Meisenheimer complex from picric acid and diisopropylcarbodiimide

Reaction of picric acid with diisopropylcarbodiimide produces a pale yellow 1:1 adduct N-(2,4,6-trinitrophenyl)-N,N-di(isopropyl)urea (5) and a 1:2 adduct fluorescent red zwitterionic Meisenheimer complex (6) as approximately N,N,N-tri(isopropyl)-4-oxo-6-(isopropyliminio)-2-s-(2H)triazinespiro-1-2,4,6-trinitro cyclohexadienylide. Crystals of (5) are triclinic, P-1 (#2), with a = 10.444(13) Å, b = 15.47(2) Å, c = 17.74(2) Å, = 110.43(9)°, = 99.85(10)°, = 92.78(10)°, V = 2629(6) ų for Z = 6 (three molecules per asymmetric unit). Crystals of (6) are orthorhombic, Pna2₁ (#33), with a = 24.12(4), b = 9.011(19) Å, c = 10.87(2) Å, V = 2362(8) ų for Z = 4. Nitro groups in the Meisenheimer complex are twisted 2–8° from the mean formerly aryl ring plane; in (5), nitro groups are twisted out of the aryl plane by 11–62°. In the Meisenheimer complex, cationic charge is distributed over an iminium/guanidinium group; anion charge is distributed over the cyclohexadienide ring and attached nitro groups.     

Nonpreorganized neutral acyclic anion receptors: Structural investigations of N,N′-diphenyl-1, 3-benzenedisulfonamide and N,N′bis(4-t-butylphenyl)-1, 3-benzenedisulfonamide

The structure of N,N-diphenyl-1,3-benzenedisulfonamide (1) was determined by single crystal X-ray diffraction. It crystallizes in P2₁/n with cell dimensions: a = 11.8390(6) Å, b = 12.3950(10) Å, c = 12.1184(10) Å, = 94.388(6)°, and V = 1773.1(2) ų. Its di-t-butyl derivative, N,N-bis(4-t-butylphenyl)-1,3-benzenedisulfonamide (2), was prepared and structurally characterized as two solvated structures. Both crystallize in P with cell dimensions: 2 CF₃CH₂OH, a = 9.469(2) Å, b = 10.0039(18) Å, c = 16.385(3) Å, = 85.561(16)°, = 83.035(18)°, = 72.459(16), and V = 1467.7(5) ų; 2 ClCH₂CH₂Cl, a = 9.559(2) Å, b = 9.8125(12) Å, c = 17.100(6) Å, = 82.495(19)°, = 83.47(2)°, = 70.100(15), and V = 1491.1(6) ų. The structures exhibit hydrogen-bonding, and are evaluated in terms of preorganization for anion binding.     

Crystal structures and supramolecular assembly of 1:2 piperazine with o- and p-nitrophenol

1:2 Cocrystals of piperazine (PPN) with o- and p-nitrophenol (oNPH and pNPH) were obtained from aqueous solution. The co-crystal structure of PPN, 2pNPH, and 2H₂O is triclinic space group : a = 6.401(1) Å, b = 6.7515(1) Å, c = 11.219(1) Å, = 100.37(1)°, = 97.10(1)°, = 99.99(1)°,V= 465.5(1) ų, Z = 2. Refinement led to a final conventional R value of 0.0365 for 2081 reflections. PPN, 2oNPH, and 2H₂O cocrystallize in the monoclinic space group P2₁ : a = 7.753(1) Å, b = 10.888(2) Å, c = 11.378(2) Å, = 92.89(1)°, V = 953.1(3) ų, Z = 2. Refinement led to a final conventional R value of 0.0347 for 1978 reflections. It was found in both cocrystals that the hydroxyl H-atom of pNPH and oNPH was transferred to a N-atom of PPN, forming new ionic complexes PPNH₂ ²⁺2(oNP^–) and PPNH₂ ²⁺2(pNP^–), respectively.     

A novel class of naturally occurring halogenated pyrroles, 1,1′-dimethyl-3,3′,4,4′,5,5′-hexabromo-2,2′-bipyrrole, 5,5′-dichloro-1,1′-dimethyl-3,3′,4,4′-tetrabromo-2,2′-bipyrrole, and 1,1′-dimethyl-3,3′,4,4′,5,5′-hexachloro-2,2′-bipyrrole

Crystal structure determinations of the three title hexahalogenated bipyrroles, (I) C₁₀H₆Br₆N₂, (II) C₁₀H₆Br₄Cl₂N₂, and (III) C₁₀H₆Cl₆N₂, reveal essentially planar pyrrole rings having dihedral angles of 64.7, 65.1, and 64.2° between the least-squares planes, favoring in each case a closer methyl–halogen conformation. All three complexes crystallize in the orthorhombic space group Pbcn with the following cell dimensions: (I) a = 12.654(3) Å, b = 8.853(2) Å, c = 13.753(3) Å, = = = 90°, Z = 4; (II) a = 12.438(6) Å, b = 8.753(6) Å, c = 13.696(3) Å, = = = 90°, Z = 4; (III) a = 12.088(6) Å, b = 8.566(4) Å, c = 13.486(8) Å, = = = 90°, Z = 4.     

Crystal structures and vibrational spectra of racemic and chiral 4-phenyl-1,3-oxazolidine-2-thione

The crystal structures of (rac)- and (R)-4-phenyl-1,3-oxazolidine-2-thione (4-POT) have been determined by X-ray diffraction. The structure of (rac)-4-POT is monoclinic P2₁/n with a = 11.9096(9) Å, b = 5.9523(6) Å, c = 12.3563(8) Å, = 91.054(6)°, V = 875.8(1) ų, and Z = 4. The structure of (R)-4-POT is orthorhombic P2₁2₁2₁ with a = 7.7197(6) Å, b = 21.603(2) Å, c = 5.4613(9) Å, V = 910.8(2) ų, and Z = 4. (rac)-4-POT and (R)-4-POT crystals are shown to have different hydrogen-bonding patterns. In the racemic crystals, the enantiomeric (R)- and (S)-4-POT molecules are connected to form a cyclic dimer via the N–H S hydrogen bond of the cis thioamide moiety [N Sⁱ 3.438(2) Å, N–H Sⁱ 176(2)° symmetry code: (i) 1 – x, 1 – y, 1 – z]. In the chiral (R)-4-POT crystals, the N–H S intermolecular hydrogen bond forms a zigzag chain around the twofold screw axis [N Sⁱⁱ 3.347(3) Å, N–H Sⁱⁱ 161(3)° symmetry code: (ii) 1/2 + x, 1/2 – y, 2 – z]. Observed difference of 46°C in the melting points between the (rac)-4-POT and (R)-4-POT crystals is correlated with difference in the crystal packing. Vibrational spectra of (rac)- and (R)-4-POT crystals are discussed both in the solid state and in solution.     

Crystal and molecular structure of cesium isothiocyanatotrimethylaluminate,Cs[Al(CH3)3NCS]

The crystal structure of the title compound has been determined from three-dimensional X-ray diffraction data, and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP2₁/c, witha = 8.849(4),b = 13.798(5),c = 7.943(4) Å, = 102.98(3) °, andD _x = 1.85g cm^–3 forZ = 4. The finalR factor for 1283 observed reflections is 0.046. The aluminum atom is bonded to the nitrogen atom of the thiocyanate ligand, where the Al-N bond length is 1.94(1) Å. The SCN is linear, and the CN-Al angle is 175(1) °. The cesium ion exhibits four contacts less than 3.60 Å: Cs C(thiocyanate) = 3.39(1) Å, Cs C(methyl) = 3.52(1) Å, Cs C.(methyl) = 3.56(1) Å, and Cs N = 3.575(9) Å. The closest Cs S is 3.772(3) Å.     

Synthesis and crystal structure of 3,5-di(2-propenyl)-6-phenyl-1,3,5-triazine-2,4-dione and 2-dimethylamino-4-ethoxycarbonylmethoxy-6-phenyl-1,3,5-triazine

The title compound 3,5-di(2-propenyl)-6-phenyl-1,3,5-triazine-2,4-dione has been synthesized by the reaction of 6-phenyl-1,3,5-triazine-2,4-dione with allyl bromide. Its structure was determined by X-ray single crystal diffraction. The crystal belongs to orthorhombic, space group Pbca with the following crystallographic parameters: a = 16.282(4) Å, b = 8.888(2) Å, c = 19.281(5) Å, = 90°, = 90°, = 90°, = 0.088 mm^–1, V = 2790.1(13) ų, z = 8, Dx = 1.282 mg/m³, F(000) = 1136, T = 293(2) K, 2.11° 25.02°, the final R factor: R ₁ = 0.0430, wR₂ = 0.0981. The X-ray results demonstrate that the reaction of 6-phenyl-1,3,5-triazine-2,4-dione with allyl bromide in the presence of N,N-dimethylformamide and potassium carbonate yields the N-alkylated product. The title compound 2-dimethylamino-4-ethoxycarbonylmethoxy-6-phenyl-1,3,5-triazine has been synthesized by a new reaction, in which the solvent N,N-dimethylformamide involves. Its structure was determined by X-ray single crystal diffraction. The crystal belongs to triclinic, space group P-1 with the following crystallographic parameters: a = 7.977(2) Å, b = 10.394(3) Å, c = 10.837(3) Å, = 111.774(5)°, = 104.050(5)°, = 99.446(5)°, = 0.093 mm^–1, V = 776.6(4) ų, z = 2, Dx = 1.293 mg/m³, F(000) = 320, T = 293(2) K, 2.14° 25.03°, the final R factor: R ₁ = 0.0582, wR ₂ = 0.1399. The distance of N(4) C(2) (1.339 Å) is much shorter than the length of normal C N (1.47 Å) and very close to that of C-N (1.33 Å), which is indicative of the significant double bond character.     

Syntheses and structures of dihydrocalix[4]arenes bearing O-benzonitrile and O-acetonyl substituents

Three 25,27-dihydrocalix[4]arene derivatives, bearing benzonitrile and acetone groups on the oxygens, were prepared and structurally characterized. All three structures crystallize in , with cell dimensions: bis(benzonitrile)calix[4]arene·toluene, a = 11.530(2) Å, b = 12.013(2) Å, c = 14.089(4) Å, = 103.555(18)°, = 94.341(18)°, = 104.704(16)°, and V = 1815.9(7) ų; anti-bis-acetone-calix[4]arene, a = 7.5847(8) Å, b = 12.0948(17) Å, c = 15.3375(16) Å, = 78.982(10)°, = 76.932(9)°, = 73.129(10)°, and V = 1299.6(3) ų; syn-bis-acetone-calix[4]arene, a = 9.080(3) Å, b = 10.391(3) Å, c = 14.816(3) Å, = 96.998(19)°, = 100.02(2)°, = 103.93(3)°, and V = 1299.6(3) ų.     

Crystal structure and thermal analysis of 1,5-diammonium-2-methyl pentane sulfate monohydrate

Chemical preparation, x-ray single crystal, and thermal analysis of C₆H₁₈N₂SO₄·H₂O (denoted DMPS) are described. The compound crystallizes in the triclinic system with P space group. Its unit cell dimensions are a = 5.826(1) Å, b = 10.014(1) Å, c = 11.221(1) Å, = 66.716(1)°, = 84.395(1)°, = 83.759(1)°, V = 596.7(1) ų, and Z = 2. The DMPS structure is built up from inorganic chains parallel to the a axis and linked via O(W)-H···O hydrogen bonds. These chains are interconnected by organic groups. Thermal analysis reveals the presence of one water molecule in the structure and shows a reversible weak phase transition.     

Schiff bases and their complexes with metal ions. Part II. Structures of N-n-butyl-2-hydroxy-1-naphthaldimine and bis[N-n-pentyl-2-hydroxy-1-naphthaldiminato]nickel(II)

The Schiff base ligand (1), [C₁₅H₁₇NO] crystallizes in the monoclinic space group P2₁/c witha=10.054(3),b=10.313(3), c=13.173(4)Å, =107.42(4)°,V=1303.2(7)ų,Z=4,Dx=1.159 g cm^–3, and (MoK)=0.674 cm^–1. The C2-O[1.23(1)Å] and C3–C4 [1.33(2)Å] bond lengths are short, due to its quinoidal structure. In the Schiff base nickel complex (2), [Ni(C₁₆H₁₈NO)₂] the asymmetric unit is comprised of two half-complexes. It crystallizes in the triclinic space group witha=5.124(3),b=16.227(3),c=16.886(4)Å, =95.47(8), =96.00(1), =90.71(4)°,V=1389.6(9) ų,Z=2,Dx=1.289 g cm^–3, and (MoK) =12.1 cm^–1. The coordination of the Ni(II) ions are square planar with bond angles between 87.9(1) and 92.1(1)°. The Ni–O and Ni–N distances are 1.819(2), 1.922(2) and 1.823(2), 1.914(3)Å in these two complexes.     

A comparison of the coordination preferences of Zn, Co, and Cd(II) with the heteroscorpionate ligand (2-hydroxy-3-t-butyl-methylphenyl)bis (3,5-dimethylpyrazolyl)methane

Reaction of the Zn, Cd, or Co nitrate salts with the deprotonated ligand (2-hydroxy-3-t-butyl-methylphenyl)bis(3,5-dimethylpyrazolyl)methane (L1O^–) in methanol produced the following complexes: [(L1OH)Zn(NO₃)₂] in two isomorphs, a = 40.983(8) Å, b = 9.571(2) Å, c = 15.667(8) Å, = 90, = 106.38(1), = 90, C2/c, and a = 13.027(3) Å, b = 14.781(4) Å, c = 16.107(3) Å, = 90, = 105.30(1), = 90, P2₁/n; [(L1OH)Cd(pz)(NO₃)₂] a = 14.7476(2) Å, b = 13.5411(2) Å, c = 16.7223(2) Å, = 90, = 110.3840(10), = 90, P2₁/c; and [(L1O)Co(pz)(NO₃)] a = 11.4240(2) Å, b = 13.4498(2) Å, c = 13.8056(2) Å, = 105.2080(10), = 105.8130(10), = 112.7470(10), P . The Zn adopts a pseudotetrahedral four-coordinate geometry where the potentially tridentate ligand is actually bidentate with a protonated and uncoordinated phenoxy arm. The Co complex is pseudooctahedral six-coordinate where the phenoxy arm is deprotonated and coordinated. Finally the Cd complex is seven-coordinate but the metal is not coordinated through the phenoxy group that is again protonated.     

Bis(2,6-(2′,6′-diisoproylanil)diformyl-4-chloro-phenolate) nickel(II)

Bis(2,6-(2,6-diisoproylanil)diformyl-4-chloro-phenolate) nickel(II) was prepared by the reaction of 2,6-(2,6-diisoproylanil)diformyl-4-chloro-phenol with nickel chloride. The title complex crystallized in P2₁/c, with cell dimensions a = 9.962(2) Å, b = 12.087(3) Å, c = 24.445(6) Å, and = 97.032(5), giving a volume of 2921.4(13) ų. The bis(2,6-(2,6-diisoproylanil)diformyl-4-chloro-phenolate) nickel(II) adapts an ideal parallelogram, in which the Ni atom is coordinated with two phenolic oxygen atoms [O(1), O(1A)] and two imino nitrogen atoms [N(1), N(1A)].     

Crystal structure of barbituric acid (1,4)-dioxane solvate at −173°C

The structure of barbituric acid (1,4)-dioxane solvate has been determined by X-ray diffraction at 100 K. The compound crystallizes in the triclinic space group P , with cell dimensions of a = 6.7770(16) Å, b = 9.583(2) Å, c = 9.697(2) Å, = 85.868(5)°, = 82.566(5)°, = 70.675(5)°, V = 589.0(2) ų, and Z = 1. In the solid state, one asymmetric unit consists of C₄H₄N₂O₃ 3/2(C₄H₈O₂), each barbituric acid molecule being involved in two hydrogen bonds. The two nitrogen atoms of the acid act as hydrogen donors to two oxygen atoms, each from a different molecule of (1,4)-dioxane, which serve as the acceptors. Not all of the hydrogen-bonding capacity of the chemical moieties is used, and the principal feature of the supramolecular structure is a sawtooth ribbon composed of alternating barbituric acid and (1,4)-dioxane molecules, connected through hydrogen bonds and C H O interactions.     

Syntheses and structural characterization of two novel α-diketone bisacylhydrazones

Benzil bis(3,4,5-trimethoxybenzohydrazone) (I) and 3,3-dimethoxybenzil bis(benzohydrazone) (II) were synthesized by condensation, acid catalyzed, of the proper -diketone and the corresponding hydrazide. Compound I crystallizes in the monoclinic system, space group P2₁/n, with a = 11.464(2), b = 21.098(4), c = 13.837(2) Å, = 109.50(1)° V = 3154.8(9) ų and D _c = 1.319 g/cm³ for Z = 4. Compound II crystallizes in the triclinic system, space group P , with a = 11.106(3), b = 11.728(10), c = 10.656(5) Å, = 91.86(2), = 92.68(3), = 110.00(2)° V = 1301.1(7) ų and D _c = 1.293 g/cm³ for Z = 2.     

Structure of the larvicideN-(2-chlorobenzoyl)-N′-[4-(2-chloro-3,3,3-trifluoroprop-1-enyl)phenyl]urea,C17H11Cl2F3O2N2

Mw=403,2 amu,P2₁/c,a 18.944(8) Å,b=8.540(4) Å,c=10.794(7) Å,=98.11(4)°,V=1729(2) ų,Z=4,D _x=1.548 g·cm^–3, (MoK)=4.26 cm^–1; m.p. 202–204°C. FinalR=0.083 for 1632 independent observed reflections having 2 (Mo K)<50° andI>2 (I). The molecule has an extended overall nonplanar conformation with onecis and twotrans-C(O)-NH- units and intramolecular hydrogen bridges. The relatively highR factor is on account of conformational disorder of the trifluoromethyl and chloro substituents of the 2-chloro-3,3,3-trifluoropropenyl moiety.     

Crystal and molecular structure of an ion-pair complex based on [Ni(mnt)<Subscript>2</Subscript>]<Superscript>2−</Superscript> anion and imidazolium derivative cations

A new ion-pair complex, 1-methyl-3-benzylimidazolium bis(maleonitrile-dithiolato) nickelate(II), has been synthesized and characterized by IR spectroscopy, UV-visible spectroscopy and X-ray crystallography. The crystallographic data for the complex: triclinic , a = 8.415(1) Å, b = 9.924(1) Å, c = 11.333(2) Å, = 114.11(1), = 102.46(1), = 100.88(1), V = 801.8(2) ų, Z = 1. The molecular packing pattern showed a completely separated column stacking for cations and anions of the complex along with the b-axis. The anion is not completely planar. The five-membered nickel-containing rings are slightly puckered. The cation, [BzIm]⁺, adopts a conformation where the benzene ring and imidazole ring twisted with the reference plane C10–C11–N3.     

Molecular structure of P-(2,4,6-tri-tert-buthylphenyl)-phenylmethylene(phenylsulfonylimino)-σ3λ5-phosphorane

The crystal and molecular structure of P-(2,4,6-tri-tert-buthylphenyl)-phenylmethylene (phenylsulfonylimino)-³⁵-phosphorane, 2,4,6-Bu^t ₃-C₆H₂-P(=CHPh)(=N--SO₂Ph), has been determined. Crystal data: triclinic, , a = 9.472(5), b = 11.427(5), c = 13.684(5) Å, = 90.61(3), = 101.21(4), = 97.02(4)°, V = 1441.1 ų, Z = 2, D _c = 1.20 g cm^–3. The observed in 1 noticeable elongation of the P=N bond 1.563(3) Å and shortening of the P=C bond 1.617(3)Å have been discussed in terms of the electron withdrawing ability of substituents on the basis of ab initio (HF/6–31+G**) calculations of the model systems.     

The crystal structure of 2-nitroresorcinol

2-Nitroresorcinol is triclinic, space group P; at –100°Ca=7.083(2),b=7.696(2),c=6.607(2) Å, =74.61(2), =77.81(2), =68.64(2)°,V=320.8(2) ų,D _x=1.606(1) g cm^–3,Z=2. The two hydroxyl groups form symmetric intramolecular hydrogen bonds to the nitro group. The molecules pack in stacks held together by - interaction with adjacent molecules in a head-to-tail arrangement.     

Hydrothermal synthesis of catena(triaqua-(μ-2-croconato-O,O′,O″,O‴)-calcium(II)) calcium croconate trihydrate

The title compound exists as a 1D coordination polymer consisting of alternating calcium cations and croconate anions. Three water molecules complete the 7-coordination sphere of Ca in the form of a pentagonal bipyramid and form hydrogen bonds which link the polymeric chains into layers and also interconnect the layers. The structure has a triclinic space group P–1 with a = 6.642(3)Å, b = 7.793(4)Å, c = 8.854(5) Å, = 106.97(5), = 92.43(4), = 106.98(4)°, V = 415.1(4) ų, and Z = 2.     

A crystallographic and vibrational study of cesium di-μ-aqua bis[tetraaquasodium(I)] decavanadate, Cs4[Na2(H2O)10](V10O28)

The title compound crystallizes in the triclinic space group , with a = 8.6161(4) Å, b = 10.591(1) Å, c = 11.406(1) Å, = 67.976(7)°, = 86.868(6)°, = 67.798(6)°, and Z = 1. The structure was refined to R1 = 0.0413. The decavanadate anion V₁₀O₂₈ ^6– and the [Na₂(H₂O)₁₀]²⁺ bridged cation are located at inversion centers. Partial deuteration of the substance indicates that the coordinated water molecules are strongly asymmetric, forming weak hydrogen bonds with acceptor oxygen atoms from the decavanadate anion. The infrared and Raman spectra are dominated by the water and decavanadate anion bands.