Associations of squaric acid and its anions as multiform building blocks of hydrogen-bonded molecular crystals

2001 ◽  
Vol 57 (6) ◽  
pp. 859-865 ◽  
Author(s):  
Gastone Gilli ◽  
Valerio Bertolasi ◽  
Paola Gilli ◽  
Valeria Ferretti
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Engineering ◽  
Negative Charge ◽  
Three Dimensional ◽  
Molecular Crystals ◽  
Building Blocks ◽  
Squaric Acid ◽  
Orthosilicic Acid ◽  
Molecular Plane ◽  
Dimensional Crystal

Squaric acid, H2C4O4 (H2SQ), is a completely flat diprotic acid that can crystallize as such, as well as in three different anionic forms, i.e. H2SQ·HSQ−, HSQ− and SQ2−. Its interest for crystal engineering studies arises from three notable factors: (i) its ability of donating and accepting hydrogen bonds strictly confined to the molecular plane; (ii) the remarkable strength of the O—H...O bonds it may form with itself which are either of resonance-assisted (RAHB) or negative-charge-assisted [(−)CAHB] types; (iii) the ease with which it may donate a proton to an aromatic base which, in turn, back-links to the anion by strong low-barrier N—H+...O1/2− charge-assisted hydrogen bonds. Analysis of all the structures so far known shows that, while H2SQ can only crystallize in an extended RAHB-linked planar arrangement and SQ2− tends to behave much as a monomeric dianion, the monoanion HSQ− displays a number of different supramolecular patterns that are classifiable as β-chains, α-chains, α-dimers and α-tetramers. Partial protonation of these motifs leads to H2SQ·HSQ− anions whose supramolecular patterns include ribbons of dimerized β-chains and chains of emiprotonated α-dimers. The topological similarities between the three-dimensional crystal chemistry of orthosilicic acid, H4SiO4, and the two-dimensional one of squaric acid, H2C4O4, are finally stressed.

Biguanide and squaric acid as pH-dependent building blocks in crystal engineering

CrystEngComm ◽  
2014 ◽  
Vol 16 (46) ◽  
pp. 10631-10639 ◽  
Author(s):  
Mihaela-Diana Şerb ◽  
Irmgard Kalf ◽  
Ulli Englert
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Engineering ◽  
Building Blocks ◽  
Squaric Acid ◽  
Protonation Equilibria ◽  
Crystallization Experiments ◽  
Ph Dependent

Biguanides and squaric acid are attractive partners for crystal engineering: they incorporate multiple sites that can donate or accept hydrogen bonds. Protonation equilibria in their solutions and the outcome of crystallization experiments are pH dependent: 10 different salts have been obtained from N,N-dimethylbiguanide, N-phenylbiguanide and N-o-tolylbiguanide.

Reaction-path calculations and crystal structures of 1,1′-(ethylene-1,2-diyl)dipyridinium dichloride dihydrate and 1,1′-(ethylene-1,2-diyl)dipyridinium dibromide

2016 ◽  
Vol 72 (2) ◽  
pp. 112-118
Author(s):  
Mwaffak Rukiah ◽  
Mahmoud M. Al-Ktaifani ◽  
Mohammad K. Sabra
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Engineering ◽  
Materials Science ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Substitution Reactions ◽  
Nucleophilic Substitutions ◽  
Triclinic Space Group ◽  
Pyridinium Bromide ◽  
Multinuclear Nmr Spectroscopy

The design of new organic–inorganic hybrid ionic materials is of interest for various applications, particularly in the areas of crystal engineering, supramolecular chemistry and materials science. The monohalogenated intermediates 1-(2-chloroethyl)pyridinium chloride, C5H5NCH2CH2Cl+·Cl−, (I′), and 1-(2-bromoethyl)pyridinium bromide, C5H5NCH2CH2Br+·Br−, (II′), and the ionic disubstituted products 1,1′-(ethylene-1,2-diyl)dipyridinium dichloride dihydrate, C12H14N22+·2Cl−·2H2O, (I), and 1,1′-(ethylene-1,2-diyl)dipyridinium dibromide, C12H14N22+·2Br−, (II), have been isolated as powders from the reactions of pyridine with the appropriate 1,2-dihaloethanes. The monohalogenated intermediates (I′) and (II′) were characterized by multinuclear NMR spectroscopy, while (I) and (II) were structurally characterized using powder X-ray diffraction. Both (I) and (II) crystallize with half the empirical formula in the asymmetric unit in the triclinic space groupP\overline{1}. The organic 1,1′-(ethylene-1,2-diyl)dipyridinium dications, which display approximateC2hsymmetry in both structures, are situated on inversion centres. The components in (I) are linkedviaintermolecular O—H...Cl, C—H...Cl and C—H...O hydrogen bonds into a three-dimensional framework, while for (II), they are connectedviaweak intermolecular C—H...Br hydrogen bonds into one-dimensional chains in the [110] direction. The nucleophilic substitution reactions of 1,2-dichloroethane and 1,2-dibromoethane with pyridine have been investigated byab initioquantum chemical calculations using the 6–31G** basis. In both cases, the reactions occur in two exothermic stages involving consecutive SN2 nucleophilic substitutions. The isolation of the monosubstituted intermediate in each case is strong evidence that the second step is not fast relative to the first.

scholarly journals Crystal structures of 2-aminopyridine citric acid salts: C5H7N2 +·C6H7O7 − and 3C5H7N2 +·C6H5O7 3−

2018 ◽  
Vol 74 (8) ◽  
pp. 1111-1116 ◽  
Author(s):  
Shet M. Prakash ◽  
S. Naveen ◽  
N. K. Lokanath ◽  
P. A. Suchetan ◽  
Ismail Warad
Keyword(s):  
Hydrogen Bond ◽  
Citric Acid ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Crystal Engineering ◽  
Molecular Conformation ◽  
Crystal Packing ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Almost All

2-Aminopyridine and citric acid mixed in 1:1 and 3:1 ratios in ethanol yielded crystals of two 2-aminopyridinium citrate salts, viz. C5H7N2 +·C6H7O7 − (I) (systematic name: 2-aminopyridin-1-ium 3-carboxy-2-carboxymethyl-2-hydroxypropanoate), and 3C5H7N2 +·C6H5O7 3− (II) [systematic name: tris(2-aminopyridin-1-ium) 2-hydroxypropane-1,2,3-tricarboxylate]. The supramolecular synthons present are analysed and their effect upon the crystal packing is presented in the context of crystal engineering. Salt I is formed by the protonation of the pyridine N atom and deprotonation of the central carboxylic group of citric acid, while in II all three carboxylic groups of the acid are deprotonated and the charges are compensated for by three 2-aminopyridinium cations. In both structures, a complex supramolecular three-dimensional architecture is formed. In I, the supramolecular aggregation results from Namino—H...Oacid, Oacid...H—Oacid, Oalcohol—H...Oacid, Namino—H...Oalcohol, Npy—H...Oalcohol and Car—H...Oacid interactions. The molecular conformation of the citrate ion (CA3−) in II is stabilized by an intramolecular Oalcohol—H...Oacid hydrogen bond that encloses an S(6) ring motif. The complex three-dimensional structure of II features Namino—H...Oacid, Npy—H...Oacid and several Car—H...Oacid hydrogen bonds. In the crystal of I, the common charge-assisted 2-aminopyridinium–carboxylate heterosynthon exhibited in many 2-aminopyridinium carboxylates is not observed, instead chains of N—H...O hydrogen bonds and hetero O—H...O dimers are formed. In the crystal of II, the 2-aminopyridinium–carboxylate heterosynthon is sustained, while hetero O—H...O dimers are not observed. The crystal structures of both salts display a variety of hydrogen bonds as almost all of the hydrogen-bond donors and acceptors present are involved in hydrogen bonding.

scholarly journals Bis(4-benzoyl-3-methyl-1-phenyl-1H-pyrazol-5-olato-κ2O,O′)bis(ethanol-κO)cobalt(II)

2012 ◽  
Vol 68 (8) ◽  
pp. m1107-m1108 ◽  
Author(s):  
Omoruyi G. Idemudia ◽  
Eric C. Hosten
Keyword(s):  
Hydrogen Bonds ◽  
Hydroxy Group ◽  
Title Compound ◽  
Negative Charge ◽  
Three Dimensional ◽  
Cobalt Complexes ◽  
Dimensional Structure ◽  
Asymmetric Unit ◽  
Ethanol Molecule ◽  
Three Dimensional Structure

The title compound, [Co(C17H13N2O2)2(C2H5OH)2], is a CoIIcomplex with two 4-benzoyl-3-methyl-1-phenyl-1H-pyrazol-5-olate (BMPP) ligands and two coordinating ethanol molecules. In the asymmetric unit, there are two half molecules, with the CoIIatoms located on inversion centres. The two cobalt complexes have slightly different geometries and in one, the ethyl group of the ethanol is disordered over two sets of sites [occupancy ratio 0.757 (7):0.243 (7)]. Each BMPP ligand is deprotonated with the negative charge delocalized. The hydroxy group of each ethanol molecule forms hydrogen bonds with a pyrazole N atom in an adjacent BMPP ligand. Weaker C—H...O and C—H...N interactions link the molecules into a three-dimensional structure.

Salts of maleic and fumaric acids with organic polyamines: comparison of isomeric acids as building blocks in supramolecular chemistry

2003 ◽  
Vol 59 (1) ◽  
pp. 100-117 ◽  
Author(s):  
Katharine F. Bowes ◽  
George Ferguson ◽  
Alan J. Lough ◽  
Christopher Glidewell
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Supramolecular Chemistry ◽  
Fumaric Acid ◽  
Maleic Acid ◽  
Rotation Axis ◽  
Three Dimensional ◽  
Building Blocks ◽  
Ionic Components ◽  
Acid Compound

Maleic acid and fumaric acid both readily form adducts with organic diamines: maleic acid usually forms 2:1 adducts with bases, while fumaric acid usually forms 1:1 adducts, and the supramolecular stuctures within the two series are not simply related. The 1:2 adducts formed by 1,2-bis(4-pyridyl)ethane and by 4,4′-bipyridyl, respectively, with maleic acid, compounds (1) and (2), are salts [{(diamine)H2}2+]·[(C4H3O4)−]2 in which the cations lie across a centre of inversion and a twofold rotation axis, respectively. The ions are linked by N—H...O hydrogen bonds into three-ion aggregates, which are further linked by C—H...O hydrogen bonds into two- and three-dimensional arrays, respectively. In the fumarate salts formed by 2,2′-dipyridylamine (1:1) and 1,4-diazabicyclo[2.2.2]octane (1:2), compounds (3) and (4), the ionic components are linked into molecular ladders. The 1:1 adduct of 4,4′-bipyridyl and fumaric acid, compound (5), contains two neutral components, both of which lie across centres of inversion; these components are linked into chains by a single O—H...N hydrogen bond and thence into sheets by C—H...O hydrogen bonds. The corresponding adduct formed by 1,4-diazabicyclo[2.2.2]octane, compound (6), is a salt that again contains chains linked into sheets by C—H...O hydrogen bonds. In the 1:1 adducts, compounds (7), (8) and (10), that are formed between 1,2-bis(4-pyridyl)ethane, 4,4′-trimethylenedipyridine and hexamethylenetetramine, respectively, with fumaric acid, and in the 1:2 adduct, compound (9), of 2,2′-dipyridylamine and maleic acid, the chains that are generated by the hard hydrogen bonds are linked by C—H...O hydrogen bonds to form, in each case, a single three-dimensional framework. In the 1:1 adduct, compound (11), of 2,2′-bipyridyl and fumaric acid the hydrogen bonds generate two interwoven three-dimensional frameworks.

scholarly journals Crystal structure of ethyl 2-phenyl-4-(prop-2-yn-1-yloxy)-5,6,7,8-tetrahydropyrido[4′,3′:4,5]thieno[2,3-d]pyrimidine-7-carboxylate

2015 ◽  
Vol 71 (11) ◽  
pp. o836-o837
Author(s):  
Mehmet Akkurt ◽  
Victoria A. Smolenski ◽  
Shaaban K. Mohamed ◽  
Jerry P. Jasinski ◽  
Essam K Ahmed ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Phenyl Ring ◽  
Crystal Packing ◽  
Three Dimensional ◽  
Chair Conformation ◽  
Pyrimidine Ring ◽  
Ring System ◽  
Compound C ◽  
Dimensional Crystal

In the title compound, C21H19N3O3S, the 5,6,7,8-tetrahydropyridine ring adopts a half-chair conformation. The fused-thieno[2,3-d]pyrimidine ring system is essentially planar (r.m.s. deviation = 0.001 Å) and forms a dihedral angle of 2.66 (6)° with the attached phenyl ring. The three-dimensional crystal packing is stabilized by C—H...O and C—H...N hydrogen bonds and C—H...π interactions.

Chiral versus racemic building blocks in supramolecular chemistry: malate salts of organic diamines

2002 ◽  
Vol 58 (3) ◽  
pp. 530-544 ◽  
Author(s):  
Dorcas M. M. Farrell ◽  
George Ferguson ◽  
Alan J. Lough ◽  
Christopher Glidewell
Keyword(s):  
Hydrogen Bonds ◽  
Supramolecular Chemistry ◽  
Malic Acid ◽  
Three Dimensional ◽  
Building Blocks ◽  
Partial Transfer ◽  
Molecular Components ◽  
N Vector ◽  
Hydrogen Bonded

(S)-Malic acid forms a salt with N,N′-dimethylpiperazine, [MeN(CH2CH2)2NMe]H2 2+·2C4H5O5 − (1) (triclinic, P1, Z′ = 1), in which the cations link pairs of hydrogen-bonded anion chains to form a molecular ladder. With 4,4′-bipyridyl, (S)-malic acid forms a 1:1 adduct which crystallizes from methanol to yield two polymorphs, (2) (triclinic, P1, Z′ = 1) and (3) (monoclinic, C2, Z′ = 1), while racemic malic acid with 4,4′-bipyridyl also forms a 1:1 adduct, (4) (monoclinic, P21/c, Z′ = 1). In each of (2), (3) and (4) the components are linked by O—H...N and N—H...O into chains of alternating bipyridyl and malate units, which are linked into sheets by O—H...O hydrogen bonds. In each of the 1:1 adducts (5) and (6), formed by, respectively, (S)-malic acid and racemic malic acid with 1,2-bis(4′-pyridyl)ethene, the diamine is disordered over two sets of sites, related by a 180° rotation about the N...N vector. In (5), (C12H10N2)H+·C4H5O5 − (triclinic, P1, Z′ = 1), the components are again linked by a combination of N—H...O and O—H...O hydrogen bonds into sheets, while in (6) (triclinic, P{\overline 1}, Z′ = 0.5) there is only partial transfer of the H atom from O to N and the malate component is disordered across a centre of inversion. With 1,4-diazabicyclo[2.2.2]octane, racemic malic acid forms a 1:2 salt, [(C6H12N2)H2]2+·2C4H5O5 − (7) (monoclinic, P21/c, Z′ = 2), while (S)-malic acid forms a 1:1 adduct, (8) (monoclinic, P21, Z′ = 3). There are thus six independent molecular components in each. In (7) the ions are linked by an extensive series of N—H...O and O—H...O hydrogen bonds into a three-dimensional framework, but in (8) there is extensive disorder involving all six components, and no refinement proved to be feasible.

Synthesis and characterization of two novel bimetallic macrocyclic complexes generated from 1,2,4-triazole-containing semi-rigid ligands andM(NO3)2units (M= Ni and Zn)

2016 ◽  
Vol 72 (4) ◽  
pp. 285-290 ◽  
Author(s):  
Xiang-Wen Wu ◽  
Shi Yin ◽  
Wan-Fu Wu ◽  
Jian-Ping Ma
Keyword(s):  
Hydrogen Bonds ◽  
Mixed Solvents ◽  
Three Dimensional ◽  
Building Blocks ◽  
Macrocyclic Complexes ◽  
Organic Ligands ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Coordination Environment ◽  
Dimensional Network

Bimetallic macrocyclic complexes have attracted the attention of chemists and various organic ligands have been used as molecular building blocks, but supramolecular complexes based on semi-rigid organic ligands containing 1,2,4-triazole have remained rare until recently. It is easier to obtain novel topologies by making use of asymmetric semi-rigid ligands in the self-assembly process than by making use of rigid ligands. A new semi-rigid ligand, 3-[(pyridin-4-ylmethyl)sulfanyl]-5-(quinolin-2-yl)-4H-1,2,4-triazol-4-amine (L), has been synthesized and used to generate two novel bimetallic macrocycle complexes, namely bis{μ-3-[(pyridin-4-ylmethyl)sulfanyl]-5-(quinolin-2-yl)-4H-1,2,4-triazol-4-amine}bis[(methanol-κO)(nitrato-κ2O,O′)nickel(II)] dinitrate, [Ni2(NO3)2(C17H14N6S)2(CH3OH)2](NO3)2, (I), and bis{μ-3-[(pyridin-4-ylmethyl)sulfanyl]-5-(quinolin-2-yl)-4H-1,2,4-triazol-4-amine}bis[(methanol-κO)(nitrato-κ2O,O′)zinc(II)] dinitrate, [Zn2(NO3)2(C17H14N6S)2(CH3OH)2](NO3)2, (II), by solution reactions with the inorganic saltsM(NO3)2(M= Ni and Zn, respectively) in mixed solvents. In (I), two NiIIcations with the same coordination environment are linked byLligands through Ni—N bonds to form a bimetallic ring. Compound (I) is extended into a two-dimensional network in the crystallographicacplaneviaN—H...O, O—H...N and O—H...O hydrogen bonds, and neighbouring two-dimensional planes are parallel and form a three-dimensional structureviaπ–π stacking. Compound (II) contains two bimetallic rings with the same coordination environment of the ZnIIcations. The ZnIIcations are bridged byLligands through Zn—N bonds to form the bimetallic rings. One type of bimetallic ring constructs a one-dimensional nanotubeviaO—H...O and N—H...O hydrogen bonds along the crystallographicadirection, and the other constructs zero-dimensional molecular cagesviaO—H...O and N—H...O hydrogen bonds. They are interlinked into a two-dimensional network in theacplane through extensive N—H...O hydrogen bonds, and a three-dimensional supramolecular architecture is formedviaπ–π interactions between the centroids of the benzene rings of the quinoline ring systems.

Two novel alkaline earth coordination polymers constructed from cinnamic acid and 1,10-phenanthroline: synthesis and structural and thermal properties

2018 ◽  
Vol 74 (2) ◽  
pp. 240-247 ◽  
Author(s):  
Nassima Bendjellal ◽  
Chahrazed Trifa ◽  
Sofiane Bouacida ◽  
Chaouki Boudaren ◽  
Mhamed Boudraa ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Coordination Polymers ◽  
Crystal Engineering ◽  
Alkaline Earth ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Carboxylate Groups ◽  
A Chain

In coordination chemistry and crystal engineering, many factors influence the construction of coordination polymers and the final frameworks depend greatly on the organic ligands used. The diverse coordination modes of N-donor ligands have been employed to assemble metal–organic frameworks. Carboxylic acid ligands can deprotonate completely or partially when bonding to metal ions and can also act as donors or acceptors of hydrogen bonds; they are thus good candidates for the construction of supramolecular architectures. We synthesized under reflux or hydrothermal conditions two new alkaline earth(II) complexes, namely poly[(1,10-phenanthroline-κ2N,N′)bis(μ-3-phenylprop-2-enoato-κ3O,O′:O)calcium(II)], [Ca(C10H7O2)2(C10H8N2)]n, (1), and poly[(1,10-phenanthroline-κ2N,N′)(μ3-3-phenylprop-2-enoato-κ4O:O,O′:O′)(μ-3-phenylprop-2-enoato-κ3O,O′:O)barium(II)], [Ba(C10H7O2)2(C10H8N2)]n, (2), and characterized them by FT–IR and UV–Vis spectroscopies, thermogravimetric analysis (TGA) and single-crystal X-ray diffraction analysis, as well as by powder X-ray diffraction (PXRD) analysis. Complex (1) features a chain topology of type 2,4 C4, where the Ca atoms are connected by O and N atoms, forming a distorted bicapped trigonal prismatic geometry. Complex (2) displays chains of topology type 2,3,5 C4, where the Ba atom is nine-coordinated by seven O atoms of bridging/chelating carboxylate groups from two cinnamate ligands and by two N atoms from one phenanthroline ligand, forming a distorted tricapped prismatic arrangement. Weak C—H...O hydrogen bonds and π–π stacking interactions between phenanthroline ligands are responsible to the formation of a supramolecular three-dimensional network. The thermal decompositions of (1) and (2) in the temperature range 297–1173 K revealed that they both decompose in three steps and transform to the corresponding metal oxide.

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