O-atom Acceptors Research Articles

41-Azido-41-deoxyrapamycin

The title compound, C51H78N4O12, is a derivative of rapamycin, a triene macrolide anti­biotic mol­ecule isolated from Streptomyces hygroscopicus. The macrocyclic ring structure has 15 chiral centres, with one of the substituent hy­droxy groups giving an intra­molecular hydrogen bond to a ketone O-atom acceptor. The mol­ecules also form inter­molecular hy­droxy–ketone O—H⋯O hydrogen-bonding associations, giving one-dimensional chains extending along (010). The crystal has 108 Å3 solvent-accessible voids.

3-Carbamoyl-2,2-dimethylcyclopentane-1,1-dicarboxylic acid

In the title compound, C10H15NO5, the five-membered cyclo­pentane ring has an envelope conformation, with four atoms lying in a plane (mean deviation = 0.0213 Å), while the fifth atom deviates from this plane by 0.626 (2) Å. A three-dimensional structure is formed through N—H⋯O and O—H⋯O hydrogen bonds between the amide and carb­oxy­lic acid groups and both carb­oxy­lic acid and amide O-atom acceptors.

4-[(4-Aminophenyl)sulfonyl]aniline–3,5-dinitrobenzoic acid (1/1)

The title compound, C7H4N2O6·C12H12N2O2S, is a 1:1 cocrystal of the drug dapsone with 3,5-dinitro­benzoic acid. The dihedral angle between the two aromatic rings of the dapsone mol­ecule is 75.4 (2)°, and the dihedral angles between these rings and that of the 3,5-dinitro­benzoic acid are 64.5 (2) and 68.4 (2)°. A strong inter­molecular carb­oxy­lic acid O—H⋯Namine hydrogen bond is found, together with inter­molecular amine N—H⋯O hydrogen-bonding associations with carboxyl, nitro and sulfone O-atom acceptors. In addition, weak π–π inter­actions between one of the dapsone benzene rings and the 3,5-dinitro­benzoic acid ring [ring centroid separation = 3.774 (2) Å] results in a two-dimensional network structure.

4-(4-Aminophenylsulfonyl)aniline–1,3,5-trinitrobenzene (1/2)

The asymmetric unit of the title co-crystalline 1:2 adduct, C12H12N2O2·2C6H3N3O6, contains two independent mol­ecules of bis­(4-amino­phen­yl) sulfone (the drug Dapsone) and four mol­ecules of 1,3,5-trinitro­benzene and is extended into a two-dimensional hydrogen-bonded network structure through amino N—H⋯O hydrogen-bonding associations with nitro O-atom acceptors. In the two independent Dapsone mol­ecules, the inter-ring dihedral anges are 69.6 (3) and 63.63 (9)°. Aromatic π–π inter­actions are also found between one of the Dapsone aromatic rings and a trinitro­benzene ring [minimum ring centroid separation = 3.596 (3) Å]. A 4-amino­phenyl ring moiety of one of the Dapsone mol­ecules and two nitro groups of a trinitro­benzene are disordered in a 50:50 ratio.

4-(4-Bromophenyl)-1-(2,6-difluorobenzyl)-3-(3,4,5-trimethoxyphenyl)-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C24H20BrF2N3O3S, the triazole ring (r.m.s. deviation = 0.0107 Å) makes dihedral angles of 28.18 (14), 63.76 (14) and 77.01 (18)°, respectively, with the trimeth­oxy-, bromo-, and difluoro-substituted benzene rings. The C atoms of the meta meth­oxy groups are roughly coplanar with their ring [displacements = −0.289 (4) and 0.083 (7) Å], whereas the C atom of the para group is displaced [1.117 (3) Å]. In the crystal, inversion dimers linked by two pairs of C—H⋯O hydrogen bonds occur. The ring motif of the two hydrogen bonds to their symmetry-generated O-atom acceptors is R 2 2(8).

N′-(2-Hydroxybenzylidene)-3-methylbenzohydrazide

The title compound, C15H14N2O2, is the product of the reaction of 2-hy­droxy­benzaldehyde and 3-methyl­benzo­hydrazide. The dihedral angle between the substituted benzene rings is 19.5 (3)° and an intra­molecular O—H⋯N hydrogen bond generates an S(6) ring motif. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds to generate C(4) chains propagating in [001] and C—H⋯O inter­actions to the same O-atom acceptor reinforce the chains.

Poly[tetra-n-butylammonium [(μ5-benzene-1,3,5-tricarboxylato)(μ4-benzene-1,3,5-tricarboxylato)-μ3-hydroxido-trizincate] 0.25-hydrate

In the asymmetric unit of title coordination polymer, {(C16H36N)[Zn3(C9H3O6)2(OH)]·0.25H2O}n, there are three independent Zn2+ cations, two benzene-1,3,5-tricarboxyl­ate ligands and a μ3-bridging hydroxide group, together with a tetra-n-butyl­ammonium counter-cation and a partially occupied water molecule of solvation (occupancy 0.25). Each Zn ion is coordinated by three carboxyl­ate O atoms and one O atom from the bridging hydroxide ion, displaying a slightly distorted tetra­hedral stereochemistry [overall Zn—O range = 1.875 (3)–1.987 (2) Å]. An intra­molecular hydrogen bond involving the hydroxide H atom and a carboxyl­ate O-atom acceptor is also present in the complex unit. The bridging benzene-1,3,5-tricarboxyl­ate anions generate a three-dimensional framework structure.

Tuberostemoamide hemihydrate

In the crystal structure of the title compound {systematic name: (1′S,2R,2′R,3′S,6′R)-3′-ethyl-4-methyl-5H-5′-oxa-10′-aza­spiro­[furan-2,4′-tricyclo­[8.3.0.02,6]trideca­ne]-5,11′-dione hemihydrate}, C17H23NO4·0.5H2O, the asymmetric unit contains two mol­ecules of tuberostemoamide with similar conformations and one water mol­ecule. The tuberostemoamide mol­ecule is composed of one seven-membered ring (A) and three five-membered rings (B, C and D). Ring A exists in a chair conformation, both rings B and C exist in envelope conformations, and ring D is almost planar with a mean deviation of 0.0143 (4) Å in one molecule and 0.0095 (3) Å in the other.. The dihedral angles between the planes of rings C and D are 75.1 (3)° in one mol­ecule and 74.5 (3)° for the other. The solvent water mol­ecule links the tuberostemoamide mol­ecules through O—H⋯O(ketone) hydrogen bonds. Weak C—H⋯O inter­actions are also present, involving both the water mol­ecule and a heterocyclic ether O-atom acceptor.

Poly[tetra-μ-aqua-diaquatetrakis[μ-(E)-2-nitrocinnamato]tetrarubidium

In the structure of the title compound, [Rb4(C9H6NO4)4(H2O)6]n, the asymmetric unit comprises four rubidium cations, two of which have an RbO7 coordination polyhedron with a monocapped distorted octa­hedral stereochemistry and two of which have a distorted RbO6 octa­hedral coordination. The bonding about both the seven-coordinate cations is similar, comprising one monodentate water mol­ecule together with three bridging water mol­ecules and three carboxyl­ate O-atom donors, two of which are bridging. The environments around the six-coordinate cations are also similar, comprising a monodentate nitro O-atom donor, a bridging water mol­ecule and four bridging carboxyl­ate O-atom donors [overall Rb—O range = 2.849 (2)–3.190 (2) Å]. The coordination leads to a two-dimensional polymeric structure extending parallel to (001), which is stabilized by inter­layer water O—H⋯O hydrogen-bonding associations to water, carboxyl and nitro O-atom acceptors, together with weak inter-ring π–π inter­actions [minimum ring centroid–centroid separation = 3.5319 (19) Å].

(E)-N′-[1-(Thiophen-2-yl)ethylidene]benzohydrazide

The title compound, C13H12N2OS, was obtained from the condensation reaction of 2-acetyl­thio­phene and benzohydrazide. In the mol­ecule, the formohydrazide fragment is approximately planar (r.m.s deviation = 0.0146 Å) and the mean plane is oriented at dihedral angles of 24.47 (11) and 28.86 (13)°, respectively, to the phenyl and thio­phene rings. The thio­phene and phenyl rings make a dihedral angle of 53.21 (8)°. The benzamide fragment and thio­phene ring are located on the opposite sides of the C=N bond, showing an E conformation. Classical inter­molecular N—H⋯O hydrogen bonds and weak C—H⋯O inter­actions are present in the crystal structure: three such bonds occur to the same O-atom acceptor.

Poly[di-μ-aqua-bis-(μ-2-amino-4-nitro-benzoato)dicaesium

In the structure of title compound, [Cs2(C7H5N2O4)2(H2O)2]n, the asymmetric unit contains two independent Cs atoms comprising different coordination polyhedra. One is nine-coordinate, the other seven-coordinate, both having irregular configurations. The CsO9 coordination polyhedron comprises O-atom donors from three bridging water mol­ecules, one of which is doubly bridging, three from carboxyl­ate groups, and three from nitro groups, of which two are bidentate chelate bridging. The CsO6N coordination polyhedron comprises the two bridging water mol­ecules, one amine N-atom donor, one carboxyl­ate O-atom donor and four O-atom donors from nitro groups (two from the chelate bridges). The extension of the dimeric unit gives a three-dimensional polymeric structure, which is stabilized by both intra- and inter­molecular amine N—H⋯O and water O—H⋯O hydrogen bonds to carboxyl­ate O-atom acceptors, as well as inter-ring π–π inter­actions [minimum ring centroid–centroid separation = 3.4172 (15) Å].

5-(1H-Indol-3-ylmethylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione

In the title compound, C15H13NO4, the conjugated double-bond system between the two rings adopts a cis configuration and there is an intra­molecular indole–ketone C—H⋯O inter­action. The indole N—H group forms an inter­molecular hydrogen bond with a ketone O-atom acceptor, giving a chain structure along the ab direction. The O-heterocyclic ring adopts a boat conformation and makes a dihedral angle of 16.72 (6)° with the indole ring system.

Bis[dicyclohexyl(phenyl)phosphane-κP]silver(I) perchlorate dichloromethane monosolvate

In the title compound, [Ag{P(C6H11)2(C6H5)}2]ClO4·CH2Cl2, the AgI atom in the mononuclear complex cation is coordinated by two P atoms of the phosphane ligands [Ag—P = 2.3993 (4) and 2.4011 (4) Å; P—Ag—P = 177.473 (18)°] and the perchlorate anion acts as the counter-anion. There is an Ag⋯Operchlorate inter­action of 2.873 (2) Å, which contributes to the slightly non-linear bond angle about the AgI atom. Weak inter­molecular C—H⋯O hydrogen-bonding inter­actions involving phenyl, cyclo­hexyl and dichloro­methane H-atom donors and perchlorate O-atom acceptors contribute to the stabilization of the crystal structure.

2-(4-Aminophenyl)-1-phenyldiazenium 2,4,6-trinitrophenolate

In the title salt, C12H12N3 +·C6H2N3O7 −, the diazenyl group of the 4-(phenyl­diazen­yl)aniline mol­ecule is protonated and forms a hydrogen bond with the phenolate O-atom acceptor of the picrate anion. Structure extension occurs through two symmetrical inter-ion three-centre amine N—H⋯O,O′nitro hydrogen-bonding associations [graph set R 1 2(4)], giving a convoluted two-dimensional network structure.

Adamantan-1-aminium p-toluene-sulfonate.

There are two unique cations and anions in the asymmetric unit of the title mol­ecular salt, C10H15NH3 +·C7H7O3S−. In the crystal, all three hydrogen-bond donors of the protonated amine group make hydrogen-bond inter­actions with sulfonate O-atom acceptors, linking the cations and anions into chains parallel to the a axis. C—H⋯π inter­actions are also present.

Rac-Ammoniumcis-2-carboxycyclohexane-1-carboxylate

In the structure of the title compound, NH4 +·C8H11O4 −, the carboxyl and carboxyl­ate groups of the cation adopt C—C—C—O torsion angles of 174.9 (2) and −145.4 (2)°, respectively, with the alicyclic ring. The ammonium H atoms of the cations give a total of five hydrogen-bonding associations with carboxyl­ate O-atom acceptors of the anion which, together with a carboxyl O—H⋯Ocarboxyl­ate inter­action give sheet structures which lie in the (101) planes.

4-Carbamoylpiperidinium phenylacetate hemihydrate

The asymmetric unit of the title compound, C6H13N2O+·C8H7O2 −·0.5H2O, comprises two isonipecotamide cations, two phenyl­acetate anions and a water mol­ecule of solvation. The hydrogen-bonding environments for both sets of ion pairs are essentially identical with the piperidinium and amide ‘ends’ of each cation involved in lateral heteromolecular hydrogen-bonded cyclic N—H⋯O associations [graph set R 2 2(11)] which incorporate a single carboxyl O-atom acceptor. These cyclic motifs enclose larger R 5 5(21) cyclic systems, forming sheet substructures which lie parallel to (101) and are linked across b by the single water mol­ecule via water O—H⋯Oc (c = carboxylate) associations, giving a duplex-sheet structure.

Hydrogen bonding in the anhydrous 1:1 proton-transfer compounds of isonipecotamide with nitro-substituted benzoic acids: the salts of the three isomeric mononitrobenzoic acids and of 3,5-dinitrobenzoic acid

The structures of the anhydrous 1:1 proton-transfer compounds of isonipecotamide (piperidine-4-carboxamide) with the three isomeric mononitro-substituted benzoic acids and with 3,5-dinitrobenzoic acid, namely 4-carbamoylpiperidinium 2-nitrobenzoate, (I), 4-carbamoylpiperidinium 3-nitrobenzoate, (II), and 4-carbamoylpiperidinium 4-nitrobenzoate, (III), all C(6)H(13)N(2)O(+)·C(7)H(4)NO(4)(-), and 4-carbamoylpiperidinium 3,5-dinitrobenzoate, C(6)H(13)N(2)O(8)(+)·C(7)H(3)N(2)O(6)(-), (IV), respectively, have been determined at 200 K. All the salts form hydrogen-bonded structures, viz. three-dimensional in (I), two-dimensional in (II) and (III), and one-dimensional in (IV). Featured in the hydrogen bonding of three of these [(I), (II) and (IV)] is the cyclic head-to-head amide-amide homodimer motif [graph set R(2)(2)(8)] through a duplex N-H...O association, the dimer then giving structure extension via either piperidinium or amide H-atom donors and carboxylate O-atom and, in some examples [(II) and (IV)], nitro O-atom acceptors. In (I), the centrosymmetric amide-amide homodimers are expanded laterally through N-H...O hydrogen bonds via cyclic R(4)(2)(8) interactions, forming ribbons which extend along the c cell direction. These ribbons incorporate the 2-nitrobenzoate cations through centrosymmetric cyclic piperidine-carboxylate N-H...O associations [graph set R(4)(4)(12)], giving interconnected sheets in the three-dimensional structure. In (II), in which no amide-amide homodimer is present, duplex piperidinium-amide N-H...O homomolecular hydrogen-bonding associations [graph set R(2)(2)(14)] give centrosymmetric head-to-tail dimers. Structure extension occurs through hydrogen-bonding associations between both the amide H-atom donors and carboxylate and nitro O-atom acceptors, as well as a three-centre piperidinium-carboxylate N-H...O,O' cyclic R(1)(2)(4) association, giving the two-dimensional network structure. In (III), the centrosymmetric amide-amide dimers are linked through the two carboxylate O-atom acceptors of the anions via bridging piperidinium N-H...O,O'...H-N(amide) hydrogen bonds, giving the two-dimensional sheet structure which features centrosymmetric cyclic R(4)(4)(12) associations. In (IV), the amide-amide dimer is also centrosymmetric, with the dimers linked to the anions through amide-nitro N-H...O interactions. The piperidinium groups extend the structure into one-dimensional ribbons via N-H...O(carboxylate) hydrogen bonds. The structures reported here further demonstrate the utility of the isonipecotamide cation in molecular assembly. They also highlight the efficacy of the cyclic R(2)(2)(8) amide-amide hydrogen-bonding homodimer motif in this process and provide an additional homodimer motif type in the head-to-tail R(2)(2)(14) association.

Anhydrous 1:1 proton-transfer compounds of isonipecotamide with picric acid and 3,5-dinitrosalicylic acid: 4-carbamoylpiperidinium 2,4,6-trinitrophenolate and two polymorphs of 4-carbamoylpiperidinium 2-carboxy-4,6-dinitrophenolate

The structures of the anhydrous 1:1 proton-transfer compounds of isonipecotamide (piperidine-4-carboxamide) with picric acid and 3,5-dinitrosalicylic acid, namely 4-carbamoylpiperidinium 2,4,6-trinitrophenolate, C(6)H(13)N(2)O(+)·C(6)H(2)N(3)O(7)(-), (I), and 4-carbamoylpiperidinium 2-carboxy-4,6-dinitrophenolate [two forms of which were found, the monoclinic α-polymorph, (II), and the triclinic β-polymorph, (III)], C(6)H(13)N(2)O(+)·C(7)H(3)N(2)O(7)(-), have been determined at 200 K. All three compounds form hydrogen-bonded structures, viz. one-dimensional in (II), two-dimensional in (I) and three-dimensional in (III). In (I), the cations form centrosymmetric cyclic head-to-tail hydrogen-bonded homodimers [graph set R(2)(2)(14)] through lateral duplex piperidinium-amide N-H...O interactions. These dimers are extended into a two-dimensional network structure through further interactions with phenolate and nitro O-atom acceptors, including a direct symmetric piperidinium-phenol/nitro N-H...O,O cation-anion association [graph set R(1)(2)(6)]. The monoclinic polymorph, (II), has a similar R(1)(2)(6) cation-anion hydrogen-bonding interaction to (I) but with an additional conjoint symmetrical R(1)(2)(4) interaction as well as head-to-tail piperidinium-amide N-H...O,O hydrogen bonds and amide-carboxyl N-H...O hydrogen bonds, giving a network structure which includes large R(4)(3)(20) rings. The hydrogen bonding in the triclinic polymorph, (III), is markedly different from that of monoclinic (II). The asymmetric unit contains two independent cation-anion pairs which associate through cyclic piperidinium-carboxyl N-H...O,O' interactions [graph set R(1)(2)(4)]. The cations also show the zigzag head-to-tail piperidinium-amide N-H...O hydrogen-bonded chain substructures found in (II), but in addition feature amide-nitro and amide-phenolate N-H...O associations. As well, there is a centrosymmetric double-amide N-H...O(carboxyl) bridged bis(cation-anion) ring system [graph set R(4)(2)(8)] in the three-dimensional framework. The structures reported here demonstrate the utility of the isonipecotamide cation as a synthon with previously unrecognized potential for structure assembly applications. Furthermore, the structures of the two polymorphic 3,5-dinitrosalicylic acid salts show an unusual dissimilarity in hydrogen-bonding characteristics, considering that both were obtained from identical solvent systems.

Three-dimensional hydrogen-bonded structures in the guanidinium salts of the monocyclic dicarboxylic acidsrac-trans-cyclohexane-1,2-dicarboxylic acid (2:1, anhydrous), isophthalic acid (1:1, monohydrate) and terephthalic acid (2:1, trihydrate)

The structures of bis(guanidinium) rac-trans-cyclohexane-1,2-dicarboxylate, 2CH(6)N(3)(+)·C(8)H(10)O(4)(2-), (I), guanidinium 3-carboxybenzoate monohydrate, CH(6)N(3)(+)·C(8)H(5)O(4)(-)·H(2)O, (II), and bis(guanidinium) benzene-1,4-dicarboxylate trihydrate, 2CH(6)N(3)(+)·C(8)H(4)O(4)(2-)·3H(2)O, (III), all reveal three-dimensional hydrogen-bonded framework structures. In anhydrous (I), both guanidinium cations form classic cyclic R(2)(2)(8) N-H...O,O'(carboxylate) and asymmetric cyclic R(2)(1)(6) hydrogen-bonding interactions, while one cation forms an unusual enlarged cyclic interaction with O-atom acceptors of separate ortho-related carboxylate groups [graph set R(2)(2)(11)]. Cations and anions also associate across inversion centres, giving cyclic R(4)(2)(8) motifs. In the 1:1 guanidinium salt, (II), the cation forms two separate cyclic R(2)(1)(6) interactions, one with a carboxyl O-atom acceptor and the other with the solvent water molecule. The structure is unusual in that both carboxyl groups form short interanion O...H...O contacts, one across a crystallographic inversion centre [O...O = 2.483 (2) Å] and the other about a twofold axis of rotation [O...O = 2.462 (2) Å], representing shared sites on these elements for the single acid H atom. The water molecule links the cation-anion ribbon structures into a three-dimensional framework. In (III), the repeating molecular unit comprises a benzene-1,4-dicarboxylate dianion which lies across a crystallographic inversion centre, two guanidinium cations and two solvent water molecules (each set related by twofold rotational symmetry), and a single water molecule which lies on a twofold axis. Each guanidinium cation forms three types of cyclic interaction with the dianions: one R(2)(1)(6), the others R(3)(2)(8) and R(3)(3)(10) (both of these involving the water molecules), giving a three-dimensional structure through bridges down the b-cell direction. The water molecule at the general site also forms an unusual cyclic R(2)(2)(4) homodimeric association across an inversion centre [O...O = 2.875 (2) Å]. The work described here provides further examples of the common cyclic guanidinium-carboxylate hydrogen-bonding associations, as well as featuring other less common cyclic motifs.