Kristallstrukturen der selenid- bzw. sulfidverbrückten Gold(I)verbindungen [Se(AuPPh3)+3]PF6- und [S(AuPPh3)2] · CH2Cl2/Crystal Structures of the Selenide- and Sulphide-Bridged Gold(I) Complexes [Se(AuPPh3)3]+PF6- and [S(AuPPh3)2] · CH2Cl2

1982 ◽  
Vol 37 (8) ◽  
pp. 944-949 ◽  
Author(s):  
Cornelia Lensch ◽  
Peter G. Jones ◽  
George M. Sheldrick
Keyword(s):  
Crystal Structures ◽  
Structure Determination ◽  
Asymmetric Unit ◽  
Light Atom ◽  
X Ray ◽  
Ray Methods

Abstract The Compound [S(AUPPh3)2] · CH2Cl2 was prepared from Ph3PAuCl and H2S in CH2Cl2 and characterised by X-ray structure determination [P21/c, a = 1851.6(4), b = 2225.1(6), c = 880.3(2) pm, β = 96.32(1)°, Z = 4, R = 0.053]. A constrained refinement of the light atom positions was necessary because of pseudosymmetry. Ph3PAuPF6 reacts with Se(Sn)(CH3)3)2 to give [Se(AuPPh3)3]+PF6- which was also characterised by X-ray methods [P1̄, a = 1539.5(6), b = 1800.5(7), c = 2289.5(9) pm, α = 89.35(3), β = 72.44(3), γ = 69.75(3)°, Z = 4, R = 0.061]. There are two formula units in the asymmetric unit. Both structures show short Au···Au contacts (ca. 300-340 pm).

Influence of 3-{5-[4-(diethylamino)benzylidene]rhodanine}propionic acid on the conformation of 5-(4-chlorobenzylidene)-2-(4-methylpiperazin-1-yl)-3H-imidazol-4(5H)-one

2018 ◽  
Vol 74 (11) ◽  
pp. 1427-1433 ◽  
Author(s):  
Ewa Żesławska ◽  
Wojciech Nitek ◽  
Waldemar Tejchman ◽  
Jadwiga Handzlik
Keyword(s):  
Crystal Structures ◽  
Crystal Packing ◽  
Protonated Form ◽  
Acid Form ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Basic Form ◽  
Piperazine Ring ◽  
X Ray ◽  
Intermolecular Contacts

The arylidene–imidazolone derivatives are a group of compounds of great interest in medicinal chemistry due to their various pharmacological actions. In order to study the possible conformations of an arylidene–imidazolone derivative, two new crystal structures were determined by X-ray diffraction, namely (Z)-5-(4-chlorobenzylidene)-2-(4-methylpiperazin-1-yl)-3H-imidazol-5(4H)-one, C15H17ClN4O, (6), and its salt 4-[5-(4-chlorobenzylidene)-5-oxo-4,5-dihydro-3H-imidazol-2-yl]-1-methylpiperazin-1-ium 3-{5-[4-(diethylamino)benzylidene]-4-oxo-2-thioxothiazolidin-3-yl}propionate, C15H18ClN4O+·C17H19N2O3S2 −, (7). Both compounds crystallize in the space group P\overline{1}. The basic form (6) crystallizes with two molecules in the asymmetric unit. In the acid form of (6), the N atom of the piperazine ring is protonated by proton transfer from the carboxyl group of the rhodanine acid derivative. The greatest difference in the conformations of (6) and its protonated form, (6c), is observed in the location of the arylidene–imidazolone substituent at the N atom. In the case of (6c), the position of this substituent is close to axial, while for (6), the corresponding position is intermediate between equatorial and axial. The crystal packing is dominated by a network of N—H...O hydrogen bonds. Furthermore, the crystal structures are stabilized by numerous intermolecular contacts of types C—H...N and C—H...Cl in (6), and C—H...O and C—H...S in (7). The geometry with respect to the location of the substituents at the N atoms of the piperazine ring was compared with other crystal structures possessing an N-methylpiperazine moiety.

Structural Studies of Some o- and p-Nitrophenylcarbamates by IR Spectroscopy and X-Ray Diffraction

2008 ◽  
Vol 63 (12) ◽  
pp. 1402-1406
Author(s):  
Monika Simon ◽  
Carol Csunderlik ◽  
G. Jones
Keyword(s):  
Ir Spectroscopy ◽  
Crystal Structures ◽  
Ir Spectrum ◽  
Structural Studies ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray

N-Alkyl-o-nitrophenylcarbamates as solids present two carbonyl stretching bands in the region 1700 - 1800 cm−1 but similar N-alkyl-p-nitrophenylcarbamates have only one such band in the IR spectrum. In solution both kinds of carbamate present one carbonyl stretching band, but for the former, the splittings occur when the carbamates crystallize. Four crystal structures were analyzed by X-ray diffraction. The two ortho derivatives have more than one molecule in the asymmetric unit, which is consistent with the IR observations.

Zur Struktur und Dotierung von Selenosilikaten: die Kristallstruktur von Er2SeSiO4 und Er3,75Ca0,25Se2,75Cl0,25Si2O7 Structure and Doping of Seleno Silicates: the Crystal Structures of Er2SeSiO4 and Er3,75Ca0,25Se2,75Cl0,25Si2O7

1994 ◽  
Vol 49 (6) ◽  
pp. 733-740 ◽  
Author(s):  
Klaus Stöwe
Keyword(s):  
Crystal Structures ◽  
Structure Analysis ◽  
Rare Earths ◽  
Structure Determination ◽  
Lattice Parameters ◽  
Energy Dispersive ◽  
Space Group ◽  
X Ray ◽  
By Products

Well-shaped brown and pink isometric crystals were obtained as by-products of the synthesis of erbium selenides from the elements in evacuated and sealed silica ampoules with graphite inlets. They could be identified as erbium seleno mono- and disilicates by energy dispersive X-ray fluorescence and X-ray structure determination. The monosilicate Er2SeSiO4 crystallizes isotypically to Nd2SeSiO4 in the space group Pbcm with the lattice parameters a = 600.2(2), b = 688.0(2), c = 1075.2(2) pm and represents the second known seleno inosilicate of the rare earths. From X-ray structure analysis an isotypic relation between the disilicate Er3,75Ca0,25Se2,75Cl0,25Si2O7 and the compound Sm4S3Si2O7 was found, the former crystallizing in the space group I41/amd with the lattice parameters a - 1177.7(2) and c = 1376.5(2) pm. The doping o f the sorosilicate with the elements Ca and Cl originated from contam inations in the graphit inlets used in the procedure

Studies on Crown Ether Complexes. XXXI. Synthesis, Properties and Structure of the Complexes of Lighter Lanthanide Nitrates With (Z)-2,3-Diphenyl-1,4,7,10,13-pentaoxacyclopentadec-2-ene (Stilbeno-15-crown-5)

1993 ◽  
Vol 46 (11) ◽  
pp. 1817 ◽  
Author(s):  
TB Lu ◽  
N Tang ◽  
MY Tan ◽  
Y Liu ◽  
KB Yu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Monoclinic Space Group ◽  
Asymmetric Unit ◽  
Conductivity Measurements ◽  
X Ray ◽  
Elemental Analyses ◽  
Crown Ether Complexes ◽  
Synthesis Properties ◽  
Lanthanide Nitrates ◽  
Ray Methods

Complexes of the lighter lanthanide nitrates with stilbeno-15-crown-5 (L) have been prepared in ethyl acetate. These new complexes with the general formula Ln (NO3)3.L.H2O ( Ln = La, Ce , Pr, Nd ) have been characterized by means of elemental analyses, i.r . spectra, 1H n.m.r. spectra and conductivity measurements. The crystal structure of La(NO3)3.L has been determined by X-ray methods, and refined to a residual R 0.0513 for 4937 independent reflections with I ≥ 1.5σ(I). It crystallizes in the monoclinic space group P21/a with a 16.090(5), b 15.654(8), c 22.687(2) Ǻ, β 93.96(4)°, V 5700(4)Ǻ3, and Z 8. There are two independent La(NO3)3.L monomers in one asymmetric unit; in each the coordination number is 11.

Crystal Structures of Seven Terephthaldiamide Derivatives

2002 ◽  
Vol 57 (8) ◽  
pp. 914-921 ◽  
Author(s):  
P. G. Jones ◽  
J. Ossowski ◽  
P. Kus
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Layer Structure ◽  
Inversion Symmetry ◽  
Asymmetric Unit ◽  
X Ray ◽  
Layer Structures ◽  
Structure Determinations ◽  
Independent Molecules

N,N′-Dibutyl-terephthaldiamide (1), N,N′-dihexyl-terephthaldiamide (2), N,N′-di(tert-butyl)- terephthaldiamide (3), N,N,N′,N′-tetrabutyl-terephthaldiamide (4), 1,1′-terephthaloylbis- pyrrolidine (5), 1,1′-terephthaloyl-bis-piperidine (6), and 4,4′-terephthaloyl-bis-morpholine (7) have been synthesised and physicochemically characterised. The X-ray structure determinations reveal imposed inversion symmetry for compounds 1-6; compound 3 has two independent molecules with inversion symmetry in the asymmetric unit. Compounds 1-3 form classical hydrogen bonds of the type N-H···O=C, leading to a ribbon-like arrangement of molecules (1 and 2) or a layer structure (3). Compound 3 also displays a very short C-H···O interaction, a type of hydrogen bond that is also observed in compounds 4-7, which lack classical donors; thereby compounds 4-6 form layer structures and 7 a complex threedimensional network.

Über die Reaktion von C(NMe2)4 mit zweikernigen Übergangsmetallcarbonylen; Kristallstrukturen von [C(NMe2)3][Mn(CO)5] und [C(NMe2)3][Co(CO)4] / On the Reaction of C(NMe2)4 with Binuclear Transition Metal Carbonyls: Crystal Structures of [C(NMe2)3][Mn(CO)5] and [C(NMe2)3][Co(CO)4]

1991 ◽  
Vol 46 (3) ◽  
pp. 297-302 ◽  
Author(s):  
Wolfgang Petz ◽  
Frank Weller
Keyword(s):  
Transition Metal ◽  
Crystal Structures ◽  
Structure Determination ◽  
Metal Carbonyls ◽  
Space Group ◽  
X Ray ◽  
Transition Metal Carbonyls ◽  
C Nmr

The reactions of C(NMe2)4 (1) with Mn2(CO)10 or Co2(CO)8 in THF yield[C(NMe2)3][Co(CO)4] (3) and [C(NMe2)3][Mn(CO)5] (4), respectively. The compounds Co(CO)4NMe2 (5) and Mn(CO)5NMe2 (6) could not be found. With CH2Cl2 4 is quantitatively converted into [C(NMe2)3][Mn(CO)4Cl2] (7) as shown by IR and 13C NMR investigations. 3 and 4 were characterized by an X-ray structure determination. 3: Space group Pnma, Z = 4, a = 7.435(2), b = 10.79(2), c = 20.299(5)Å. 4: Space group C2/c, Z = 4, a = 11.378(2), b = 10.165(1), c = 14.533(1) Å; β = 103.37(1)°. The compounds form independent ions with no bonding interactions between cation and anion; the central CN3 unit of the [C(NMe2)3]+ cation in 3 and 4 is disordered.

Synthese und Kristallstrukturen der neuen Zinn-Chalkogen-Vierringe [{Cp(Ph3P)Ni}2Cl2Sn2E2] (E = Se, S) / Synthesis and Crystal Structures of the New Four-M em bered Tin-Chalcogen Rings [{Cp(Ph3P)Ni}2Cl2Sn2E2] (E = Se, S)

1997 ◽  
Vol 52 (5) ◽  
pp. 635-638 ◽  
Author(s):  
Harald Kraus ◽  
Kurt Merzweiler
Keyword(s):  
Crystal Structures ◽  
Structure Determination ◽  
Analogous Reaction ◽  
Analogous Structure ◽  
X Ray

Abstract [{Cp(Ph3P)Ni}SnCl3] reacts with Se(SiMe3)2 within several days to give [{Cp4(Ph3P)3Ni5Sn6Se9] (1). If the reaction is stopped after 16h, green crystals of the intermediate [{Cp(Ph3P)Ni}2Cl2Sn2Se2] (2) can be isolated. According to the X -ray structure determination, 2 consists of a planar Sn2Se2 ring with terminal {Cp(Ph3P)Ni} and Cl substituents in a trans arrangement. The analogous reaction of [{Cp(Ph3P)Ni}SnCl3] with S(SiMe3)2 leads to the sulfur derivative [{Cp(Ph3P)Ni}2Cl2Sn2S2] 3 which has an analogous structure.

scholarly journals Crystallographic studies of meteoric iron

1939 ◽  
Vol 238 (794) ◽  
pp. 393-421 ◽  
Keyword(s):  
Crystal Structures ◽  
X Ray ◽  
Cubic Lattice ◽  
Principal Axes ◽  
Ray Methods

The first study of meteoric iron by X-ray methods was undertaken at the instigation of Professor S. W. J. Smith, F.R.S. some years ago. This research (Young 1926) resulted not only in the determination of the crystal structures of two of the main constituents, kamacite and taenite, but also in the important discovery of the nature of the mutual orientations of these constituents when the meteorite exhibits a Widmanstätten structure. As is well known, the Widmanstätten figures in meteorites arise from the arrangement of kamacite lamellae on the planes of an octahedron, and for that reason a meteorite exhibiting these figures is generally referred to as an octahedrite. The kamacite lamellae, therefore, fix the {I I I}-planes of a hypothetical cubic lattice whose principal axes, XYZ , will be referred to as “ the axes of the octahedrite”.

Die Kristallstrukturen von Magnesiumdibromid-Diglym-Addukten / Crystal Structures of Magnesium Dibromide Diglyme Adducts

1994 ◽  
Vol 49 (10) ◽  
pp. 1448-1452 ◽  
Author(s):  
Nils Metzler ◽  
Heinrich Nöth ◽  
Martin Schmidt ◽  
Andreas Treitl
Keyword(s):  
Crystal Structures ◽  
Structure Determination ◽  
Mononuclear Complex ◽  
Common Edge ◽  
X Ray ◽  
Ether Solution ◽  
In Cis ◽  
Tetrahydrofuran Solution ◽  
Oxygen Atoms

Abstract(MgBr2·diglyme)2 (1) crystallized in low yield from an ether solution of the Grignard compound mesMgBr (mes = mesityl) on adding diglyme. It is more conveniently prepared from an ether solution of MgBr2 by addition of diglyme. The mixed solvate MgBr2·diglyme thf (2) crystallized from a diglyme/tetrahydrofuran solution of 1 after addition of ether. An X-ray structure determination of 1 reveals dimeric units containing hexacoordinated Mg atoms surrounded by three oxygen atoms and three bromide atoms, with each kind of atoms arranged in a meridional fashion. The two octahedral MgO3Br3 units share a common edge with two Br atoms. Compound 2 is a mononuclear complex with the Br atoms in cis-position. The diglyme ligand occupies meridional positions of a distorted MgBr2O4 octahedron.

Conformational study of the 3,6-dihydro-2H-1,4-oxazin-2-one fragment in 8-tert-butyl-7-methoxy-8-methyl-9-oxa-6-azaspiro[4.5]decane-2,10-dione stereoisomers

2017 ◽  
Vol 73 (7) ◽  
pp. 556-562
Author(s):  
Ewa Żesławska ◽  
Anna Jakubowska ◽  
Wojciech Nitek
Keyword(s):  
Amino Acids ◽  
Crystal Structures ◽  
Stereoselective Synthesis ◽  
Biologically Active ◽  
Asymmetric Unit ◽  
Conformational Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Natural Amino Acids ◽  
Heterocyclic Moiety

Unnatural cyclic α-amino acids play an important role in the search for biologically active compounds and macromolecules. Enantiomers of natural amino acids with a D configuration are not naturally encoded, but can be chemically synthesized. The crystal structures of two enantiomers obtained by a method of stereoselective synthesis, namely (5R,8S)-8-tert-butyl-7-methoxy-8-methyl-9-oxa-6-azaspiro[4.5]decane-2,10-dione, (1), and (5S,8R)-8-tert-butyl-7-methoxy-8-methyl-9-oxa-6-azaspiro[4.5]decane-2,10-dione, (2), both C14H21NO4, were determined by X-ray diffraction. Both enantiomers crystallize isostructurally in the space group P21, with one molecule in the asymmetric unit and with the same packing motif. The crystal structures are stabilized by C—H...O hydrogen bonds, resulting in the formation of chains along the [100] and [010] directions. The conformation of the 3,6-dihydro-2H-1,4-oxazin-2-one fragment was compared with other crystal structures possessing this heterocyclic moiety. The comparison showed that the title compounds are not exceptional among structures containing the 3,6-dihydro-2H-1,4-oxazin-2-one fragment. The planar moiety was more frequently observed in derivatives in which this fragment was not condensed with other rings.

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