Unusual occurrence of photooxidation of a cage diol

An unusual photooxidation was noted upon photolytic cage closure of a substituted tricyclo[6.2.1.0^2.7]undecane-exo, exo-diol. The resultant compound, which may be regarded as a mono-reduced pentacyclo[5.4.0.0^2,6.0^3,10.0^5,9]undecane-8,11-dione, was characterizedvia X-ray crystallography. This species could be reduced to the tricyclo[6.2.1.0^2,7]undecane-endo, exo-diol under conditions previously shown to be inert for the parent dione.     

Molecular structure of PhOCH2CH(OH)CH2OPh

The molecular structure of PhOCH₂CH(OH)CH₂OPh has been determined. The C—O—C—C—C—O—C backbone adopts an anti-anti-anti-anti conformation. Inter-molecular O—H ··· O hydrogen-bonding results in dimeric units which stack into zig-zag tapes. Crystal data: orthorhombic, Pbca, a = 10.383(1), b = 8.0532(0), c = 31.295(3) Å, V = 2616.8(3) ų, and Z = 8.     

Raman spectrum of solid glyoxal

The Raman spectrum of solid glyoxal has been recorded from 100 to 3500 cm^–1. Fundamental frequencies were observed at 2882, 1729, 1364, 1078, 1050, and 551 cm^–1 and assigned as the C—H stretching, C=O stretching, C—H in-plane bending, C—C stretching, C—H out-of-plane bending and COH rocking modes, respectively. The infrared spectrum of the solid has been investigated from 33 to 4000 cm^–1, and the values observed for the fundamentals are compared with those previously reported from studies of the vapor. The unusual frequency shifts upon solidification are discussed. A comparison of the infrared and Raman bands in the crystal shows that the mutual exclusion principle is operative. It is concluded from this alternate forbiddance that the molecule has a centrosymmetric structure in the crystal and that each molecule occupies a C _i (¯1) site. The factor group of the crystal is believed to be eitherC _2h (2/m) orD _2h (mmm) with two or four molecules per primitive unit cell.We thank the National Aeronautics and Space Administration for supporting this research by Grant NGR-41-002-003.     

Absolute configuration of C27H41NO8Si, the diastereoselective product of the rhodium(II) octanoate catalyzed decomposition of a chiral vinyldiazomethane in the presence of 2-acetylpyrrole: A structural study rendered difficult by disorder of a “heavy” atom

The title compound crystallized in space group P2₁ with a = 12.647(8), b = 14.542(4), c = 17.077(16) Å, = 97.51(6)°, and D _calc = 1.143 mg/m³ for Z = 4. There are two chemically-equivalent C₂₇H₄₁NO₈Si molecules in the crystallographic asymmetric unit. Each contains three chiral centers, one of known absolute configuration based upon the (R)-pantolactone,—CH*—CMe₂—CH₂—O—CO—, moiety. The structural study was greatly complicated by disorder of an —OSiMe₂(t-Bu) group in one molecule.     

Crystal and molecular structure of dichlorotetrakis(propanol-2) titanium (III) chloride,C12H32Cl3O4Ti

The crystal and molecular structure of dichlorotetrakis(propanol-2)titanium (III) chloride, C₁₂H₃₂Cl₃O₄Ti, has been determined by X-ray methods. The complex crystallizes in the monoclinic system:a = 15.968(4),b = 11.610(5),c = 11.90(5) Å, = 94.15(2) °, space groupC2/c andZ = 4. The positions of all non-hydrogen atoms have been refined by least squares to giveR = 0.126 for 1211 observed structure factors. The crystal structure consists of {TiCl₂(HOCH(CH₃)₂)₄}⁺ cations and Cl^– anions. From the space-group symmetry, it follows that the complex cation has 2(C ₂) symmetry. The 2 chlorine and 4 oxygen atoms of the inner coordination sphere are arranged in the form of a distorted octahedron around the central Ti atom. Two chlorine atoms, with the interatomic distance Ti—Cl of 2.32 Å, are in acis-conformation. The interatomic distances Ti—O, two oxygen atoms opposite to the chlorine atoms, are 2.10 Å. The pair oftrans-oriented oxygen atoms are at distances Ti—O= 2.09 Å. The Cl^– ions occupy positions at symmetry centres. Each of them is in contact with four oxygen atoms, the paired Cl—O distances being 3.04 Å and 3.12 Å.     

Spectroscopic study of phosphine selenide complexes of Au(I) and X-ray structure of [(cyclohexyl)3PSeAuBr]

The X-ray structure determination of the complex, [(cyclohexyl)₃PSe-AuBr], revealed a triclinic space group P-1, with a = 9.7654(7), b = 10.9441(9), c = 11.2064(9) Å, = 117.076(6)°, = 99.076(6)° = 95.417(6)°, V = 1034.07(14) ų and Z = 2. The Au(I) atom in this complex has a linear coordination with Se1 atom at 2.3776(9) Å on one side and Br1 at 2.3843(9) Å at the trans position making the Se1-Au1-Br1 angle of 177.97(4)°. The P1 atom in the phosphine has tetrahedral geometry. All three cyclohexyl groups are in their usual boat conformation. The phosphorus atom of the triphenylphosphine is approximately perpendicular to the Se1—Au1—Br1 linkage with P1—Se1—Au1 angle of 99.19(6)°. The in the ³¹P NMR of the free ligands and their corresponding L—Se—Au—Br (L—Se = trialkyl/arylphosphine selenides) complexes, and the changes in the P—Se bond frequencies in the FTIR upon complexation, are indicative of the bonding of the ligand to Au(I) through selenium. There is a strong corelation between the chemical shifts of the ³¹P NMR and the C—P—C angle in the phosphines.     

Crystal structure of a bulky cyclic sulfite

The structure of the cyclic sulfite derived from the reaction of thionyl chloride withendo-8-hydroxy-exo-8-(endo-8-hydroxypentacyclo[5.4.0.0.^2,6.0^3,10.0^5,9]undec-exo-8-yl)pentacyclo-[5.4.0.0.^2,6.0^3,10.0^5,9]undecane is reported. All bond lengths and angles are consistent with the strained cage geometry. A static disorder of the terminal oxygen was found to be present.     

Structure, absolute configuration, and conformation of the antimalarial drug artesunate

The crystal and molecular structure of the antimalarial compound artesunate has been determined by direct methods. Crystals are orthorhombic, P2₁2₁2₁, a = 9.8371(12), b = 10.517(2), c = 18.7594(5) Å, Z = 4, D _c = 1.316 mg/mL. The molecule is comprised of a fused ring system containing a six-membered ring C which includes an oxygen bridge and a peroxy bridge. The 9-atom oxygen–carbon chain from O(5)—C(12)... to ... O(2)—C(6) displays a striking sequence of short, long, short, long ... bonds while these distances are all within the ranges of a normal single bond or partial double bond. It is proposed that this pattern is caused by the delocalization of the lone pair electrons on the oxygen atoms. The ring C has a distorted boat conformation and the C—O—O—C torsion angle is 46.3(2)°. Rings A and D have ideal chair conformations. Ring junctions A/B and A/D are cis junctions, B/D and C/D are trans. Packing of the molecules is stabilized by one strong hydrogen bond involving the hydroxyl group on the ester linkage and the oxygen atom of the lactone ring.     

X-ray crystallographic structure of the 9,10-dihydro-11,12bis[(1,3,3-trimethylureido)methyl]-9,10ethanoanthracene dihydrate

As a part of studies on MDR reversal agents, structure of the 9,10-dihydro-11,12-bis[(1,3,3-trimethylureido)methyl]-9,10-ethanoanthracene dihydrate is reported. Crystal data: C₂₆H₃₄N₄O₂ × 2 H₂O; mol. mass 470.60; monoclinic; space group: C2/c, a = 15.7492(6) Å; b = 7.2245(3) Å; c = 24.3442(10) Å; β = 106.795(2)^∘; V = 2651.73(22) ų; z = 4; dx = 1.179 mg/m³; μ = 0.64 mm⁻¹; F(000) = 1016; final R = 0.061 for 2501 reflections [I > 4 σ (I)]. Only half of the molecule is unique. The two nonplanar rings from the independent part of 9,10-dihydro-9,10-ethanoanthracene adopt a boat conformation. Crystallographic data demonstrate the “syn-syn” conformation of urea substituents in the molecule. In the crystal, water molecules are linked to the main species by H-bonds: O3′⋅sH12w—O1—H11w⋅sO3′(1.5 − x, 0.5 − y, 1 − z).     

syn,E-1-cyclopentano-4-ethyl-3-thiosemicarbazone and syn,E-1-cyclopentano-4-phenyl-3-thiosemicarbazone

The structures of two thiosemicarbazones are described: syn,E-1-cyclopentano-4-ethyl-3-thiosemicarbazone (1) and syn,E-1-cyclopentano-4-phenyl-3-thiosemicarbazone (2). Crystal data: for 1: tetragonal, P4₃ (#78), a = b = 8.922(7) Å, c = 12.899(13) Å, and Z = 4; for 2: monoclinic a = 15.163(18) Å, b = 7.482(5) Å, c = 12.467(15) Å, = 119.04(7)°, and Z = 4. In 1, molecules are linked by hydrogen-bonding into infinite chains with non-planar 9-ring subunits in which thioamides interact with the H—N—C—N—N groups of neighbors. Thioamide groups in 2 form dimers linked by N—B···HS hydrogen-bonds with a planar 8-ring as in solid state structures of carboxylic acids. The semicarbazide syn conformation fosters formation of N—H···N intramolecular hydrogen-bonding in each structure. The solid state structures are consistent with their infrared and proton nuclear magnetic resonance spectra.     

Crystal and molecular structure of pyridinium di-μ-oxo-bis(oxodichloroaquomolybdate(V)) monohydrate, (pyh)2[Mo2O4Cl4(H2O)2] · H2O

The crystal and molecular structure of pyridinium di--oxo-bis(oxodichloroaquomolybdate(V)) monohydrate has been determined from MoK diffractometer data. The compound crystallizes in the monoclinic space groupP2 ₁/m witha = 7.544(1),b= 17.046(3),c = 7.894(1) Å, = 106.00(1) ° andZ = 2. The structure was solved by the heavy-atom technique and refined by full-matrix least-squares method toR = 0.046, using 1800 reflections for whichF> 4(F). Molybdenum atoms are linked by the double oxygen bridge with an Mo—O distance of 1.943(4) Å and an Mo—O—Mo angle of 83.4(2) °. The Mo—Mo distance is 2.584(1) Å, indicating direct Mo—Mo bonding. The pyridinium and [Mo₂O₄C1₄(H₂O)₂]^2- ions are hydrogen bonded through N—H ... O bonds. The N ... O contact is 2.656(8) Å.     

Gas-solid structure differences in the donor-acceptor complex (CH3)2HN−SO2

The crystal structure of the donor — acceptor adduct (CH₃)₂HN–SO₂ is reported. Crystals of the compound are clear prisms, space group Pna2₁; at –96°C,a=9.894(1),b=6.051(2),c=16.478(3) Å,D=1.469 g/cm³,V=786.6(5) Å,Z=8. The unit cell contains two crystallographically independent adducts, with N–S bond lengths of 2.015(3) Å and 1.991(3) Å. The average value, 2.00(1) Å is 0.33(4) Å shorter than the 2.34(3) Å value previously determined from microwave spectroscopy of the gas phase species, revealing a large medium effect on the length of the donor — acceptor bond. The structural results are compared with published data for the trimethylamine — SO₂ adduct, and discussed in terms of existing experimental and theoretical results for other donor — acceptor systems.     

Crystal structure and physical properties of a ruthenium(II) bipyridine dimethylsulfoxide complex

The complex [Ru(bpy)₂(DMSO)C1]PF₆, where bpy is 2,2-bipyridine and DMSO is dimethylsulfoxide, crystallizes in the triclinic space group P1¯ (#2) with a = 8.873 (2), b = 12.805 (4), c = 12.864 (4) Å, = 97.76(3), = 106.45(2), = 107.88(2); Z = 2, and d _calc = 1.75 mg/m³. The coordination geometry is that of a distorted octahedron with a cis –RuN₄SCl arrangement of coordinating atoms. The four Ru—N distances to the bpy ligands are 2.082(5), 2.092(4), 2.044(4), and 2.078(5) Å. The Ru—Cl distance is 2.421(2) Å and the Ru—S distance to DMSO is 2.260(1) Å. The Ru—N bond distance trans to Cl is the shortest; the Ru—N bond distance trans to S is the longest. The complex is oxidized and reduced reversibly at 1.13 and –1.37 V vs. SSCE, respectively. It displays electronic absorptions at 515, 480 (1.5 × 10⁴), 342 (1.5 × 10⁴), 292 (1.2 × 10⁵), and 240 nm (6.2 × 10⁴) and has a broad emission band centered at 607 nm at 77 K in a 4:1 ethanol/methanol glass. The emission lifetime at room temperature is less than the pulse width of the laser, < 20 ns.     

Synthesis and X-ray diffraction study of hexaamminecobalt(III) sodium ethylenediaminetetraacetate 3.5-hydrate

The title compound [Co(NH₃)₆] [Na(EDTA-4H)],3.5H₂O has been synthesized, and its crystal structure has been determined from 2064 independent single-crystal reflections measured on a diffractometer. The crystals are tetragonal, space groupP42₁2, with unit-cell parametersa = 14.618(5) andc = 10.658(4) Å. There are four formula entities in the unit cell givingD _c = 1.562(2) g cm^–3 compared withD _m = 1.56(1) g cm^–3. The structure was solved by conventional Patterson and Fourier techniques, and refined by full-matrix least-squares methods to a final agreement factor of 3.6%. The compound contains two crystallographically independent octahedral [Co(NH₃)₆]³⁺ ions, with an average Co—N distance of 1.966(6) Å, and a seven-coordinate sodium ion which is coordinated to four carboxyl oxygens, two amine nitrogens, and a water molecule which bridges to another sodium ion. The EDTA is therefore acting in its normal hexadentate manner. The range of Na—O distances is 2.25 to 2.93 Å whereas the Na—N distance is 2.46 Å. The crystal structure is additionally stabilized by extensive hydrogen bonding among coordinated ammonias, carboxyl oxygens, and water molecules.     

Crystal structure of the hemitoluene solvate of racemiccis-bis(bipyridyl)chloro(tri-n-propylphosphine)ruthenium(II) perchlorate,a species with disordered PPr3 and toluene moieties

The complexcis-[Ru(bpy)₂(PPr₃)Cl⁺][ClO ₄ ^– ] · 0.5 (toluene) crystallizes as a racemate in the monoclinic space group P2₁/n. Both the PPr₃ ligand and the toluene of crystallization are subject to disorder. Ruthenium—ligand distances are: Ru–PPr₃=2.348(2) Å, Ru–Cl=2.426(2) Å and Ru–N(bpy)=2.035(6)–2.112(5) Å.     

Crystal and molecular structure of 1,1′-ferrocene-dicarbaldehyde

The crystal and molecular structure of 1,1-ferrocene-dicarbaldehyde 1 is reported. Crystal data for 1: monoclinic, space group P2₁/n, a = 5.876(1), b = 11.349(1), c = 29.460(3) Å, = 95.067(2)°, V = 1956.9(3) ų, and D _c = 1.64 g/cm³, for Z = 8. The complex crystallizes such that two molecules are located in the asymmetric unit in which the complexes display different degrees of twisting of the cyclopentadienyl (Cp) rings and formyl substituents about the Cp—Fe—Cp and Cp—COH axes, respectively. The molecule self-assembles in the solid state to form a 2D layered structure held together by - interactions and C—H···O hydrogen bonds.     

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 of chloritopentamminecobalt(III) tetracyanopalladate(II)

The X-ray crystal structure of [(NH₃)₅Co(ClO₂)][Pd(CN)₄]·H₂O consists of two discrete complex ions and a water of hydration. The red crystals are triclinic, P , with lattice parameters a = 7.1992(5), b = 9.4873(7), c = 11.7752(8) Å. = 66.680(1), = 75.784(1), = 82.203(1)°, and Z = 2 giving a cell volume of 715.27(9) ų and a calculated density of 2.043 g/cm³ at 293°. The chlorite ion is O-bonded to the cobalt atom with amine N—Co distances all equal. The chlorite ion is bent with a O—Cl—O angle of 110.8(2)° and the Cl—O distances being 1.601(3) and 1.558(3) Å, the longer value for the O atom also coordinated to Co. The Pd(CN)^–2 ₄ ions are planar, C-coordinated and stack along the x-axis, separated by 3.599(1) Å and alternatively rotated by 29.9(5)°.     

Crystal structure of 2-chloroacetamide (α form): A reinvestigation

The crystal structure of the form of 2-chloroacetamide, grown by sub-limation, has been determined from three-dimensional counter data and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP2₁/c witha=10.263(8),b=5.142(5),c=7.458(6) Å, =98.72(4) °, andD _x=1.60 g cm^–3 forZ=4. The finalR factor for 518 observed reflections is 0.037. The molecule exists as a hydrogen-bonded dimer in the crystal structure. The configuration of atoms C(1), C(2), O, and N is planar to within 0.008 Å, and the Cl—C(1)—C(2)—O dihedralangle equals 168 °. The dimeric hydrogen bonding as well as the CH₂ conformation favors the stabilization of a transient oxygen-centered radical.     

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.