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1.
Paul D. Robinson Hisham G. Lutfi Yuqing Hou Cal Y. Meyers 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(5):582-584
The preparation of sp‐9‐acetylfluorene from the reaction of 9‐fluorenyllithium with acetyl chloride also provided 9‐(1‐acetoxyethylidene)fluorene (`diacetylfluorene') and 1,1‐di(9‐fluorenyl)ethanol, (II), as by‐products recently characterized by X‐ray analysis. A third by‐product, 1,1‐di(9‐fluorenyl)ethyl acetate, (III), C30H24O2, has now been unequivocally identified for the first time, and emanates from the acetylation of the oxyanion of (II). In the asymmetric unit, compound (III) exists as two almost identical structures which differ slightly, but significantly, in conformation. Neither possesses the significant fluorene‐ring bowing or the perpendicularity of the two ring planes exhibited by (II). The angle between the least‐squares planes of the two fluorene rings of (III) is 58.45 (9) and 60.95 (10)°, respectively, for the two conformations, and their corresponding bonding parameters also differ slightly in a number of instances. 相似文献
2.
Yuqing Hou Paul D. Robinson Hisham G. Lutfi Cal Y. Meyers 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(4):428-430
Treatment of 9‐fluorenyllithium with acetyl chloride produces 9‐acetylfluorene, (I), and several by‐products, among which is `diacetylfluorene', now characterized definitively as 9‐(1‐acetoxyethylidene)fluorene [IUPAC name: (1‐fluoren‐9‐ylidene)ethyl acetate], (II), C17H14O2, derived from acetylation of initially formed (I). Various parameters disclose substantial structural distortion within (II) emanating from A(1,3) strain associated with the 9‐(acetoxyethylidenyl)fluorene system. 相似文献
3.
Cal Y. Meyers Hisham G. Lutfi Paul D. Robinson 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(9):e418-e419
The reaction of 9‐fluorenyllithium with acetyl chloride (tetrahydrofuran, 213 K, under argon) provided four products which we have isolated and whose structures we have unequivocally identified for the first time. That of the initially formed component, 9‐acetylfluorene (C15H12O), described here, shows it to be exclusively the sp rotamer in its crystalline form. The acetyl C—C=O plane is essentially perpendicular to the planar fluorene ring and there is no indication of rotational restriction. In contrast, related 9‐pivaloylfluorene, which we reported previously, is rotationally restricted and exists exclusively as its ap rotamer, in which the pivaloyl C—C=O plane is also almost perpendicular to the fluorene ring. 相似文献
4.
Anthony Linden Andreas Gebert Heinz Heimgartner 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(6):764-766
The tetrathiane ring of the title compound, C26H16S4, has a chair conformation and the molecule has approximate C2 symmetry. Each of the two fluorene ring systems is virtually planar, with the ring planes intersecting at an angle of 67.58 (5)°. This novel compound has been formed as a side product from the treatment of 9H‐fluorene‐9‐thione with methyl N‐[(benzylidene)phenyl]glycinate in the presence of LiBr and 1,6‐diazabicyclo[5.4.0]undecane. 相似文献
5.
Cal Y. Meyers Paul D. Robinson Aaron W. McLean 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(2):o156-o157
While the barriers of rotation of the sp and ap rotamers of 9‐(o‐methylphenyl)fluorene, C20H16, are sufficiently similar to permit them to equilibrate, both being observed (NMR) in solution, crystallization provides the sp rotamer, (I), exclusively. Although in the sp conformation the intramolecular distance between adjacent C atoms of the phenyl and fluorene rings is small [3.382 (4) Å, within 0.02 Å of the sum of the van der Waals radii], in the ap conformation the distance between the adjacent o‐CH3 group on the phenyl ring and C atom of the fluorene ring would be much closer, based on that exhibited in the crystalline ap progenitor 9‐(o‐methylphenyl)‐9‐fluorenol. The angle between the fluorene and 9‐aryl planes of (I) is 75.82 (10)°. 相似文献
6.
Shaune McFarlane Robert McDonald Jonathan G. C. Veinot 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(12):o671-o673
The title compound, C29H42, crystallizes from the melt as a triclinic crystal. The unit cell contains three crystallographically independent molecules. The three fluorene ring systems are oriented such that two non‐equivalent ring systems related by a roto‐translation are separated by a third ring system oriented orthogonally to them. The octyl chains of all three molecules are perpendicular to the fluorene ring system and force a 7.4 Å separation between the two coplanar molecules, thereby preventing molecular π‐stacking. 相似文献
7.
Jacek Zaleski Grzegorz Spaleniak Janusz B. Kyzio 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(9):o627-o629
The geometries of the thiazole ring and the nitramino groups in N‐(3H‐thiazol‐2‐ylidene)nitramine, C3H3N3O2S, (I), and N‐methyl‐N‐(thiazol‐2‐yl)nitramine, C4H5N3O2S, (II), are very similar. The nitramine group in (II) is planar and twisted along the C—N bond with respect to the thiazole ring. In both structures, the asymmetric unit includes two practically equal molecules. In (I), the molecules are arranged in layers connected to each other by N—H⋯N and much weaker C—H⋯O hydrogen bonds. In the crystal structure of (II), the molecules are arranged in layers bound to each other by both weak C—H⋯O hydrogen bonds and S⋯O dipolar interactions. 相似文献
8.
S. Thamotharan V. Parthasarathi P. Gupta D. P. Jindal P. Piplani Anthony Linden 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(8):o467-o469
The title compounds, 4‐(2‐naphthyloxymethylcarbonyl)morpholine, C16H17NO3, (I), and 4‐methyl‐1‐(2‐naphthyloxymethylcarbonyl)piperazine, C17H20N2O2, (II), are potential antiamnesics. The morpholine ring in (I) and the piperazine ring in (II) adopt chair conformations. In (I), the molecules are linked by weak intermolecular C—H⃛O interactions into chains that have a graph‐set motif of C(10), while in (II), the molecules are linked by weak intermolecular C—H⃛O interactions that generate two C(7) graph‐set motifs. The dihedral angle between the naphthalene moiety and the best plane through the morpholine ring is 20.62 (4)° in (I), while the naphthalene moiety is oriented nearly perpendicular to the mean plane of the piperazine ring in (II). 相似文献
9.
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
10.
Nobuhiro Yasuda Hidehiro Uekusa Yuji Ohashi 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):1364-1366
The crystal structures of two styrene analogues, 4‐vinylbenzoic acid, C9H8O2, (I), and 9‐vinylanthracene, C16H12, (II), were determined by X‐ray analyses at 108 and 293 K for (I) and at 123 and 293 K for (II). In (I), a pair of molecules around an inversion center form a dimer connected by two carboxyl groups. The anthracene planes of two molecules in (II) are antiparallel to each other around an inversion center. The vinyl group of (I) is almost coplanar with the phenyl ring, whereas the vinyl group of (II) is nearly perpendicular to the anthracene plane. In (I), the bond length of the vinyl group at 293 K is significantly shorter than that at 108 K [1.288 (2) versus 1.3248 (14) Å] suggesting a bias of the thermal motion, whereas the bond lengths are not so different between the two temperatures in (II) [1.3266 (15) versus 1.310 (2) Å]. 相似文献
11.
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
12.
Andrew P. J. Brunskill Roger A. Lalancette Hugh W. Thompson 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(9):1075-1078
The anhydrous form, (I), of the title compound, (?)‐2‐(1,2,3,4,4a,7‐hexahydro‐4a,8‐dimethyl‐1,7‐dioxo‐2‐naphthyl)propionic acid, C15H18O4, derived from a naturally occurring sesquiterpenoid, has two molecules in the asymmetric unit, (I) and (I′), differing in the conformations of the saturated ring and the carboxyl group. The compound aggregates as carboxyl‐to‐ketone hydrogen‐bonding catemers [O?O = 2.776 (3) and 2.775 (3) Å]. Two crystallographically independent sets of single‐strand hydrogen‐bonding helices with opposite end‐to‐end orientation pass through the cell in the b direction, one consisting exclusively of molecules of (I) and the other entirely of (I′). Three C—H?O=C close contacts are found in (I). The monohydrate, C15H18O4·H2O, (II), with two molecules of (I) plus two water molecules in its asymmetric unit, forms a complex three‐dimensional hydrogen‐bonding network including acid‐to‐water, water‐to‐acid, water‐to‐ketone, water‐to‐water and acid‐to‐acid hydrogen bonds, plus three C—H?O=C close contacts. In both (I) and (II), only the ketone remote from the acid is involved in hydrogen bonding. 相似文献
13.
Cal Y. Meyers Hisham G. Lutfi Pninit Varol Yuqing Hou Paul D. Robinson 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):1468-1470
Methylation of 9‐lithiated ap‐9‐pivaloylfluorene, (I), as well as pivaloylation of 9‐lithiated 9‐methylfluorene provided rotationally stable sp‐9‐methyl‐9‐pivaloylfluorene, (III), C19H20O, which lies about a crystallographic mirror plane. Fluorene (I) exists exclusively in the ap configuration in solution (NMR) as well as in the crystalline state, reflecting the unfavorable interaction between the tert‐butyl and fluorene‐ring π electrons in the sp configuration. The existence of (III) exclusively in the sp configuration indicates that, in this case, the interaction between the tert‐butyl group and the fluorene‐ring π electrons provides relatively more thermodynamic stability than the steric interaction between the tert‐butyl and 9‐methyl groups (ap configuration). 相似文献
14.
Markos M. Papadakis Jorge A. Pavon Roger A. Lalancette Hugh W. Thompson 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):o167-o170
The two δ‐keto carboxylic acids of the title, both C10H14O3, are epimeric at the site of carboxyl attachment. The endo (3α) epimer, (I), has its keto‐acid ring in a boat conformation, with the tilt of the carboxyl group creating conformational chirality. The molecules form hydrogen bonds by centrosymmetric pairing of carboxyl groups across the corners of the chosen cell [O⃛O = 2.671 (2) Å and O—H⃛O = 179 (2)°]. Two close intermolecular C—H⃛O contacts exist for the ketone. The exo (3β) epimer exists in the closed ring–chain tautomeric form as the lactol, 8‐hydroxy‐9‐oxatricyclo[5.3.1.03,8]undecan‐10‐one, (II). The molecules have conformational chirality, and the hydrogen‐bonding scheme involves intermolecular hydroxyl‐to‐carbonyl chains of molecules screw‐related in b [O⃛O = 2.741 (2) Å and O—H⃛O = 177 (2)°]. 相似文献
15.
Miroslav Zabadal Dominik Heger Marek Ne
as Petr Kln 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(2):o77-o79
The structures of the bichromophoric compounds N‐(1‐naphthylacetyl)glycine phenacyl ester, C22H19NO4, (I), and its oxygen analogue, phenacyl (1‐naphthylacetoxy)acetate, C22H18O5, (II), have been determined. The molecules of (I) are held together by intermolecular N—H⋯O hydrogen bonds between the carbonyl and N—H groups, while compound (II) does not show any hydrogen bonding in the crystal. 相似文献
16.
Onur ahin Orhan Büyükgüngr Selami amaz Nurhan Gümrüküolu Cihan Kantar 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(11):o643-o646
The title compounds, C10H12N4, (I), and C9H10N4, (II), have been synthesized and characterized both spectroscopically and structurally. The dihedral angles between the triazole and benzene ring planes are 26.59 (9) and 42.34 (2)°, respectively. In (I), molecules are linked principally by N—H⋯N hydrogen bonds involving the amino NH2 group and a triazole N atom, forming R44(20) and R24(10) rings which link to give a three‐dimensional network of molecules. The hydrogen bonding is supported by two different C—H⋯π interactions from the tolyl ring to either a triazole ring or a tolyl ring in neighboring molecules. In (II), intermolecular hydrogen bonds and C—H⋯π interactions produce R34(15) and R44(21) rings. 相似文献
17.
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
18.
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
19.
Alexander S. Lyakhov Andrey N. Vorobiov Pavel N. Gaponik Ludmila S. Ivashkevich Vadim E. Matulis Oleg A. Ivashkevich 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(12):o690-o693
In the molecules of 5‐amino‐1‐phenyltetrazole, C7H7N5, (I), and 5‐amino‐1‐(1‐naphthyl)tetrazole, C11H9N5, (II), the tetrazole rings and aryl fragments are not coplanar; corresponding dihedral angles are 50.58 (5) and 45.19 (7)° for the two independent molecules of (I), and 64.14 (5)° for (II). Intermolecular N—H⋯N hydrogen bonds between the amino groups and tetrazole N atoms are primarily responsible for formation of two‐dimensional networks extending parallel to the bc plane in both compounds. The presence of the amino group has a distinct effect on the geometry of the tetrazole rings in each case. 相似文献
20.
Anwar Usman Ibrahim Abdul Razak Hoong‐Kun Fun Suchada Chantrapromma Yan Zhang Jian‐Hua Xu 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(8):o477-o479
In the title compounds, C24H17NO3, (I), and C43H27NO5, (II), the dioxine ring is not planar and tends toward a boat conformation. The oxazoline ring adopts a twisted conformation in molecule (I) but is essentially planar in molecule (II). The configuration of the dioxine–oxazoline system is determined by the sp3 state of the two shared atoms. The phenanthrene moiety is nearly coplanar with the dioxine ring, while the phenyl ring is perpendicular to the attached oxazole ring. The triclinic unit cell of (II) contains two crystallographically independent molecules related by a pseudo‐inversion centre. 相似文献