共查询到20条相似文献,搜索用时 15 毫秒
1.
Carl Henrik Grbitz 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(11):o810-o812
The asymmetric unit in the crystal structure of the title compound, C15H22N2O3·0.88H2O, contains two peptide molecules with completely different conformations. The structure is divided into hydrophobic and hydrophilic layers, with channels of water molecules at the layer interface. 相似文献
2.
Franois Loiseau Reinhard Neier Gaël Labat Helen Stoeckli‐Evans 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(11):o636-o638
In the title compound, C9H12Br2O3, a (tetrahydrofuran‐2‐ylidene)acetate, the double bond has the Z form. In the tetrahydrofuran group, the relative configuration of the Br atom in the 3‐position and the methyl group in the 5‐position is anti. The compound crystallizes with two independent molecules per asymmetric unit and, in the crystal structure, the individual molecules are linked to their symmetry‐equivalent molecules by C—H⋯O hydrogen bonds, so forming centrosymmetric hydrogen‐bonded dimers. 相似文献
3.
Carl Henrik Grbitz 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(6):o328-o330
The title compound, C20H21N3O3·0.75H2O, crystallizes as exceedingly thin fibers. The crystal packing arrangement is related to those of other hydrophobic dipeptides with phenylalanine residues, but the structure has pseudo‐tetragonal symmetry in an orthorhombic space group with four peptide molecules and three water molecules in the asymmetric unit. 相似文献
4.
Damon A. Parrish A. Alan Pinkerton 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(2):o80-o82
The title solvate of the steroid 17β‐estradiol (E2) with methanol and water, C18H24O2·0.67CH4O·0.33H2O, is the first E2 derivative to contain three crystallographically independent molecules in the asymmetric unit. The three steroid molecules, along with two methanol molecules and a water molecule, create a three‐dimensional hydrogen‐bonded system. Three‐sided columns are formed, with the estradiol molecules aligned lengthwise parallel to (101), and joined by solvent molecules at both hydrophilic ends. The three estradiol molecules differ slightly in their ring‐bowing angles, i.e. the angle between the mean plane of the A ring and that of the BCD ring; this angle ranges from 7.1 to 12.2°. 相似文献
5.
Arne Johansen Randi Midtkandal Heidi Roggen Carl Henrik Grbitz 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(4):o198-o200
The valine side chains in the crystal structure of the title compound [systematic name: 2‐(2‐ammonio‐3‐methylbutanamido)‐3‐hydroxypropanoate trihydrate], C8H16N2O4·3H2O, stack along an a axis of 4.77 Å to form hydrophobic columns surrounded by remarkable water/hydroxyl shells. The peptide main chains are connected by hydrogen bonds in two‐dimensional layers. The peptide molecules in each layer are related only by translation, and generate a very rare pattern. This is rendered possible through the formation of the shortest Cα—H·O(carboxylate) interaction ever recorded. 相似文献
6.
Carl Henrik Grbitz 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(12):o730-o732
The side chains of l ‐alanyl‐l ‐methionine hemihydrate, C8H16N2O3S·0.5H2O, form hydrophobic columns within a three‐dimensional hydrogen‐bond network that includes extended polymers of cocrystallized water molecules and Cα—H⋯S interactions. 相似文献
7.
Boris Shivachev Rosica Petrova Emilia Naydenova 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(8):o524-o526
The title compound [systematic name: 1′‐aminocyclohexanespiro‐4′‐imidazole‐2′,5′(3′H,4′H)‐dione], C8H13N3O2, has been synthesized and was found to crystallize in two different structures, both monoclinic and both with the same P21/c space group. In the first structure, there are two molecules in the asymmetric unit, one of which uses all of its hydrogen‐bond donors and acceptors and forms undulating layers, while the other forms chains propagating perpendicular to the layers. In the second structure, there is only one independent molecule and the packing is based on a chain structure mediated by hydrogen bonding between the hydantoin moieties and further grouped into hydrophilic layers separated by layers of the hydrophobic cyclohexyl groups. 相似文献
8.
John Nicolson Low Justo Cobo Braulio Insuasty Henry Insuasty Manuel Nogueras Adolfo Snchez 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(2):o103-o105
In both title compounds, i.e. 3‐methyl‐1,5‐diphenyl‐1,6,7,8‐tetrahydropyrazolo[3,4‐b][1,4]diazepine, C19H18N4, (I), and 5‐(4‐chlorophenyl)‐3‐methyl‐1‐phenyl‐1,6,7,8‐tetrahydropyrazolo[3,4‐b][1,4]diazepine, C19H17ClN4, (II), an N—H?N hydrogen bond links six molecules to form an R(30) ring. Compound (I) crystallizes in the R space group and (II) crystallizes in P with three molecules in the asymmetric unit. The molecule of (I) contains a disordered seven‐membered ring. 相似文献
9.
A. Subbiah Pandi D. Velmurugan S. Shanmuga Sundara Raj Hoong‐Kun Fun P. R. Seshadri D. Thirumalai 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(7):821-824
10‐(4‐Fluorophenyl)‐3,3,6,6,9‐pentamethyl‐3,4,6,7,9,10‐hexahydroacridine‐1,8(2H,5H)‐dione, C24H28FNO2, (I), crystallizes with two crystallographically independent molecules (which differ slightly in conformation), while 10‐(4‐fluorophenyl)‐9‐propyl‐3,3,6,6‐tetramethyl‐3,4,6,7,9,10‐hexahydroacridine‐1,8(2H,5H)‐dione, C26H32FNO2, (II), crystallizes with one molecule per asymmetric unit. In both structures, the central ring in the acridine moiety is in a sofa conformation, while the outer rings adopt intermediate half‐chair/sofa conformations. The central pyridine ring is orthogonal to the substituted phenyl ring. In both structures, the packing of the crystal is stabilized by C—H?O intermolecular hydrogen bonds. 相似文献
10.
Marius Bruvoll Selma Dizdarevic Nina Fimland Jasmina Hafizovic Carl Henrik Grbitz Helen Therese Kalfjs Kristian Vestli Alexander Krivokapic 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(1):o22-o25
The structures of the title dipeptides, C9H18N2O4·0.33H2O, C12H16N2O4 and C8H16N2O4S·0.34H2O, complete a series of investigations focused on l ‐Xaa‐l ‐serine peptides, where Xaa is a hydrophobic residue. All three structures are divided into hydrophilic and hydrophobic layers. The hydrophilic layers are thin for l ‐phenylalanyl‐l ‐serine, rendered possible by an unusual peptide conformation, and thick for l ‐isoleucyl‐l ‐serine and l ‐methionyl‐l ‐serine, which include cocrystallized water molecules on the twofold axes. 相似文献
11.
Carl Henrik Grbitz 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(8):o533-o536
The crystal structure of N‐(l ‐2‐aminobutyryl)‐l ‐alanine, C7H14N2O3, is closely related to the structure of l ‐alanyl‐l ‐alanine, both being tetragonal, while the retro‐analogue 2‐(l ‐alanylamino)‐l ‐butyric acid 0.33‐hydrate, C7H14N2O3·0.33H2O, forms a new type of molecular columnar structure with three peptide molecules in the asymmetric unit. 相似文献
12.
Eleonora Freire Sergio Baggio Juan Carlos Muoz Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(5):o259-o262
The structures of the mono‐ and sesquihydrates of 2,6‐bis(1H‐benzimidazol‐2‐yl)pyridine (bbip) are reported. Phase (I), C19H13N5·H2O, has one water and one bbip molecule in the asymmetric unit, while phase (II), C19H13N5·1.5H2O, has three water molecules and two bbip molecules in the asymmetric unit. The compounds exhibit very similar molecular geometries but different packing organizations, which result from intricate hydrogen‐bonding schemes. 相似文献
13.
eljko K. Jaimovi Zoran D. Tomi Gerald Giester Vukadin M. Leovac 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(10):m381-m383
In the crystal structure of the title complex, [Co(C6H8N3S)3], the CoIII atom is octahedrally coordinated by three monodeprotonated bidentate 3,5‐dimethyl‐1H‐pyrazole‐1‐thiocarboxamide ligands with two thiocarboxamide N atoms in axial positions. The asymmetric unit contains two molecules (A and B) and these molecules are arranged in chains in an alternating fashion connected by N—H⋯S interactions. 相似文献
14.
Canan Kazak Veysel T. Yilmaz Suleyman Servi Murat Koca Frank W. Heinemann 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(6):o348-o350
The title compounds, 1,3‐dibenzoylimidazolidine‐2‐thione, C17H14N2O2S, (I), and 1,3‐dibenzoyl‐3,4,5,6‐tetrahydropyrimidine‐2(1H)‐thione, C18H16N2O2S, (II), were obtained from the reactions of imidazolidine‐2‐thione and 1,4,5,6‐tetrahydropyrimidine‐2‐thiol, respectively, with benzoyl chloride. Compounds (I) and (II) contain, respectively, imidazolidinethione [C=S = 1.6509 (14) Å] and pyrimidinethione [C=S = 1.6918 (19) Å] moieties bonded to two benzoyl rings. The molecules of (I) exhibit C2 symmetry, the C=S bond lying along the twofold rotation axis, while the molecules of (II) have mirror symmetry (Cs). The imidazolidine ring in (I) is essentially planar, while the pyrimidine ring in (II) adopts a boat conformation. Molecules of (I) are linked by weak intermolecular C—H⋯O interactions, while molecules of (II) are held together by van der Waals interactions. 相似文献
15.
Alvaro B. Onofrio Eliezer Jger Tiago A. S. Brando Adailton J. Bortoluzzi Faruk Nome 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(5):o237-o239
The title compound (with the systematic name 2‐{[(1S)‐1‐(methoxycarbonyl)‐3‐methylbutyl]aminocarbonyl}benzoic acid), C15H19NO5, crystallizes in the monoclinic space group P21, with two independent molecules per asymmetric unit. The most notable difference between the two molecules is in the dihedral angles between the planes of the carboxyl group and the benzene ring, which are 3.5 (3) and 25.7 (1)°. This difference may account for the fact that two competing reactions are observed in aqueous solution, namely cyclization to form the imide N‐phthaloylleucine and hydrolysis of N‐(2‐carboxybenzoyl)‐l ‐leucine methyl ester to phthalic acid and leucine. 相似文献
16.
Nigel L. Pickett Oliver Just Donald G. VanDerveer William S. Rees 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(5):560-561
The title compound, [GaCl2(C3H10NSi)(C4H8O)], is the tetrahydrofuran‐coordinated monomer of the previously structurally characterized dimer [GaN(H)SiMe3Cl2]2. The title compound consists of discrete monomeric molecules with two crystallographically independent molecules within the unit cell. The crystal structure is composed of a Ga atom in a four‐coordinate tetrahedral arrangement, with Ga—N distances of 2.025 (3) and 2.026 (3) Å in the two independent molecules. 相似文献
17.
Yi‐Xun Zhang Shauntina H. Jackson Mohamed S. Rajab Frank R. Fronczek Steven F. Watkins 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(4):o219-o221
3β‐Hydroxy‐7‐drimen‐12,11‐olide hemihydrate, C15H22O3·0.5H2O, (I), has two sesquiterpene molecules and one water molecule in the asymmetric unit. The OH groups of both molecules and both H atoms of the water molecule are involved in near‐linear intermolecular hydrogen bonds, having O⋯O distances in the range 2.632 (3)–2.791 (2) Å. 3β‐Acetoxy‐7‐drimen‐12,11‐olide, C17H24O4, (II), has its ring system in very nearly the same conformation as the two molecules of (I). 相似文献
18.
John Nicolson Low Justo Cobo Manuel Nogueras Adolfo Snchez Braulio Insuasty Harlen Torres 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(1):o39-o41
2,2‐Dimethyl‐5‐[3‐(4‐methylphenyl)‐2‐propenylidene]‐1,3‐dioxane‐4,6‐dione, C16H16O4, crystallizes in the triclinic space group , with two molecules in the asymmetric unit. These molecules and a centrosymmetrically related pair, linked together by weak C—H?O hydrogen bonds, form a tetramer. 5‐[3‐(4‐Chlorophenyl)‐2‐propenylidene]‐2,2‐dimethyl‐1,3‐dioxane‐4,6‐dione, C15H13ClO4, also crystallizes in the triclinic space group , with one molecule in the asymmetric unit. Centrosymmetrically related molecules are linked together by weak C—H?O hydrogen bonds to form dimers which are further linked by yet another pair of centrosymmetrically related C—H?O hydrogen bonds to form a tube which runs parallel to the a axis. 相似文献
19.
Gloria A. Benavides Frank R. Fronczek Nikolaus H. Fischer 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):o131-o132
The title compound, stigmasta‐5,22‐dien‐3β‐ol hemihydrate, C29H48O·0.5H2O, previously thought to be the monohydrate, has two sterol molecules and one water molecule in the asymmetric unit. In both sterol molecules, the methyl group of the ethyl substituent at the end of the hydrocarbon chain is disordered over two sites. The OH group of molecule A donates a hydrogen bond to a water molecule and accepts a hydrogen bond from the OH group of molecule B. The OH group of molecule B accepts two hydrogen bonds from water molecules. 相似文献
20.
M. T. Duarte V. Gama S. Rabaa I. C. Santos 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(7):m278-m280
The title compound, [Fe(C10H15)2][Ni(C3OS4)2]·C4H8O or [Fe(Cp*)2][Ni(dmio)2]·THF, where [Fe(Cp*)2]+ is the decamethylferrocenium cation, dmio is the 2‐oxo‐1,3‐dithiole‐4,5‐dithiolate dianion and THF is tetrahydrofuran, crystallizes with two independent half‐anion units [one Ni atom is at the centre of symmetry (, , 0) and the other is at the centre of symmetry (, 0, )], one cation unit (located in a general position) and one THF solvent molecule in the asymmetric unit. The crystal structure consists of two‐dimensional layers composed of parallel mixed chains, where pairs of cations alternate with single anions. These layers are separated by sheets of anions and THF molecules. 相似文献