Structure Analysis Of Compound Research Articles

Single Crystal X‐Ray Structure Analyses of Binary and Ternary Compounds A49Tl108+x (A=K, Rb, Cs; x=0–1.76) Related to the K49Tl108 Type Structure

AbstractThe structural chemistry of alkali metal thallides shows a broad range of type structures. At an alkali metal : thallium proportion A : Tl 1 : 2 the perceived dependency on the alkali metal involved is conspicuous. Two main structure types are reported with A15Tl27 (A=K, Rb, Cs) and K49Tl108. The compound K49K108 with a 3‐dimensional Tl‐substructure has been known since 1993 from Cordier and Müller but so far only with potassium. We here present single crystal X‐Ray structure analyses of the compounds K49‐yRbyTl108, and K49‐yCsyTl108 ( belonging to the K49Tl108 type structure. Additionally, structures of Rb49Tl109.67, Cs3.35Rb45.65Tl109.71 and Cs7.49Rb41.51Tl109.76 are introduced, which prove the possibility of Tl incorporation in the Tl12 icosahedra in K49Tl108 type structures. The effects of the change in alkali metals on the thallium substructure are discussed as well as the preferred Wyckoff sites of the different alkali metals.

Phytochemical Profile, Antioxidant Activity, and Cytotoxicity Assessment of Tagetes erecta L. Flowers.

Tagetes erecta L. is a popular ornamental plant of the Asteraceae family, which is widely cultivated not only for its decorative use, but also for the extraction of lutein. Besides carotenoid representatives, which have been extensively studied, other important classes of secondary metabolites present in the plant, such as polyphenols, could exhibit important biological activities. The phytochemical analysis of a methanolic extract obtained from T. erecta inflorescences was achieved using liquid chromatography–mass spectrometry (LC-MS) techniques. The extract was further subjected to a multistep purification process, which allowed the separation of different fractions. The total extract and its fractions contain several polyphenolic compounds, such as hydroxybenzoic and hydroxycinnamic acid derivatives, flavonols (especially quercetagetin glycosides), and several aglycons (e.g., quercetin, patuletin). One of the fractions, containing mostly quercetagitrin, was subjected to two different antioxidant assays (metal chelating activity and lipoxygenase inhibition) and to in vitro cytotoxicity assessment. Generally, the biological assays showed promising results for the investigated fraction compared to the initial extract. Given the encouraging outcome of the in vitro assays, further purification and structural analysis of compounds from T. erecta extracts, as well as further in vivo investigations are justified.

Structural, Hirshfeld surface and in vitro cytotoxicity evaluation of five new N-aryl-N’-alkoxycarbonyl thiocarbamide derivatives

Five new compounds, N-(2, 4-dichlorophenyl)-N’-(methoxycarbonyl) thiocarbamide (1), N-(2, 4-dichlorophenyl)-N’-(ethoxycarbonyl) thiocarbamide (2), N-(2, 4-dichlorophenyl)-N’-(2, 2, 2-trichloroethoxycarbonyl) thiocarbamide (3), N-(2,4-dichlrophenyl)-N’-(pentoxycarbonyl) thiocarbamide (4) and N-(4-nitrophenyl)-N’-(pentoxycarbonyl) thiocarbamide (5), have been synthesized by the reaction of various alkoxy chloroformates with 2, 4-dichloroaniline/4-nitroaniline.The molecular structures of the compounds were elucidated by using spectroscopic methods (FT-IR, 1H and 13C NMR) and single-crystal X-ray structure analysis of compounds 2 and 5. Antiperiplanar orientation of C = O and C = S group across C–N bonds of thiocarbamide core may be due to the presence of intramolecular (N–H···O–C) hydrogen bond in the crystal structure of both the compounds. The presence of intermolecular interactions (C–H···S, C–H···O and N–H···S) in the molecular structure of the compounds has been studied in detail using Hirshfeld surfaces and their associated two-dimensional fingerprint plots. In vitro cytotoxicity screening of the synthesized compounds evaluated on a panel of seven human cancer cell lines (cervical carcinoma (2008, C13*), colorectal (HT29 and HCT116) and ovarian carcinoma (A2780, A2780/CP and IGROV-1)) demonstrated significant inhibitory properties.

New complex bearing end-to-end dicyanamide as a double bridging ligand: Crystallography study and magnetic properties

A new polymeric, two-dimensional compound [Fe(4,4’-bpy)(µ1,5-dca)2].0.24(4,4’-bpy).0.5(EtOH) (1), in which dca= dicyanamide and 4,4’-bpy = 4,4’-bipyridine, has been synthesized under solvothermal conditions and fully characterized by elemental analysis, FT-IR spectroscopy and X-ray single crystal diffraction. Structural analysis of compound 1 showed it is a novel two dimensional coordination polymer, constructed from repetition of 4,4’-bpy and dca as a bidentate bridging ligand. Using the co-ligand 4,4’-bpy, lead to completely different structure geometry and network, which confirms the substantial effect of co-ligand. Furthermore, magnetic properties have been performed to understand the correlation structure-properties.

The first Fe(II) complex bearing end-to-end dicyanamide as a double bridging ligand: Crystallography study and Hirshfeld surface analysis; completed with a CSD survey

Two new polymeric, one and two-dimensional compounds [Fe(dmbpy) (μ1,5-dca)2] (1) and [Fe(4,4′-bpy) (μ1,5-dca)2].0.24(4,4′-bpy).0.5(EtOH) (2), in which dmbpy = 5,5′-dimethyl-bipyridine, dca = dicyanamide and 4,4′-bpy = 4,4′-bipyridine, has been synthesized under solvothermal conditions and fully characterized by elemental analysis, FT-IR spectroscopy and X-ray single crystal diffraction. Compound 1, with a rare coordination environment, is the only well-known example in which end-to-end double bridged dca ligands and a bidentate bulky aromatic ligand (dmbpy) are coordinated simultaneously to the iron center. Structural analysis of compound 2 showed it is a novel two-dimensional coordination polymer, constructed from repetition of 4,4′-bpy and dca as a bidentate bridging ligand. Changing the co-ligand to 4,4′-bpy, lead to completely different structure geometry and network, which confirms the substantial effect of co-ligand. Furthermore, Hirshfeld surfaces analyses have been performed to help understand the packing.

Ruthenium–Triazene Complexes as Latent Catalysts for UV‐Induced ROMP

AbstractThree novel ruthenium(II) complexes, RuX2(IMesH2)[N,N‐diethyl‐N′‐(2‐benzylidene)triazene] [IMesH2 = 1,3‐dimesitylimidazolin‐2‐ylidene; X = Cl– (2), CF3COO– (3), C6F5COO– (4)] are described. Single‐crystal X‐ray structure analysis of compounds 2–4 revealed that the triazene ligand exists in the trans form and that the aryl‐connected nitrogen atom of the triazene binds to the ruthenium atom to form a five‐membered chelate ring. Compounds 2–4 were applied to the UV‐induced ring‐opening metathesis polymerization (ROMP) of cis‐cyclooctene (5) and dicyclopentadiene (6). Whereas all three precatalysts show pronounced thermal latency in the presence of 5 or 6, only compound 2 displays significant photo‐ROMP activity. The photoreactivity of precatalysts 2–4, which decreases with increasing electron‐withdrawing character and with decreasing pKa of the X groups, is discussed and correlated with the X‐ray data of 2–4, with low‐temperature 1H NMR measurements as well as with cyclovoltammetric measurements.

Synthesis, Phase and Structural Analysis of Compounds in the System Gd2-xNdxZr2O7 (0.0 ≤ x ≤ 2.0)

A series of compounds with the general formula Gd2-xNdxZr2O7 (0.0 ≤ x ≤ 2.0) was synthesized by high- temperature solid state method and characterized by powder X-ray diffraction. Trivalent neodymium was used as the surrogate for americium with three valences, an actinide found in radioactive nuclear wastes. The X-ray diffraction patterns show that the whole system of Gd2-xNdxZr2O7 (0.0 ≤ x ≤ 2.0) consistently possesses the pyrochlore structure. In order to get the accurate data of structural changes of zirconate pyrochlores incorporating Am3+, the Rietveld structural refinement method was employed to calculate the crystal cell parameters of zirconate pyrochlores. The calculated results indicated that the value of x in the system Gd2-xNdxZr2O7 (0.0 ≤ x ≤ 2.0) and the crystal cell parameter a accord with a = 10.52696 + 0.07036 x, x and the volume of crystal cell V follow the relation of V = 1166.45459 + 23.72163 x.

Synthesis and Structural Characterization of Metallogermylenes, Cp-Substituted Germylene, and a Germanium(II)-Borane Adduct from Pyridyl-1-azaallyl Germanium(II) Chloride

The reaction of [{N(SiMe3)C(Ph)C(SiMe3)(C5H4N-2)}GeCl] (1) with Na[M(η5-C5H5)(CO)3]·2DME (M = Mo, W) afforded the metallogermylenes [{N(SiMe3)C(Ph)C(SiMe3)(C5H4N-2)}Ge-M(η5-C5H5)(CO)3] (M = Mo (2), W (3)). Compounds 2 and 3 have been characterized by X-ray crystallography and NMR and IR spectroscopy. Structural analyses of compounds 2 and 3 are consistent with the presence of lone-pair electrons at the germanium(II) center. The Ge–Mo and Ge–W bond distances of 2.875(1) and 2.852(1) Å are consistent with Ge–metal single bonds. The chlorogermylene 1 was also used in the synthesis of a substituted germylene, [{N(SiMe3)C(Ph)C(SiMe3)(C5H4N-2)}Ge(η1-C5H5)] (4), by reaction with sodium cyclopentadienylide. The reaction of compound 1 with tris(pentafluorophenyl)borane led to the formation of a Lewis acid–base adduct, [{N(SiMe3)C(Ph)C(SiMe3)(C5H4N-2)}Ge(Cl)→B(C6F5)3] (5).

Cyclopentadienyl Dicarbonyl Iron‐Bismuth Compounds – Synthesis, Structure, and Reactivity

AbstractAbstract. The cyclopentadienyl‐substituted iron‐bismuth complexes [{Cp(CO)2Fe}BiCl2] (1), [{Cp(CO)2Fe}BiBr2] (2), [{Cp′′(CO)2Fe}BiBr2] (3) and [{Cp*(CO)2Fe}BiBr2] (4) were prepared with high yields starting from [Cpx(CO)2Fe]2 [Cpx = C5H5 (Cp), C5H3‐1, 3‐tBu2 (Cp′′), C5Me5 (Cp*)] and the corresponding bismuth halides. The single crystal X‐ray structure analyses of compounds 2–4 are reported. Comparison of their solubility demonstrates that the steric hindrance in this type of compounds is only slightly higher for compound 3 compared with compound 2 but significantly lower compared with the Cp* derivative 4. Compounds 1–4 react with nucleophililic reagents such as KOtBu, NaOCH2CH2OCH3, and NaOSiMe3 as well as with water in the presence of an amine to give a mixture of [{Cpx(CO)2Fe}BiX] (X = Cl, Br) and [{Cpx(CO)2Fe}3Bi]. In case of a reaction with nBu4NCl and DMAP (dimethylaminopyridine) no such dismutation is observed. Instead the complexes [{Cp(CO)2Fe}BiBr2(DMAP)2] (5), [NnBu4]2[{{Cp(CO)2Fe}BiBr3}2] (6) and [NnBu4]2[{{Cp(CO)2Fe}BiCl3}2] (7) were isolated and characterized by single‐crystal X‐ray diffraction.

Identification of chemicals to inhibit the kinase activity of leucine-rich repeat kinase 2 (LRRK2), a Parkinson’s disease-associated protein

Parkinson's disease (PD) is a late-onset neurodegenerative disease which occurs at more than 1% in populations aging 65-years and over. Recently, leucine-rich repeat kinase 2 (LRRK2) has been identified as a causative gene for autosomal dominantly inherited familial PD cases. LRRK2 G2019S which is a prevalent mutant found in familial PD patients with LRRK2 mutations, exhibited kinase activity stronger than that of the wild type, suggesting the LRRK2 kinase inhibitor as a potential PD therapeutics. To develop such therapeutics, we initially screened a small chemical library and selected compound 1, whose IC(50) is about 13.2 μM. To develop better inhibitors, we tested five of the compound 1 derivatives and found a slightly better inhibitor, compound 4, whose IC(50) is 4.1 μM. The cell-based assay showed that these two chemicals inhibited oxidative stress-induced neurotoxicity caused by over-expression of a PD-specific LRRK2 mutant, G2019S. In addition, the structural analysis of compound 4 suggested hydrogen bond interactions between compound 4 and Ala 1950 residue in the backbone of the ATP binding pocket of LRRK2 kinas domain. Therefore, compound 4 may be a promising lead compound to further develop a PD therapeutics based on LRRK2 kinase inhibition.

Structural analysis of compounds with actions similar to local anesthetics and antipsychotic phenothiazines in yeast

Local anesthetics and antipsychotic phenothiazines cause a rapid shutdown of both actin polarization and translation initiation in yeast cells, like some environmental stresses. These compounds all have an amphiphilic structure, surfactant activity and the ability to lyse yeast cells. To elucidate the structures responsible for the shutdown activity and cell lysis, we investigated a variety of amphiphiles. In the hydrophobic region, the straight alkyl structure was sufficient for the shutdown of actin polarization and translational initiation. In the hydrophilic region of the straight alkyl compounds, cationic trimethyl ammonium (TMA) and non-ionic hydroxyl structure (alcohols) shut down both reactions, while an anionic structure, sulphate, with a long alkyl chain (≥C6) shut down actin polarization only. On the compounds that shut down both reactions, including the clinical drugs, TMA compounds and alcohols, the potencies of shutdown and lysis exponentially increased with increasing the number of carbons in the hydrophobic region, whereas safety was affected by the structures of both hydrophilic and hydrophobic regions. These results indicate that the yeast system can easily evaluate clinical drugs, and provide a structural basis for designing compounds to shut down intracellular reactions.

Mono- and dinuclear Fe(III) complexes with the N2O2 donor 5-chlorosalicylideneimine ligands; synthesis, X-ray structural characterization and magnetic properties

Two novel monomeric [C18H17Cl3N2O2Fe] (1) and dimeric [C38H36N4O4Cl6Fe2] (2) Fe(III) tetradentate Schiff base complexes have been synthesized and their crystal structures have been determined by single crystal X-ray diffraction analysis. In complex (1) the Schiff base ligand coordinates toward one iron atom in a tetradentate mode and each iron atom is five coordinated with the coordination geometry around iron atom which can be described as a distorted square pyramid. The presence of a short (2.89Å) non-bonding interatomic Fe···O distances between adjacent monomeric Fe(III) complexes results in the formation of a dimer. Structural analysis of compound (2) shows that the structure is a centrosymmetric dimer in which the six coordinated Fe(III) atoms are linked by μ-phenoxo bridges from one of the phenolic oxygen atoms of each Schiff base ligand to the opposite metal center. The variable-temperature (2–300K) magnetic susceptibility (χ) data of these two compounds have been investigated. The results show that for both complexes Fe(III) centers are in the high spin configuration (S=5/2) and indicate antiferromagnetic spin-exchange interaction between Fe(III) ions. The obtained results are briefly discussed using magnetostructural correlations developed for other class of iron(III) complexes.

Magnesium Diimidosulfinates – Conformational Studies in the Solid State and in Solution

AbstractThe magnesium diimidosulfinates [(thf)2MgX{(NR)2SR′}] (X = Cl, Br; R = tBu, SiMe3; R′ = Ph, Bz, Me, nBu; 1–5) have been synthesised by treating sulfur diimides with different Grignard reagents and characterized by X‐ray crystallography and NMR spectroscopy. The structural analyses of compounds 1–5 show that they contain either monomeric or dimeric structural motifs, depending on the steric requirements of the sulfur‐bound organic substituent. NMR experiments suggest a temperature‐dependent dynamic equilibrium between different conformers for all compounds.

Synthesis, spectral characterization and structural investigation on some 4-aminoantipyrine containing Schiff base Cu(II) complexes and their molecular association

Compounds [Cu(L 1) 2] ( 1) and [Cu(L 2) 2] ( 2), where L 1 and L 2 are Schiff base ligands of 4-aminoantipyrine and substituted salicylaldehydes, were synthesized and characterized using various spectroscopic techniques such as elemental analysis, UV–Vis, IR, and NMR. The single crystal X-ray structures for L 1, L 2, and their corresponding Cu(II) complexes assembled in a 1:2 metal to ligand ratio were analyzed for their various weak H-bonding and dimeric association. The structural analysis of compounds 1 and 2, being the first crystal structures in this series, deserves special attention to help further the understanding in this area of structure–reactivity correlation studies. Further these compounds, composed of very similar chemical composition with a small difference in the substituent on the salicylaldehyde moiety, influenced through various weak inter- and intramolecular H-bonding and C–H⋯π interactions, rearrange the geometry around Cu(II) from a tetrahedrally distorted square planar geometry in [Cu(L 1) 2] ( 1) to square planar in [Cu(L 2) 2] ( 2). Steric strain imposed by the methyl substitution on the 4-aminoantipyrine moiety of the Schiff base ligand, causing this small change of the Cu(II) geometry, along with various weak interactions is analyzed in detail.

Synthesis and structural characterization of some arylamidinium diphenylphosphinates: Formation of one-, two- and three-dimensional networks by charge-assisted hydrogen bonds

In the presence of air, the interaction of AgSO 3CF 3 with phosphorus–nitrogen π-electron-rich compounds ArC( NPPh 2)[N(SiMe 3) 2] (Ar = phenyl, p-tolyl, 4-pyridyl, 3-pyridyl and 2-pyridyl) and 1,4-C 6H 4{C( NPPh 2)[N(SiMe 3) 2]} 2 in acetonitrile led to the formation of metallic silver and the oxidative cleavage product {[ArC(NH 2) 2](Ph 2PO 2)} n (Ar = phenyl, 1; p-tolyl, 2; 4-pyridyl, 3; 3-pyridyl, 4; 2-pyridyl, 5) and [{1,4-C 6H 4[C(NH 2) 2] 2}(Ph 2PO 2) 2] n ( 6), respectively. Structural analyses of compounds 1– 6 revealed that these ionic salts are held together by charge-assisted hydrogen bonds forming 1D, 2D and 3D polymeric networks.

Synthesis of Group 14 Metal Enamido, Alkenyl, Imido and Alkenyl‐Amido Complexes from a Monoanionic Pyridyl‐1‐azaallyl Ligand

AbstractThe reactivity of the lithium pyridyl‐1‐azaallyl complex [Li{N(SiMe3)C(Ph)C(R)(C5H4N‐2)}]2 [R = SiMe3 (1) or H (10)] with group 14 metal halides has been studied under various conditions. It undergoes a salt‐elimination reaction with MCl2 (M = Ge, Sn or Pb) to form [Ge{C(C5H4N‐2)C(Ph)N(SiMe3)2}{N(SiMe3)C(Ph)C(SiMe3)(C5H4N‐2)}] (2), [M{N(SiMe3)C(Ph)C(SiMe3)(C5H4N‐2)}2] [M = Sn (3), Pb (4)], and [M{N(SiMe3)C(Ph)C(SiMe3)(C5H4N‐2)}Cl] [M = Ge (5), Sn (6), Pb (7)], where the azaaalyl moiety acts as a monodentate ligand. However, the reaction of 1 with GeCl4 or HSiCl3 forms [Ge{C(C5H4N‐2)C(Ph)N(SiMe3)}Cl2]2 (8) or [{(C5H4N‐2)C(SiMe3)C(Ph)N}(μ‐SiHCl)]2 (9), respectively, by elimination of both the lithium salt and Me3SiCl; the reaction of 10 with GeCl4 gives [{(C5H4N‐2)C(H)C(Ph)N}(μ‐GeCl2)]2 (11) in a similar manner. X‐ray structural analysis of compounds 2−5, 7−9 and 11 showed that the pyridyl‐1‐azaallyl ligand bonds to the metal center in enamido, alkenyl, alkenylamido, and imido bonding modes. A mechanism for the formation of these compounds is proposed and discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

The synthesis of carboacycles derived from B,B'-bis(aryl) derivatives of icosahedral ortho-carborane.

Reactions of both closo-9,12-I2-1,2-C2B10H10 and closo-9,10-I2-1,7-C2B10H10 with an excess of aryl magnesium bromide in the presence of [PdCl2(PPh3)2] afford the corresponding closo-9,12-(4-R-C6H4)2-1,2-C2B10H10 [R=H (1), Me (2), OMe (3), SMe (4), N(CH3)2 (5), Cl (6)] and closo-9,10-(4-R-C6H4)2-1,7-C2B10H10 [R'=Me (7), OMe (8), N(CH3)2 (9), Cl (10), and -C[(OCH2)2]CH3 (11)] compounds in high yields. The anisole derivatives 3 and 8 were deprotected to yield the corresponding bis-phenols 12 and 13, respectively. Structural analyses of compounds 1, 3, 6, and 12 are reported. Re-etherification of compound 12 by using gamma-bromotriethyleneglycol methyl ether provided 14 (R=(CH2CH2O)3CH3). Oxidation of 4 with ceric(IV) ammonium nitrate (CAN) generated the bis-sulfoxide 15 (R=S(O)Me). Deprotection of compound 11 led to the corresponding acetyl derivative 18 (R'=C(O)Me). Bis-anisole 3 was tethered with 1,3-dibromopropane, 1,6-dibromohexane, 1,8-dibromooctane, 4,4'-bis(iodomethyl)-1,1'-biphenyl, and alpha,alpha'-dibromo-2,6-lutidine to afford the dimers 20b, 21b, 22b, 23b, and 24b, respectively. The tetrameric carboracycles 27a and 30a, as well as the dimeric 29c were obtained through repetitive coupling of the dimeric compounds 20b, 24b, and 22b with 1,3-dibromopropane, alpha,alpha'-dibromo-2,6-lutidine, and 1,8-dibromooctane, respectively. The tetrameric carboracycle 28a was obtained upon consecutive reactions of 1 with 1,4-dibromobutane. Hexameric carboracycle 28b was identified as a byproduct. Exhaustive ether cleavage of 27a generated octaphenol 31a. Re-etherification of 31a with trimethylenesultone provided the octasulfonate 32a, the first example of a water-soluble carboracycle. Linkage of dimer 23b with alpha,alpha'-dibromolutidine yielded the cyclic tetrameric tetrapyridyl derivative 30a in low yield. The structures of the carboracycles 27a, 28a, 28b, and 30a have been confirmed by Xray crystallography. In addition, the compounds 28a,b are the first reported carboracycles that interact with solvent molecules in a host-guest fashion.

Synthese von Dibenzodiazoninonen

Efficient total syntheses of dibenzodiazoninones 4/5 are reported which are of chemical and pharmacological interest as structural modifications of the bryophyte constituent anthocerodiazonin 1. The nine-membered aza lactam structure was confirmed by X-ray structural analysis of compound 5.

Structural analysis of compound I in hemoproteins: Study on Proteus mirabilis catalase

Ferryl catalysis has attracted considerable interest, because a diverse variety of enzymes use ferryl intermediates to perform difficult chemistry. The structure of the reactional intermediate compound I of Proteus mirabilis catalase (PMC) has been solved using time-resolved X-ray diffraction techniques and single crystal microspectrophotometry. Formation of compound I is characterized by significant changes in the absorbance spectrum, and the creation of an oxoferryl group on the distal side of the heme. This group is clearly visible in the X-ray electron density maps. An unidentified electron density, likely to be an anion because of the nature of its environment, appears during the reaction, in a site distant from the heme. The structure of compound I in PMC is compared with that of compound I in cytochrome c peroxidase (CCP).

Proof of Inversion of Configuration on Stannylation of a Configurationally Stable, Tertiary Benzyllithium Compound from a Single‐Crystal X‐Ray Structure Analysis

AbstractConfigurationally stable, dipole‐stabilised benzyllithium compounds (R)‐and (S)‐1 b, prepared by deprotonation of the corresponding esters with sBuLi in toluene/di‐ethyl ether (5:1), reacted with (–)‐menthyldimethyltin bromide to afford the stannanes (–)‐3 and ( + )‐4, respectively. A single‐crystal X‐ray structure analysis of compound (–)‐3 proved that stannylation occurred with inversion of the configuration at the benzylic centre, assuming retention for the deprotonation step. Lithio‐destannylation and deuteration with MeOD follow a retentive course.