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Ring Motifs (ring + motif)
Selected Abstracts"Tail,Tail Dimerization" of Ferrocene Amino Acid DerivativesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 25 2010Daniel Siebler Abstract Acid anhydrides of N-protected 1,-aminoferrocene-1-carboxylic acid (Fca) have been prepared and spectroscopically characterized (protection group Boc, Fmoc, Ac; 4a,4c). The structure of the Boc-derivative 4a has been determined by single-crystal X-ray crystallography. An intramolecular N,H···O hydrogen bond involving the carbamate units results in a ring structure containing the two ferrocene units, the anhydride moiety, and the hydrogen bond. In the crystal, the individual molecules are connected by intermolecular N,H···O hydrogen bonds of the carbamate unit. Experimental and theoretical studies suggest that the ring motif is also a dominant species in solution. Electronic communication across the anhydride moiety is found to be very weak as judged from electrochemical, spectroscopic, and theoretical experiments. [source] 4-Aminopyridinium 4-aminobenzoate dihydrate and 4-aminopyridinium nicotinateACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2009Samuel Robinson Jebas In the title compounds, 4-aminopyridinium 4-aminobenzoate dihydrate, C7H6NO2,·C5H7N2+·2H2O, (I), and 4-aminopyridinium nicotinate, C5H7N2+·C6H4NO2,, (II), the aromatic N atoms of the 4-aminopyridinium cations are protonated. In (I), the asymmetric unit is composed of two 4-aminopyridinium cations, two 4-aminobenzoate anions and four water molecules, and the compound crystallizes in a noncentrosymmetric space group. The two sets of independent molecules of (I) are related by a centre of symmetry which is not part of the space group. In (I), the protonated pyridinium ring H atoms are involved in bifurcated hydrogen bonding with carboxylate O atoms to form an R12(4) ring motif. The water molecules link the ions to form a two-dimensional network along the (10) plane. In (II), an intramolecular bifurcated hydrogen bond generates an R12(4) ring motif and inter-ion hydrogen bonding generates an R42(16) ring motif. The packing of adduct (II) is consolidated via N,H...O and N,H...N hydrogen bonds to form a two-dimensional network along the (10) plane. [source] The influence of sulfur substituents on the molecular geometry and packing of thio derivatives of N -methylphenobarbitalACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2009Alicja Janik The room-temperature crystal structures of four new thio derivatives of N -methylphenobarbital [systematic name: 5-ethyl-1-methyl-5-phenylpyrimidine-2,4,6(1H,3H,5H)-trione], C13H14N2O3, are compared with the structure of the parent compound. The sulfur substituents in N -methyl-2-thiophenobarbital [5-ethyl-1-methyl-5-phenyl-2-thioxo-1,2-dihydropyrimidine-4,6(3H,5H)-dione], C13H14N2O2S, N -methyl-4-thiophenobarbital [5-ethyl-1-methyl-5-phenyl-4-thioxo-3,4-dihydropyrimidine-2,6(1H,5H)-dione], C13H14N2O2S, and N -methyl-2,4,6-trithiophenobarbital [5-ethyl-1-methyl-5-phenylpyrimidine-2,4,6(1H,3H,5H)-trithione], C13H14N2S3, preserve the heterocyclic ring puckering observed for N -methylphenobarbital (a half-chair conformation), whereas in N -methyl-2,4-dithiophenobarbital [5-ethyl-1-methyl-5-phenyl-2,4-dithioxo-1,2,3,4-tetrahydropyrimidine-6(5H)-one], C13H14N2OS2, significant flattening of the ring was detected. The number and positions of the sulfur substituents influence the packing and hydrogen-bonding patterns of the derivatives. In the cases of the 2-thio, 4-thio and 2,4,6-trithio derivatives, there is a preference for the formation of a ring motif of the R22(8) type, which is also a characteristic of N -methylphenobarbital, whereas a C(6) chain forms in the 2,4-dithio derivative. The preferences for hydrogen-bond formation, which follow the sequence of acceptor position 4 > 2 > 6, confirm the differences in the nucleophilic properties of the C atoms of the heterocyclic ring and are consistent with the course of N -methylphenobarbital thionation reactions. [source] N -Cyclohexyl-2-[5-(4-pyridyl)-4-(p -tolyl)-4H -1,2,4-triazol-3-ylsulfanyl]acetamide dihydrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2006Muharrem Dinçer In the title compound, C22H25N5OS·2H2O, the molecules are stacked in columns running along the b axis. In this arrangemant, the molecules are linked to each other by a combination of one two-centre N,H,O hydrogen bond and four two-centre O,H,O hydrogen bonds containing two types of ring motif, viz.R44(10) and R33(11). In the crystal structure, centrosymmetric ,,, interactions between the triazole rings, with a distance of 3.691,(2),Å between the ring centroids, also affect the packing of the molecules. [source] Charge-assisted hydrogen-bonded supramolecular networks in acetoguanaminium hydrogen phthalate, acetoguanaminium hydrogen maleate and acetoguanaminium 3-hydroxypicolinate monohydrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2010Kaliyaperumal Thanigaimani In 2,4-diamino-6-methyl-1,3,5-triazin-1-ium (acetoguanaminium) hydrogen phthalate, C4H8N5+·C8H5O4,, (I), acetoguanaminium hydrogen maleate, C4H8N5+·C4H3O4,, (II), and acetoguanaminium 3-hydroxypicolinate monohydrate, C4H8N5+·C6H4NO3,·H2O, (III), the acetoguanaminium cations interact with the carboxylate groups of the corresponding anions via a pair of nearly parallel N,H...O hydrogen bonds, forming R22(8) ring motifs. In (II) and (III), N,H...N base-pairing is observed, while there is none in (I). In (II), a series of fused R32(8), R22(8) and R32(8) hydrogen-bonded rings plus fused R22(8), R62(12) and R22(8) ring motifs occur alternately, aggregating into a supramolecular ladder-like arrangement. In (III), R22(8) motifs occur on either side of a further ring formed by pairs of N,H...O hydrogen bonds, forming an array of three fused hydrogen-bonded rings. In (I) and (II), the anions form a typical intramolecular O,H...O hydrogen bond with graph set S(7), whereas in (III) an intramolecular hydrogen bond with graph set S(6) is formed. [source] 4-(3,5-Dimethyl-1H -pyrazol-4-ylmethyl)-3,5-dimethyl-1H -pyrazol-2-ium dihydrogen phosphate: a combined X-ray and DFT studyACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2010Dipak K. Hazra The molecular structure of the title salt, C11H17N4+·H2PO4,, has been determined from single-crystal X-ray analysis and compared with the structure calculated by density functional theory (DFT) at the BLYP level. The crystal packing in the title compound is stabilized primarily by intermolecular N,H...O, O,H...N and O,H...O hydrogen bonds and ,,, stacking interactions, and thus a three-dimensional supramolecular honeycomb network consisting of R42(10), R44(14) and R44(24) ring motifs is established. The HOMO,LUMO energy gap (1.338,eV; HOMO is the highest occupied molecular orbital and LUMO is the lowest unoccupied molecular orbital) indicates a high chemical reactivity for the title compound. [source] Hydrogen-bonded supramolecular motifs in pyrimethaminium 4-methylbenzoate, pyrimethaminium 3-hydroxypicolinate and pyrimethaminium 2,4-dichlorobenzoateACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2010Kaliyaperumal Thanigaimani In 2,4-diamino-5-(4-chlorophenyl)-6-ethylpyrimidin-1-ium (pyrimethaminium, PMNH) 4-methylbenzoate, C12H14ClN4+·C8H7O2,, (I), pyrimethaminium 3-hydroxypicolinate, C12H14ClN4+·C6H4NO3,, (II), and pyrimethaminium 2,4-dichlorobenzoate, C12H14ClN4+·C7H3Cl2O2,, (III), the PMNH cations interact with the carboxylate groups of the corresponding anion via nearly parallel N,H...O hydrogen bonds, forming R22(8) ring motifs. A description of the observed arrays of quadruple hydrogen bonds in (I) and (II) in terms of hydrogen donors and acceptors (the DA model), their graph-set motifs and the resulting supramolecular ladder is given. In (III), supramolecular chains along the b axis and helical chains along the a axis are formed via N,H...O hydrogen bonds involving the 2-amino and 4-amino groups of the PMNH cation, respectively. Weak Cl...Cl interactions are also found in (III). [source] A hydrogen-bonded ribbon in 6-amino-3-methyl-5-nitroso-2-(pyrrolidin-1-yl)pyrimidin-4(3H)-one monohydrate and hydrogen-bonded sheets in 6-amino-2-dimethylamino-3-methyl-5-nitrosopyrimidin-4(3H)-one monohydrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2009Fabían Orozco In each of 6-amino-3-methyl-5-nitroso-2-(pyrrolidin-1-yl)pyrimidin-4(3H)-one monohydrate, C9H13N5O2·H2O, (I), and 6-amino-2-dimethylamino-3-methyl-5-nitrosopyrimidin-4(3H)-one monohydrate, C7H11N5O2·H2O, (II), the interatomic distances indicate significant polarization of the electronic structures of the pyrimidinone molecules. In each compound, the organic component contains an intramolecular N,H...O hydrogen bond. The molecular components in (I) are linked by a combination of two-centre O,H...O, O,H...N and N,H...O hydrogen bonds and a three-centre O,H...(NO) hydrogen bond to form a broad ribbon containing five distinct ring motifs. In compound (II), three intermolecular hydrogen bonds, one each of the O,H...O, O,H...N and N,H...O types, link the molecules into sheets containing equal numbers of centrosymmetric R44(10) and R108(34) rings. [source] Hydrogen-bonded supramolecular motifs in 2-amino-4,6-dimethoxypyrimidinium picrate and pyrimethaminium picrate dimethyl sulfoxide solvateACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2009Kaliyaperumal Thanigaimani In the crystal structures of 2-amino-4,6-dimethoxypyrimidinium 2,4,6-trinitrophenolate (picrate), C6H10N3O2+·C6H2N3O7,, (I), and 2,4-diamino-5-(4-chlorophenyl)-6-ethylpyrimidin-1-ium (pyrimethaminium or PMN) picrate dimethyl sulfoxide solvate, C12H14ClN4+·C6H2N3O7,·C2H6OS, (II), the 2-amino-4,6-dimethoxypyrimidine and PMN cations are protonated at one of the pyrimidine N atoms. The picrate anion interacts with the protonated cations through bifurcated N,H...O hydrogen bonds, forming R21(6) and R12(6) ring motifs. In (I), Z, = 2. In (II), two inversion-related PMN cations are connected through a pair of N,H...N hydrogen bonds involving the 4-amino group and the uncharged N atom of the pyrimidine ring, forming a cyclic hydrogen-bonded R22(8) motif. In addition to the pairing, the O atom of the dimethyl sulfoxide solvent molecule bridges the 2-amino and 4-amino groups on both sides of the paired bases, resulting in a self-complementary ,DADA, array of quadruple hydrogen-bonding patterns. [source] Halide salts of antimigraine agents eletriptan and naratriptanACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2008K. Ravikumar Molecules of eletriptan hydrobromide monohydrate (systematic name: (1S,2R)-1-methyl-2-{5-[2-(phenylsulfonyl)ethyl]-1H -indol-3-ylmethyl}pyrrolidinium bromide monohydrate), C22H27N2O2S+·Br,·H2O, (I), and naratriptan hydrochloride (systematic name: 1-methyl-4-{5-[2-(methylsulfamoyl)ethyl]-1H -indol-3-yl}piperidinium chloride), C17H26N3O2S+·Cl,, (II), adopt conformations similar to other triptans. The C-2 and C-5 substituents of the indole ring, both of which are in a region of conformational flexibility, are found to be oriented on either side of the indole ring plane in (I), whilst they are on the same side in (II). The N atom in the C-2 side chain is protonated in both structures and is involved in the hydrogen-bonding networks. In (I), the water molecules create helical hydrogen-bonded chains along the c axis. In (II), the hydrogen bonding of the chloride ions results in macrocyclic R42(20) and R42(24) ring motifs that form sheets in the bc plane. This structural analysis provides an insight into the molecular structure,activity relationships within this class of compound, which is of use for drug development. [source] Hydrogen-bonded supramolecular motifs in 2-amino-4,6-dimethoxypyrimidinium 4-hydroxybenzoate monohydrate, 2-amino-4,6-dimethoxypyrimidinium 6-carboxypyridine-2-carboxylate monohydrate and 2-amino-4,6-dimethoxypyrimidinium hydrogen (2R,3R)-tartrate 2-amino-4,6-dimethoxypyrimidineACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2007Kaliyaperumal Thanigaimani In the crystal structures of the title compounds, C6H10N3O2+·C7H5O3,·H2O, (I), C6H10N3O2+·C7H4NO4,·H2O, (II), and C6H10N3O2+·C4H5O6,·C6H9N3O2, (III), the 2-amino-4,6-dimethoxypyrimidinium cation [abbreviated as (MeO)2 -Hampy+] interacts with the carboxylate group of the corresponding anion through a pair of nearly parallel N,H...O hydrogen bonds to form R22(8) ring motifs. In (I), the (MeO)2 -Hampy+ cation is centrosymmetrically paired through a pair of N,H...N hydrogen bonds involving the 2-amino group and a ring N atom forming an R22(8) motif. In (II), inversion-related R22(8) motifs (amino,pyrimidine,carboxylate motifs) are further bridged by N,H...O hydrogen bonds on either side forming a DDAA array of quadruple hydrogen bonds. This array is extended further on either side by Owater,H...Omethoxy hydrogen bonds, resulting in an array of six hydrogen bonds (ADDAAD). The water molecule plays a pivotal role, and five hydrogen-bonded fused rings are formed around the water molecule. In (III), the carboxy group of the tartrate anion interacts with the ring N atom and 2-amino group of the neutral (MeO)2 -ampy molecule through N,H...O and O,H...N hydrogen bonds. There is also an intramolecular O,H...O hydrogen bond in the tartrate anion. In all three crystal structures, C,H...O hydrogen bonds are observed. [source] Hydrogen-bonded chains of rings in 3-iodobenzaldehyde 2,4-dinitrophenylhydrazone and 4-iodobenzaldehyde 2,4-dinitrophenylhydrazone, and a three-dimensional framework in 4-iodobenzaldehyde 4-nitrophenylhydrazone generated by the combination of N,H,O and C,H,O hydrogen bonds with iodo,nitro interactionsACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2004Christopher Glidewell Molecules of 3- and 4-iodobenzaldehyde 2,4-dinitrophenylhydrazone, C13H9IN4O4, are both effectively planar. In the crystal structure of each compound, molecules are linked by a combination of N,H,O and C,H,O hydrogen bonds into complex chains of rings, containing four and three different ring motifs, respectively; neither compound contains any iodo,nitro interactions. In 3-iodobenzaldehyde 4-nitrophenylhydrazone, C13H10IN3O2, where the iodinated aryl ring is disordered over two sets of sites, the hydrogen bonds generate a chain of rings, while two independent I,O interactions generate a three-dimensional framework. [source] N,N,-Bis[tris(hydroxymethyl)methyl]ethanediamide: six O,H,O hydrogen bonds generate only a two-dimensional structureACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2001Jennifer N. Ross Molecules of the title compound, C10H20N2O8, adopt a conformation which is almost centrosymmetric. The molecules are disordered over two sets of sites with an occupancy ratio of 0.94:0.06. In the major form, there are two intramolecular O,H,O hydrogen bonds [O,O 2.756,(4) and 2.765,(4),Å; O,H,O 144 and 146°], in which the two amidic O atoms act as acceptors. In addition, there are four intermolecular O,H,O hydrogen bonds [O,O 2.650,(3),2.666,(3),Å; O,H,O 158,171°]; these link each molecule to six others in a continuous sheet structure which contains five distinct ring motifs, two of the S(7) type, two of the R(10) type and one of the R(22) type. [source] | ||||||||||