scholarly journals Two-dimensional hydrogen-bonded polymers in the crystal structures of the ammonium salts of phenoxyacetic acid, (4-fluorophenoxy)acetic acid and (4-chloro-2-methylphenoxy)acetic acid

2014 ◽  
Vol 70 (12) ◽  
pp. 528-532 ◽  
Author(s):  
Graham Smith

The structures of the ammonium salts of phenoxyacetic acid, NH4+·C8H6O3−, (I), (4-fluorophenoxy)acetic acid, NH4+·C8H5FO3−, (II), and the herbicidally active (4-chloro-2-methylphenoxy)acetic acid (MCPA), NH4+·C9H8ClO3−·0.5H2O, (III) have been determined. All have two-dimensional layered structures based on inter-species ammonium N—H...O hydrogen-bonding associations, which give core substructures consisting primarily of conjoined cyclic motifs. The crystals of (I) and (II) are isomorphous with the core comprisingR12(5),R12(4) and centrosymmetricR42(8) ring motifs, giving two-dimensional layers lying parallel to (100). In (III), the water molecule of solvation lies on a crystallographic twofold rotation axis and bridges two carboxyl O atoms in anR44(12) hydrogen-bonded motif, creating twoR43(10) rings, which together with a conjoined centrosymmetricR42(8) ring incorporating both ammonium cations, generate two-dimensional layers lying parallel to (100). No π–π ring associations are present in any of the structures.

2014 ◽  
Vol 70 (6) ◽  
pp. 606-612 ◽  
Author(s):  
Graham Smith ◽  
Daniel E. Lynch

The two-dimensional polymeric structures of the caesium complexes with the phenoxyacetic acid analogues (4-fluorophenoxy)acetic acid, (3-chloro-2-methylphenoxy)acetic acid and the herbicidally active (2,4-dichlorophenoxy)acetic acid (2,4-D), namely poly[[μ5-(4-fluorophenoxy)acetato][μ4-(4-fluorophenoxy)acetato]dicaesium], [Cs2(C8H6FO3)2]n, (I), poly[aqua[μ5-(3-chloro-2-methylphenoxy)acetato]caesium], [Cs(C9H8ClO3)(H2O)]n, (II), and poly[[μ7-(2,4-dichlorophenoxy)acetato][(2,4-dichlorphenoxy)acetic acid]caesium], [Cs(C8H5Cl2O3)(C8H6Cl2O3)]n, (III), are described. In (I), the Cs+cations of the two individual irregular coordination polyhedra in the asymmetric unit (one CsO7and the other CsO8) are linked by bridging carboxylate O-atom donors from the two ligand molecules, both of which are involved in bidentate chelateOcarboxy,Ophenoxyinteractions, while only one has a bidentate carboxylateO,O′-chelate interaction. Polymeric extension is achieved through a number of carboxylate O-atom bridges, with a minimum Cs...Cs separation of 4.3231 (9) Å, giving layers which lie parallel to (001). In hydrated complex (II), the irregular nine-coordination about the Cs+cation comprises a single monodentate water molecule, a bidentateOcarboxy,Ophenoxychelate interaction and six bridging carboxylate O-atom bonding interactions, giving a Cs...Cs separation of 4.2473 (3) Å. The water molecule forms intralayer hydrogen bonds within the two-dimensional layers, which lie parallel to (100). In complex (III), the irregular centrosymmetric CsO6Cl2coordination environment comprises two O-atom donors and two ring-substituted Cl-atom donors from two hydrogen bis[(2,4-dichlorophenoxy)acetate] ligand species in a bidentate chelate mode, and four O-atom donors from bridging carboxyl groups. The duplex ligand species lie across crystallographic inversion centres, linked through a short O—H...O hydrogen bond involving the single acid H atom. Structure extension gives layers which lie parallel to (001). The present set of structures of Cs salts of phenoxyacetic acids show previously demonstrated trends among the alkali metal salts of simple benzoic acids with no stereochemically favourable interactive substituent groups for formation of two-dimensional coordination polymers.


2015 ◽  
Vol 71 (2) ◽  
pp. 140-145 ◽  
Author(s):  
Graham Smith

The Li, Rb and Cs complexes with the herbicide (2,4-dichlorophenoxy)acetic acid (2,4-D), namely poly[[aqua[μ3-(2,4-dichlorophenoxy)acetato-κ3O1:O1:O1′]lithium(I)] dihydrate], {[Li(C8H5Cl2O3)(H2O)]·2H2O}n, (I), poly[μ-aqua-bis[μ3-(2,4-dichlorophenoxy)acetato-κ4O1:O1′:O1′,Cl2]dirubidium(I)], [Rb2(C8H5Cl2O3)2(H2O)]n, (II), and poly[μ-aqua-bis[μ3-(2,4-dichlorophenoxy)acetato-κ5O1:O1′:O1′,O2,Cl2]dicaesium(I)], [Cs2(C8H5Cl2O3)2(H2O)]n, (III), respectively, have been determined and their two-dimensional polymeric structures are described. In (I), the slightly distorted tetrahedral LiO4coordination involves three carboxylate O-atom donors, of which two are bridging, and a monodentate aqua ligand, together with two water molecules of solvation. Conjoined six-membered ring systems generate a one-dimensional coordination polymeric chain which extends alongband interspecies water O—H...O hydrogen-bonding interactions give the overall two-dimensional layers which lie parallel to (001). In hemihydrate complex (II), the irregular octahedral RbO5Cl coordination about Rb+comprises a single bridging water molecule which lies on a twofold rotation axis, a bidentateOcarboxy,Cl-chelate interaction and three bridging carboxylate O-atom bonding interactions from the 2,4-D ligand. A two-dimensional coordination polymeric layer structure lying parallel to (100) is formed through a number of conjoined cyclic bridges, including a centrosymmetric four-membered Rb2O2ring system with an Rb...Rb separation of 4.3312 (5) Å. The coordinated water molecule forms intralayer aqua–carboxylate O—H...O hydrogen bonds. Complex (III) comprises two crystallographically independent (Z′ = 2) irregular CsO6Cl coordination centres, each comprising two O-atom donors (carboxylate and phenoxy) and a ring-substituted Cl-atom donor from the 2,4-D ligand species in a tridentate chelate mode, two O-atom donors from bridging carboxylate groups and one from a bridging water molecule. However, the two 2,4-D ligands are conformationally very dissimilar, with one phenoxyacetate side chain being synclinal and the other being antiperiplanar. The minimum Cs...Cs separation is 4.4463 (5) Å. Structure extension gives coordination polymeric layers which lie parallel to (001) and are stabilized by intralayer water–carboxylate O—H...O hydrogen bonds.


IUCrData ◽  
2017 ◽  
Vol 2 (8) ◽  
Author(s):  
Graham Smith

In the structure of the ammonium hydrogen salt of (3-chloro-2-methylphenoxy)acetic acid, NH4+·C18H17Cl2O6−, the dimeric anion comprises two inversion-related head-to-head components linked through a short symmetric carboxyl O...H...O hydrogen bond in which the delocalized acid H atom lies on an inversion centre. The ammonium cation is disordered over another inversion centre. The crystal structure is based on a number of inter-species ammonium N—H...O hydrogen-bonding associations, giving two-dimensional layers lying parallel to (001).


2015 ◽  
Vol 71 (10) ◽  
pp. o717-o718 ◽  
Author(s):  
Graham Smith

In the structure of the title hydrated salt, NH4+·C8H5Cl2O3−·0.5H2O, where the anion derives from (3,5-dichlorophenoxy)acetic acid, the ammonium cation is involved in extensive N—H...O hydrogen bonding with both carboxylate and ether O-atom acceptors giving sheet structures lying parallel to (100). The water molecule of solvation lies on a crystallographic twofold rotation axis and is involved in intra-sheet O—H...Ocarboxylatehydrogen-bonding interactions. In the anion, the oxoacetate side chain assumes anantiperiplanarconformation with the defining C—O—C—C torsion angle = −171.33 (15)°.


2015 ◽  
Vol 71 (10) ◽  
pp. 1177-1180 ◽  
Author(s):  
Graham Smith

The two-dimensional coordination polymeric structures of the hydrated potassium and rubidium salts of (3,5-dichlorophenoxy)acetic acid (3,5-D), namely, poly[μ-aqua-bis[μ3-2-(3,5-dichlorophenoxy)acetato]dipotassium], [K2(C8H5Cl2O3)2(H2O)]n, and poly[μ-aqua-bis[μ3-2-(3,5-dichlorophenoxy)acetato]dirubidium], [Rb2(C8H5Cl2O3)2(H2O)]n, respectively, have been determined and are described. The two compounds are isotypic and the polymeric structure is based on centrosymmetric dinuclear bridged complex units. The irregular six-coordination about the alkali cations comprises a bridging water molecule lying on a twofold rotation axis, the phenoxy O-atom donor and a triple bridging carboxylate O atom of the oxoacetate side chain of the 3,5-D ligand, and the second carboxyate O-atom donor also bridging. The K—O and Rb—O bond-length ranges are 2.7238 (15)–2.9459 (14) and 2.832 (2)–3.050 (2) Å, respectively, and the K...K and Rb...Rb separations in the dinuclear units are 4.0214 (7) and 4.1289 (6) Å, respectively. Within the layers which lie parallel to (100), the coordinating water molecule forms an O—H...O hydrogen bond to the single bridging carboxylate O atom.


2013 ◽  
Vol 69 (12) ◽  
pp. m628-m628 ◽  
Author(s):  
Graham Smith

In the structure of the title complex, [Cs(C8H4Cl3O2)(H2O)]n, the caesium salt of the commercial herbicide fenac [(2,3,6-trichlorophenyl)acetic acid], the irregular eight-coordination about Cs+comprises a bidentateO:Cl-chelate interaction involving a carboxylate-O atom and anortho-related ring-substituted Cl atom, which is also bridging, a triple-bridging carboxylate-O atom and a bridging water molecule. A two-dimensional polymer is generated, lying parallel to (100), within which there are water–carboxylate O—H...O hydrogen-bonding interactions.


2012 ◽  
Vol 68 (4) ◽  
pp. m379-m379 ◽  
Author(s):  
Qiong Liu

In the title compound, [K2(C8H6N3O2)2(H2O)]n, each K+ion is seven-coordinated by one O atom from a bridging water molecule, five carboxylate O atoms and one N atom from a benzotriazole group, forming a distorted mono-capped octahedral geometry. In the crystal, the carboxylate groups act as bridging ligands, forming a two-dimensional polymer parallel to (001). The aqua ligand, which lies on a twofold rotation axis, forms intermolecular O—H...O hydrogen bonds within these layers.


CrystEngComm ◽  
2016 ◽  
Vol 18 (1) ◽  
pp. 62-67
Author(s):  
Yoona Jang ◽  
Seo Yeon Yoo ◽  
Hye Rin Gu ◽  
Yu Jin Lee ◽  
Young Shin Cha ◽  
...  

6-Chloro-9-propyl-purin-2-amine (pr-GCl) forms two-dimensional hydrogen-bonded networks which in turn stack via π–π interactions, leading to the formation of bilayers that can accommodate organic guest molecules.


Author(s):  
Alejandro Hernandez ◽  
Indranil Chakraborty ◽  
Gabriela Ortega ◽  
Christopher J. Dares

The title compound, [UO2(acac)2(H2O)] consists of a uranyl(VI) unit ([O=U=O]2+) coordinated to two monoanionic acetylacetonate (acac, C5H7O2) ligands and one water molecule. The asymmetric unit includes a one-half of a uranium atom, one oxido ion, one-half of a water molecule and one acac ligand. The coordination about the uranium atom is distorted pentagonal–bipyramidal. The acac ligands and Ow atom comprise the equatorial plane, while the uranyl O atoms occupy the axial positions. Intermolecular hydrogen bonding between complexes results in the formation of two-dimensional hexagonal void channels along the c-axis direction with a diameter of 6.7 Å. The monoclinic (P21/c space group) polymorph was reported by Alcock & Flanders [(1987). Acta Cryst. C43, 1480–1483].


2020 ◽  
Vol 76 (11) ◽  
pp. 1010-1023
Author(s):  
Mercy Okezue ◽  
Daniel Smith ◽  
Matthias Zeller ◽  
Stephen R. Byrn ◽  
Pamela Smith ◽  
...  

Bedaquiline [systematic name: 1-(6-bromo-2-methoxyquinolin-3-yl)-4-(dimethylamino)-2-(naphthalen-1-yl)-1-phenylbutan-2-ol, C32H31BrN2O2] is one of two important new drugs for the treatment of drug-resistant tuberculosis (TB). It is marketed in the US as its fumarate salt {systematic name: [4-(6-bromo-2-methoxyquinolin-3-yl)-3-hydroxy-3-(naphthalen-1-yl)-4-phenylbutyl]dimethylazanium 3-carboxyprop-2-enoate, C32H32BrN2O2 +·C4H3O4 −}, and about a dozen other salts of bedaquiline have been described in patent literature, but none have so far been structurally described. In a first communication, we present the crystal structure of bedaquilinium fumarate and of two new benzoate salts, as well as that of a degradation product of the reaction of bedaquilinium fumarate with sodium ethoxide, 3-benzyl-6-bromo-2-methoxyquinoline, C17H14BrNO. The fumarate and benzoate salts both feature cations monoprotonated at the dimethylamino group. The much less basic quinoline N atom remains unprotonated. Both salts feature a 1:1 cation-to-anion ratio, with the fumarate being present as monoanionic hydrofumarate. The conformations of the cations are compared to that of free base bedaquiline and with each other. The flexible backbone of the bedaquiline structure leads to a landscape of conformations with little commonalities between the bedaquiline entities in the various structures. The conformations are distinctively different for the two independent molecules of the free base, the two independent molecules of the hydrofumarate salt, and the one unique cation of the benzoate salt. Packing of the salts is dominated by hydrogen bonding. Hydrogen-bonding motifs, as well as the larger hydrogen-bonded entities within the salts, are quite similar for the salts, despite the vastly differing conformations of the cations, and both the hydrofumarate and the benzoate structure feature chains of hydrogen-bonded anions that are surrounded by and hydrogen bonded to the larger bedaquilinium cations, leading to infinite broad ribbons of anions, cations, and (for the benzoate salt) water molecules. The benzoate salt was isolated in two forms: as a 1.17-hydrate (C32H32BrN2O2 +·C7H5O2 −·1.166H2O), obtained from acetone or propanol solution, with one fully occupied water molecule tightly integrated into the hydrogen-bonding network of anions and cations, and one partially occupied water molecule [refined occupancy 16.6 (7)%], only loosely hydrogen bonded to the quinoline N atom. The second form is an acetonitrile solvate (C32H32BrN2O2 +·C7H5O2 −·0.742CH3CN·H2O), in which the partially occupied water molecule is replaced by a 74.2 (7)%-occupied acetonitrile molecule. The partial occupancy induces disorder for the benzoate phenyl ring. The acetonitrile solvate is unstable in atmosphere and converts into a form not distinguishable by powder XRD from the 1.17-hydrate.


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