Influence of multi-stress factors on the growth of Chlorella pyrenoidosa and Scenedesmus abundans using response surface methodology.

This study evaluated the biofuel production potential of two algal species, Chlorella pyrenoidosa and Scenedesmus abundans, under stress conditions induced by nutrient supplementation or starvation at varying light intensities. Central composite face-centered design response surface methodology (CCFD-RSM) was employed to optimize stress conditions by varying the sodium nitrate (NaNO), potassium dihydrogen phosphate (KHPO), dipotassium hydrogen phosphate (KHPO), cultivation time, and light intensity. The study included both C.

Design of two series of 1:1 cocrystals involving 4-amino-5-chloro-2,6-dimethylpyrimidine and carboxylic acids.

Two series of a total of ten cocrystals involving 4-amino-5-chloro-2,6-dimethylpyrimidine with various carboxylic acids have been prepared and characterized by single-crystal X-ray diffraction. The pyrimidine unit used for the cocrystals offers two ring N atoms (positions N1 and N3) as proton-accepting sites. Depending upon the site of protonation, two types of cations are possible [Rajam et al.

Cation tautomerism, twinning and disorder in the triclinic and monoclinic forms of 4-amino-5-chloro-2,6-dimethylpyrimidinium 5-chloro-2-hydroxybenzoate and a new disordered refinement of 2-amino-4,6-dimethoxypyrimidin-1-ium thiophene-2-carboxylate.

Pyrimidines are important compounds in biology and medicine, and the aminopyrimidine fragment can be identified in three of the four bases in DNA. The targeted drug action of pharmaceuticals containing this functionality is likely to depend heavily on molecular recognition processes involving hydrogen bonding. Crystallization of an equimolar mixture of 4-amino-5-chloro-2,6-dimethylpyrimidine and 5-chloro-2-hydroxybenzoic acid yielded two forms of the 1:1 salt, CHClN·CHClO, each containing a different tautomeric form of the cation.

Supramolecular hydrogen-bonding patterns in 1:1 cocrystals of 5-fluorouracil with 4-methylbenzoic acid and 3-nitrobenzoic acid.

The design of a pharmaceutical cocrystal is based on the identification of specific hydrogen-bond donor and acceptor groups in active pharmaceutical ingredients (APIs) in order to choose a `complementary interacting' molecule that can act as an efficient coformer. 5-Fluorouracil (5FU) is a pyrimidine derivative with two N-H donors and C=O acceptors and shows a diversity of hydrogen-bonding motifs. Two 1:1 cocrystals of 5-fluorouracil (5FU), namely 5-fluorouracil-4-methylbenzoic acid (5FU-MBA), CHFNO·CHO, (I), and 5-fluorouracil-3-nitrobenzoic acid (5FU-NBA), CHFNO·CHNO, (II), have been prepared and characterized by single-crystal X-ray diffraction.

Hydrogen-bonding patterns in 5-fluoro-cytosine-melamine co-crystal (4/1).

The asymmetric unit of the title compound, 4C4H4FN3O·C3H6N6, comprises of two independent 5-fluoro-cytosine (5FC) mol-ecules (A and B) and one half-mol-ecule of melamine (M). The other half of the melamine mol-ecule is generated by a twofold axis. 5FC mol-ecules A and B are linked through two different homosynthons [R 2 (2)(8) ring motif]; one is formed via a pair of N-H⋯O hydrogen bonds and the second via a pair of N-H⋯N hydrogen bonds.

Crystal structure of 2-amino-pyridinium 6-chloro-nicotinate.

In the title salt, C5H7N(+)·C6H3ClNO(-), the 2-amino-pyri-din-ium cation inter-acts with the carboxyl-ate group of the 6-chloro-nicotinate anion through a pair of independent N-H⋯O hydrogen bonds, forming an R 2 (2)(8) ring motif. In the crystal, these dimeric units are connected further via N-H⋯O hydrogen bonds, forming chains along [001]. In addition, weak C-H⋯N and C-H⋯O hydrogen bonds, together with weak π-π inter-actions, with centroid-centroid distances of 3.

Crystal structure of 2-amino-4,6-di-meth-oxy-pyrimidinium thio-phene-2-carboxyl-ate.

In the title salt, C6H10N3O2 (+)·C5H3O2S(-), the 2-amino-4,6-di-meth-oxy-pyrimidinium cation inter-acts with the carboxyl-ate group of the thio-phene-2-carboxyl-ate anion through a pair of N-H⋯O hydrogen bonds, forming an R 2 (2)(8) ring motif. These motifs are centrosymmetrically paired via N-H⋯O hydrogen bonds, forming a complementary DDAA array. The separate DDAA arrays are linked by π-π stacking inter-actions between the pyrimidine rings, as well as by a number of weak C-H⋯O and N-H⋯O inter-actions.

Crystal structure of 4-[(5-methyl-isoxazol-3-yl)amino-sulfon-yl]anilinium 3,5-di-nitro-salicylate.

The title mol-ecular salt, C10H12N3O3S(+)·C7H3N2O7 (-), protonation occurs at the amino N atom attached to the benzene ring of sulfamethoxazole. In the anion, there is an intra-molecular O-H⋯O hydrogen bond and the cation is linked to the anion by an N-H⋯O hydrogen bond. In the extended structure, the cations and anions are linked via N-H⋯O, N-H⋯N and C-H⋯O hydrogen bonds, forming a three-dimensional framework.

Hydrogen bonding patterns in salts of derivatives of aminopyrimidine and thiobarbituric acid.

Three salts, namely 2-amino-4,6-dimethylpyrimidin-1-ium thiobarbiturate trihydrate (I), 2-amino-4,6-dimethoxypyrimidin-1-ium thiobarbiturate dihydrate (II) and 2,4-diamino-5-(3',4',5'-trimethoxybenzyl)pyrimidin-1-ium thiobarbiturate (III), were synthesized and characterized by IR and X-ray diffraction techniques. The primary interaction between the acid and base happens via N-H..

Vibrational spectra (experimental and theoretical), molecular structure, natural bond orbital, HOMO-LUMO energy, Mulliken charge and thermodynamic analysis of N'-hydroxy-pyrimidine-2-carboximidamide by DFT approach.

The FT-IR, FT-Raman, (1)H, (13)C NMR and UV-Visible spectral measurements of N'-hydroxy-pyrimidine-2-carboximidamide (HPCI) and complete analysis of the observed spectra have been proposed. DFT calculation has been performed and the structural parameters of the compound was determined from the optimized geometry with 6-311+G(d,p) basis set and giving energies, harmonic vibrational frequencies and force constants. The results of the optimized molecular structure are presented and compared with the experimental.

Crystal structure of 2-{[(2-chloro-phen-yl)imino]-meth-yl}phenol.

In the title compound, C13H10ClNO, the dihedral angle between the planes of the aromatic rings is 51.42 (9)° and an intra-molecular O-H⋯N hydrogen bond closes an S(6) ring. The Cl atom and the N atom are syn.

Crystal structure of N'-hy-droxy-pyrimidine-2-carboximidamide.

The title compound, C5H6N4O, is approximately planar, with an angle of 11.04 (15)° between the planes of the pyrimidine ring and the non-H atoms of the carboximidamide unit. The mol-ecule adopts an E configuration about the C=N double bond.

Design of co-crystals/salts of some Nitrogenous bases and some derivatives of thiophene carboxylic acids through a combination of hydrogen and halogen bonds.

Background: The utility of N-heterocyclic bases to obtain molecular complexes with carboxylic acids is well studied. Depending on the solid state interaction between the N-heterocyclic base and a carboxylic acid a variety of neutral or ionic synthons are observed. Meanwhile, pyridines and pyrimidines have been frequently chosen in the area of crystal engineering for their multipurpose functionality.

2-Amino-4,6-di-methyl-pyrimidine-sorbic acid (1/1).

In the crystal of the title compound, C6H9N3·C6H8O2, the 2-amino-4,6-di-methyl-pyrimidine and sorbic acid mol-ecules are linked through N-H⋯O and O-H⋯N hydrogen bonds, which generate a cyclic bimolecular heterosynthon with an R 2 (2)(8) graph-set motif. Further, two inversion-related pyrimidine mol-ecules are base-paired via a pair of N-H⋯N hydrogen bonds, forming a cyclic bimolecular homosynthon with a graph-set of R 2 (2)(8). A discrete hetero tetra-meric supra-molecular unit along the b axis is formed by the fusion of two heterosynthons and one homosynthon.

Tetraammine(carbonato-κ(2) O,O')cobalt(III) perchlorate.

In the title complex, [Co(CO3)(NH3)4]ClO4, both the cation and anion lie on a mirror plane. The Co(III) ion is coordinated by two NH3 ligands and a chelating carbonato ligand in the equatorial sites and by two NH3 groups in the axial sites, forming a distorted octa-hedral geometry. In the crystal, N-H⋯O hydrogen bonds connect the anions and cations, forming a three-dimensional network.

Dual-layered-coated mechanically-durable superomniphobic surfaces with anti-smudge properties.

Bio-inspired surfaces that exhibit high contact angle and low contact angle hysteresis for various liquids and demonstrate mechanical durability and anti-smudge properties are of interest for various applications. The fabrication of such surfaces has often involved complex or expensive processes, required techniques that may not be suitable for various substrates and particles, may require surface post-treatment, or may lack durability. Dual layered coatings of roughness-induced superomniphobic surfaces that demonstrate good mechanical durability were fabricated on glass substrates using hydrophobic SiO2 nanoparticles and low surface energy fluorobinders using dip coating and spray coating techniques.

1, 5-Bis (2-hydroxyacetophenone)thiocarbohydrazone: a novel colorimetric and fluorescent dual-mode chemosensor for the recognition of fluoride.

1,5-Bis (2-hydroxyacetophenone)thiocarbohydrazone (H4L) has been synthesized and characterized by means of spectroscopic and single crystal X-ray diffraction methods. Interactions of the H4L with a variety of anions were investigated using a combination of UV-visible and fluorescence spectroscopic methods in a biological competing solvent DMSO. The H4L has a high degree of selectivity for fluoride over other anions.

Synthesis, characterization and X-ray structural studies of four copper (II) complexes containing dinuclear paddle wheel structures.

Background: Various dinuclear copper (II) complexes with octahedral geometry have been reported. The majority of these complexes contain N containing aromatic rings as axial ligands. There are also a few cases where the solvent used in the reaction occupies the axial position of the dinuclear copper (II) complex.

2-Amino-4,6-dimethyl-pyrimidin-1-ium 2,3,5-triiodo-benzoate 2,3,5-triiodo-benzoic acid monosolvate.

In the crystal structure of the title compound, C(6)H(10)N(3) (+)·C(7)H(2)I(3)O(2) (-)·C(7)H(3)I(3)O(2), two R(2) (2)(8) motifs are observed. One is generated by the inter-action of the 2-amino-4,6-dimethyl-pyrimidin-1-ium cation with the carboxyl-ate group of the 2,3,5-triiodo-benzoate anion via N-H⋯O hydrogen bonds. The other R(2) (2)(8) motif is formed by the inter-action of two centrosymmentrically related pyrimidine moieties through N-H⋯N hydrogen bonds.

2,6,6-Trimethyl-cyclo-hexene-1-carbaldehyde oxime.

In the crystal of the title compound C(10)H(17)NO, synthesized by the reaction of β-cyclo-citral with hydroxyl-amine hydro-chloride, inversion-related mol-ecules are linked by a pair of O-H⋯N hydrogen-bonding inter-actions between the oxime functionalities, forming R(2) (2)(6) loops. The molecular conformation is stabilized by intra-molecular methyl C-H⋯N inter-actions. The cyclohexene ring has the typical half-chair conformation.

2-Amino-4,6-dimeth-oxy-pyrimidin-1-ium p-toluene-sulfonate.

In the title salt, C(6)H(10)N(3)O(2) (+)·C(7)H(7)O(3)S(-), the 2-amino-4,6-dimeth-oxy-pyrimidinium cation inter-acts with the sulfonate group of the p-toluene-sulfonate anion via a pair of N-H⋯O hydrogen bonds, forming a cyclic hydrogen-bonded R(2) (2)(8) motif, which in the crystal is linked by further intemolecular N-H⋯O hydrogen bonds, forming supra-molecular chains along the c axis. Furthermore, neighboring chains are inter-linked via weak C-H⋯O hydrogen bonds and C-H⋯π inter-actions, forming layers.

2,4-Diamino-6-methyl-1,3,5-triazin-1-ium tetra-fluoro-borate.

In the crystal structure of the title salt, C(4)H(8)N(5) (+)·BF(4) (-), centrosymmetrically related cations undergo base pairing via a pair of N-H⋯N hydrogen bonds, forming an R(2) (2)(8) ring motif. The cations and anions inter-act via N-H⋯F hydrogen bonds, generating supra-molecular layers parallel to ([Formula: see text]20), which are in turn linked into a three-dimensional network, forming rings of R(6) (6)(24) graph-set motif. The crystal structure is further stabilized by π-π stacking inter-actions [centroid-centroid distance = 3.