Structure ofcis-2,4-bis (trichloromethyl)-1,3,5,-trioxane

cis-2,4-Bis(trichloromethyl)-1,3,5-trioxane is monoclinic,C2/c, a=19.432(4),b=5.895(1),c=20.721(6) Å,=100.66(2)°,Z=8. 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 0.034 using 1786 reflections. The molecule is in the chair conformation with the –CCl₃ groups located equatorially [at C(2) and C(6) in the numbering scheme used in the paper]. Endocyclic parameters quoted cyclically are O(1)-C(2) 1.418(3), C(2)-O(3) 1.387(3), O(3)-C(4) 1.419(3), C(4)-O(5) 1.416(3), O(5)-C(6) 1.391(4), C(6)-O(1) 1.415(3) Å; and angles at O(1) 108.7(2), C(2) 110.5(2), O(3) 110.1(2), C(4) 109.5(2), O(5) 109.9(2), C(6) 110.5(2)°. The average endocyclic torsion angle is 59.1(5)°.     

Structure of the α-(allcis) form of 2,4,6-tris(trichloromethyl)-1-oxa-3,5-dithian

The higher-melting (mp 236°C)-isomer of dithioparachloral, i.e.,-2,4,6-tris(trichloromethyl)-1-oxa-3,5-dithian, is orthorhombic,Pnma,a=9.983(2),b=15.318(2),c=10.416(2) Å,V=1592.81 ų,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 0.040 using 1017 reflections. The molecule is in the chair conformation with all threecis-CCl₃ groups located pseudoequatorially. Endocyclic parameters are: torsion angles (deg) C-O-C-S 75.1(3), O-C-S-C –63.2(3), C-S-C-S 62.4(3); angles (deg) C-O-C 111.9(2), O-C-S 112.6(3), C-S-C 94.8(2), S-C-S 113.2(1); bond lengths (Å) O-C 1.426(5), C-S 1.824(4), S-C 1.818(3) (quoted in cyclic order).     

Structure and conformation of the 6-carboxylic acid and the 6-methylsulfonate of 2,4-bis(trichloromethyl)-1,3-benzdioxin

The 6-methylsulfonate (I) and the 6-carboxylic acid (II) of 2,4-bis(trichloromethyl)-1,3-benzdioxin both crystallize in the space groupP2₁/n withZ=4. Unit cell parameters of I are:a=13.398(7),b=14.553(2),c=8.945(2) Å, =99.16(2)°; those of II are:a=6.010(16),b=25.741(16),c=10.505(10) Å, =100.05(16)°. The structures were solved by direct methods and refined by full-matrix least squares, from room-temperature data obtained with an Enraf-Nonius CAD4 diffractometer, to conventionalR factors of 0.035 for I and 0.041 for II. The methylsulfonate group of I is disordered except for the sulfur atom and in II, which forms hydrogen-bonded dimers through the –COOH group, the hydrogen atom of the –COOH group is distributed equally between two positions.The conformation and molecular parameters of the 2,4-bis(trichioromethyl)-1,3-benzdioxin fragment for both compounds is very similar to that in 6-nitro-2,4-bis(trichloromethyl)-1,3-benzdioxin (Irving A., and Irving H. M. N. H. (1986)J. Cryst. Spectrosc. Res. 16, 703). The dioxin ring has an approximate envelope conformation with a pseudoequatorial –CCl₃ group in the 2-position and a pseudoaxial –CC1₃ group in the 4-position. C(ring)-C_eq(Cl₃) is 1.525(5) Å for I and 1.536(6) Å for II, whereas the C(ring)-C_ax(Cl₃) bond length is 1.547(5) Å for I and 1.550(4) Å for II. The chemical shifts of the two protons in the heterocyclic ring do not appear to be altered by these changes in the 6-substituent.     

X-ray structure oftrans-4-chloro-2,4,6-tris(trichloromethyl)-1-oxa-3,5-dithian: An unexpected demonstration of the reaction path preceding double-bond formation at the 4 position

trans-4-chloro-2,4,6-tris(trichloromethyl)-1-oxa-3,5-dithian is orthorhombic,Pbca,Z=16,a=12.236(2),b=43.051(4),c=13.010(5) Å. 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 0.042 using 3725 reflections. The structure has provided a unique demonstration of the reaction path preceding the 1,2-trans elimination of a molecule of chlorine from the>CCl·CCl₃ group at the 4 position. Both molecules exhibit twist-boat conformations but abnormal bond lengths and angles in one molecule are consistent with a structure showing an incipient S₂CCCl₂ group.     

Isomerism in some 1-oxa-3,5-dithians and the X-ray structure determination of 2,6-bis(trichloromethyl)-4-dichloromethylene-1-oxa-3,5-dithian

2,6-bis (trichloromethyl)-4-dichloromethylene-1-oxa-3,5-dithian is triclinic,P¯1,a=10.125(3),b=10.294(3),c=14.631(10) Å,=92.84(5),=96.51(5), =96.18(2)°,V=1503 ų,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 0.035 using 3961 reflections. The conformation of the molecules is twist-boat, one molecule being almost symmetrically twisted about the O-C(Cl₂) direction. The range of endocyclic O-C-S angles is 111.8(3) to 115.1(3)° and data are given which support the possibility of there being a correlation between the endocyclic O-C(X)-S angle, the C-O-C(X)-C(Cl₃) torsion angle, and the C-S-C(X)-C(Cl₃) torsion angle. The -CCl₃ groups are in pseudoequatorial positions. Average bond lengths (Å) for the two molecules are C-O 1.405, C(sp ³)-S 1.822, C(sp ²)-S 1.759, C-C_eq 1.529 and average endocyclic angles (°) are O 117.3, C (sp ³) 113.5, S 97.4, C(sp ²) 119.3, the esds on the individual bond lengths and angles being in the ranges of 0.003–0.004 Å and 0.2–0.4° respectively.     

Structure and conformation of 6-nitro-2,4-bis(dichloromethyl)-1,3-benzdioxin

6-Nitro-2,4-bis(dichloromethyl)-1,3-benzdioxin is monoclinic,P2₁/c, witha=8.514(1),b=22.187(3),c=7.931(1) Å,=117.96(1)°,Z=4. The structure was solved, from data collected with MoK radiation on an Enraf-Nonius CAD4 diffractometer, by direct methods and refined by full-matrix least squares using 2170 unique reflections to give a finalR factor of 0.032. The heterocyclic ring in the title compound has an envelope conformation with thecis-dichloromethyl groups in pseudoequatorial positions. The average C-C(HCl₂) distance is 1.516(4) Å. A comparison is given with the structure of the analogous compound 6-nitro-2,4-bis(trichloromethyl)-1,3-benzdioxin (Irving, A., and Irving, H. M. N. H. (1986)J. Crystallogr. Spectrosc. Res. 16, 703) which also containscis-halogenoalkyl groups but in which the –CCl₃ group at the 4-position occupies a pseudoaxial position.     

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).     

Structure and conformation of 6,8-dinitro-2,4-bis(trichloromethyl)-1,3-benzdioxin: X-ray crystallographic determination

6,8-dinitro-2,4-bis(trichloromethyl)-1,3-benzdioxin is monoclinic,P2₁/c,Z=4,a=12.348(2),b=11.575(3),c=12.183(4) Å,=107.48(2)°. 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 0.032 using 2192 reflections. The heterocyclic ring is an envelope structure, the dihedral angle between the plane of the aromatic ring and that containing five of the atoms of the heterocycle being 4.98(6)°. One -CCl₃ group is pseudoequatorial while the (Ar-C)CCl₃ group is pseudoaxial. C-C_eq 1.526(3) Å; C-C_ax 1.537(3) Å; C-C(C_ax)-O 112.4(2)°; C(C_ax)-O-C(C_eq) 115.2(2)°.     

Structure of (Z)-1-p-methoxyphenyltelluro-1,4-diphenyl but-1-en-3-yne

C₂₃H₁₈TeO,M _r=437.97, ,a=9.940(2),b=13.664(3),c=7.895(2) Å, =80.60(1), =69.71(2), =75.95(1)°,V=972.0(4) ų,Z=2,R=0.041 for 2668 observed reflections. The Te–C bond distances are 2.109(5)Å and the C–Te–C angle is 96.0(2)°. The phenyl rings are planar to within experimental accuracy, making dihedral angles of 64.6(2), 65.3(2) and 31.1(3)°.     

The crystal structure of a magnesium(II) ethyl diglyme complex

Dibromo[1,1-oxybix[2-ethoxyethane]-O,O,O]-(tetrahydrofuran-O) magnesium, C₁₂H₂₆O₄MgBr₂, crystallizes in space group Pbca witha=7.402(1),b=16.726(2),c=29.248(3) Å,V=3620.9(12) ų,Z=8. The structure was refined toR=0.083 andR _w =0.055 for 1880 observed reflections. Magnesium is octahedrally coordinated by twocis bromine atoms and four oxygen atoms, three from the meridional ethyl diglyme and one from tetrahydrofuran. The Mg–Br distances are 2.614(3)trans to thf and 2.529(3) Åtrans to the central O of the diglyme. The Br–Mg–Br angle is 97.9(1)° and the Mg–O(thf) distance is 2.196(6) Å. The O–Mg–O bite angles subtended by the diglyme are 75.3(2) and 75.7(2)°. The Mg–O(ethyl diglyme) distances are 2.127(6), 2.136(6), and 2.090(6) Å.     

Molecular structure of an extremely crowded iron(II) dihydride complex: FeH2(PMePh2)4

The crystal structure of FeH₂(PMePh₂)₄ shows this to exist as thecis isomer in the solid state with major distortions of the FeP₄ skeleton:cis P-Fe-P angles 98.1(1)–107.2(1)° andtrans P-Fe-P angle 143.3(1)°. All hydrogen atoms were refined, and the mean Fe-H separation is 1.59 Å. Long Fe-P distances, 2.187(3)–2.251(3) Å, emphasize the crowding in this molecule. Crystallographic data:a=11.684(4) Å,b=37.793(17),c=9.765(3),=90.81(1)°, andZ=4 in space groupP2₁/n (No. 14).R(F)=6.3% andR _w (F)=6.0% for 2585 observed reflections collected at —162°C.     

The structure of a tetrabromotetrahydrodibenzocyclooctene

5, 6, 11, 12-Tetrabromo-5, 6, 11, 12-tetrahydrodibenzo[a, e]cyclooctene, C₁₆H₁₂Br₄, crystallizes in monoclinic space group P2₁/c witha=8.6917(7),b=15.135(2),c=12.892(2) Å, =101.836(8)°, V=1660.0(7) ų,Z=4. The structure was refined toR=0.058 for 3137 observed reflections. The molecule has approximate C₂ symmetry, with the eight-membered ring adopting the twist-boat conformation. The planes of the two phenyl rings form a dihedral angle of 117.3(2)°, C–Br distances range 1.965(5)–1.981(5) Å.     

X-ray structural and spectroscopic investigation of 1-piperidine-2,4-dinitrobenzene

The crystal structure of the title compound (C₁₁H₁₃N₃O₄) has been determined by single-crystal X-ray diffraction. The compound is monoclinic, space group P2₁/n, witha=9.968(2),b=9.156(2),c=13.249(2)Å, =102.05(2)°, andD _x=1.563 gcm^–3 forZ=4. The aromatic ring shows a slight boat deformation. Theo- andp-NO₂ groups are twisted out of the plane of the phenyl ring by 39.0(2)° and 4.4(1)°, respectively. The piperidine ring exhibits a slightly deformed chair conformation. Short C–H...O intermolecular contacts stabilize the three dimensional structure. UV and NMR data indicate that the molecule in solution presents a conformation similar to that of the the solid state.     

X-ray crystal structure of the 1∶2 triethyleneglycol dimethyl ether (triglyme): Dichloropicric acid adduct

The anhydrous 12 triglyme:Dichloropicric acid adduct is triclinic, space group ; at 24°Ca=8.703(5),b=10.381(4), c=10.404(3) Å, =114.42(3), =99.69(5), =106.40(6)°,D _x=1.656 g cm^–3, V = 776(2)ų,Z=1. Bond lengths and angles are normal except that one C–C–O–C torsion angle in the triglyme is approximately 90° rather than the expected 60 or 180°. Each phenolic OH group hydrogen bonds with a terminal OCH₃ of the polyether. The O...O distance, 2.557(3) Å, is in fair agreement with the 2.52 Å estimated from the single observed IRv (OH) stretch at 1714 cm^–1.     

Isomerism due to the rotation of an alkyl side-chain attached to a heterocyclic ring: Crystal and molecular structure of two forms of 6-nitro-2,4-bis(1′,1′,2′-trichloropropyl)-1,3-benzdioxin

Compound I crystallizes in the space groupP2₁/c withZ=4,a=5.889(5),b=30.755(10),c=10.815(3) Å,=92.95(6)°. Compound II crystallizes in the space groupP2₁/n withZ=4,a=10.235(2),b=10.144(1),c=18.346(2) Å,=92.00(1)°. The structures were solved by direct methods and refined by full-matrix least squares, from room-temperature data obtained with an Enraf-Nonius CAD4 diffractometer, to conventionalR factors of 0.041 for I and 0.048 for II.In both isomers the dioxin ring has an approximate envelope conformation with a pseudoequatorial –CC1₂·CHCl·CH₃ group in the 2-position and a pseudoaxial –CCl₂·CHCl·CH₃ group in the 4-position. The molecular structures of I and II differ in that the group at the 2-position is rotated by about 120° in one isomer relative to its position in the other. Both compounds have packing patterns with a wave motif. In II there are interactions of the –NO₂ group with other atoms both between molecules in the same wave and also between molecules in adjacent waves. In I the interactions of the –NO₂ group with other atoms are in the same wave only with adjacent waves being packed together by van der Waals forces alone.     

Crystal structure of 751-1751-1751-1751-2751-2751-2

The title compound crystallizes in the centrosymmetric triclinic space group (No. 2) witha=10.818(1)Å,b=10.876(1)Å,c=11.072(2)Å, =98.74(1)°, =98.83(1)°, =96.61(1)°,V=125906(3)ų andZ=2. Interatomic distances include Fe–P=2.243(2)Å, Fe–CO=1.771(6)–1.781(5)Å, Fe–C(C₅H₅)=2.074(6)–2.103(5)Å and P–F=1.511(6)–1.571(4)Å.     

Structures of Z-(nitrostilbene)chromium tricarbonyl complexes: The effect of metal coordination on the nonplanarity of the stilbene system

The structures of the nitrostilbene complexes Z-(4-R–C₆H₄–CH=CH–C₆H₄-4-NO₂)Cr(CO)₃ (R=Me₂N,1; H,2; F₃C,3), are reported. The copounds were prepared as part of a study of the synthesis of organometallic complexes with potential nonlinear optics applications. For Z-(4-Me₂N–C₆H₄–CH=CH–C₆H₄-4-NO₂)Cr(CO)₃,1, triclinic, ,a=7.214 (3) Å,b=7.340 (3) Å,c=17.238 (9)Å, =88.23 (5)°, =88.76 (4)°, =87.66 (3) °,Z=2. For Z-(C₆H₅–CH=CH–C₆H₄-4-NO₂)Cr(CO)₃,2, monoclinic, P2₁/C,a=12.255 (3) Å,b=9.415 (1) Å,c=13.579 (4) Å, =105.60 (2)°,Z=4. For Z-(4-F₃C–C₆H₄–CH=CH–C₆H₄-4-NO₂)Cr(CO)₃,3, triclinic, ,a=7.094 (2) Å,b=8.057 (5) Å,c=17.295 (9) Å, =87.95 (5)° =85.94 (4)°, =64.24 (5)°,Z=2. The structural data show that the Z isomers exhibit bond lengths and angles similar to those observed in the E isomers, but the stilbene fragment is considerably more nonplanar. As a consequence, these molecules are unlikely to behave as NLO materials.     

Structure of chlorotris(1,3,5-triaza-7-phosphaadamantane)platinum(II) chloride hydrate methanolate, [Pt(PTA)3Cl] [Cl]·H2O·CH3OH

The title compound chlorotris(PTA)platinum(II) chloride hydrate methanolate (PTA=1,3,5-triaza-7-phosphaadamantane), [C₁₉H₄₂Cl₂N₉O₂P₃Pt] is monoclinic, witha=10.832(1),b=21.306(7),c=12.702(3)Å,=100.42(5)°,V=2883(2)ų,Z=4,D _x=1.814 g cm^–3,=53.0 cm^–1,F(000)=1568,T=298K in space groupP2₁/c. The structure was solved by heavy atom and Fourier methods and refined toR=0.051 for 4319 unique observed reflections. The complex exhibits approximately square-planar geometry about the Pt atom and a significant trans effect, with bond lengths Pt-Cl1=2.3371(2), Pt-C12 (ionic)=4.463(4), Pt-P _{trans(to cl)}=2.233(2), Pt-P _cis,ave=2.323(3)Å and bond angles Cl-Pt-P _cisave 83.60(3), P _trans -Pt-P _cis,ave 96.49(6)°. The H₂O is apparently hydrogen bonded to two N atoms on different cations, and the methanol OH group to the chloride anion.     

The N,N-diacetylaminobenzene group in the structure of 6-methyl-8-N,N-diacetylamino-2,4-bis(trichloromethyl)-1,3-benzdioxin

Crystals of 6-methyl-8-N,N-diacetylamino-2,4-bis(trichloromethyl)-1,3-benzdioxin are triclinic, P¯1,Z=2,a=9.586(3),b=9.914(2),c=12.308(5) Å,=67.19(3),=71.95(3), =74.14(2)°. 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 0.039 using 3038 reflections. The heterocyclic ring has an envelope conformation. Of thecis-CCl₃ groups one CC1₃ group is pseudoequatorial while the –(C_Ar·C)CCl₃ group is pseudoaxial. (C_Ar)O-C 1.405(4); (C_Ar·O)C-O 1.387(4) Å; C_Ar-C(C_ax)-0 112.3(3); C(C_ax)-O-C(C_eq) 116.1(2)°; (C_Ar)O-C-O-C(C_Ar)58.2(3)°. The configuration of the diacetylamino group (DAA) issyn-anti. The -systems of the DAA and of the aromatic ring are approximately orthogonal, the deviations from orthogonality probably being caused by an intermolecular bifurcated hydrogen bond, each such interaction involving two molecules only, between thesyn O(=C) of the DAA and both hydrogen atoms bonded to the heterocyclic ring in a molecule of the enantiomer. The geometry of the DAA-benzene fragment is compared with those found in the other three published X-ray structures containing this group.     

The crystal structure of tris(4-methylpyridine) tricarbonylmolybdenum(0)

The title compound, Mo(4-CH₃C₅H₄N)₃(CO)₃, is monoclinic, P2₁/c, with cell dimensionsa=10.385(1),b=13.572(2),c=15.522(2) Å, =105.08(1)°,Z=4. The complex isfac-octahedral with approximate three-fold symmetry. The Mo–C bond lengths are 1.901–1.904(7) Å, distinctly shorter than in the parent Mo(CO)₆, and the Mo–N bond lengths are 2.297–2.331(5) Å.