)Å). The dinuclear complex Ag₂(C₆H₂O₄N₂)(NH₃) (2) crystallizes in space groupP2₁/c witha=7.775(2),b=16.455(2),c=7.174(1) Å, -115.21(1)° andZ =4. Each of the two silver atoms shows a trigonal environment. The first silver atom involves two O carboxylic atoms (Ag–O=2.312(4), 2.374(4)Å) and one N pyrazine atom (Ag–N=2.277(3)Å) belonging to three different ligands. The second one involves one O carboxylic atom (Ag–O=2.364(3)Å) and one N pyrazine atom (Ag–N=2.304(4)Å) from the same chelating ligand and one N ammine atom (Ag–N=2.158(5)Å).     

The molecular structure of acetato[2-(pyridin-2′-yl)phenyl]mercury(II)

The crystal structure of the title compound was determined by X-ray crystallography. The compound crystallizes in the monoclinic crystal system witha=8.152(4),b=17.994(7),c=8.634(9) Å, =108.92(5)°, space group P2₁/c (N:14),V=1198.02 ų,Z=4. The mercuryl(II) atom forms two strong, almost colinear bonds (bond angle 176.1(4)°) with a carbon of the phenyl ring (Hg–C=1.99(1) Å) and one of the acetate oxygen atoms (Hg–O(1)=2.005(7) Å). These primary bonds are supplemented by secondary intramolecular interactions with the pyridine nitrogen (Hg...N=2.727(9) Å) and the other acetate oxygen (Hg...O(2)=2.925(8) Å), although the latter is very weak and the acetate anion therefore practically monodentate. Weak additional intermolecular Hg–C and Hg–O(1)interactions contribute to the lattice structure.     

Crystal structure of the keto-enamine form of (+) (1S,2S)-2-(2-hydroxybenzylidene)amine-1-phenyl-1,3-propanediol

The title compound crystallizes in the orthorhombic space group P2₁2₁2₁, withZ=4,a=6.068(1)Å,b=10.922(1)Å, andc=21.713(2)Å. The compound is the chiral ligand of a copper complex used as an enantioselective catalyst. It crystallizes from methanol in the keto-enamine form, though the enol-imine isomer predominates in the solution. Most N-salicylideneamines studied by X-ray are enol-imines. The two tautomeric forms may interchange through anintramolecular hydrogen bond and the distances between non-H atoms in the resulting cyclic –O–H...N=C–C=C- or –C=O...H–N–C=C- fragment may be misleading, so that H atom position is the crucial factor for determination of the proper tautomeric form.     

Synthesis and crystal structure of 1-acetyl-3-bromo-3-phenylazetidine and 1-phenyl-2-(N-acetyl-N-formyl)-aminoethanone

1-Acetyl-3-bromo-3-phenylazetidine (1), C₁₁H₁₂BrNO, has been synthesized and characterized by spectroscopic methods and single crystal X-ray analysis. It crystallizes in the space group P2 ₁/c with a = 8.633(1), b = 7.461(1), c = 17.204(1) Å, = 98.403(7)°, V = 1096.2(2) ų, Z = 4, D _calc = 1.540 g cm^–3. The azetidine ring is nearly planar since the four atoms are within ±0.039(5) Å of the mean square plane calculated for the heterocycle. The attempt to obtain a highly strained 2-azetine derivative from the above compound gave, surprisingly, 1-phenyl-2-(N-acetyl-N-formyl)-aminoethanone (2), C₁₁H₁₁NO₃. This compound has been also characterized by spectroscopic methods and single crystal X-ray analysis. It crystallizes in the space group P2₁2₁2₁, with a = 5.4719(3), b = 8.3205(6), c = 23.298(3) Å, V = 1060.7(2) ų, Z = 4, D _calc = 1.286 g cm^–3. The aminoethanone residue is in a near planar conformation where the torsion angles are 7(2)° for N–C–C–=O and –173(2)° for N–C–C–C(Ph).     

Crystal and molecular structure of 1,1,2-trifluorobuta-1,3-diene

A single crystal of 1,1,2-trifluorobuta-1,3-diene, m.p. –108°C, was obtained by in situ crystallization in a capillary directly on a diffractometer. 1,1,2-Trifluorobutadiene crystallizes monoclinic, space group Pc, a = 4.4030(12), b = 6.4160(16), c = 8.293(3) Å, = 91.728(14)°, V = 234.17(12) Å, d _calc = 1.5326 g cm^–3, Z = 2, wR ₂ = 0.1332. The 1,1,2-trifluorobutadiene molecules have an anti conformation, C4–C3–C2–C1 179.17(1)°. There is no fluorine substitution effect on the bond lengths of the conjugated C–C double bonds, C1–C2 1.331(3), C3–C4 1.336(4) Å. The central bond C2–C3 1.436(4) Å is shorter than a single bond because of conjugation. The C–F bond lengths of the CF₂ group are significantly shorter than the one of the CF moiety.     

The crystal structures of (p-ClPh)3PO and (p-OMePh)3PO, including an analysis of the P-O bond in triarylphosphine oxides

The crystal structures of the compounds tris(para-chlorophenyl)phosphine oxide {(p-ClPh)₃PO} and tris(para-methoxyphenyl)phosphine oxide {(p-OMePh)₃PO} were determined by X-ray diffraction methods. (p-ClPh)₃PO crystallizes in the space group P-1 (no. 2) with a = 11.828(2), b = 12.645(2), c = 14.072(2) Å, = 97.90(1), = 109.45(1), = 115.43(1), V = 1692.3(2) ų and Z = 4. The mean O–P and C–P distances are 1.481(6) and 1.806(2) Å, respectively, and the mean C–P–C angle is 106.5(1.1). (p-OMePh)₃PO crystallizes in the space group P2₁/c (no. 14) with a = 18.8642 (10), b = 10.3999(5), c = 21.3462(16) Å, = 115.414(6)°, V= 3782.6(4) ų, and Z = 8. The mean O–P and C–P distances are 1.484(5) and 1.798(4) Å, respectively, and the mean C–P–C angle is 106.5(1.0). These two structures were analyzed along with the previously determined structures of triphenylphosphine oxide {Ph₃PO} and tri-p-tolylphosphine oxide {(p-MePh)₃PO}, and IR data were collected on all four compounds. Both the observed P–O distances and the IR stretching frequencies for these triarylphosphine oxides support the interpretation of the P–O bond as having substantial multiple-bond character, with a bond order between 1.7 and 1.8. The para-substituents on these triarylphosphines were shown to have a statistically insignificant effect on the P–O bond.     

Crystal structure of [Mn2(III)(salpa)2Cl2(H2O)2] (H2salpa = 1-(salicylaldeneamino)-3-hydroxypropane)

The manganese complex, (Mn₂(III)(salpa)₂Cl₂(H₂O)₂], has been prepared and its structure determined using x-ray crystallography. The dimer is a di-₂-alkoxo complex which is a six-coordinate manganese dimer with unsupported alkoxide bridges and a rare example of a chloride- and water-containing manganese dimer. The complex crystallizes in the monoclinic space group P2₁/c with a = 9.315(5), b = 11.130(4), c = 11.637(5) Å, = 104.33(3)°, V = 1169.0(9) ų, and Z = 2. The structure comprises discrete binuclear clusters in which the metal atoms are bridged by two alkoxo oxygens of the salpa^2– ligands. The Mn—O and Mn—N distances are in good agreement with those found for other manganese(III) Schiff base complexes. The Mn—Cl and Mn—O3 distances are 2.585(2) and 2.371(2) Å, respectively, and the Mn ··· Mn distance is 3.001(1) Å. In the crystal, there are two types of hydrogen bonding between the H₂O molecule and the Cl atom with Cl ··· H(H₂O) distance of 2.33(6) (intramolecule: –1 + x, y, –1 + z) and 2.68(6) Å (intermolecule: –1 + x, 0.5–y, –0.5 + z).     

Crystal structure and two-stage hydrolysis of dimethoxo (meso-tetra(4-methoxyphenylporphyrinato))tin(IV), Sn(tmpp)(OMe)2

In this work, we determine the crystal structure of dimethoxo(meso-tetra(4-methoxyphenylporphyrinato))tin(IV), Sn(tmpp)(OMe)₂ (1). Experimental results indicate that the tin atom has an octahedral geometry. The geometry around the tin center has Sn(1)–O(5) = 2.020(6), Sn(1)–O(6) = 2.003(7) Å and an average Sn(1)–N = 2.10(1) Å. The two methoxo groups are unidentately coordinated to the tin(IV) atom. Two-stage hydrolysis of Sn(tmpp)(OMe)₂ in CDCl₃ was observed by ¹H and ¹³C NMR spectroscopy. Compound (1) crystallizes in the space group P2₁/n with a = 14.7492(1), b = 19.2022(3), c = 16.0806(2) Å, = 94.104(1)°, and Z = 4.     

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 [(C6H5)2P(=0)(CH2CH2N(CH3)3 +][I−]

The title compound crystallizes in the centrosymmetric triclinic space group withZ=4. The crystallographic asymmetric unit contains two independent cations; interatomic distances within these include P=O=1.47(1) and 1.47(1) Å, P–C₆H₅=1.78(2)–1.81(1)Å and P–CH₂CH₂NMe₃ ⁺=1.80(1) and 1.81(1) Å. The phosphine oxide moiety is involved in intermolecular hydrogen bonding ()...H–C, with O...H2.42Å) and the iodide is involved in I...H–C contacts with I...H3.10Å.     

Molecular structure of ThBr4(DME)2 (DME = 1,2-dimethoxyethane)

The molecular structure of ThBr₄(DME)₂ (DME = 1,2-dimethoxyethane), the first structurally characterized thorium complex containing a simple bidentate ether ligand, is described. The eight-coordinate complex presents a distorted dodecahedral geometry, with Th—Br and Th—O bond lengths in the ranges 2.8516(13)–2.8712(13) Å and 2.564(8)–2.620(8) Å, respectively. ThBr₄(DME)₂ is monoclinic, space group P2₁/n, a = 7.672(1), b = 14.581(1), c = 15.847(2) Å, = 102.24(1)°, V = 1732.4(3) ų, and Z = 4.     

Intramolecular hydrogen bonding and tautomerism in N-(3-pyridil)-2-oxo-1-naphthylidenemethylamine

N-(3-pyridil)-2-oxo-1-naphthylidenemethylamine (C₁₆H₁₂N₂O) was studied by elemental analysis, IR, ¹H NMR, and UV–visible techniques and X-ray diffraction methods. The UV–visible spectrum of the compound was investigated in solutions effect polarity. The polarity of the some solvents was modifierly the additional (CF₃COOH) and [(C₂H₅)₃N]. The compound is in tautomeric equilibrium (phenol-imine O–H···N and keto-amine O···H–N forms) in polar and nonpolar solvents. The keto-amine form is observed in basic solutions of DMSO, ethanol, chloroform, benzene, cyclohexane, and in acidic solutions of chloroform and benzene, but not in acidic solutions of DMSO and ethanol. The compound crystallizes in the monoclinic, space group P2₁/a with a = 7.010(5) Å, b = 13.669(4) Å, c = 12.764(4) Å, = 101.23(4)°, V = 1199.6(10) ų, Z = 4, D _c = 1.375 g/cm³, (Mo K) = 0.088 mm^–1, R = 0.045 for 1658 reflections [I > 2(I)]. The title compound is not planar two Schiff base moieties A [C1–C11, O1] and B [N1, C12, C13, N2, C14, C15, C16] are inclined at an angle of 27.4(1)° reflecting mainly the twist about C12–N1 [C11–C12–N1–C13, 29.7(2)°]. There is a strong intramolecular hydrogen bond (O–H···N) of 2.529(2) Å.     

Synthesis and crystal structure of a palladium dimer containing ferrocenyldiphenylphosphine, trans-[Pd(μ-Cl)(CH3)(PPh2Fc)]2

The chloro-bridged dimeric complex, trans-[Pd(-Cl)(CH₃)(PPh₂Fc)]₂, was prepared by reaction of [Pd(Cl)(CH₃)(COD)] (COD = cis,cis-1,5-cyclooctadiene) with 1 equivalent of PPh₂Fc (PPh₂Fc = ferrocenyldiphenylphosphine) in acetone medium. The complex was characterized by ¹H and ³¹P NMR spectroscopy and a single crystal X-ray diffraction study revealed a trans geometry. The compound crystallizes in the triclinic space group P1, a = 11.476(2) Å, b = 14.059(3) Å, c = 14.658(3) Å and = 82.34(3)°, = 75.09(3)°, and = 68.48(3)° with Z = 2. Most important geometrical parameters include bond lengths Pd(1)–P(1) 2.2165(10), Pd(2)–P(2) 2.2290(10), Pd(1)–C(1) 2.157(3), Pd(2)–C(2) 2.079(4), Pd(1)–Cl(1) 2.4329(13), Pd(1)–Cl(2) 2.4106(11), Pd(2)–Cl(1) 2.4169(10), and Pd(2)–Cl(2) 2.4414(13) Å and bond angles P(1)–Pd(1)–C(1) 87.47(8), P(1)–Pd(1)–Cl(2) 176.88(4), C(1)–Pd(1)–Cl(1) 173.93(7), P(2)–Pd(2)–C(2) 89.03(11), P(2)–Pd(2)–Cl(1) 174.18(4), and C(2)–Pd(2)–Cl(2) 173.50(11)°. The effective and Tolman cone angles for P(1) were calculated as 170 and 167° and that for P(2) as 179 and 177°, respectively.     

Synthesis and X-ray structure of p-tolyl phenylthioglyoxylate

The title compound (C₁₅H₁₂O₂S) is triclinic witha=7.077(10),b=8.825(2),c=11.068(2) Å, =106.66(3)^o, Z=2, and space group P. The significant structural features lies in the two carbonyl groups of the thioglyoxylate which are oriented antiperiplanar to each other [–168.2(2)^o]. The central C(8)–C(9) bond is 1.553(3) Å. The phenyl rings are twisted with respect to the carbonyl groups. Short contacts are present between S and O(1) [2.652(2) Å] and also between S and O(2) [2.758(2) Å].     

Crystal structure and conformation of the antimalarial drug 5,7-methoxy-8-(3-methyl-1-buten-3-ol)-coumarin

The crystal and molecular structure of the antimalarial compound 5,7-methoxy-8-(3-methyl-1-buten-3-ol)-coumarin, C₁₆H₁₈O₅, M _r = 290.3 Da, has been determined from X-ray diffraction data. The material crystallizes in the monoclinic space group P2₁/c with 4 molecules per unit cell of dimensions a = 8.9044(9), b = 17.623(1), c = 10.175(1) Å, = 113.97(1)°, crystal density D _c = 1.322 g/cm³. The structure was determined using direct methods and refined by full-matrix least squares to a conventional R index of 0.066 for 2416 measured reflections and 206 parameters.The coumarin ring system is almost planar with the methoxy C atoms rotated slightly out of the coumarin mean plane. Apart from the terminal CH₃ groups C(12) and C(13), which are 1.184(3) Å above and –1.315(3) Å below the plane, the 3-methyl-1-buten-3-ol substituent is planar (rms deviation 0.009 Å) making an angle of 6.31(7)° with the phenyl ring. One intermolecular hydrogen bond is present in the crystal structure between O(5)–HO(5) and the symmetry related O(2) oxygen, generated by the symmetry operation (x, 1/2 – y, –1/2 + z).     

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.     

Synthesis and crystal structure of a binuclear maleatocopper(II) complex with phenanthroline

The title copper(II) complex [Cu₂(C₄H₂O₄)₂(phen)₂]⋅4H₂O (phen = 1,10-phenanthroline) was prepared and its crystal structure was determined by X-ray diffraction method. The crystal belongs to space group C2/c with cell of a = 18.136(5), b = 12.505(5), and c = 14.617(5) Å, β = 103.440(5)^∘ and Z = 4. The Cu(II) atom assumes a square pyramidal coordination geometry with a longer Cu–O3 coordination distance [2.308(3) Å] in the apical direction. The carboxyl O3 atoms from two maleate dianion bridges two Cu(II) atoms to form the binuclear complex with a shorter Cu⋅sCu separation of 3.349(1) Å. The separations of 3.39(1) and 3.41(1) Å between parallel phen rings indicate the existence of aromatic stacking.     

The triethyl ammonium salt of O,O′-bis(o-tolyl) dithiophosphate [Et3NH]+[(2-MeC6H4O)2PS2]?

The X-ray structure of the triethyl ammonium salt of O,O′-bis(o-tolyl)dithiophosphate, [Et₃NH]⁺[(2-MeC₆H₄O)₂PS₂]⁻, has been determined. Crystal data: Monoclinic, P2₁/c, a = 15.4342(6) Å, b = 10.1913(4) Å, c = 14.0729(6) Å, β = 100.855(1)^∘, V = 2174.0(2) Å⁻³, Z = 4. The immediate environment around phosphorous is distorted tetrahedral with two sulfur and two oxygen atoms in the coordination sphere, with N–H–S bonding involving only one of the sulfur atoms.     

Nickel(II) complexes with N,N,O-donor Schiff bases. Self-assembly to two-dimensional network via hydrogen bonding

The syntheses, characterization and crystal structures of two mononuclear nickel(II) complexes are described. Reactions of Ni(O₂CCH₃)₂⋅4H₂O with the Schiff bases derived from 2-pyridinecarbaldehyde and ortho-aminophenol (Hpaap) and 2-pyridinecarbaldehyde and ortho-aminobenzoic acid (Hpaab) in methanolic media afford the complexes in good yields. The elemental analysis, magnetic moments, and spectral features of the complexes are consistent with the formulae [Ni(paap)₂]⋅CH₃COOH⋅H₂O and [Ni(paab)₂]⋅2H₂O. Crystal data for [Ni(paap)₂]⋅CH₃COOH⋅H₂O: monoclinic, P2₁/c, a = 9.675(2) Å, b = 17.109(5) Å, c = 14.403(4) Å, β = 92.903(11)^∘, V = 2381.1(11) ų, and Z = 4 and for [Ni(paab)₂]⋅2H₂O: triclinic, P 1, a = 9.834(3) Å, b = 11.319(3) Å, c = 13.130(4) Å, α = 84.68(3), β = 67.54(3), γ = 85.49(2)^∘, V = 1343.4(6) ų, and Z = 2. In each complex, two tridentate monoanionic meridionally spanning ligands form a distorted octahedral N₄O₂ coordination sphere around the metal ion. In [Ni(paap)₂]⋅CH₃COOH⋅H₂O, two metal coordinated phenolate-O atoms are hydrogen bonded to CH₃COOH and H₂O, respectively. Intramolecular C–H⋅ < eqid1 > ⋅O interactions involving the water molecule and the C–H from azomethine and aromatic fragments lead to a two-dimensional network of [Ni(paap)₂]⋅CH₃COOH⋅H₂O in the crystal lattice. An uncoordinated carboxylate O-atom in [Ni(paab)₂]⋅2H₂O is hydrogen bonded to both water molecules. One of the water molecules is again hydrogen bonded to the corresponding symmetry related water molecule forming a dimer. The azomethine groups and the metal coordinated carboxylate-O atoms in [Ni(paab)₂] are involved in intermolecular C–H⋅ < eqid2 > ⋅O interactions forming a chain-like arrangement of the molecules. The water dimers act as bridges between these chains and a two-dimensional network of [Ni(paab)₂]⋅2H₂O is formed.     

The structure of nitrocubane: the last in the series of nitrocubanes

The structure of nitrocubane, C₈H₇NO₂, 1, reported herein, is the last to be reported in a series of nitrocubanes, ranging from mono- to octanitrocubane. Compound 1 crystallizes in the orthorhombic space group Pnma with cell dimensions a = 17.507(5), b = 6.584(2), and c = 5.832(2) Å and Z = 4. Thus the nitrocubane molecule possesses a crystallographically imposed mirror plane. Since the nitro group is in the mirror plane, it is coplanar with the C1–C6 bond in the cubane skeleton. As has been found previously, the C1–C6 bond in the cubane skeleton that is coplanar to its attached nitro groups is shortened (1.533(4) compared to an average value of 1.543(2) Å for all other cubane C–C bonds). In addition the single substitution of the nitro group into the cubane skeleton causes a tetrahedral distortion which is exhibited by alternating C–C–C angles which are greater than and less than 90°.