Crystal and molecular structures of trichloro (π-cis-but-2-en- 1,4-diammonium) platinum(II) chloride and trichloro(π-cis-pent-2-enylammonium) platinum(II)

The structures of the olefinic complexes of platinum(II) withcis-but-2-en-1,4-diammonium, [PtCl₃(C₄H₁₂N₂)]⁺, and withcis-pent-2-enylammonium, [PtCl₃(C₅H₁₂N)], the first one as its chloride, have been determined by single-crystal X-ray methods. The compounds form yellow monoclinic crystals, witha=11.238(3),b=12.234(4),c=7.769(1) Å, = 112.99(2) ° anda= 11.530(3),b=9.037(3),c= 10.067(3) Å, =105.50(2) °, respectively; both crystallize in the space groupP2₁/c withZ=4. The structures, solved by standard methods, have been refined anisotropically by full-matrix least-squares methods, both toR=0.040, on, respectively, 1808 and 1849 independent reflections collected by counter methods.In both complexes, platinum is four-coordinate to the three chlorine atoms and the double bond of the olefinic ligand. The structures are discussed, and comparison with the analogous platinum(II)-olefin complexes with the trans isomers of the olefinic ligands is made.     

The crystal and molecular structure of dichloro-(bis-1,2-diphenylphosphinoethane)platinum(II)

Crystals of PtCl₂(PPh₂)(CH₂)₂(PPh₂) (1), produced from attempts to prepare hydridochloroplatinum complexes, are monoclinic, space groupP2 ₁ /c, with four molecules in a unit cell of dimensionsa=11.478(3),b=13.263(2)c=16.343(3) Å, and =99.00(2)°. The structure was solved by the heavy-atom method and refined by block-diagonal least-squares calculations with anisotropicthermal parameters;R=0.048 andR=0.061 for 1843 observed reflections. The crystal structure contains discrete well-resolved molecules. The Pt atom has distorted square-planar coordination with Pt-P 2.208(6), Pt-Cl 2.355 and 2.341(6) Å distances, and Cl-Pt-Cl 90.2(2) and P-Pt-P 86.3(2)° angles.     

Synthesis,redox properties,and X-ray diffraction structure of the platinum catecholate complex Pt(1,5-COD)(1,2-O2C6H4)

The new compound Pt(1,5-COD)(1,2-O₂C₆H₄)(1) (where COD=cyclooctadiene) has been prepared from the reaction between Pt(1,5-COD)Cl₂ and the disodium salt of catechol. Pt(1,5-COD)(1,2-O₂C₆H₄) has been isolated and structurally characterized by X-ray diffraction analysis, which confirms the monomeric nature of this compound and the chelating mode adopted by the ancillary 1,5-COD and catecholate ligands. Pt(1,5-COD)(1,2-O₂C₆H₄) crystallized in the monoclinic space groupP2₁/n,a=10.208(1) Å,b=10.3829(8) Å,c=11.473(2) Å, =103.817(9)°,V=1180.9(2) ų,Z=4,d _calc=2.314 g·cm^–3;R=0.0307,R _w =0.0445 for 1216 observed reflections withI>3(I). Cyclic voltammetric studies on1 reveal an irreversible oxidation (E _p ^a =0.78 V) and an irreversible reduction (E _p ^c =–1.99 V) in CH₂Cl₂ solution. The nature of the HOMO and LUMO in Pt(1,5-COD)(1,2-O₂C₆H₄) was examined by using the model compound Pt(ethylene)₂(1,2-O₂C₆H₄), with the results discussed relative to compound1.     

X-ray structural investigation of two optically active 1N-epimers of 2,5,7,10,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) diperchlorate. A novel conformation of the macrocyclic ligand

The structures oftrans-1NH,8NH- (I) andcis-1NH,8NH-(II)-2,5,7,10,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) diperchlorates have been investigated by X-ray diffractometric methods. CompoundI crystallizes in a monoclinic system, space groupP2₁,Z=4,a=11.225(1),b=13.710(1),c=15.898(2) Å,=109.22(1)°. CompoundII crystallizes in an orthorhombic system, space groupP2₁2₁2₁,Z=4,a=15.529(2),b=14.129(2),c=10.621(1) Å. The structures were solved by the heavy-atom method followed by a series of Fourier syntheses, and refined by full-matrix least squares to give forI andII R=0.051 (for 3787 independent reflections) andR=0.048 (for 1494 reflections), respectively. Conformational analysis of chelate rings and of the macrocyclic ring was performed forI andII, and the results were compared with those of some known 1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel (II) complexes. A novel conformation of the macrocycle was found in cationI. Conformations of the methyl groups are forI andII 2(a),7(e),10(a),14(e) and 2(a),7(e),10(a),14(a), respectively, with a 1,3-syn-axial interaction of the 2,14-methyl groups inII. The absolute configuration of cationI is 1N(S), 2(R), 7(R), 8N(S), 10(R), 14(S), and differs from that of cationII by 1N(R) exclusively (1N-epimeric compounds).     

The structure ofcis-dichloro-bis-(triphenylphosphine)platinum(II); a product in the reaction ofcis-[PtCl2(CO)(PPh3)] with tin (II) chloride

The reaction ofcis-[PtCl₂(CO)(PPh₃)] with two equivalents of SnCl₂. 2H₂O in acetone solution allows isolation ofcis-[PtCl₂(PPh₃)₂] as the acetone solvate, the crystal structure of which has been determined. Crystals ofcis-[PtCl₂(PPh₃)₂]·C₃H₆O are monoclinic, space groupP2₁/c (No. 14) with four formula units in a cell of dimensionsa=10.288(3),b=24.372(5),c= 15.367(3) Å, /gb=98.07(2)°. The structure was solved by the heavy-atom method and refined by full-matrix least-squares calculations to a finalRof 0.033 for 3761 reflections withI>(I). The crystal structure contains discrete well-resolvedcis-PtCl₂(PPh₃)₂ molecules with acetone of solvation filling cavities in the crystal structure. The Pt coordination is slightly distorted square-planar with Pt-Cl 2.333(2) and 2.356(2), Pt-P 2.251(2) and 2.265(2) Å, P-Pt-P 97.8(1), and Cl-Pt-Cl 87.1(1)°.     

Crystal and molecular structure of palladium(II), copper(II) and zinc(II) complexes of 1-methyl-3-(4-methyl)phenyltriazen-1-oxide

The structures of palladium(II), copper(II) and zinc(II) bis(chelates) of 1-methyl-3-(4-methyl)phenyltriazen-1-oxide have been determined by single-crystal X-ray methods. The crystals of [Pd(OMeN₃C₆H₄Me-4)₂] (I) are triclinic witha=7.410(3),b=7.806(3),c=8.371(2) Å, =65.80(2), =88.73(3), =81.04(3)°,Z=1, space group . The crystals of [Cu(OMeN₃C₆H₄Me-4)₂] (II) are monoclinic,a=14.934(5),b=10.111(4),c=11.762(3) Å, =96.00(2)°,Z=4, space group P2₁/c. The crystals of [Zn(OMeN₃C₆H₄Me-4)₂] (III) are triclinic witha=7.912(2),b=10.056(2),c=11.600(2) Å, =87.31(3), =74.96(3), =74.02(3)°,Z=2, space group . The structures of (I), (II), and (III) were solved to final values ofR=0.029, 0.043 and 0.034, respectively. A planar structure has been found for (I), (II) exhibits a tetrahedrally distorted square planar structure, whereas (III) is tetrahedral. The crystals of all three complexes are held by networks of stacking interactions.     

X-ray crystal structures ofcis-bis(diphenylphosphinamide)tetracarbonylmolybdenum(0) andtrans-bis(N-methyl diphenylphosphinamide)tetracarbonylmolybdenum(0)

The X-ray crystal structures ofcis-Mo(CO)₄(Ph₂PNH₂)₂,I, andtrans-Mo(CO)₄(Ph₂PNHMe)₂,II, are presented. ComplexI crystallizes in the monoclinic space groupP2₁/c(a=13.433(1),b=12.2719(8),c=17.318(2)Å;=109.79(1)°;V=2686.1(8)ų;Z=4). ComplexII crystallizes in the triclinic space groupP¯1 (a=6.9986(8),b=10.328(1),c=11.241(2)Å,=107.58(1)°,=91.76(1)°, =101.28(1)°,V=756.1(4)ų,Z=1). The molybdenum coordination geometry in each complex is a slightly distorted octahedron. The molybdenum-carbon bond lengths for the carbonyls trans to phosphorus in complexI are shorter than those the carbonyls trans to other carbonyls. The average molybdenum-phosphorus distance inI (2.525(5)Å) is similar to those in other diphenylphosphinamide complexes and longer than the molybdenum-phosphorus distance inII in 2.4585(7)Å). The distance between two nitrogen atoms incis Mo(CO)₄(Ph₂PNH₂)₂ (3.74(3)Å) is significantly larger than the sum of their van der Waals radii (3.10 Å) indicating that the two nitrogens are not hydrogen bonded.     

Structure of trans-aqua-bis(pyridine)dibenzoatocopper(II)

Crystals oftrans-aqua-bis(pyridine)dibenzoatocopper(II), Cu(NC₅H₅)₂(C₇H₅O₂)₂(H₂O), are monoclinic,P2₁/n, witha=5.9847(10),b=18.874(5),c=19.728(10)A,=92.97(4)°,Z=4, andV=2225.5(13)A³. The full-matrix least-squares refinement used 3030 reflections withI> 2.5(I) and converged toR=0.067. The benzoate ions bond as monodentate ligands in this five-coordinate complex. The copper ion is in a square pyrimidal environment with trans pyridine groups and benzoate ions in a slightly distorted square planar arrangement and a water ligand in the axial position. The Cu-O distance to the water molecule is significantly longer (2.273(4) Å) than the distances to the O atoms of the carboxyl groups (1.934(3) and 1.930(4)Å).     

Crystal and molecular structures of trans-bis(acetonitrile)bis(bipyridine)ruthenium(II) perchlorate and trans-diamminebis(bipyridine)ruthenium(II) perchlorate

The structures of trans-[(MeCN)₂(bpy)₂Ru](ClO₄)₂(I) andtrans-[(NH₃)₂(bpy)₂Ru](ClO₄)₂(II) have been determined by single crystal X-ray diffraction methods. (I) forms monoclinic crystals in the space groupP2₁/c witha=8.399(2),b=10.406(2),c=15.590(3) Å,=93.78(2)° andZ=2 atT=293 K. The final refinement gaveR=0.040 for 2448 reflections withF _o ² >3(F _o ² ). (II) crystallizes in the triclinic space groupP¯1 witha=1.702(1),b=8.439(2),c=10.525(2) Å,=107.56(2),=104.63(1), =100.89(2)° andZ=1 atT=293 K. Refinement using 1878 reflections withF _o ² >3(F _o ² ) produced a finalR value of 0.036. Both of these structures have the ruthenium atom located on a crystallographic inversion center. The bipyridine ligands in both structures are in the bowed conformation as a means of circumventing the steric problems associated with the trans arrangement of the bipyridine ligands. The Ru-N(monodentate) distance is longer for the ammonia complex (2.106(3) Å) than for the acetonitrile complex (2.008(4) Å); there are no significant differences in the distances and angles of the two Ru(bpy)₂ frameworks.     

X-ray structural investigation of N-epimeric 1,8-cis- and 1,8-trans-5,12-dimethyl-1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) diperchlorates,C12H24N4Ni(ClO4)2

The structures of 1,8-cis- and 1,8-trans-5, 12-dimethyl-1,4,8,11-tetra-azacyclotetradeca-4,11-dienenickel(II) diperchlorates (I andII, respectively) have been investigated by X-ray diffracto-metric methods. CompoundI crystallizes in a monoclinic system, space group P2₁/n, with cell dimensionsa=13.732(2),b=13.526(2),c=10.658(2) Å,=99.20(2)°; compoundII crystallizes in a monoclinic system, space group C2/c, with cell dimensionsa=15.776(2),b=9.919(1),c=12.451(1) Å,=102.27(1)°. The structures were solved by heavy atommethods and refined by a full-matrix least-squares method to giveR=0.0601 and 0.0575 forIandII, respectively. Both N-epimers show the square planar Ni(II) coordination arrangements. The ligand ofI has approximate twofold symmetry (C₂ perpendicular to the coordination plane), the moleculeII is crystallographically centrosymmetric (C_i).     

Solid state conformational parameters in dibenzo[b,f]heteroepin drugs: Crystal structures of 3-methoxy-10-methyl-11-phenyldibenzo[b,f]thiepine and 3-allyloxy-10-ethyl-11-phenyldibenzo[b,f]oxepine

The structures of 3-methoxy-10-methyl-11-phenyldibenzo[b, f]thiepine (I) [C₂₂H₁₈OS, tetragonal,I4₁/a, witha=33.81(1),c=6.065(5)Å,Z=16] and 3-allyloxy-10-ethyl-11-phenyldibenzo[b,f]oxepine (II) [C₂₅H₂₂O₂, mono-clinic,P2₁/c,a=12.115(7),b=16.316(9),c=10.136(7)Å,=105.05(9)°,Z=4] have been determined by the symbolic addition procedure and refined by least-squares method to anR of 0.090 for 784 diffractometer-measured reflections (I) and to anR of 0.083 for 442 reflections (II). The dihedral angle between the phenyl-ring mean planes is 111.3° in (I) and 121.1° in (II), the middle seven-membered ring has the boat conformation, and the tricyclic moiety has twist and skew values of 6° and 0.42 Å in (I) and 0.3° and 0.79 Å in (II). The overall conformational characteristic for the tricyclic (6, 7, 6)-dibenzo[b,f]heteroepin derivatives have been reviewed to gain a better understanding of what requirements may be important for interaction of drugs of this class at the receptor site.     

Isolation and crystal structures of triethylenediamine-hydroquinone (1/1) and triethylenediamine-phenol (1/2)

Two crystalline adducts of triethylenediamine with hydroquinone [N(CH₂CH₂)₃N·C₆H₄(OH)₂,I] and phenol [N(CH₂CH₂)₃N·2C₆H₅OH,II] have been isolated and characterized by X-ray analysis. ComplexI crystallizes in the monoclinic space groupC2/c, witha=11.944(2),b=9.491(2),c=11.986(2) Å,=121.70(1)°, andZ=4. Both molecular components occupy sites of symmetry 2, and are linked alternately by N H-O hydrogen bonds to form infinite zigzag chains. Crystals ofII are also monoclinic, with space groupP2₁/c,a=12.987(2),b=6.376(1),c=21.350(3) Å,=106.94(1)°, andZ=4. The structure is composed of discrete hydrogen-bonded molecular aggregates corresponding to the stoichiometric formula. The triethylenediamine moieties in both adducts closely approximate to the idealizedD ₃ h conformation. The structures have been refined toR values of 0.097 (I) and 0.092 (II) using, respectively, 479 and 1580 observed MoK data.     

Structure of a styrylbenzoselenazole platinum(II) complex: [NEt4][Pt(nsbse)Br3]

Tetraethylammonium tribromo[2-(2-chloro-5-nitrostyryl)benzoselenazole] platinate (II), [(C₂H₅)₄N][PtBr₃(C₁₅H₉ClN₂O₂Se)], is monoclinic, in space groupP2₁/c, witha=9.496(2),b=20.321(7),c=15.166(3)Å,=100.18(1)°,V=2880(2)ų,M _r =928.72,Z=4,D _x =2.141 g cm^–3, (MoK)=0.71073 Å,=104.1 cm^–1,F(000)=1752,T=298 K. The structure was solved by direct methods and refined toR=0.032 for 2626 unique observed reflections withI>3(I). The [Pt(nsbse)Br₃)] unit has square-planar geometry about the Pt atom, with the nsbse coordinated to the Pt through the N of the selenazole ring. The ligand molecule is non-planar, with a dihedral angle of 61.6(2)° between the benzoselenazole and phenyl rings. The dihedral angles between the PtBr₃ plane and the benzoselenazole and phenyl planes are 105.2(1) and 80.7(1)°, respectively.     

Crystallographic and IR spectral study ofcis-bis(creatinine-N)dinitro platinum(II)

Acis-Pt(creat)₂(NO₂)₂ complex was synthesized stereoselectively in a high yield (65%) and characterized by IR spectral and X-ray diffraction analysis. Crystal data: Pt(C₄H₇N₃O)₂(NO₂)₂,M _r=767.55, monoclinic, space groupP2₁/n,a=9.736(1),b=13.433(1),c=12.098(1) Å,=110.55(1)°,V _c=1482(1) ų,Z=2,D _x=3.441 g cm^–3,(MoK)=0.71073 Å,=97.0 cm^–1,F(000)=1504,T=292 K,R=0.026 andR _w=0.028 for 2061 observed reflections with I>2(I). The structure consists of Pt(creat)₂(NO₂)₂ molecules disposed in general positions and joined by N-HO and N-HN hydrogen bonds. The platinum atom has square-planar PtN₄ coordination of twocis disposed pairs of nitro [Pt-N_av 2.023(7) Å] and creatinine [Pt-N(endo)_av 1.991(8) Å] ligands. The creatinine moieties are planar and tilted to the equatorial plane by ~80°.     

X-ray crystal structure analysis of nitroxazepine: 10-(3-dimethylaminopropyl)-2-nitro-10,11-dihydrodibenz [b,f][l,4]oxazepin-11-one

The title compound, C₁₈H₁₉O₄N₃,M _r=341, the base (I) of the dibenzoxazepine anti-depressant drug Sintamil, crystallizes in the orthorhombic space group,Pbca withZ=8 in a cella=8.636(2),b=23.687(3),c=16.787(3)Å,V _c=3434 ų. The structure was solved by direct methods and refined toR=0.102 (R _w=0.093) with 1348 observed CuK reflections. The tricyclic framework takes up a saddle shape with the heterocyclic ring in boat conformation; the flanking planar aromatic rings make angles 148.2(3), 150.8(3)° with the central ring plane, compared with 143.5(5), 158.1(5)° in Sintamil monohydrate (II). BothI andII have extended-CNMe₂ side chains (with appreciable thermal motion); this conformation, and the distances of the -N(CH₃)₃ nitrogen to the centers of aromatic rings (6.4 and 7.8 Å inI), are consistent with inhibition of uptake mechanisms underlying the pharmacological action.     

Crystal structures of difluoro[2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato]boron(III), [BF2(C16H13O3)], and bis[2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato]copper(II), [Cu(C16H13O3)2]

The crystal structures of difluoro[2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato]boron(III), [BF₂(C₁₆H₁₃O₃)], and bis[2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato]copper(II), [Cu(C₁₆H₁₃O₃)₂], have been determined by single-crystal X-ray diffraction methods. The structures were solved by direct methods and electron density calculations and were refined by the full-matrix least-squares method. Difluoro[2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato]-boron(III) crystallizes as yellow rhombs in the monoclinic space groupP2₁/c witha=11.429(3),b=11.364(4),c=11.412(4) Å,=92.19(2)°,V=1481.0(8) ų andZ=4. A total of 2754 unique reflections were collected. Of these 1342 were considered observed [I>3(I)] leading to a finalR-value of 0.045. Boron is tetrahedrally coordinated to the two fluorine atoms and to two oxygen atoms of the bidentate 2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato ligand, C₁₆H₁₃O ₃ ^– . Average bond distances: C-C (aromatic) 1.378(10) Å, B-O 1.473(7) Å and B-F 1.343(4) Å. bis[2-(4-Methoxyphenyl)-3-oxo-3-phenylpropanalato]copper(II) crystallizes as dark yellow-green plates in the monoclinic space groupC2/c witha=23.410(7),b=13.856(3),c=8.039(3) Å,=101.79(2)°,V=2553(1) ų andZ=4. Of the unique set of 3076 scanned reflections 2401 hadI>3(I) for whichR became 0.040. Copper is coordinated to four oxygen atoms, two from each of the two bidentate 2-(4-methoxyphenyl)-3-oxo-3-phenylpropanalato ligands, in a distorted square planar manner. The molecule hasC ₂ symmetry. Average bond distances: C-C (aromatic) 1.383(6) Å and Cu-O 1.896(8) Å. The crystals of both compounds consist of monomeric molecular complexes held together by van der Waals forces.     

Crystal and molecular structure of tetrapyridyl-copper(II)-bis-nitrato-bis-pyridine

The crystal and molecular structure of a pyridine complex of anhydrous copper(II)nitrate is described. The structure has been solved by vector search methods and refined by least-squares methods to R₁=0.049 [I>2(I)]. The complex lies on a twofold axis parallel toa, and two solvent pyridine molecules lie on twofold axes parallel toc. The copper atom is coordinated by four pyridyl groups and two monodentate NO₃ groups. Crystal data: C₃₀H₃₀N₈O₆Cu, orthorhombic, space group Pnna(52),a=14.446(7),b=12.154(5),c=16.881(4) Å,V=2964(2) ų,Z=4.     

Crystal and molecular structure of (Z)-2-(1,3-benzothiazol-2-yl)-2-(6,7,8,9-tetrahydro-5H-benzocyclohepten-5-ylidene)ethanonitrile

The title compound C₂₀H₁₆N₂S is crystallized in the monoclinic space groupP2₁/c with cell parametersa=10.663(4),b=17.585(9),c=9.418(5)Å,=115.23°(4),V=1598(3)ų,Z=4. The structure was refined by full-matrix least-squares methods using X-ray data set collected at room temperature. A finalR _F =0.033 andR _w =0.048 for 2225 unique reflections withI> 3(I) and 272 variables was obtained. The X-ray crystallographic study establishes theZ stereochemistry of the title compound.     

Preparative and structural studies of halodimolybdates (II), III. Crystal and molecular structure of bis(4-methylpyridinium)hexaiododiaquo-dimolybdate(II)

The title compound (C₆H₈N)₂Mo₂I₆(H₂O)₂ crystallizes in theP¯1 space group, witha = 8.127(3),b = 8.337(3),c = 10.415(4) Å, = 73.99(2), = 84.35(2), = 73.91(2) ° andZ = 1. The structure was solved by direct methods and refined to the unweighted and weighted residuals of 0.044 and 0.052. The structure is characterized by the eclipsed configuration of the iodide ions and water molecules within Mo₂I₆(H₂O) ₂ ^2– ion and very short Mo-Mo bond distance 2.115(1) Å. Three independent Mo-I distances are 2.784(1), 2.760(2) and 2.797(1) Å. 4-Methylpyridinium ion is planar within 0.02° Å. The compound is isostructural with (C₆H₈N)₂Mo₂Br₆(H₂O)₂.Part II, Breni, J. V., Leban, I., and egedin, P. (1976).Z. Anorg. Allg. Chem. 427, 85.     

Crystal structures of three 1-arylpropane-1,2-diol 2-aryl ether derivatives and the acetate of 2,6-dimethoxy-4-(1-(E)-propenyl)phenol

The crystal structures ofthreo-2-[2,6-dimethoxy-4-(1-(Z)-propenyl)phenoxy]-1-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanol (7b),threo-2-(2,6-dimethoxy-4-propylphenoxy)-1-(3,4-5-trimethoxyphenyl)-1-propanol (7c), the diacetate oferythro-2-[2,6-dimethoxy-4-(1-(Z)-propenyl)phenoxy]-1-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanol (8d) and the acetate of 2,6-dimethoxy-4-(1-(E)-propenyl)phenol (9) have been determined by single-crystal X-ray diffraction methods;7b,7c, and8d are structurally closely related to a class of optically-active neolignans of 1-arylpropane-1,2-diol 2-aryl ether type occurring in plant extracts. The reflection intensities were recorded at room temperature for7b and8d, at -140°C for7c and at -120°C for9. Compound7b crystallized as needles in the orthorhombic space groupPna2₁ witha=27.055(3),b=11.850(8),c=6.717(4)Å andZ=4.R became 0.041 for 1792 observed [I>3(I)] reflections used in the refinement of the structure. Compound7c crystallized as prisms in the monoclinic space groupP2₁/a witha=12.565(4),b=13.96(1),c=12.846(7)Å,=93.86(3)° andZ=4. The refinement gaveR=0.051 for 2101 observed [I>3(I)], unique reflections. Compound8d crystallized as prisms in the monoclinic space groupP2₁/n witha=13.182(4),b=8.518(5),c=23.322(5)Å,=106.12(2)° andZ=4. The finalR-valuebecame 0.042 for 2131 observed [I>3(I)], unique reflections. Compound9 crystallized as prisms in the orthorhombic space groupPca2₁ witha=18.216(4),b=9.483(3),c=7.416(2)Å andZ=4. TheR-value became 0.038 for 1502 observed [I>3(I)], unique reflections. The crystals of7b are stabilized by moderately strong hydrogen bonds. All the 1-arylpropane-1,2-diol 2-aryl ethers examined adopted conformations in which the aromatic groups tend to be as remote as possible. Observed double bond lengths in the propenyl groups of the compounds examined (1.30 Å) deviate significantly from the expected value (1.34 Å). The cause of this discrepancy is discussed.