Showing papers in "Journal of Chemical Crystallography in 1988"

Crystal structure of octacalcium bis(hydrogenphosphate) tetrakis(phosphate)pentahydrate, Ca8(HP04)2(PO4)4·5H2O

Abstract: The crystal structure of octacalcium bis(hydrogenphosphate) tetrakis(phosphate)pentahydrate, Ca8(HPO4)2(PO4)4·5H2O, has been refined toR=0.051 for 4502 reflections. The crystals are triclinic:P¯1,a=19.692(4),b=9.523(2),c=6.835(2) A,α=90.15(2),β=92.54(2), and γ=108.65(1)°,Z=2. The structure can be considered to consist of two layers parallel to (100), an apatitic layer which corresponds very closely to that of hydroxyapatite and a hydrated layer which contains all the water molecules. Several atoms in the hydrated layer are probably disordered. Possibilities for the hydrogen-bonding arrangement are discussed.

Heteropolymetallic complexes of 1,1'-bis(diphenylphosphino) ferrocene (dppf). II: Crystal structure of dppf and NiCl2(dppf)

Abstract: The crystal structures of dppf [dppf=1,1′-bis(diphenylphoshino)ferrocene] and (dppf)NiCl2 were determined by X-ray crystallography and refined toR=0.043 (both). The molecule of dppf is centrosymmetric, with the inversion center at the Fe atom. The ferrocene rings are parallel and staggered. In (dppf)NiCl2 the coordination around nickel is tetrahedral, with a significantly large Cl-Ni-Cl angle (125°) due to repulsion of the chlorine atoms. The ferrocene ligand exhibits a slightly distorted (9°) eclipsed conformation, very similar to that observed in (dppf)NiBr2.

Crystal structure of bis(methyltributylammonium) penta-μ-bromo-di-μ5-bromo-pentacuprate(I), a compound containing a discrete [Cu5Br7]2− aggregate

Abstract: The structure of the title compound has been determined from single-crystal X-ray diffraction data. [N(CH3)(C4H9)3]2[Cu5Br7] crystallizes in space groupP¯1, witha=12.276(15),b=14.903(23),c=11.777(16) A,α=105.1(1),β=95.0(1), γ=92.8(1)°, andZ=2. Full-matrix least-squares refinement of 361 structural parameters gaveR=0.067 for 3618 observed [I>3σ(I)] reflections, measured at 170 K. Bis(methyltributylammonium) penta-μ-bromo-di-μ 5-bromo-pentacuprate(I) contains a discrete [Cu5Br7]2− anion that can be described as a distorted pentagonal bipyramidal cage of bromide ions, containing copper(I) ions in tetrahedral holes, i.e., as being composed of five face-sharing Cu-Br tetrahedra. The coordination polyhedra associated with all five copper(I) centers are, however, severely distorted, a more adequate description of the copper(I) coordination in this anion thus being 2×(2+2) and 3×(3+1). Cu-Br distances range from 2.296(5) to 3.534(6) A, and Cu⋯Cu contacts from 2.566(7) to 2.637(6) A.

Intra- versus intermolecular hydrogen bonds in salicylamide derivatives

Abstract: The crystal structures, solid-state infrared patterns, and thermal properties of two polymorphs of 4′-nitrosalicylanilide are presented. In both polymorphs, intramolecular hydrogen bonds are found between the phenol oxygen and the amide proton, and intermolecular hydrogen bonds are found between the amide carbonyl oxygen and the phenol proton. These hydrogen bond patterns are compared to those found in other known salicylamide derivatives and an analysis is given of the factors contributing to preferences for intra- or intermolecular hydrogen bonds in these structures. Crystal data:α polymorph, orthorhombic,Pbca,a=11.003(4),b=27.959(7),c=7.622(5) A,Z=4,V=2345(3) A3, andR=0.038 (1351 reflections);β polymorph, monoclinic,P21/a,a=28.36(1),b=11.64(1),c=7.293(8) A,β=90.68(6)°,Z=8,V=2408 A3, andR=0.043 (2425 reflections).

On the organoaluminum chemistry of multidentate phosphine ligands. Reaction of trimethylaluminum with bis(diphenylphosphino)methane: Synthesis and molecular structure of [Al(CH3)3]2[(C6H5)2PCH2P(C6H5)2]

Abstract: Reaction of an excess of trimethylaluminum with bis(diphenylphosphino)-methane in heptane affords the crystalline complex [A1(CH3)3]2[(C6H5)2PCH2P(C6H5)2]. The title compound crystallizes in the triclinic space group P¯1 with unit cell parametersa=10.053(6),b=11.017(6),c=15.908(8) A,α=85.58(4),β=71.80(4), γ=77.49(4)°,V=1634(1) A3, andDc=1.07 g cm−3 forZ=2. Least-squares refinement based on 2924 observed reflection with intensitiesI≥3σI) in the range 2.00≤2θ≤45.0° converged atR=0.050 (Rw=0.067). The Al-P distances are 2.585(2) and 2.521(2) A, and the P-C-P angle is 121.4(2)°.

Crystal structure and spectroscopic study of polymolybdates. The crystal structure and bonding of hexakis(n-pentylammonium) heptamolybdate(VI) trihydrate

Abstract: Three new heptamolybdates ofn-alkylammonium have been synthesized, with the general formula: (BH)6[Mo7O24]·3H2O, where B=n-butyl-,n-pentyl-, andn-hexylamine (hereafter abbreviated as BUTMO, PENTMO, and HEXMO, respectively). Crystal structure analyses of these compounds show that all of them are isostructural and crystallize in the monoclinic system, the space group beingP21/n,Z=4. Crystal data for PENTMO are: (C5H14N)6[Mo7O24]·3H2O,a=17.085(2),b=31.344(4),c=11.487(12) A,β=93.04(3)°,V=6143(6) A3,F(000)=3288,Dx=1.77, D0=1.78(1) Mg·m−3,R=0.059, andRw=0.066 for 5526 observed reflections. Only slight differences in cell dimensions have been observed for these compounds, except for the parameterb which is significantly different in all of them. Thermogravimetric studies show that the compounds contain three water molecules. IR spectra indicate that the organic bases are protonated and the polyanion presents the well-known infrared spectrum for heptamolybdates in the solid state. The structure solution confirms that the compound PENTMO contains discrete [Mo7O24]6− anions, (C5H14N)+ cations, and water molecules, connected through hydrogen bonds; the distinguishing features of the compound PENTMO are its extensive hydrogen bonding. The cations and the water molecules are positioned so as to be able to form hydrogen bonds with either molybdate oxygen atoms or water oxygen atoms. The proposed strong hydrogen bonding interactions appear to stabilize the structure. Some of these hydrogen bonds can play an important role in the possible photochromism of this compound.

Structure, IR, and NMR spectra of tetrakis(4-methyl piperidinedithiocarbamate) dimercury(II)

Abstract: The compound C14H24HgN2S4 was prepared and characterized by means of X-ray, IR, and NMR measurements. The crystals are monoclinic, space group P21/c, (No. 14) witha=8.697(2),b=19.156(3),c=12.098(2) A,β=108.14(1)° andZ=4. The structure was solved by the heavy-atom method, and least-squares refinement of structural parameters led to a conventionalR factor of 0.027 for 2469 independent reflections. The structure consists of discrete dimeric units with the metals coordinated to five sulphur atoms. The IR and NMR spectra are discussed on the basis of the known structure.

The crystal and molecular structures of formyl-, cyano-, and amino-cyclopentadienyldicarbonylnitrosylchromium

Abstract: The x-ray crystallographic structures of (η5-C5H4CHO)Cr(CO)2NO (I), (η5-C5H4CN)Cr(CO)2NO (II), and (η5-C5H4NH2)Cr(CO)2NO (III) are described. The formyl and amino derivatives were obtained from a literature preparation (Macomber and Rausch, 1983). The cyano derivative (II) was obtained by conversion of (η5-C5H4COOH)Cr(CO)2NO into [(η5-C5H4C(O)NH2]Cr(CO)2NO, followed by dehydration of the amide in acetic anhydride. (I) crystallizes in the monoclinic space groupP21/n witha=8.028(3),b=11.605(4),c=9.730(3)A,β=90.04(2)°, andDcalc=1.69 g cm−3 forZ=4. Refinement led to anR value of 0.031 based on 1279 observed reflections ([I>-3σ(I)]). (II) belongs to the triclinicP¯1 witha=6.838(3),b=6.879(3),c=10.130(3)A,α=92.23(2),β=92.98(2), γ=107.65(3)°, andDcalc=1.67 g cm−3 forZ=2. Refinement gaveR=0.042 for 1543 observed reflections. (III) was found to be orthorhombicPbca witha=7.259(3),b=13.449(3),c=18.090(5)A, andDcalc=1.64 g cmsu−3 forZ=8. Refinement producedR=0.026 for 767 observed reflections. In (I) the electron-withdrawing formyl group is foundtrans to the nitrosyl. The same holds for the cyano group in (II), but the amino function in (III) is nottrans to any of the tripod ligands.

Solution and solid-state hydrogen bond patterns ofo-methoxy- ando-ethoxybenzoic acids

Abstract: The hydrogen bond patterns ofo-alkoxybenzoic acids have been shown previously to involve intramolecular hydrogen bonds. In this paper we show thato-methoxybenzoic acid (I) and o-ethoxybenzoic acid (II) both exist as monomers with intramolecular hydrogen bonds in solution but that, in the solid-state,I crystallizes as hydrogen-bonded dimers whileII crystallizes with an intramolecular hydrogen bond. The correlation between solution and solid-state hydrogen bond patterns is made using solution and solid-state IR and NMR methods and by correlating the solid-state patterns with known X-ray crystal structures. The crystal structure ofI is reported here. Crystal data: monoclinicP21/n;a=7.002(2),b=14.945(9),c=7.719(4) A,β=115.44(3)°,Z=4,V=729.4 A3, andR=0.046 (1660 reflections).

Organosilanols: The structure of 1,1,3,3-tetraphenyldisiloxane-1,3-diol

Abstract: The title compound is triclinic, space groupP¯1, witha=13.468(2),b=20.289(2),c=14.247(1) A,α=98.92(1),β=113.42(1),γ=99.52(1)°,Vc=3416(1) A3, andZ=6. The structure was solved by direct methods and refined by full-matrix least squares toR=0.078,Rw=0.089, for 6511 observed data. The molecules hydrogen-bond into helical chains parallel to [111], each oxygen being involved in one donor and one acceptor hydrogen bond. The geometry of the siloxane link is different in the three independent molecules present, with Si-O-Si angles of 147.8(3), 157.0(3), and 162.5(3)°.

Molecular structure of tetrapropylammonium-2,3-dichloro-5,6-dicyano-p-benzoquinone compared to M+ TCNQ− (M+=Rb+, K+, Cs+, or organic cations; TCNQ−=tetracyanoquinomethane) charge-transfer complexes

Abstract: The crystal and molecular structure of tetrapropylammonium-2,3-dichloro-5,6-dicyano-p-benzoquinone (TPA+ DDQ−) has been determined from single-crystal X-ray diffraction analysis. The crystals are monoclinic, space groupP21/n, witha=13.297(5),b=12.851(4),c=13.099(5) A,β=101.34(2)°, andZ=4. The compound consists of discrete (DDQ)22− anion dimers and two TPA+ cations inserted between the (DDQ)22− dimers, with an infinite stack running along b of the type ⋯(DDQ)22−[(C3H7)4N+] (DDQ)22−2[(C3H7)4N+]⋯

Crystal and molecular structure of dibromobis(benzimidazole)copper(II)

Abstract: The reaction of CuBr2 with benzimidazole and HBr in aqueous solution leads to the formation of Cu(C7H6N2)2Br2 as dark-brown, stable monoclinic crystals. Space groupP21/c witha=13.794(5),b=7.875(2),c=14.510(6) A;β=105.82(5)°;V c =1516(5) A3;D x =2.010(3) Mg m−3. The structure was refined by a full-matrix least-squares procedure to giveR=R w =0.045 for 1932 intensities above 3σ(I). The copper (II) ions are four coordinates in the form of a distorted flattened tetrahedron CuN2Br2, with the bond lengths Cu-Br(1)=2.402(1), Cu-Br(2)=2.446(1), Cu-N(1)=1.976(7), and Cu-N(11)=1.946(7) A. The flattened angles are Br-Cu-Br=139.0(1) and N-Cu-N=154.6(3)°. The geometry of intermolecular and intramolecular hydrogen bonds is discussed.

Studies on peroxomolybdates. XV: Crystal structure of ammonium difluorooxodiperoxomolybdate (VI), (NH4)2 [MoF2O(O2)2], and a survey of important distances in pentagonal-bipyramidal peroxomolybdates

Abstract: The crystal structure of ammonium difluorooxodiperoxomolybdate(VI), (NH4)2[MoF2O(O2)2], has been determined by single-crystal X-ray diffraction methods. The yellow compound crystallizes in the triclinic space groupP¯1 witha=7.752(2),b=7.498(3),c=6.066(2) A,α=86.37(3),β=109.60(3),γ=94.45(3)°, andZ=2. A total of 3857 reflexion intensities was recorded on a SyntexP21 diffractometer using MoKα radiation at room temperature. The structure was solved by the Patterson method and successive electron density calculations. Full-matrix least-squares refinement yielded a finalR value of 0.027 for 3729 observed [I>3σ(I)] reflexions. In the complex anion molybdenum is surrounded by a pentagonal-bipyramidal arrangement of ligand atoms. Two side-on bonded peroxo groups and a fluorine atom form the equatorial plane and one fluorine atom and a double-bonded oxygen atom occupy the apical positions. The molybdenum atom is displaced 0.311(1) A from the equatorial plane in the direction of the double-bonded oxygen atom. Bond distances: Mo-Operoxo 1.931(2)-1.976(2) A, Mo=Oapical 1.688(2) A, Mo-Fequatorial 1.979 (1) A, Mo-Fapical 2.199(1) A and (O-O)peroxo 1.474(2)-1.480(2) A.

Crystal and molecular structure of 1R,3S,5S,7R,10R-3,6,6,10,14-Pentamethyltricyclo[10.3.0.05,7]pentadeca-11,14-diene-1, 10-dihydroxy-2,13-dione (Japodagrol), C20H28O4

Abstract: A new cytotoxic macrocyclic diterpenoid named Japodagrol, C20H28O4, has been isolated from the ornamental plantJatropha podagrica, family Euphorbiaceae, grown in Nigeria. The structure of the title compound, C20H28O4, was solved by X-ray analysis.M r =332.44, monoclinic space groupC2,a=23.285(4),b=6.5105(12),c=12.505(3) A,β=98.504(17),V=1874.8 A3,Z=4,D c =1.178 Mg/m3. CuKα radiation (graphite crystal monochromator, λ=1.54184 A),μ (CuKα)=6.13 cm−1,F(000)=720,T=290 K. Final conventionalR factor=0.035,R w =0.038 for 3349 “observed” reflections. The structure was solved with the programDirdif. The 5-membered ring is closed to a half-chair form. The compound contains inter- and intramolecular hydrogen bonds.

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

Abstract: 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,Mr=767.55, monoclinic, space groupP21/n,a=9.736(1),b=13.433(1),c=12.098(1) A,β=110.55(1)°,Vc=1482(1) A3,Z=2,Dx=3.441 g cm−3,λ(MoKα)=0.71073 A,μ=97.0 cm−1,F(000)=1504,T=292 K,R=0.026 andRw=0.028 for 2061 observed reflections with I>2σ(I). The structure consists of Pt(creat)2(NO2)2 molecules disposed in general positions and joined by N-H⋯O and N-H⋯N hydrogen bonds. The platinum atom has square-planar PtN4 coordination of twocis disposed pairs of nitro [Pt-Nav 2.023(7) A] and creatinine [Pt-N(endo)av 1.991(8) A] ligands. The creatinine moieties are planar and tilted to the equatorial plane by ~80°.

Crystal and molecular structure of 2-(7-cyanonorcaran-7-yl)-5-(ethoxycarbonyl)-4,5,6,11b-tetrahydro(Δ4-1,2,4-oxadiazolino)-[2,3-a]-β-carboline, C23H24N4O3

Abstract: The structure of the title compound, C23H24N4O3, was determined by X-rays.M r =404.47, orthorhombic, space groupPna21; unit cell dimensionsa=9.0386(4),b=28.0249(14),c=7.8936(9) A,V c =1999.49(3) A3,Z=4,D x =1.344 Mg m−1. CuKα radiation (graphite crystal monochromator, λ=1.54178 A),μ(CuKα)=0.699 mm−1,F(000)=856,T=295 K. Final conventionalR-factor=0.030,R w =0.037 for 3215 unique reflections and 366 variables. The structure was solved by automated rotation functions in vector space, usingDirdif. The absolute configuration of the structure is reported.

Crystal structures of thetrans-cyclooctene complexes of copper(I) chloride and silver nitrate

Abstract: The crystal and molecular structures of the title compounds CuCl·C8H14 and AgNO3·C8H14, have been determined by single-crystal X-ray diffraction techniques, and refined by full-matrix least squares. Both compounds crystallize in the orthorhombic space groupPbca witha=6.191(7),b=12.456(2),c=23.272(4) A for CuCl·C8H14, anda=7.383(2),b=9.825(2),c=26.980(5) A for AgNO3·C8H14;Z=8 in both cases. FinalR factors are 0.047 and 0.029 respectively. The cyclooctene ring has the twist chair-chair (TCC) conformation, with approximateD 2 symmetry, in both compounds, and the torsion angles around the double bonds are −134.2(4) and −137.0(4)° respectively. Slight lengthening of the metal-complexed double bond is attributed to enhanced olefin → metal σ-donation of thetrans bond.

Crystal and molecular structure of 6-nitro-1,3-benzdioxin: Comparison with the molecular structures of the 2,4-bis(dichloromethyl) and 2,4-bis(trichloromethyl) derivatives

Abstract: 6-Nitro-1,3-benzdioxin is orthorhombic,Pbca,a=7.278(4),b=19.292(3),c=10.978(1) A,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 0.041 using 725 reflections. Some parameters associated with the heterocycle are torsion angle (CAr)O-C-O-C(CAr) 69.1(4)°; bond lengths CAr-O 1.362(3), (CAr)O-C 1.434(5), (CAr.O)C-O 1.377(5), O-C(CAr) 1.431(5), C-CAr 1.501(5) A; bond angles CAr-O-C 113.5(3), O-C-O 111.5(3), C-O-C(CAr) 110.3(3), O-C-CAr 109.9(3)°;Hax⋯Hax 2.52(5) A.

Crystal and molecular structure of the spin-crossover complex bis(pyridine) [N,N′-ethylenebis (3-carboxysalicylaldimine)] cobalt (II)

Abstract: The average structure of the title compound, Co(H2fsa2en)(py)2, which has been shown previously to exhibit a thermally induced high-spin ↔ low-spin crossover, has been investigated by single-crystal X-ray diffraction. This structure has been solved in the monoclinic space groupC2/c (No. 15), with cell dimensionsa=16.641(5),b=9.496(4),c=16.329(6) A, andβ=95.47(3)°;V=2569(3) A3,Mr=571.46,Z=4,Dx=1.478 mg m−3; MoKα radiation (graphite crystal monochromator),λ=0.71073 A,μ(MoKα)=7.138 cm−1;T=295 K andR=0.081 for 681 observed [I>3σ(I)] independent reflections. The cobalt(II) ion resides on a twofold axis in an elongated octahedral environment, the length of the apical bond (formed with pyridine) being 2.262(12) A and the mean length of the equatorial bonds (formed with the Schiff base) 2.079(12) A. These values are consistent with the magnetic behavior, which suggested a distorted surrounding for the metal atom. The packing is essentially governed by the parallelism of the salicylaldimine ligands. The two pyridine rings of the molecule are twisted by ~98° on each side of the basal plane; they are probably affected by orientational disorder or, if ordered, they might be described in a superstructure not yet established.

Substituted cyclopentadienyl complexes. 5. Crystal and molecular structure of [(η5-C5H4Me)Fe(CO)(L)I] [L = 2,6-Me2C6H3NC, P(OMe)3, and P(C6H11)3]

Abstract: The crystal and molecular structures of three derivatives of [(η 5-C5H4Me)Fe(CO)(L)I] [L=2,6-Me2C6H3NC, P(OMe)3, and P(C6H11)3] have been determined. [(η 5-C5H4Me)Fe(CO)(CNC6H3Me2-2,6)I] (1): Space groupP¯1,Z=2,a=13.193(7),b=8.183(5),c=7.465(4) A,α=95.13(5),β=94.39(5), γ=91.09(5)°. [(η 5-C5H4Me)Fe(CO)[P(OMe)3]I] (2): Space groupP21/c,Z=4,a=7.296(3),b=24.471(6),c=8.877(3) A,β=111.92(4)°. [(η 5-C5H4Me)Fe(CO)[P(C6H11)3]I] (3): Space groupP21/c,Z=4,a=9.809(3),b=14.147(2),c=8.276(3) A,β=103.07(2)°. The structures were refined toR values of 0.045, 0.070, and 0.061, respectively. Disorder was observed in the P(OMe)3 ligands on2. Structural data for1 and3 reveal (i) a small movement of the Fe atom away from the ringC atom containing the methyl group, (ii) a larger movement of ring C atoms away from the ring least-squares plane for3 than for1, and (iii) a shift toward an allyl-ene bond length variation in the ring distances for3. Molecular mechanics calculations performed on2 produce a low-energy conformation similar to that found in the crystal structure determination of2 with an energy barrier to ring rotation of ±5 kcal mol−1. A correlation of the structural and molecular mechanics data with the nmr spectra of complexes1 to3 indicates that the steric influence ofL on the ring rotation could be due to ring distortion and/or interaction with the ring methyl group.

Transition metal coordination compounds with the dithiooxalate ligand. Synthesis, spectroscopic studies, crystal structure, and bonding of (C5H5NH)2[Ni(S2C2O2)2]

Abstract: Several new compounds belonging to the family of bis(dithiooxalato)-nickelate(II) complex anion with the general formula (BH)2[Ni(S2C2O2)2], where B=pyridine, 3-methylpyridine, 3-ethylpyridine, 4-methylpyridine, and 4-ethylpyridine (hereafter abbreviated as PYNIDT, M3NIDT, E3NIDT, M4NIDT, and E4NIDT, respectively) have been prepared. PYNIDT, M3NIDT, and E3NIDT are isostructural between them and different from the two other compounds, M4NIDT and E4NIDT, which are also isostructural. All of these compounds crystallize in the monoclinic system, space groupP21/n withZ=2. Crystal parameters for PYNIDT are:a=5.793(3),b=14.280(5),c=11.222(3) A,β=97.29(4)°,V=920.8(9) A3,F(000)=468,D x =1.66,D o=1.65(1) Mg m−3,R=0.048, andR w =0.057 for 1236 observed reflections. The IR and UV-V spectra show that the organic bases are protonated and the anion presents the well-known spectrum for the bis(dithiooxalato)-nickelate(II) anions. Thermogravimetric studies indicate that the compounds are anhydrous. The structure solution of PYNIDT confirms that this compound contains discrete quasi-planar complex [Ni(S2C2O2)2]2− anions and (C5H5NH)+ planar cations linked through hydrogen bonds. The structure stacks into layers where the ions are associated into cation⋯anion⋯cation entities through bifurcated hydrogen bonds.

Crystal and molecular structure of tetraiodo (1,8-di-2-pyridyl-3,6-dithiaoctane-N,S,S′,N′)dimercury(II)

Abstract: The X-ray crystal structure of the title compound, [Hg2(C16H20N2S2)I4], has been determined. The crystals are monoclinic (space groupP21/c), with cell dimensionsa=15.016(2),b=6.201(3),c=15.273(2) A,β=115.18(1)°;V o =1287.0(7) A3,M r =1213.266,Z=4,D x =6.26mg m−3, MoKα radiation (graphite crystal monochromator, $$\bar \lambda = 0.71070 {\AA}$$ ),μ(MoKα)=336 cm−1,F(000)=4272, andT=290°K. The final conventionalR factor=0.054, andR w =0.062 for 2799 observed reflections. The structure was solved by Patterson and Fourier methods and refined by block-diagonal least-squares methods. The coordination around the mercury atoms is approximately tetrahedral, although with considerable distortion, with two iodine atoms and the N and S atoms of one-half of the ligand molecule.

Synthesis and molecular structure of [Al(CH3)2]2 [C10H22N4] [Al(CH3)3]2: condensation product of trimethylaluminum and a multidentate open-chain amine

Abstract: The crystalline condensation product [Al(CH3)2]2[C10H22N4][Al(CH3)3]2 is prepared from reaction of the multidentate open-chain amine 1,4-bis(3-aminopropyl)piperazine with trimethylaluminum in methylene chloride. The compound crystallized in the monoclinic space groupC2/c with unit cell parametersa=25.166(12),b=7.268(4),c=17.316(4) A,β=115.3(4)°, andDc=1.06 g cm−3 forZ=4. Least-squares refinement based on 1054 observed reflections with intensitiesI≥ 3σ(I) in the range 2<2θ<45° led to a finalR factor of 0.053 (Rw=0.064). The title compound resides on a crystallographic center of symmetry with independent Al-N distances of 1.889(5), 2.058(5), and 2.030(5) A.

Crystal and molecular structure of inner-chelatecis-1,7-dioxa-4,10-diazacyclododecane-4,10-diacetatocopper(II) dihydrate

Abstract: cis-1,7-Dioxa-4,10-diazacyclododecane-4,10-diacetato-copper(II) dihydrate crystallizes in the monoclinic space groupP21/n witha=11.318(2),b=12.129(2),c=12.160(2) A,β=110.09(1)°, andZ=4. The structure was solved by the heavy-atom technique, followed by full-matrix least-squares refinement with anisotropic thermal parameters for non-H atoms. The Cu(II) atom is in a very distorted octahedral environment, with two nitrogen and two oxygen atoms located approximately coplanar with Cu(II), and the two remaining oxygen atoms in apical positions forming an angle of about 147° at Cu(II). The 12-membered ring has noncrystallographicmm2 symmetry. Two five-membered rings containing acetato groups are located in acis arrangement relative to the macrocyclic ring.

Crystallographic study of restricted rotation ino-formanilides

Abstract: The crystal structures ofcis- andtrans-o-methylformanilide, of itscis-thio analogue, and oftrans-o-phenylformanilide have been studied with a view to clarifying the anomalously high barrier to rotation of the carbonyl group. The pair of resolved geometrical isomers is shown to be stabilized in the solid state primarily by hydrogen bonding. The increased barrier to rotation is inferred not to arise from mesomeric involvement of the carbonyl group, but from nuclear screening by the nitrogen lone pair.

Structural investigation of (Z)-N-acetyl-β(3′-pyridyl)-dehydroalanine methyl ester

Abstract: The crystal and molecular structure of the methyl ester of (Z)-N-acetyl-β(3′-pyridyl)-dehydroalanine [methylZ-2-acetamido-3(3′-pyridyl) propenoate] have been determined from three-dimensional X-ray data. Crystals are monoclinic, space groupP21]. The molecular [φ=−51.5(5),ψ=157.0(4)°] conformation is discussed making reference to previous experimental results of analogous amino acid derivatives (in particular, ethyl (Z)-N-acetyldehydrophenylalaninate) and theoretical predictions. On the basis of He(I) and He(II) photoelectron spectra, a similar conformation is proposed for the title molecule in the vapor phase also.

Crystal and molecular structure of 15-oxosparteine-N(1)-oxide perchlorate

Abstract: [C15H25N2O2 +·ClO 4 − ,M r =364.83, is monoclinic:P21,a=7.885(1),b=10.685(1),c=10.658(1) A,β=105.63(1)°,V c =864.8(2) A3,Z=2,D x =1.39(1)g cm−3, λ(CuKα)=1.54178 A,μ(CuKα)=21.4 cm−1,F(000)=388 e,T=292K,R=0.066 for 1205 unique reflections. The piperidine ringsA, B, C, andD have chair, chair, boat, and half-chair conformations, respectively. The quinolizidine system (ringsA/B) has atrans configuration. The cations are interconnected by a hydrogen bond O(N1)⋯O(C15) of 2.552(10) A into chains along [010]. Atoms C(12) and C(13) from ringD of the cation are disordered. Very high thermal parameters of the oxygen atoms of the perchlorate anion may indicate its orientational disorder.

Crystal and molecular structure of [Pd(η5-C5H5) (bis-1,2-diphenylphosphinoethane)] [CF3SO3]

Abstract: The crystal structure of the complex [Pd(η 5-C5 H5) (PPh2) CH2CH2PPh2]+ [CF3SO3]− has been determined from single crystal X-ray data and refined by least-squares methods toR=0.046. The monoclinic crystals have unit cell dimensionsa=9.832(3),b=12.104(4),c=13.765(4)A,β=111.22(3)°, space group P21, andz=2. In the cationic complex the palladium atom is coordinated to theη 5-cyclopentadienyl moiety and to the phoshorus atoms of the chelating diphosphine. The arrangement of the two phosphorus atoms and the centroid of the cyclopentadienyl ring is approximately trigonal.