Crystal structures of the benzene and ethanol solvates of neotame

The benzene and ethanol solvates of neotame crystallized from solutions of neotame anhydrate in benzene and ethanol, respectively. The crystal structures of the two solvates were determined by single-crystal X-ray diffraction using synchrotron radiation. The benzene solvate crystallizes in the monoclinic space group, P2₁, Z = 2, with one neotame molecule and one benzene molecule per asymmetric unit. The cell constants are a = 13.060 (6) Å, b = 5.582 (2) Å, c = 17.954 (9) Å, and = 102.079 (15)°. The ethanol solvate crystallizes in the orthorhombic space group, P2₁2₁2₁ with Z = 8 (Z = 2). The cell constants are a = 10.047 (4) Å, b = 17.001 (4) Å, and c = 28.948 (7) Å. Intermolecular hydrogen bonding among neotame molecules is evident in the two crystals. The benzene solvate has a nonpolar region containing the benzene molecules, with the benzene rings and alkyl chains of the neotame molecules.     

Synthesis and Novel Crystal Structure Analysis of Anthracene-Based Chalcone Derivatives

Abstract

Four novel anthracene-based chalcone derivatives, (E)-1-(anthracen-9-yl)-3-(4-nitrophenyl)prop-2-en-1-one 1, (E)-1-(anthracen-9-yl)-3-(3-chlorophenyl)prop-2-en-1-one 2, (E)-1-(anthracen-9-yl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one 3, and (E)-1-(anthracen-9-yl)-3-(pyridin-4-yl)prop-2-en-1-one four were synthesized and their structures were solved by single crystal X-ray diffraction methods. The anthracenyl chalcone 1 crystallizes in the centrosymmetric monoclinic P2₁/c space group. The crystal structure analysis shows that the molecules of one form two dimensional (2D) corrugated layer structure. The anthracenyl chalcone 2 crystallizes in the centrosymmetric triclinic P-1 space group and forms one dimensional (1D) tape like structure in the crystal. Compound 3 crystallizes in the centrosymmetric monoclinic P2₁/n space group. Anthracenyl chalcone 4 crystallizes in the centrosymmetric triclinic P-1 space group.     

Syntheses and X-ray structures of new phenoxy imino compounds

Four new phenoxy imino compounds were synthesized, and the solid-state structures of 1–3 were determined by single-crystal X-ray diffraction study, giving crystallographic data as follows. 2-Acetyl-6-[1-(2,6-diisopropylphenylimino)ethyl]-4-methylphenol (1): a = 13.5893(5) Å, b = 10.5781(4) Å, c = 15.6778(4) Å, = 113.1804(18), P2₁/c. 2,6-[1-(2,6-Diisopropylphenylimino)ethyl]-4-methylphenol (2): a = 12.1909(5) Å, b = 16.3324(6) Å, c = 15.9456(7) Å, = 96.990(2), P2₁/c. 2-Acetyl-6-[1-(4-bromine-2,6-dimethylphenylimino)ethyl]-4-methylphenol (3): a = 7.5337(4) Å, b = 10.0457(5) Å, c = 12.6163(4) Å, = 90.139(3), = 104.003(3), = 106.485(2), P–1. Their molecular structures show that the 2,6-substituted phenyl ring is located approximately orthogonal to the hydroxyphenyl ring with the dihedral angle varying from 85.2 to 101.4.for X-ray Diffraction     

Crystal structures and hydrogen bond analysis of three arenesulfonate salts ofl-alanine,glycine, andl-serine

Single crystal X-ray structures are presented for three amino acid arenesulfonate salts:l-alanine 2,4-dinitrobenzenesulfonate hydrate (1), 21 glycine 1,5-naphthalene-disulfonate dihydrate (2), andl-serine 4-hydroxybenzenesulfonate (3). Hydrogen bond patterns of each salt are analyzed systematically by using hydrogen bond graph set notation. First-, second-, and selected third-level graph set motifs of the three salts are presented and discussed. Hydrogen-bonded diad, chain, ring, ribbon, and two-dimensional sheet patterns are identified in these structures. Even though the three salts contain apparently similar types of hydrogen-bonding interactions, their graph sets are quite different.Deceased June 10, 1992.     

Crystal structures of two monoamine-coordinated zinc complexes obtained via solid-vapor reaction

The solid-vapor reaction properties of [Zn(p-NH₂C₆H₄SO₃)₂(H₂O)₂] _n and alkyl monoamines were investigated. Two of the resulting complexes, [Zn(C₂H₅NH₂)₄](p-H₂NC₆H₄ SO₃)₂ and [Zn(n-C₃H₇NH₂)₄](p-H₂NC₆H₄SO₃)₂, grew into single crystals in situ during the solid-vapor reaction process and their structures were characterized by single-crystal structural analysis.     

Crystal structure and physical characterization of neotame methanol solvate

The crystal structure of the methanol solvate (empirical formula: 2C₂₀H₃₀N₂O₅·3CH₃OH) of a new dipeptide sweetener, neotame (N-(3,3-dimethylbutyl)-L--aspartyl-L-phenylalanine 1-methyl ester), has been determined. Crystal data: a = 9.8989(1), b = 18.1331(1), c = 27.5725(1) Å, orthorhombic, space group P2₁2₁2₁, with Z = 4. Each unit cell includes 8 neotame and 12 methanol molecules. Disorder exists in one neotame molecule and one methanol molecule. The crystals were characterized by the following techniques: hot-stage microscopy (HSM), Karl-Fischer titrimetry (KFT), powder X-ray diffractometry (PXRD), differential scanning calorimetry (DSC), thermogravimetry (TGA), ¹³C solid-state nuclear magnetic resonance (SSNMR) spectroscopy. Under HSM at a heating rate of 10°C/min in silicone oil, the sample melts at 64–84°C and liberates bubbles at 71–86°C. DSC in open pans shows two overlapping endotherms at 56 and 71°C, probably due to melting and desolvation, respectively. TGA in open pans shows 5.9% weight loss due to desolvation below 70°C. Under house vacuum (23 mm Hg) over phosphorus pentoxide at 23°C, the methanol solvate produces pure amorphous anhydrate, which converts to crystalline neotame monohydrate in the presence of moisture.     

Crystal structures of the hydrated disodium and paraquat salts of 1,8-disulfonato-3,4,5,6-acridinetetracarboxylic acid

Two hydrated salts of 1,8-disulfonato-3,4,5,6-acridinetetracarboxylic acid, H₂L, have been characterized by single-crystal X-ray analysis. Compound 1, Na₂L·9 H₂O, crystallizes in the monoclinic space group C2/c with a = 42.005(1), b = 6.838(1), c = 23.807 (1) Å, = 122.71 (1)°, and Z = 8. Compound 2, (paraquat)L·2H₂O, belongs to the triclinic space group with a = 9.940(1), b = 11.543(1), c = 14.033(1) Å, = 105.45(1), = 95.82(1), = 100.14(1)° and and Z = 2. All four carboxyl groups in the 3,4,5,6-tetracarboxyacridine-1,8-disulfonate dianion L^2– are un-ionized. In 1 the distorted octahedrally coordinated sodium cations, the anions, and the lattice water molecules are joined together by hydrogen bonds to generate a three-dimensional network. In the crystal structure of 2, a host framework composed of L^2– ions and water molecules accommodate the paraquat dications within two channel systems running parallel to the a and b axes.     

Investigation of the Solution Structures and Determination of the Growth Units of Cadmium Mercury Thiocyanate Crystal

To get a better understanding of the growth of cadmium mercury thiocyanate (CMTC), a promising nonlinear optical crystal, we have investigated the structures of its growth solutions by using Raman spectra. It has been found that Hg(II) ions coordinate with SCN^‐ through S atoms, forming the most stable complex of [Hg(SCN)₄]^2‐ in the solutions while Cd(II) ions bind to SCN^‐ around Hg(II) through the other end N atom. Thereby, taking [Hg(SCN)₄]^2‐ anions as centers, a network structure of Cd(II)‐N‐C‐S‐Hg(II) is formed in the solutions as in the crystal lattice. It is notably that there are other complexes, mostly the Cd(SCN)_n (n < 4) complexes, in the solutions. Therefore, the solution structure of CMTC is complicated, which is believed to contribute greatly to the difficulty of growing large single crystals. Based on the analysis of the solution structures, the reasonable growth units of CMTC are proposed.     

Crystal and molecular structure of 2,6-dihydroxybenzoic acid

The crystal and molecular structure of 2,6-dihydroxybenzoic acid has been determined by single crystal X-ray diffraction. The crystals are monoclinic witha=5.4084(5),b=5.2240(7),c=22.986(4) Å, =94.69(3)°, space group P2₁/c,Z=4,V=647.27(16) ų,d _c =1.58Mg m^–3, The acid crystallizes as hydrogen bonded carboxylic dimers which pack to generate a herringbone motif of the type typically encountered in polycyclic aromatic compounds.     

Crystal structure and vibrational spectra of two complexes of manganese(II) with glicyne

Two polymeric complexes of glicyne with manganese(II) have been prepared and characterized by means of spectroscopic and x-ray analyses. The first complex of the formula [Mn(Gly)Cl₂(H₂O)₂] crystallizes in the monoclinic space group P2₁/n with a = 6.519(2), b = 15.981(3), c = 7.893(2) Å, and = 97.18(3)°. The Mn atoms are in distorted octahedral environments with all ligands in cis positions. The adjacent manganese(II) ions are linked in polymeric chains via carboxylate groups. The second complex [Mn(Gly)₂Cl₂] crystallizes in the triclinic space group P with a = 4.968(2), b = 6.582(2), c = 7.925(3) Å, = 106.17(3), = 92.86(3), and = 107.21(3)°. The octahedral-coordinated manganese(II) ion is situated on a crystallographic center of symmetry and is bound to four carboxylate oxygen atoms from different glicyne molecules and two chloride ions.     

Isolation,characterization and phase transformation of new ginsenoside compound k hydrate and methanol solvates

Two new solvates of ginsenoside compound K (nonstoichiometric hydrate/CKH and methanol solvate/CKM) have been discovered and characterized in this paper. They were obtained through cooling crystallization in different solvents, and CKM could be prepared by transformation from CKH as well. The solvates were analysed by Power X‐ray diffraction (PXRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and fourier transform infrared (FTIR) spectroscopy. From the thermal studies, it is shown that the two new products are both solvates with different onset melting points. The PXRD and FTIR data support different crystal structures of them. It also describes the solution‐mediated phase transformation from CKH to CKM with a combination usage of process analytical technology tools. It is shown that the transformation process can be divided into three stages. The results reveal that seeding and low temperature help to accelerate the transformation, but initial solution concentration do little to the transformation kinetics. The kinetics and the rate‐controlling step for the transformation depend on the nucleation of the CKM. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal structures and supramolecular assembly of 1:2 piperazine with o- and p-nitrophenol

1:2 Cocrystals of piperazine (PPN) with o- and p-nitrophenol (oNPH and pNPH) were obtained from aqueous solution. The co-crystal structure of PPN, 2pNPH, and 2H₂O is triclinic space group : a = 6.401(1) Å, b = 6.7515(1) Å, c = 11.219(1) Å, = 100.37(1)°, = 97.10(1)°, = 99.99(1)°,V= 465.5(1) ų, Z = 2. Refinement led to a final conventional R value of 0.0365 for 2081 reflections. PPN, 2oNPH, and 2H₂O cocrystallize in the monoclinic space group P2₁ : a = 7.753(1) Å, b = 10.888(2) Å, c = 11.378(2) Å, = 92.89(1)°, V = 953.1(3) ų, Z = 2. Refinement led to a final conventional R value of 0.0347 for 1978 reflections. It was found in both cocrystals that the hydroxyl H-atom of pNPH and oNPH was transferred to a N-atom of PPN, forming new ionic complexes PPNH₂ ²⁺2(oNP^–) and PPNH₂ ²⁺2(pNP^–), respectively.     

Crystal and molecular structure of diphenylphosphinylacetic acid

Diphenylphosphinylacetic acid crystallizes in the monoclinic space groupP2_l/n with unit cell dimensionsa=5.6875(7),b=17.049(4),c=13.471(2) Å, =93.36(1)° and Z=4. The molecular packing consists of hydrogen bonded chains arising from intermolecular interactions between a carboxylic acid hydroxyl group and an oxygen of an adjacent phosphine oxide moiety.     

Crystal and molecular structure of glutaconic acid

Crystals of Glutaconic acid, C₅O₄H₆, are triclinic, space group P , with the cell dimensions (294 K), a = 4.843(1) Å, b = 10.188(1) Å, c = 12.609(1) Å, = 83.46(1)°, = 80.02(1)°, = 78.71(1)°, V = 598.8(3) ų with D _m = 1.47, D _x = 1.443 gcm ^–3. There are two independent molecules in the asymmetric unit. The crystal structure was solved by multi solution techniques with three-dimensional data collected (to the limit of 2_max of 154° for Cu K) on a CAD-4 diffractometer. The crystal structure was refined by full matrix least squares method to a final R value of 0.058 for 1894 reflections (I 2). The two independent molecules are conformationally similar. In both the molecules, the carboxyl ends are trans to each other with respect to the central C=C double bond in the structure. The molecules are self-paired through dimeric type of hydrogen bonding involving the terminal carboxyl groups, characteristic of many dicarboxylic acid structures. The crystal structure is stabilized by a series of O–HO hydrogen bonds of the glutaconic acid dimeric units. Free radicals have been shown to be involved in a number of chemical and biological processes and lipid peroxidation is one such process. Glutaconic acid was chosen as a simple unsaturated model of a fatty acid. When irradiated with X-rays, it was found to form a stable free radical structure. ESR (electron spin resonance) and ENDOR (electron nuclear double resonance) studies were used to characterize the free radical structure and correlate with the X-ray structure. The free radical was found to be HOOC–CH=CH–CH–COOH with the glutaconic acid in the trans conformation. The damage occurs at the -carbon atom (the first carbon of the double bond). The damage consists of a loss of an hydrogen atom. This results in an unpaired electron in the p-orbital delocalized over the three central carbon atoms. The two -proton couplings were resolved in the ENDOR spectrum. ESR spectra show that the two molecules are magnetically similar that is in agreement with the crystal structure that reveals that the two independent molecules are conformationally similar. This is the characteristic type of damage that occurs in lipids when they form free radicals that in turn reacts with oxygen and other compounds and ultimately results in cellular damage.     

绿柱石晶体的水热法生长及特征研究

采用温差水热法,以分析纯的Al(OH)3和BeO以及无色纯净的石英为原材料,球形和//s(1121)的片状无色绿柱石为籽晶,在复杂的盐酸混合溶液中生长了无色透明的绿柱石晶体.利用双圈反射测角仪、电子探针、X射线衍射仪和红外光谱仪等仪器,对合成绿柱石晶体的形态、成分及晶体结构进行了详细的研究.结果表明,合成的绿柱石晶体为六方短柱状,主要发育平行双面c{0001}、六方柱m{1010}、a{1120}和六方双锥p{1011}四种单形.合成的绿柱石晶体的成分中(Na2O+ K2O)的质量分数约为0.59;,且c0/a0值为0.9988,可归属于"正常"绿柱石向"四面体"绿柱石的过渡范畴.在中性或弱碱性环境体系中,通过调整绿柱石中各成分的百分含量,有望在更低的温度、压力条件下合成出高质量的板柱状绿柱石晶体.     

Crystal structures of substituted imidazolidine derivatives

The crystal structures of isoxazole, 3-[[dihydro-2-[(Z)-2-oxohyrazono]-1H-imidazol-1-(3H)-yl]methyl-5-phenyl-,N-oxide] (C₁₃H₁₃N₅O₃) (I), isoxazole,3-[[dihydro-2-[(Z)-2-oxohyrazono]-1H-imidazol-1-(3H)-yl]-methyl-5-(4-methylphenyl)-,N-oxide] (C₁₄H₁₅N₅O₃) (II) and isoxazole, 3-[[dihydro-2-[(Z)-2-oxohyrazono]-1H-imidazol-1-(3H)-yl]-methyl-5-(2-methoxyphenyl)-,N-oxide] (C₁₄H₁₅N₅O₄) (III) have been determined by X-ray diffraction studies. The compound I, crystallized in triclinic space group with unit cell dimensions a = 7.2405(7) ?, b = 7.9936(8) ?, c = 11.6573(11) ?, α = 97.801(2)°, β = 90.884(2)°, γ = 96.250(2)° and Z = 2. Compound II crystallized in orthorhombic space group Pna2₁ with unit cell dimensions a = 10.1778(10) ?, b = 28.228(3) ?, c = 5.1206(5) ?, and Z = 4. Compound III crystallized in monoclinic space group P2₁/n with unit cell dimensions a = 7.8439(9) ?, b = 7.8544(9) ?, c = 23.534(3) ?, β = 99.464(2)° and Z = 4. For all three compounds, the five-membered imidazolidine ring adopts an envelope conformation. The crystal structures are stabilized by both the intramolecular N–H···O and intermolecular N–H···N hydrogen bonding.     

Crystallization of mefenamic acid and polymorphs

The crystallization of Mefenamic Acid, (MA), which has a prevalent usage in drug formulation, was investigated. MA is a high‐dose, anti‐inflammatory, analgesic agent used for pain in menstrual disorders. Some negative properties of MA are a high hydrophobicity and propensity to stick to surfaces, which cause great problems during granulation and tabletting. To facilitate tabletability, enhance dissolution rates, and develop a stable and reproducible dosage form, investigation of the physicochemical properties of mefenamic acid is necessary. Pharmaceutical drugs are commonly crystalline materials and are therefore subject to polymorphism. Polymorphism, the ability of a substance to exist in more than one crystalline form, is a significant phenomenon in the field of chemical engineering sciences, including pharmaceutical development. Establishing the polymorphic behaviour of a drug molecule early in development minimizes the number of unsuitable candidates developed and reduces the risk of encountering issues later which may have a major financial and time impact. Mefenamic acid crystals were recrystallized from five different solvents of N, N‐dimethylformamide (DMF), acetone, N, N‐dimethylacetamide (DMA), Dimethylsulfoxide (DMS) and Ethyl Acetate (EA). In order to characterize the Mefenamic Acid crystal structure and the polymorphic forms of the crystals obtained by recrystallization, the scanning electron microscopy (SEM), Raman diffractometry and X‐ray pattern were used. From the industrial crystallization point of view, the crystal size distribution (CSD), the crystal shape, the polymorphic form and the crystallization steps are important factors that affect the quality and bioavailability of a drug. For the determination of crystal size distribution of MA, The Focused Beam Reflectance Measurement (FBRM) technique was practiced and CSD profiles were obtained. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal structures of complexes of tri-, tetra-, or nonaethyleneglycol dimethyl ether with dichloropicric acid and water

The 1:2:2 triglyme/dichloropicric acid/water adduct is triclinic, space group P ; at 172(2) K, a = 4.9210(10), b = 13.424(3), c = 14.068(3) Å, = 115.04(3), = 90.93(3), = 92.24(3)°, D _x = 1.600(5) g cm^–3, V = 840.8(3) ų, and Z = 1. Each water molecule is hydrogen bonded to a terminal OCH₃ group of one polyether and to an oxygen adjacent to an OCH₃ of a neighboring polyether, resulting in two-dimensional ribbons. These ribbons, in turn, are assembled into a three-dimensional structure held together by chains of dichloropicric acid molecules connected to each other through chlorine–nitro group oxygen intermolecular interactions. The picric acid chains are attached to the water–polyether ribbons by hydrogen bonds from the picric acid to the water. The 1:2:2 tetraglyme/dichloropicric acid/water adduct is monoclinic, space group C2/c; at 172(2) K, a = 30.529(6), b = 5.4210(11), c = 25.413(5) Å, = 122.33(3)°, D _x = 1.597(3) g cm^–3, V = 3553.7(12) ų, and Z = 4. The hydrogen bonding pattern resembles that of the analogous 1:2:2 pentaglyme complex reported previously, with the exception that both of the lone pairs of the central oxygen atom participate in hydrogen bonding to protons of water molecules. The second water proton is hydrogen bonded to a terminal OCH₃ group. In this complex the dichloropicric acid molecules form a two-dimensional layer through chlorine–nitro group oxygen intermolecular interactions. The water molecules bond each isolated polyether molecule to adjacent dichloropicric acid layers. The 1:4:4 nonaglyme/dichloropicric acid/water complex is triclinic, space group P ; at 172(2) K, a = 8.0830(16), b = 13.570(3), c = 16.751(3) Å, = 102.01(3), = 102.39(3), = 96.43(3), D _x = 1.637(6) g cm^–3, V = 1731.5(6), and Z = 1. The hydrogen bonding pattern is similar to that in the pentaglyme complex, except that four dichloropicric acid molecules and four water molecules are coordinated to a single polyether, and the polyether chain is appreciably disordered. In this case there are again chains of dichloropicric acid molecules held together by intermolecular chlorine–oxygen interactions. The chains are packed into two-dimensional layers held together through hydrogen bonds to water. Each isolated polyether is connected to four water molecules, two attached to dichloropicric acid molecules in one layer and the other two connected to the adjacent layer.