Primary to secondary sphere coordination of 18-crown-6 to lanthanide (III) nitrates: Structural analysis of [Pr(NO3)3-(18-crown-6)] and [M(NO3)3(OH2)3]·18-crown-6 (M=Y,Eu, Tb−Lu)

The direct reaction of hydrated lanthanide nitrate salts with 18-crown-6 in 31 CH₃CNCH₃OH has resulted in the isolation and structural characterization of [Pr(NO₃)₃(18-crown-6)] and [M(NO₃)₃(OH₂)₃]·18-crown-6 (M=Y, Eu, Tb–Lu). (The Eu and Yb analogs were confirmed with preliminary cell data only.) [Pr(NO₃)₃(18-crown-6)] is 12-coordinate icosahedral and crystallizes in the orthorhombic space group Pbca with (at 20°C)a=12.230(2),b=15.598(4),c=21.777(9)Å andD _calc=1.89 g cm^–3 forZ=8. The seven isostructural [Pr(NO₃)₃(18-crown-6)] complexes all contain 9-coordinate capped square antiprismatic metal centers hydrogen bonded via the bound water molecules to D_3d 18-crown-6 within the lattice to form hydrogen bonded polymeric chains. Each complex is orthorhombic Pnma with cell parameters as follows: M=Tb (20°C):a=15.242(6),b=14.253(11),c=11.070(6)Å,D _calc=1.83 g cm^–3 forZ=4; M=Dy (20°C):a=15.248(3),b=14.239(5),c=11.058(3)Å,D _calc=1.84 g cm^–3 forZ=4; M=Y (19°C):a=15.260(2),b=14.238(2),c=11.048(3) Å,D _calc=1.64 g cm^–3 for Z=4; M=Ho (20°C):a=15.226(4),b=14.208(15),c=11.028(3)Å,D _calc=1.86 g cm^–3 forZ=4; M=Er (20°C):a=15.250(3),b=14.208(7),c=11.028(3)Å,D _calc=1.87 g cm^–3 forZ=4; M=Tm (20°C):a=15.246(6),b=14.190(16),c=11.013(6) Å,D _calc=1.88 g cm^–3 forZ=4; M=Lu (21°C):a=15.244(9),b=14.158(6),c=10.980(7)Å,D _calc=1.90 g cm^–3 forZ=4.     

Crystal structures of two azo compounds, 2-methyl-2-(4-bromphenylazo)-1,3-indandione and 2-methyl-2-(4-ethoxyphenylazo)-1,3-indandione

In the two title compounds, the 2-methyl-1,3-dioxoindan-2-yl and 4-(brom; ethoxy) phenyl groups aretrans with respect to one another. The phenyl ring and the azo group are not coplanar in the two molecules. The five-membered rings of the two compounds adopt an envelope conformation. The crystallographic parameters are as follows: 2-Methyl-2-(4-bromphenylazo)-1,3-indandione (I): monoclinic, P2₁/a witha=8.098(2),b=14.442(2),c=12.554(1)Å, =100.55(2)^o, andD _calc=1.58 g cm^–3 forZ=4; 2-methyl-2-(4-ethoxyphenylazo)-1, 3-indandione (II): monoclinic, P2₁/a witha=8.258(2),b=14.449(1),c=13.559(2)Å, =101.19(1)^o, andD _calc=1.29 g cm^–3 forZ=4.     

Crystal structure of cyanocalix[4]arene methyl ether

The title compound has been prepared by the addition of bromocalix[4]arene methyl ether to CuCN in N-methylpyrrolidone. The crystals belong to the monoclinic space groupP2₁/n witha=13.591(3),b=24.778(5),c=11.057(3)Å,=93.58(2)°, andD _c=1.09 g cm^–3 forZ=4. Refinement based on 1118 observed reflections led to a finalR value of 0.085. The molecule exhibits the partial cone conformation.     

Preparation,spectral studies,and X-ray crystal structures of (16S, 17R, 20S)-3-oxo-16-hydroxy-25-nor-lanostan-24-oic lactone (II) and (16S, 17R, 20S)-4,16-dihydroxy-25-nor-3,4-seco-lanostan-3,24-dioic acid dilactone (III)

The crystal and molecular structures of the title compounds have been determined by direct methods, and refined to a finalR of 0.059 forII and 0.046 forIII. Both molecules crystallize in space group P2₁2₁2₁. The cell dimensions forII area=10.096(5),b=11.255(3),c=20.300(7) Å;Z=4,D _x=1.188 g cm^–3, (MoK)=0.70 cm^–1, while the cell dimensions forIII area=7.346(1),b=10.470(3),c=30.546(5) Å;Z=4,D _x=1.212 g cm^–3, (MoK)=0.74 cm^–1. The rings of the triterpene skeletons aretrans-cis-trans-cis connected. The conformations of both molecules are discussed. Also the preparation and the spectral data of (17R, 20S)-3,16-dioxo-25-nor-lanostan-24-oic acid (V) and (17R, 20S)-3,16,24-trioxo-25-hydroxy-16,24-seco-lanostan-25-acetate (VI) are given.     

Synthesis and X-ray structures of [H3O+·18-crown-6] n [MCl 4 n− ]; (M=Fe,n=1;M=Co,n=2); compounds which form liquid clathrates with aromatic solutions

The title compounds, [H₃O⁺·18-crown-6][FeCl ₄ ^– ] (1), and [H₃O⁺·18-crown-6]₂[CoCl ₄ ^2– ] (2), were prepared by air oxidation of Fe(CO)₅ for1, and Co₂(CO)₈ for2, in the presence of 18-crown-6, H₂O and HCl(g) in toluene. Liquid clathrates formed immediately for both species:1·4.3 C₇H₈ and2·3.7 C₇H₈.1 crystallizes in the orthorhombic space group P2₁ma witha=10.357(1),b=11.824(1),c=8.961(1) Å, andD _c=1.46 g cm^–3 forZ=2. Refinement based on 935 observed reflections led to a finalR value of 0.089.2 crystallizes in the monoclinic space group C2/c witha=16.225(1),b=11.522(1),c=20.136(1)Å, =97.75(2)^o, andD _c=1.37 g cm^–3 forZ=4. Refinement based on 1322 observed reflections led to a finalR value of 0.11.     

Crystal structures of two allotropic forms of Na2CoP2O7

Na₂CoP₂O₇ may be prepared in two allotropie forms:I, rose,M _r =278.85, triclinic, P1,a=9.735(2),b=10.940(3),c=12.289(4) Å,=148.78,=121.76(1), =68.38(2)°,V=566.8(2) ų,Z=4,D _meas=3.28(5) g cm^–3,D _calc=3.267 g cm^–3, (MoK)=0.71069 Å,=37.12 cm^–1, F(000)=540,T=298 K,R=5.4% for 2911 observed reflections; andII, blue,M _r =278.85, orthorhombic, P2₁cn,a=7.713(2) Å,b=10.271(4),c=15.378(6)°,V=1218.2(8) ų,Z=8,D _meas=3.06(5) g cm^–3,D _calc=3.040 g cm^–1, (MoK ) Å,=34.55 cm^–1, F(000)=1080,T=298 K,R=9.9% for 1450 observed reflections. Cobalt displays octahedral coordination to six oxygen atoms in the rose form whereas the metal coordination is tetrahedral in the blue form.     

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.     

Crystal and molecular structure of cyclotriveratrylene

Slow evaporation of a solution made from rigorously dried toluene and cyclotriveratrylene (CTV) has led to crystals of the guest-free CTV. These belong to the monoclinic space groupP2₁/n witha=12.582(3),b=9.575(5),c=19.738(5) Å,=95.15(2)°;D _c =1.26 g cm^–3 forZ=4. Refinement based on 1708 observed reflections led toR=0.045. The nine-membered ring of the CTV has the expected crown conformation.     

X-ray structure determination of a chiral synthon,essential for the synthesis of 25-2H-stigmasterol

Synthesis of sterols with varying side chains, including deuterium labeled stigmasterol and sitosterol may be performed via the Wittig-Horner coupling of a 22 aldehyde derived from stigmasterol and a suitable sulfoxide derivative of the side chain. The X-ray structure determination of this synthon have been performed since it is a crucial step in order to know the absolute configuration of the chiral carbon atoms. Crystallographic data were as follows:a=7.437(2),b=10.103(4),c=10.274(3)Å, =100.32(6)^o, =759.4 ų, space group P2₁ (No.4),Z=2,D _c=1.239 g cm^–3.     

Crystal and molecular structures of the 4-(1H)-pyridone (=L) lanthanide complexes {[GdL(NO3)3(H2O)]·CH3OH}2 and [DyL4(NO3)2](NO3) and of L2HNO3

The crystal structures of the title compounds have been determined by single crystal diffraction methods. Crystals of the dysprosium compound are monoclinic, space groupP2₁/c witha=14.133(4),b=13.438(5),c=14.401 (4)Å,=103.98(2)°,V=2654(1)ų,Z=4,D _c =1.82 g cm^–3, finalR=0.035. The Dy atom is eight-coordinate with a distorted dodecahedral coordination geometry involving two bidentate nitrate groups and four pyridone oxygen atoms. An erbium complex with analogous stoichiometry was also prepared but not structurally characterized. Crystals of the Gd compound are monoclinic, space groupP2₁/n, witha=11.226(2),b=9.075(2),c=16.737(3)Å,=93.88(3)°,V=1701(1)ų,Z=2,D _c =1.91 g cm^–3, finalR=0.042. Each Gd atom is bonded to one pyridone oxygen atom, a water molecule and three bidentate nitrate groups. An oxygen atom of one of the bidentate nitrates additionally serves to bridge pairs of Gd atoms so as to form a dinuclear complex in which each Gd atom is nine-coordinate with a tricapped trigonal prismatic geometry. Crystals of L₂HNO₃ are monoclinic, space groupI2/a witha=12.479(4),b=6.535(2),c=14.297(6)Å,=96.07(3)°,V=1159(1)ų,Z=4,D _c =1.45 g cm^–3, finalR=0.057. The pyridones are linked in pairs by very short (2.44 Å) symmetrical OHO hydrogen bonds. Each pair is further linked via a nitrate ion by means of N-HO(nitrate)H-N hydrogen bonds, so as to form an extended chevron-like pyridone-pyridone-nitrate-pyridone-pyridone array. Adjacent chains are linked via weak C-HO(NO₃) interactions.     

Asymmetric hetero-Diels-Alder reactions: X-ray structures of three novel chiral dihydropyrimidines

Three novel dihydropyrimidine compounds N8,6-di(4-nitrophenyl)-(3R)-ethyl-(7R)-methyl-5-oxo-2,3,6,7-tetrahydrooxazolo[3,2,c] pyrimidine-8-carboxamide (2), N8,6-di((4-methylphenyl)-sulfonyl)-(3R)-ethyl-5-oxo-(7R)-phenyl-2,3,6,7-tetrahydrooxazolo [3,2,c]pyrimidine-8-carboxamide (3) and N8,6-di ((4-methylphenyl)sulfonyl)-(3R)-ethyl-(7R)-methyl-5-oxo-2,3,6,7-tetrahydrooxazolo[3,2,c] pyrimidine-8-carboxamide (4) have been prepared (from 2-amino-1-butanol of 64.4% e.e.) and structurally characterized by X-ray crystallography. All three compounds contain stereogenic centers, but the crystal of (2) chosen was found to be racemic whilst those of (3) and (4) were found to be homochiral. Compound (2) crystallizes in the monoclinic space group P2₁/c, with a = 17.958(4), b = 12.431(2), c = 9.653(2) Å, = 96.20(3)°, U = 2142.3(7) ų, Z = 4, and D _c = 1.449 g cm^–3. Compounds (3) and (4) both crystallize in the monoclinic space group P2₁, with a = 9.349(2), b = 5.824(5), c = 26.513(8) Å, = 99.43(2)°, U = 1424.1(13) ų, Z = 2 and D _c = 1.389 g cm^–3 for (3), and a = 5.9526(9), b = 16.3521(10), c = 13.2263(11) Å, = 92.81(12)°, U = 1285.9(2) ų, Z = 2 and D _c = 1.378 g cm^–3 for (4).     

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.     

Crystal structure of a nucleoside analog: 9-(R)-[6-(R)-hydroxymethyl-1-oxa-4-thiacyclohexan-2-yl] adenine

The title compound (C₁₀H₁₃N₅O₂S,M _r=267.3) crystallizes in the orthorhombic space groupP2₁2₁2₁ witha=7.579(8),b=7.686(2) andc=20.941(4)Å,V=1220(1)ų,D _x=1.456 gm cm^–3,Z=4,=23.6 cm^–1,F(000)=560 andT=293 K. The structure was solved by direct methods and refined to aR value of 0.068 for 776 unique observed reflections. The oxathiane ring adopts a chair conformation. In the crystal structure the molecules are held together by hydrogen bonds and C-HO close contacts.     

Crystal and molecular structure of rubidium azidotrimethylaluminate,Rb[Al(CH3)3N3]

The crystal structure of rubidium azidotrimethylaluminate has been determined from three-dimensional counter data, and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP2₁/n, witha= 10.003(5),b=7.497(4),c= 11.806(5) Å, = 108.70(3) °, andD _c= 1.58 g cm⁼³ forZ=4. The finalR factor for 922 observed reflections is 0.049. The compound is not isostructural with its cesium analog. The aluminum atom is coordinated in a tetrahedral fashion, and the Al-N bond length is 1.944(8) Å.     

Complexes of azobisindoles with π-organic acceptors

Complexes of azobisindoles with tetracyanoethylene and tetracyanoquinodimethane were studied by UV-Vis, FT-IR, Raman, NMR and X-ray spectroscopies. FT-IR and Raman spectra, as well as X-ray analysis, gave useful information on the participation of various sites to the association, through analysis of CN and N=N vibrational modes, while UV-Vis and NMR spectra were less helpful. The crystal structure of complexes 1-ethyl-2-phenyl-3-(1-ethyl-2-phenyl-3-azoindole)indole/TCNE,3a and 1,2-diphenyl-3-(1,2-diphenyl-3-azoindole)indole/TCNQ,5b are reported. In the two complexes, the distances between donor and acceptor planes range between 3.4 and 3.5 Å; in3a tetracyanoethylene faces the phenyl ring of the indole, while in5b the superposition of tetracyanoquinodimethane with the donor is negligible. Compound3a,P–1,a=9.504(2),b=9.513(3),c=8.941(2) Å, =97.81(4), =103.38(3), =84.14(2)°,Z=2,D _calc=2.55 g cm^–3; compound5b,P–1,a=12.648(3),b=12.205(2),c=7.263(3) Å, =103.69(2), =91.23(3), =110.61(2)°,Z=2,D _calc=2.53 g cm^–3.     

Crystal structures of (η5-C5H4COMe)M(CO)3Me (M=Mo,W)

The crystal structures of ( ⁵-C₅H₄COMe)M(CO)₃Me (M=Mo,W) have been determined. They are not isostructural. M=Mo isP2₁/c,a=10.205(6),b=14.192(8),c=8.135(6) Å,=93.43(4)° andD(calc)=1.71 g cm^–3 forZ=4. M=WisP2₁/c,a=12.580(7),b=6.830(5),c=13.750(7) Å,=93.72(4)° andD(calc)=2.20 g cm^–3 forZ=4. Both have a four-legged piano stool geometry with the substituted carbon making the closest M-C( ⁵) approach. The methyl group in the M=W derivative is disordered between twotrans-ligand positions. The average bonding parameters for the more accurately determined Mo analog are: Mo-C()⁵)=2.34(3) Å, Mo-CO=1.98(2) Å, Mo-Me=2.304(4) Å.     

Crystal structures of p-chloro- and p-bromobenzaldehyde

p-Chloro- and p-bromobenzaldehyde form isomorphous monoclinic crystals, space groupP2 ₁/a. For p-Cl at –96°C,a=12.945(3),b=3.833(3),c=26.503(9) Å, =103.68(2)°,Z=8,V=1278(2) ų,Dx=1.461(2) g cm^–3, refinement on 2714 reflections,R=0.047. For p-Br at –96°C,a=12.754(5),b=3.919(3),c=27.317(12) Å, =103.28(3)°,Z=8,V=1329(2) ų,Dx=1.849(3) g cm^–3, refinement on 1519 reflections,R=0.062. The molecules do not differ significantly from planarity. They pack in stacks with Cl...Cl or Br...Br contacts at one end and CH...O contacts that are suggestive of hydrogen bonds at the other. There are no O...Cl or O...Br contacts.     

Crystal structures and properties of catena-μ-nitrato (7-amino-5-aza-4-methyl-3-hepten-2-onato) copper(II) and μ3-hydrox-otris(μ-8-amino-5-aza-4-methyl-3-octen-2-onato) tricopper(II) dinitrate

The products of monocondensation of penta-2,4,-dione with 1,2-diaminoethane, HAE, and with 1,3-diaminopropane, HAT, react with copper nitrate hemipentahydrate to give catena--nitrato (7-amino-5-aza-4-methyl-3-hepten-2-onato) copper(II), [Cu(AE)NO₃]_n and a mixture of ₃-hydroxo-tris (-8-amino-5-aza-4-methyl-3-octen-2-onato) tricopper(II) dinitrate [Cu₃(AT)₃OH]-(NO₃)₂ and [Cu(AT)NO₃]_x, respectively. The structure of [Cu(AE)NO₃]_n has been determined from 1601 diffractometer data and refined by least squares methods toR=0.0306. The compound crystallizes in the monoclinic space groupP2₁/a witha=16.856(3)Å,b=8.109(4)Å,c=7.518(3)Å,=90.15(2)°,D _c =1.725 g cm^–3,D _o=1.72 g cm^–3 andZ=4. Copper atoms in [Cu(AE)NO₃]_n are in a 4+1+1^* environment and are linked by the pseudobidentate and bridging nitrato group into infinite chains. The structure of [Cu₃(AT)₃OH](NO₃)₂ has been determined from 3178 diffractometer data and refined toR=0.0544. The compound crystallizes in the triclinic space groupP¯1 witha=11.918(2)Å,b=14.478(2)Å,c=11.501(3)Å,=98.04(2)°,=117.72(2)°, =99.80(1)°,D _c =1.580 g cm^–3,D _o=1.59 g cm^–3 andZ=2. The compound is associated in hexanuclear clusters due to hydrogen bonding interactions. Coordination about Cu is best described as square pyramidal. Magnetic susceptibility data indicate a weak antiferromagnetic exchange within the trinuclear core withJ=–14 cm^–1.     

Crystal structure of (E)-5-hydroxypyrrolizidin-3-one and (Z)-5-thioketalpyrrolizidin-3-one

The crystal structures of (E)-5-hydroxypyrrolizidin-3-one (2) and (Z)-5-thioketalpyrrolizidin-3-one (3) have been determined by single-crystal x-ray diffraction techniques and refined by full-matrix least squares. Molecule2 crystallizes in the monoclinic space groupP2₁/a(No. 14) witha=7.887(3) Å,b=9.788(5) Å,c=9.316(4) Å,=100.6(1), andZ=4. Molecule 3 crystallizes in the monoclinic space groupP2₁/c witha=12.947(14) Å,b=10.553(14) Å,c=9.629(14) Å,=101.4(1), andZ=4. The calculated density for both molecules is 1.33 g cm^–1. FinalR-factors were 5.1% for2 and 8.59% for3. The x-ray results showed that a change in configuration occurred in the reaction going from2 to3.     

Structure of 1-tris(trimethylsilyl)silyl-3,4,5,6-tetrakis(trimethylsilyl)cyclohex-1-ene

C₂₇H₆₈Si₈,1, monoclinic, P2₁/n;a=9.849(1)Å,b=22.599(3)Å,c=18.596(3)Å, =94.78(1)Å;Z=4,D _c=0.99 g cm^–3,R=035,R _w=0.044, GOF=1.73. Compound1 is obtained in one step by the reductive silylation of PhSiCl₃ in the presence of a large excess of Li metal and Me₃SiCl. The structure of1 has been studied by X-ray crystallography and solution phase NMR techniques.