Supramolecular interactions in salts/cocrystals involving pyrimidine derivatives of sulfonate/carboxylic acid

The crystal structures of three compounds involving aminopyrimidine derivatives are reported, namely, 5-fluorocytosinium sulfanilate–5-fluorocytosine–4-azaniumylbenzene-1-sulfonate (1/1/1), C₄H₅FN₃O⁺·C₆H₆NO₃S⁻·C₄H₄FN₃O·C₆H₇NO₃S, I , 5-fluorocytosine–indole-3-propionic acid (1/1), C₄H₄FN₃O·C₁₁H₁₁NO₂, II , and 2,4,6-triaminopyrimidinium 3-nitrobenzoate, C₄H₈N₅⁺·C₇H₄NO₄⁻, III , which have been synthesized and characterized by single-crystal X-ray diffraction. In I , there are two 5-fluorocytosine (5FC) molecules (5FC-A and 5FC-B) in the asymmetric unit, with one of the protons disordered between them. 5FC-A and 5FC-B are linked by triple hydrogen bonds, generating two fused rings [two R₂²(8) ring motifs]. The 5FC-A molecules form a self-complementary base pair [R₂²(8) ring motif] via a pair of N—H…O hydrogen bonds and the 5FC-B molecules form a similar complementary base pair [R₂²(8) ring motif]. The combination of these two types of pairing generates a supramolecular ribbon. The 5FC molecules are further hydrogen bonded to the sulfanilate anions and sulfanilic acid molecules via N—H…O hydrogen bonds, generating R₄⁴(22) and R⁶₆(36) ring motifs. In cocrystal II , two types of base pairs (homosynthons) are observed via a pair of N—H…O/N—H…N hydrogen bonds, generating R₂²(8) ring motifs. The first type of base pair is formed by the interaction of an N—H group and the carbonyl O atom of 5FC molecules through a couple of N—H…O hydrogen bonds. Another type of base pair is formed via the amino group and a pyrimidine ring N atom of the 5FC molecules through a pair of N—H…N hydrogen bonds. The base pairs (via N—H…N hydrogen bonds) are further bridged by the carboxyl OH group of indole-3-propionic acid and the O atom of 5FC through O—H…O hydrogen bonds on either side of the R₂²(8) motif. This leads to a DDAA array. In salt III , one of the N atoms of the pyrimidine ring is protonated and interacts with the carboxylate group of the anion through N—H…O hydrogen bonds, leading to the primary ring motif R₂²(8). Furthermore, the 2,4,6-triaminopyrimidinium (TAP) cations form base pairs [R₂²(8) homosynthon] via N—H…N hydrogen bonds. A carboxylate O atom of the 3-nitrobenzoate anion bridges two of the amino groups on either side of the paired TAP cations to form another ring [R₃²(8)]. This leads to the generation of a quadruple DADA array. The crystal structures are further stabilized by π–π stacking ( I and III ), C—H…π ( I and II ), C—F…π ( I ) and C—O…π ( II ) interactions.     

Supramolecular architectures of two novel organic–inorganic hybrid materials containing identical monomeric uranyl units

Two isostructural uranyl complexes have been crystallized with different bipyridyl cations to yield the compounds hemi(4,4′‐bipyridinium) tris(5‐chlorothiophene‐2‐carboxylato)dioxidouranate(VI) monohydrate, (C₁₀H₁₀N₂)_0.5[U(C₅H₂ClO₂S)₃O₂]·H₂O, (I), and hemi[4,4′‐(ethane‐1,2‐diyl)dipyridinium] tris(5‐chlorothiophene‐2‐carboxylato)dioxidouranate(VI) monohydrate, (C₁₂H₁₄N₂)_0.5[U(C₅H₂ClO₂S)₃O₂]·H₂O, (II). In the [UO₂X₃]⁻ complexes (X is 5‐chlorothiophene‐2‐carboxylate), the uranyl O atoms occupy the two axial positions and the equatorial positions are occupied by six O atoms of the three X ions so that each U atom is eight coordinated in a puckered hexagonal–bipyramidal structure. In both compounds, the metal centres are linked by classical O—H...O and N—H...O hydrogen bonds involving the coordinated ligands, the diprotonated organic linker cation (which rests on a centre of inversion at the mid‐point of the central C—C bond) and water molecules. The crystal structures are further stabilized by weak C—H...O and π–π stacking interactions, forming similar three‐dimensional supramolecular architectures, forming a two‐dimensional network parallel to the (100) plane in (I) and a three‐dimensional network in (II).     

Hydrogen Bonding Patterns of Coordinated Ligands in Hybrid Materials: Crystal Structures of Hydronium Tetra(Thiocyanato-κN)-Zinc(II): Tris(2-Amino-4,6-Dimethylpyrimidinium) (2-amino-4,6-dimethylpyrimidine) Dinitrate and Bis(2-Amino-4,6-Dimethylpyrimidinium) Tetrachlorocobaltate(II) Monohydrate

Abstract  

Hydronium tetra(thiocyanato-κN)-zinc (II) tri (2-amino-4,6-dimethylpyrimidinium) 2-amino-4,6-dimethylpyrimidine dinitrate [H₃O⁺ Zn(NCS)₄ 3(C₆H₁₀N₃ ⁺) C₆H₉N₃ 2(NO₃)⁻] and bis(2-amino-4,6-dimethylpyrimidinium) tetrachlorocobaltate(II) monohydrate [2(C₆H₁₀N₃ ⁺)] CoCl₄ H₂O have been synthesized and characterized by X-ray diffraction analysis and spectroscopic studies. In compound 1, the coordination geometry around zinc is distorted tetrahedral, Zn being bonded to four N atoms from the thiocyanate anions. In compound 2, the anion [CoCl₄]²⁻ displays distortion from ideal tetrahedral geometry. The 2-amino-4,6-dimethylpyrimidine cations are not directly coordinated to zinc/cobalt, but are hydrogen bonded to the thiocyanate/chloride ions. In both the compounds the protonated nitrogen N1 and the 2-amino group are hydrogen bonded to the nitro group/chloride ions/water molecule through N–H···O and N–H···Cl hydrogen bonds to form R₂²(8) motifs. In both the compounds, the pyrimidine cations also form base pairs via a pair of N–H···N hydrogen bonds involving the amino group and the unprotonated ring N atom. The crystal structures are further stabilized by N–H···S, O–H···O, C–H···O and C–H···Cl hydrogen bonds.     

Synthesis and characterization of novel fluorophosphazene-derived cobaltacyclopentadienyl metallacycles: reagents for assembly of aryl-bridged fluorophosphazenes

Reaction of (beta-phenylethynyl)pentafluorocyclotriphosphazene, F5P3N3C identical with CPh, with in situ generated eta5-(MeOC(O)C5H4)Co(PPh3)2 resulted in the formation of two isomers of cobaltacyclopentadienylmetallacycles, (eta(5)-carbomethoxycyclopentadienyl)(triphenylphosphine)-2,5-bis(pentafluorocyclotriphosphazenyl)-3,4-diphenyl cobaltacyclopentadiene (1) and (eta5-carbomethoxycyclopentadienyl)(triphenylphosphine)-2,4-bis(pentafluorocyclotriphosphazenyl)-3,5-diphenyl cobaltacyclopentadiene (2), along with the sandwich compound [eta5-carbomethoxycyclopentadienyl]-[eta4-1,3-bis(pentafluorocyclotriphosphazenyl)-2,4-diphenylcyclobutadiene]cobalt (3). Formation of cobaltacyclopentadienylmetallacycles or cyclobutadienylmetallocene having two fluorophosphazene units on vicinal carbon atoms of the rings was not observed in this reaction. Reaction of 1 with diphenylacetylene resulted in the formation of a novel aryl-bridged fluorophosphazene, 1,4-bis(pentafluorocyclotriphosphazenyl)-2,3,5,6-tetraphenyl benzene (4), and the conversion of cobaltametallacycle to the sandwich compound, [eta5-(MeOC(O)C5H4]Co(eta4-C4Ph4) (5). Reaction of 1 with phenylacetylene resulted in the formation of aryl-bridged fluorophosphazene, 1,4-bis(pentafluorophosphazenyl)-2,3,5,-triphenyl benzene (6). New compounds 1-4 were structurally characterized. In compound 1, the two fluorophosphazene units were oriented in gauche form with respect to each other. However, in compounds 2 and 3, they were eclipsed to each other, and in compound 4, they were oriented anti to each other.     

Multivalued fixed point in Banach algebra using continuous selection and its application to differential inclusion

In this paper, we provide some fixed point results using continuous selection given by Poonguzali et al. [15]. Also, using the selection theorem we discusse the existence of fixed point for the product of two multivalued mappings, that is, of the form $Ax\cdot Bx.$ Using those fixed point results, we give the existence of solution for a newly developed differential inclusion.     

Affine PBW bases and MV polytopes in rank 2

Mirkovi?–Vilonen (MV) polytopes have proven to be a useful tool in understanding and unifying many constructions of crystals for finite-type Kac-Moody algebras. These polytopes arise naturally in many places, including the affine Grassmannian, pre-projective algebras, PBW bases, and KLR algebras. There has recently been progress in extending this theory to the affine Kac-Moody algebras. A definition of MV polytopes in symmetric affine cases has been proposed using pre-projective algebras. In the rank-2 affine cases, a combinatorial definition has also been proposed. Additionally, the theory of PBW bases has been extended to affine cases, and, at least in rank-2, we show that this can also be used to define MV polytopes. The main result of this paper is that these three notions of MV polytope all agree in the relevant rank-2 cases. Our main tool is a new characterization of rank-2 affine MV polytopes.