Cl⋯π(Ar), Cl⋯Cl,and other intermolecular interactions in the crystal structure of 8-nitro-6-methyl-2-trichloromethyl-4-dichloromethylene-1,3-benzodioxin

Crystals of the title compound are monoclinic,P2₁,a=9.791(4),b=7.129(3),c=10.428(3)Å,=91.84(3)°,V=727.50ų,Z=2. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by full matrix least squares to a finalR value of 0.045 using 2466 reflections. The molecules form stacks along theb axis of the formA, B, A, B(A=dichloromethylene group; B=aromatic ring in the molecule at –x, 1/2+y, –z to the molecule atx, y, z containing A). Cl(Ar),, ClCl, ClO(N), (Cl₃C)HO intermolecular interactions are also present. An inverse correlation between the (C)ClCl(C) distance and the difference in the corresponding pairs of C-ClCl angles is observed and is interpreted in terms of incipient nucleophile: electrophile attack.     

Crystal structure of tylophorine methiodide monohydrate,C25H30NO 4 + I−·H2O

The crystal structure of tylophorine (Chemical name 2,3,6,7 tetramethoxy phenanthro [9,10:6, 7] indolizidine. Contribution No. 0871.) methiodide monohydrate has been determined. C₂₅H₃₀NO ₄ ⁺ I^–·H₂0, triclinic, P,a=8.831(1)Å, b=10.842(2),c=13.902(2), =105.0(1)^o, =104.7(1), =97.3(1),V=1210.22ų, Z=2,D _x =1.428 g./cm^–3, (CuK)=1.54184Å, (CUK)=107.2 cm^–1, F(000)=544,T=295^oK,R=0.038,Rw=0.046, for 2331 observed reflections withI2(I). Apart from van der Waals forces, the structure is stabilized by two hydrogen bonds of the type Ow(H) ... O and Ow(H) ... I^– involving the water molecule as the donor and atom O4 of the methoxy group and I^– as acceptors.     

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.     

Crystal structure of a nucleoside analog: 2′,3′-dideoxy-3′-fluoro-5-bromocytidine

The title compound crystallizes in the orthorhombic space groupP2₁2₁2₁ witha=5.084(1),b=14.322(3),c=16.065(2)Å,Z=4. The structure was solved by the heavy atom method and refined by full-matrix least-squares calculations to a finalR value of 0.033 for 1106 unique observed reflections. The N-glycosidic torsion anglex has a value of –153.7(4)°, in the anti-range. The sugar pucker is²T₃ withP=175(1)° and=30(1)°. The C4-C5 conformation is + sc with =46.7(7)°. The structure is stabilized by N-HN, N-HO and O-HO hydrogen bonds and C-HO close contacts.     

Molecular structure of N-(2-phenylethyl)amide of α-(1,1-ethylenedioxy)-ethyl γ-hydroxybutyric acid (I) and1H NMR spectra of (I) and N-(p-methoxybenzyl)derivative (III)

The spectroscopic and X-ray investigation of the N-(2-phenylethyl) amide of -(1,1-ethylenedioxy)-ethyl--hydroxybutyric acid are reported. The¹H NMR spectra for the title structure and for the N-(p-methoxybenzyl) amide of -(1,1-ethylenedioxy)-ethyl--hydroxybutyric acid are given. The N-(2-phenylethyl)amide of -(1,1-ethylenedioxy)-ethyl--hydroxybutyric acid, C₁₆H₂₃O₄N, crustallizes in the monoclinic space groupP2 ₁/c witha=21.547(5),b=6.333(2),c=11.822(3) Å and =101.01(2)°. The dioxolane ring has a half-chair conformation with C₂(O3)=2.4° and ||_av=18.2°. The inconsiderable deviations from planarity of the six atoms of the amide group are caused mainly by twist around the C4–N1 bond and out-of-plane bending at the N1 atom ((C4–N1)=4°, X_N =7°, X_c =0.4° ). The amide group plane is nearly coplanar with the phenyl ring. The molecules are connected by two intermolecular hydrogen bonds.     

Crystallographic and spectroscopic studies on ethylenediaminetetraacetic acid (edta) III. Crystal and molecular structure of α-edta and infrared studies on α- and β-edta

-Edta is monoclinic:C2/c,a= 11.812,b = 9.647,c = 12.970 Å, = 113.23 ° andZ = 4. The structure has been determined by direct methods with CuK diffractometer data, and refined by full-matrix least squares toR = 7.2% for 737 observed reflexions. The molecule exists as a zwitter ion in acis conformation, and possesses crystallographic two-fold symmetry. The nitrogen atom is protonated and takes part in hydrogen bonding. -Edta is hydrated, in this specimen, refinement indicated a value of 0.39 H₂O per molecule of edta. A short (2.47 Å) hydrogen bond links oxygen atoms in adjacent molecules. Infrared spectra are reported for both -edta and -edta; the results are discussed in terms of the crystal structures. The formulation of -edta with 0.39 mole H₂O is explained.     

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.     

The crystal structure of 5-methyl-1-(octahydro-1-iodo-1H-1-inden-4-yl)-1H-tetrazole

The title compound is C₁₁H₁₇N₄I, F.W.=330.20, monoclinic, space groupP2₁/a,a=11.586(2),b=10.617(1),c=10.417(1) Å, =94.567(2)°,Z=4,F(000)=652, (MoK)=0.7107 Å, (MoK)=2.31 mm^–1,V=1277.31 Å₃,D _C=1.71 gcm^–3,D _m=1.70 gcm^–3. The structurewassolved by Patterson and Fourier methods and refined to anR value 0.031 for 1620 observed reflections. The connectivity and conformation of the addition product ofcis-1,5-cyclononadiene and iodine azide was determined by X-ray analysis. The reaction product contains a chair-conformation cyclohexane ring that iscis fused to a cyclopentane ring. The cyclopentane ring has an envelope conformation and an equatorially oriented iodine substituent. A planar tetrazole ring is axially substituted on the cyclohexane ring. The plane of the tetrazole ring makes a dihedral angle of 69.6° with the average plane of the carbon atoms of the cyclohexane ring.     

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 structure of 8-(3,4-dimethylphenoxy)-16H dinaphtho[2,1-d:1′,2′-g] dioxaphosphocin 8-oxide

The title compound, C₂₉H₂₃O₄P crystallizes in the triclinic space group witha=9.636(1),b=10.327(1),c=13.406(1) Å, =102.22(1), =100.59(1), =109.84(1)^o.V=1178.1(2) ų,Z=2,D _cal=1.32 M gm^–3, (CuK)=6.16 cm^–1, (CuK)=1.5418 Å andT=295K. The structure was solved by direct methods and refined by full-matrix least-squares method to a finalR=0.052 andwR=0.063 for 2708 reflections withl3(l). The napthalene ring A lies perpendicular to the best plane of the phenyl ring [91.6(1)^o] and the ring B orients at an angle of 55.7(1)^o with this plane and is inclined at an angle of 77.8(1)^o with ring A. The heterocyclic phosphorous eight-membered ring assumes a distorted boat conformation.DCB Contribution No. 822.     

Synthesis and crystal and molecular structure of newN-substituted γ-hydroxybutyramides

TheN-(2-phenylethyl)amide of-(1, 1-ethylenedioxy)-ethyl--hydroxybutyric acid (II) and theN-(p-methoxybenzyl)amide of-(1, 1-ethylenedioxy)-ethyl--hydroxybutyric acid (III) have been synthesized and the crystal structure ofIII has been solved. CompoundIII, C₁₆H₂₃O₅N, crystallizes in the monoclinic space groupP2₁/c witha=12.572(2),b=11.149(2),c=12.317(2) Å and=106.53(1)°. The structure was solved by direct methods, and refined by full-matrix least squares to giveR=0.040 (R _w =0.047) for 2004 intensities. The dioxolane ring has a deformed half-chair conformation.     

Structural investigation on hexasubstituted benzene derivatives. Part 2: The structure of metadinitrotetramethylbenzene and molecular mechanics analysis on meta and ortho derivatives

C₁₀H₁₂N₂O₄ (M r=224.2) crystallizes in the monoclinic system, space groupP2₁/mwitha=15.462(4),b=7.926(3),c=8.972(3) Å;=90.2(1)°;V=1099.5(6) ų;Z=4;D _c=1.35 gcm^–3;(Cu-K)=8.6 cm^–1; =1.5418 Å;F(000)=472. The position of the molecule on a crystallographic mirror plane forces the NO₂ plane to be normal to the benzene ring. The-electron-withdrawing character of the NO₂ groups induces a deformation on the geometry of the benzene.     

Structure of 2,2′-anhydro-3′-O-acetyl-2′thio-1-β-D-arabinofuranosylcytosine hydrochloride1

2,2-Anhydro-3-O-acetyl-2-thio-1--D-arabinofuranosylcytosine hydrochloride crystallizes in space group P2₁2₁2₁ witha=10.373(1),b=14.517(2),c=9.496(1) Å. Reflections were measured on a diffractometer and the structure was solved by direct methods. Least-squares refinement converged atR=0.056 andR _w =0.063. The study of this crystal structure showed that the alterations in the geometry of 2,2-anhydro-1--D-arabinofuranosylcytosine when the bridge oxygen is replaced by sulfur are localized in the region of the fused ring. The angle at the bridge atom decreases to nearly 90°, with concomitant enlargements of about 5°–7° in the angles opposite to the bridge atom. Angle C(1)-N(1)-C(6) decreases by 4°. Also, the amount of double bond character in the bond formed by C(2) and the bridge atom decreases. A survey of the conformational features of S,2-cyclonucleosides and comparison with O,2-cyclonucleosidcs showed that their preferred conformations are the same. However, S,2-cyclonucleosides exhibit a wider range of P and values. This correlates with a greater ease of the sulfur containing five-membered ring to pucker as compared to the oxygen-cyclo ring.This paper is part of the authors' dissertation (Vitali, 1986).     

The structure of Wallach's compound. Single-crystal X-ray structure determination oftrans-2,5-bis(trichloromethyl)-N-(1′-hydroxy-2′,2′,2′-trichloroethyl)-4-imino-1,3-dioxolane

The structure of Wallach's compound, C₇H₄O₃NCl₉, prepared in 1874 from concentrated aqueous solutions of potassium cyanide and chloral hydrate, has long been undecided. By single crystal X-ray crystallography it has now been established astrans-2,5-bis(trichloromethyl)-N-(1-hydroxy-2,2,2-trichloroethyl)-4-imino-1,3-dioxolane, confirming the tentative assignment by¹H and¹³C NMR spectrography. The title compound is monoclinic,P2₁/c;a=8.445 (1),b=10.948(1),c=17.923(4) Å;=94.36(1)°;Z=4. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by least squares to a finalR value of 0.041 using 2101 reflections.     

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.     

Hydrogen-bonded dimer of N,N′-(5-n-butyl-5-oxodibenzo[b,d]phosphole-3,7-diyl)bis(benzamide) dimethylformamide solvate

The structure of a large wing-span phosphine, in the oxide form, N,N-(5-n-butyl-5-oxodibenzo[b,d]phosphole-3,7-diyl)bis(benzamide), C₃₀H₂₇N₂O₃P, cocrystallized with dimethylformamide (DMF), C₃H₇NO, is reported. The title compound is crystallized in a triclinic system with cell dimensions of a = 10.295(8) b = 12.743(5) c = 13.239(6) Å, = 108.14(3), = 108.16(5), = 101.20(4)°, and V=1484.4(5) ų, and forms a hydrogen-bonded dimer via two hydrogen bond linkages of the P—O ··· H—N type involving one of the two amide groups.     

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.     

Structural investigation on hexasubstituted benzene derivatives. Part 1. The structure of ortho-dinitrotetramethylbenzene

C₁₀H₁₂N₂O₄ (M _r =224.2) crystallizes in the triclinic system, space groupP¯1 witha=8.327(3),b=8.734(3),c=8.453(3) Å;a=63.6(1),=97.0(1), =100.4(1)°;V=541.0(6) ų,Z=2,D _c =1.38 g cm^–3,(Cu-K)=8.7 cm^–1, =1.5418 Å, F(000)=236. Deviation from theoretic geometry of the benzene ring and from planarity is observed in accordance with the-electron-withdrawing character of the NO₂ groups and the high steric hindrance of the substituents.     

Crystal and molecular structure of: 5-(1-oxoethyl)-1-methyl-2-(5-bromo-6-methoxy-2-naphthyl)-6-oxabicyclo[3.2.1]octan-7-one and 5-(1-oxoethyl)-1-methyl-2-(5-bromo-6-methoxy-2-naphthyl)-6-oxabicyclo[3.2.1]octane

X-ray crystallographic studies of the two title compounds have shown that the molecules crystallize in the same triclinic space group, , with very similar cell dimensions. For C₂₁H₂₁BrO₄,a=12.056(5),b=13.206(5),c=7.595(3)Å, =90.38(3), =106.07(3) and =124.42(3)° and for C₂₁H₂₃BrO₃,a=12.076(6),b=13.090(5),c=7.490(3)Å, =92.65(5), =104.90(5) and =124.55(5)°. Both compounds possess the oxabicyclo[3.2.1]octane bridged ring system and differ only at the carbon to the ring oxygen where the Csp³ in the ether is replaced by Csp²=O in the lactone. Both cyclohexane rings adopt distorted chair conformations and the lactone and ether rings approximate closely to the envelope conformation. The bromine substituent at C(4) results in distortion of the naphthalene ring. Both molecules pack with the naphthalene rings parallel to each other with interplanar spacings of 3.71 Å in the ether and 3.66Å in the lactone.     

Crystal structure of 1,2,4,6-tetraphenylpyridinium tetrabromoferrate(III)

The title structure, which belongs to the triclinicP¯1 space group witha=13.901(4),b=10.732(1),c=10.570(8)Å=109.14(4),=96.17(4), =90.34(2)°, is refined toR=0.052 for 2985I3(I) reflections. The structure consists of a non-interacting 1,2,4,6-tetraphenylpyridinium and tetrahedral tetrabromoferrate (III) ions.