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Hydrogen-bonded Dimers (hydrogen-bonded + dimer)

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Chemistry	100%

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A hydrogen-bonded dimer in 6-(4-bromophenyl)-3-methyl-1-phenyl-4,5-dihydro-1H -pyrazolo[3,4- b]pyridine and a chain of rings built from N,H...N and C,H...,(pyridine) hydrogen bonds in 3-(4-nitrophenyl)-4-phenyl-1H -pyrazolo[3,4- b]pyridine

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2010
Jairo Quiroga
In 6-(4-bromophenyl)-3-methyl-1-phenyl-4,5-dihydro-1H -pyrazolo[3,4- b]pyridine, C19H16BrN3, the reduced pyridine ring adopts a conformation that is close to a screw-boat form. Molecules are linked by pairs of symmetry-related C,H...,(arene) hydrogen bonds into cyclic centrosymmetric dimers. Molecules of 3-(4-nitrophenyl)-4-phenyl-1H -pyrazolo[3,4- b]pyridine, C18H12N4O2, are linked into centrosymmetric R22(8) dimers by pairs of symmetry-related N,H...N hydrogen bonds, and these dimers are linked by pairs of C,H...,(pyridine) hydrogen bonds to form a chain of edge-fused rings, or a molecular ladder, along [100]. The molecular aggregation in this compound is completed by two weak C,H...O hydrogen bonds, one of which links the chains along [100] into sheets. [source]

3-[5-(4-Chlorophenyl)-1-(4-methoxyphenyl)-1H -pyrazol-3-yl]propionic acid and the corresponding methyl ester

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2009
Isuru R. Kumarasinghe
The synthesis of 3-[5-(4-chlorophenyl)-1-(4-methoxyphenyl)-1H -pyrazol-3-yl]propionic acid, C19H17ClN2O3, (I), and its corresponding methyl ester, methyl 3-[5-(4-chlorophenyl)-1-(4-methoxyphenyl)-1H -pyrazol-3-yl]propionate, C20H19ClN2O3, (II), is regiospecific. However, correct identification of the regioisomer formed by spectroscopic techniques is not trivial and single-crystal X-ray analysis provided the only means of unambiguous structure determination. Compound (I) crystallizes with Z, = 2. The propionic acid groups of the two crystallographically unique molecules form a hydrogen-bonded dimer, as is typical of carboxylic acid groups in the solid state. Conformational differences between the methoxybenzene and pyrazole rings give rise to two unique molecules. The structure of (II) features just one molecule in the asymmetric unit and the crystal packing makes greater use than (I) of weak C,H...A interactions, despite the lack of any functional groups for classical hydrogen bonding. [source]

Synthesis and Reactivity of the Monomeric Late-Transition-Metal Parent Amido Complex [Ir(Cp*)(PMe3)(Ph)(NH2)]

CHEMISTRY - A EUROPEAN JOURNAL, Issue 16 2004
Daniela Rais Dr.
Abstract The late-transition-metal parent amido compound [Ir(Cp*)(PMe3)(Ph)(NH2)] (2) has been synthesized by deprotonation of the corresponding ammine complex [Ir(Cp*)(PMe3)(Ph)(NH3)][OTf] (6) with KN(SiMe3)2. An X-ray structure determination has ascertained its monomeric nature. Proton-transfer studies indicate that 2 can successfully deprotonate p -nitrophenylacetonitrile, aniline, and phenol. Crystallographic analysis has revealed that the ion pair [Ir(Cp*)(PMe3)(Ph)(NH3)][OPh] (8) exists as a hydrogen-bonded dimer in the solid state. Reactions of 2 with isocyanates and carbodiimides lead to overall insertion of the heterocumulenes into the NH bond of the Ir-bonded amido group, demonstrating the ability of 2 to act as an efficient nucleophile. Intriguing reactivity is observed when amide 2 reacts with CO or 2,6-dimethylphenyl isocyanide. ,4 -Tetramethylfulvene complexes [Ir(,4 -C5Me4CH2)(PMe3)(Ph)(L)] (L=CO (15), CNC6H3 -2,6-(CH3)2 (16)) are formed in solution through displacement of the amido group by the incoming ligand followed by deprotonation of a methyl group on the Cp* ring and liberation of ammonia. Conclusive evidence for the presence of the Ir-bonded ,4 -tetramethylfulvene moiety in the solid state has been provided by an X-ray diffraction study of complex 16. [source]

Crystal and molecular structures of atropisomeric N -aryl-1,2,3,4-tetrahydro-3,3-dimethyl-2,4-quinolinediones

HETEROATOM CHEMISTRY, Issue 3 2008
Mario Cetina
The crystal structures of N -aryl-1,2,3,4-tetrahydro-3,3-dimethyl-2,4-quinolinediones bearing methoxy- (1), methyl- (2), and chloro- (3) substituents in 2,-position of the phenyl ring have been determined by X-ray crystal structure analysis. The heterocyclic ring in 1,3 adopts an envelope conformation, with the smallest ring puckering in the ortho-chloro derivative 3. The N -aryl ring is almost perpendicular with respect to the quinoline-2,4-dione ring. The corresponding dihedral angle values are 83.2(1)°, 80.0(9)°, and 83.4(2)° in 1, 2 and 3, respectively. The hydrogen bond of CH,,,O type joins the molecules of the ortho-methoxy derivative 1 into dimers. The supramolecular structure also contains two CH,,,, interactions that link the hydrogen-bonded dimers into sheets. In ortho-methyl derivative 2, one CH,,,, interaction generates infinite chains, whereas two CH,,,O hydrogen bonds and three CH,,,, interactions in the ortho-chloro derivative 3 form three-dimensional framework. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:325,331, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20436 [source]

1-[2-(2,6-Diisopropylanilino)-1-naphthyl]isoquinoline

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2010
Ruth H. Howard
The molecule of the title compound, C31H30N2, contains a single intramolecular hydrogen bond, in contrast with the related N -methyl compound which exists as hydrogen-bonded dimers in the solid state [Cortright, Huffman, Yoder, Coalter & Johnston (2004). Organometallics, 23, 2238,2250]. Application of the density functional theory programs CASTEP and DMol3 allows accurate assignment of the location of the H atoms in the structure. [source]

Seven 5-benzylamino-3- tert -butyl-1-phenyl-1H -pyrazoles: unexpected isomorphisms, and hydrogen-bonded supramolecular structures in zero, one and two dimensions

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2009
Juan C. Castillo
5-Benzylamino-3- tert -butyl-1-phenyl-1H -pyrazole, C20H23N3, (I), and its 5-[4-(trifluoromethyl)benzyl]-, C21H22F3N3, (III), and 5-(4-bromobenzyl)-, C20H22BrN3, (V), analogues, are isomorphous in the space group C2/c, but not strictly isostructural; molecules of (I) form hydrogen-bonded chains, while those of (III) and (V) form hydrogen-bonded sheets, albeit with slightly different architectures. Molecules of 3- tert -butyl-5-(4-methylbenzylamino)-1-phenyl-1H -pyrazole, C21H25N3, (II), are linked into hydrogen-bonded dimers by a combination of N,H...,(arene) and C,H...,(arene) hydrogen bonds, while those of 3- tert -butyl-5-(4-chlorobenzylamino)-1-phenyl-1H -pyrazole, C20H22ClN3, (IV), form hydrogen-bonded chains of rings which are themselves linked into sheets by an aromatic ,,, stacking interaction. Simple hydrogen-bonded chains built from a single N,H...O hydrogen bond are formed in 3- tert -butyl-5-(4-nitrobenzylamino)-1-phenyl-1H -pyrazole, C20H22N4O2, (VI), while in 3- tert -butyl-5-(3,4,5-trimethoxybenzylamino)-1-phenyl-1H -pyrazole, C23H29N3O3, (VII), which crystallizes with Z, = 2 in the space group P, pairs of molecules are linked into two independent centrosymmetric dimers, one generated by a three-centre N,H...(O)2 hydrogen bond and the other by a two-centre N,H...O hydrogen bond. [source]

Three substituted (Z)-5-benzylidene-2-thioxothiazolidin-4-ones: hydrogen-bonded dimers that can be effectively isolated or linked into chains either by aromatic ,,, stacking interactions or by dipolar carbonyl,carbonyl interactions

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2006
Paula Delgado
In each of the isomeric compounds (Z)-5-(2-fluorobenzylidene)-2-thioxothiazolidin-4-one, C10H6FNOS2, (I), and (Z)-5-(4-fluorobenzylidene)-2-thioxothiazolidin-4-one, C10H6FNOS2, (II), there is a very wide C,C,C angle (ca 130°) at the methine C atom linking the two rings. In each isomer, paired N,H,O hydrogen bonds link the molecules into centrosymmetric R22(8) dimers; the hydrogen-bonded dimers are linked into chains by an aromatic ,,, stacking interaction in isomer (I) and by an antiparallel dipolar carbonyl,carbonyl interaction in isomer (II). (Z)-5-(3,4,5-Trimethoxybenzylidene)-2-thioxothiazolidin-4-one, C13H13NO4S2, (III), which crystallizes with Z, = 2 in the space group P, shows the same very wide angle at the bridging methine C atom; the two independent molecules are linked into an isolated dimer having no crystallographic symmetry. [source]

Four 2-aryl-8,8-dimethyl-6,7,8,9-tetrahydropyrazolo[2,3- a]quinazolin-6-ones: isolated molecules, hydrogen-bonded dimers, and ,-stacked chains of hydrogen-bonded dimers

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2006
Silvia Cruz
In each of the three compounds 2-(4-chlorophenyl)-5,8,8-trimethyl-6,7,8,9-tetrahydropyrazolo[2,3- a]quinazolin-6-one, C19H18ClN3O, (I), 2-(4-methoxyphenyl)-5,8,8-trimethyl-6,7,8,9-tetrahydropyrazolo[2,3- a]quinazolin-6-one, C20H21N3O2, (II), and 8,8-dimethyl-2-(4-methylphenyl)-6,7,8,9-tetrahydropyrazolo[2,3- a]quinazolin-6-one monohydrate, C19H19N3O·H2O, (IV), the non-aromatic carbocyclic ring adopts a half-chair conformation, while in 2-(4-chlorophenyl)-8,8-dimethyl-5-phenyl-6,7,8,9-tetrahydropyrazolo[2,3- a]quinazolin-6-one, C24H20ClN3O, (III), the corresponding ring adopts a conformation intermediate between the envelope and screw,boat forms. The structure of (I) consists of isolated molecules, while that of (II) contains dimers formed by C,H,O hydrogen bonds. In (III), dimers formed by C,H,O hydrogen bonds are linked into chains by means of an aromatic ,,, stacking interaction, while in the monohydrate, (IV), the heterocyclic molecules and the water molecules are linked by O,H,O and O,H,N hydrogen bonds to form centrosymmetric four-component aggregates. [source]

Tripotassium tris(oxalato-,2O,O,)aluminate bis(hydrogen peroxide) hydrate, the first example of a cyclic hydrogen-bonded H2O2 dimer

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2003
Sunil Chohan
In addition to associating into cyclic hydrogen-bonded dimers [O,O = 2.663,(1) and 2.914,(1),Å], each hydrogen peroxide molecule in the title structure, K3[Al(C2O4)3]·1.75H2O2·0.25H2O, hydrogen bonds to a neighbouring oxalate ligand [O,O = 2.700,(1) and 2.730,(1),Å] and coordinates to two K+ ions [K,O = 2.6620,(9),2.8380,(7),Å]. [source]

Calix[4]arene-Based Bis[2]catenanes: Synthesis and Chiral Resolution

CHEMISTRY - A EUROPEAN JOURNAL, Issue 21 2007
Olena Molokanova
Abstract The exclusive formation of hydrogen-bonded dimers between tetraaryl and tetratosylurea calix[4]arenes has been used to prepare a series of ten "bisloop" tetraurea calix[4]arenes 3, in which adjacent phenylurea groups are covalently linked through ,,,-dioxyalkane chains. This dimerization with tetratosylurea 2 as template preorganizes the alkenyl residues of tetra(m -alkenyloxyphenyl) ureas 1 and enables their selective connection in high yield (up to 95,%) by olefin metathesis followed by hydrogenation. The "bisloop" calixarenes 3 also exclusively form heterodimers with 1. Thus, in a separated metathesis/hydrogenation sequence, a series of 14 cyclic bis[2]catenanes 4, in which two calix[4]arenes are connected through their wide rims by two pairs of interlocked rings (total size 29 to 41 atoms), were prepared in yields of up to 97,%. Optical resolution of these chiral bis[2]catenanes was studied by HPLC on chiral stationary phases. The single-crystal X-ray structure of one example (4(P,10)) confirmed the interlocking rings and revealed that the hydrogen-bonded dimeric capsule of the calix[4]arene can be "completely" opened. [source]