FAB Mass Spectra Research Articles

СИНТЕЗ ОКТЕНІДИНУ ГЕКСАФТОРОСИЛІКАТУ – НОВОГО ПОТЕНЦІЙНОГО КАРІЄСПРОФІЛАКТИЧНОГО І АНТИБАКТЕРІАЛЬНОГО АГЕНТА

Мета роботи. Здійснити синтез октенідину гексафторосилікату як потенційного карієспрофілактичного і антибактеріального препарату.Матеріали і методи. Вихідні реагенти, октенідину дигідрохлорид і кремнефтороводнева кислота є комерційно доступними реактивами. ІЧ-спектри поглинання реєстрували на спектрофотометрі Spectrum BX II FT-IR System (Perkіn-Elmer), мас-спектри FAB – спектрометрі VG 7070 (VG Analytіcal), спектри ЯМР 1H, 19F – на спектрометрі Varіan Gemini-400. Термогравіметричний аналіз проводили на дериватографі Q-1500 D системи F. Paulik – J. Paulik – L. Erdey.Результати й обговорення. Одержано октенідину гексафторосилікату моногідрат на основі реакції іонного обміну між метанольним розчином октенідину дигідрохлориду і кремнефтороводневою кислотою. Склад і іонна будова синтезованої сполуки підтверджено методами ІЧ-, ЯМР 1H, 19F-спектроскопії, мас-спектрометрії. Термоліз комплексу супроводжується процесами дегідратації і деструкції з подальшим окисленням фрагментів катіону.Висновки. Синтезовано октенідину гексафторосилікату моногідрат, нове похідне октенідину, що становить інтерес як потенційний карієспрофілактичний і антибактеріальний засіб.

Straightforward Preparation Method for Complexes Bearing a Bidentate N-Heterocyclic Carbene To Introduce Undergraduate Students to Research Methodology

A laboratory experiment for students in advanced inorganic chemistry is described. In this experiment, students prepare two metal complexes with a potentially bidentate-carbene ligand. The complexes are synthesized by reaction of a bis-imidazolium salt with silver(I) oxide or palladium(II) acetate. Silver and palladium complexes are binuclear and mononuclear species, respectively, in which the carbene ligand behaves in a different coordination mode. The reaction conditions are straightforward and the complexes air-stable species, even though the palladium compound must be prepared using air-free techniques. Students must also assign the signals in the 1H and 13C-{1H} NMR spectra. The complexes showed a fluxional behavior in solution as can be deduced from their 1H NMR spectra. The students are given the 3D structures of the complexes as an aid to understand this dynamic behavior. The students should also use the FAB–mass spectrum of the silver complex and the concept of isotopic pattern in order to discri...

Synthetic, Characterization, Biological, Electrical and Catalytic Studies of Some Transition Metal Complexes of Unsymmetrical Quadridentate Schiff Base Ligand

Unsymmetrical tetradentate Schiff base N-(2-hydroxy-5-methylacetophenone)-N'-(2-hydroxy acetophenone) ethylene diamine (H₂L) and its complexes with Cr(III), Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) have been synthesized and characterized by elemental analyses, magnetic susceptibility measurements, IR, electronic spectra and thermogravimetric analyses. ¹H, ¹³C-NMR and FAB Mass spectra of ligand clearly indicate the presence of OH and azomethine groups. Elemental analyses of the complexes indicate that the metal to ligand ratio is 1:1 in all complexes. Infrared spectra of complexes indicate a dibasic quadridentate nature of the ligand and its coordination to metal ions through phenolic oxygen and azomethine nitrogen atoms. The thermal behavior of these complexes showed the loss of lattice water in the first step followed by decomposition of the ligand in subsequent steps. The thermal data have also been analyzed for the kinetic parameters by using Horowitz-Metzger method. The dependence of the electrical conductivity on the temperature has been studied over the temperature range 313-403 K and the complexes are found to show semiconducting behavior. XRD and SEM images of some representative complexes have been recorded. The antimicrobial activity of the ligand and its complexes has been screened against various microorganisms and all of them were found to be active against the test organisms. The Fe(III) and Ni(II) complex have been tested for the catalytic oxidation of styrene.

Microwave-Assisted Synthesis of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) Complexes of Tridentate Schiff Base N-(2-hydroxyphenyl) 2-hydroxy-5-bromobenzaldimine: Characterization, DNA Interaction, Antioxidant, and In Vitro Antimicrobial Studies

Five mononuclear complexes of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) with the Schiff base N-(2-hydroxyphenyl) 2-hydroxy-5-bromobenzaldimine were synthesized under microwave irradiation. The microwave irradiation method was found remarkably successful and gave higher yield at a less reaction time. The complexes were fully characterized by elemental analyses, FT-IR, 1H NMR, EPR, FAB mass spectra, electronic spectra, molar conductivity, magnetic susceptibility measurements, and thermogravimetric analyses (TGA). Structural compositions were assigned by mass spectral studies. Four-coordinate geometry has been assigned to these complexes tentatively. The interaction of the complexes with calf thymus DNA (CT-DNA) was investigated by absorption spectroscopy, emission spectroscopy, and viscosity measurements. The experimental evidences indicated that the binding strength follow the order Cu(II) > Mn(II) > Co(II) > Ni(II) >Zn (II). Moreover, the complexes were examined for their antioxidant activities against reactive oxygen species (O2 · − and HO · radicals). Additionally, the ligand and its complexes were screened in vitro for their antibacterial and antifungal activities. Preliminary information obtained from the present work would help in the development of nucleic acid molecular probes and new therapeutic reagents for diseases.

Synthesis of Triphenyltin (IV) and Dibutyltin (IV) Complexes of 1-Aryl-2,5-dithiohydrazodicarbonamides and Their Characterization

Organotin complexes of the types Ph3SnL and Bu2SnL [where Ph = phenyl and Bu = butyl; HL = 1-phenyl-2,5-dithiohydrazodicarbonamide (HPhthc), 1-benzyl-2,5-dithiohydrazodicarbonamide (Hbzthc), 1-(4-ethoxyphenyl)-2,5-dithiohydrazodicarbonamide (HEtOPhthc)] have been prepared. Molar conductance studies demonstrate the nonionic behavior of the complexes. The 1H and 13C nuclear magnetic resonance and FAB mass spectra of the complexes are consistent with the proposed stoichiometry. Infrared spectra suggest an anionic bidentate coordinating behavior of the ligands.

Thermal and Microbicidal Study of Coordination Polymers: Transition Metal with 8HQMIT Ligand

A few coordination polymers of transition metal, Mn(II), Co(II), Ni(II), Cu(II), and Zn(II), obtained from the reaction of metal acetate with newly synthesized bis-indol contains ligand namely, 3,6-bis(1-((8-hydroxyquinolin-5-yl)methyl)-1H-indol-3-yl)-1,2,4-triazin-5(2H)-one (8HQMIT) are described here. The ligand has been characterized by 1H NMR, 13C NMR, IR, and FAB mass spectra. Elemental analysis, infrared and electronic reflectance spectra, magnetic susceptibility measurements, and thermogravimetry have been employed to characterize the coordination polymers. The coordination polymers have distorted octahedral geometry. The microbicidal activity of all the samples has also been monitored against plant pathogens. The thermal decomposition of the coordination polymers is studied and indicates that not only the coordinated water is lost but also that the decomposition of the ligand from the coordination polymers is necessary to interpret the successive mass loss.

Effect of substituent of terpyridines on the in vitro antioxidant, antitubercular, biocidal and fluorescence studies of copper(II) complexes with clioquinol

An octahedral complexes of copper with clioquinol(CQ) and substituted terpyridine have been synthesized. The Cu(II) complexes have been characterized by elemental analyses, thermogravimetric analyses, magnetic moment measurements, FT-IR, electronic, 1HNMR and FAB mass spectra. Antimycobacterial screening of ligand and its copper compound against Mycobacterium tuberculosis shows clear enhancement in the antitubercular activity upon copper complexation. Ferric-reducing anti-oxidant power of all complexes were measured. The fluorescence spectra of complexes show red shift, which may be due to the chelation by the ligands to the metal ion. It enhances ligand ability to accept electrons and decreases the electron transition energy. The antimicrobial efficiency of the complexes were tested on five different microorganisms and showed good biological activity.

Spectroscopic studies of oxo-centered, carboxylate-bridged, trinuclear mixed-valence iron (ІІІ, ІІІ, ІІ) complexes with aromatic hydroxycarboxylic acids

New type of oxo-centered, carboxylate-bridged, trinuclear, mixed-valence iron complexes of the general formula [Fe3O(OOCR)3(OOCR*)3L3] (where R=C13H27 or C15H31 and R*=C6H4(OH), (R′); C6H5CH(OH), (R″) or (C6H5)2C(OH), (R‴) and L=Methanol) were synthesized by the reaction of [Fe3O(OOCCH3)6(H2O)3] with straight chain carboxylic acids and aromatic hydroxycarboxylic acids. These were characterized by elemental analyses, spectral (electronic, infrared, Mössbauer, FAB mass and powder XRD) studies, conductance and magnetic susceptibility measurements. Infrared spectra suggested bidentate and bridging mode of coordination of both the carboxylate and hydroxycarboxylate anions along with Fe3O vibrations in the complexes. Mössbauer parameters indicated the presence of high-spin Fe(ІІ) (S=2) and high-spin Fe(ІІІ) (S=5/2) centers in the complexes, confirming the valence-localized type of species. An intervalence-transfer band observed at 13,690–13,850cm−1 range in the room-temperature electronic spectra of the complexes also suggested the complexes containing iron in mixed-valence state. Trinuclear nature of the complexes was confirmed by their FAB mass spectra. Magnetic moment values displayed octahedral geometry around each iron in the complexes and a net anti-ferromagnetic exchange coupling via μ-oxo atom related to mixed-valence pairs. A plausible structure for these complexes has been established on the basis of spectra and magnetic moment data.

Antioxidant, tautomerism and antibacterial studies of Fe(III)-1,2,4-triazole based complexes

New Fe(III) complexes have been synthesized by the reactions of ferric nitrate with Schiff base derived from 3-substituted phenyl-4-amino-5-hydrazino-1,2,4-triazole and indoline-2,3-dione. All these complexes are soluble in DMF and DMSO; low molar conductance values indicate that they are non-electrolytes. Elemental analyses suggest that the complexes have 1:1 stoichiometry of the type [FeLn(H2O)(OH)]·xH2O. Structural and spectroscopic properties have been studied on the basis of elemental analyses, infrared spectra, 1H and 13H NMR spectra, electronic spectra, magnetic measurements and FAB mass spectra. FT-IR, 1H and 13H NMR studies reveal that the ligand (Ln) exists in the tautomeric enol form in both the states with intramolecular hydrogen bonding. Magnetic moment and reflectance spectral studies reveal that an octahedral geometry has been assigned to all the prepared complexes. FRAP values indicate that all the compounds have a ferric reducing antioxidant power. The compounds 2 and 3 showed relatively high antioxidant activity while compound 1 and 4 shows poor antioxidant power. Also good antimicrobial activities of the complexes against Staphylococcus aureus, Bacillus subtilis, Serratia marcescens, Pseudomonas aeruginosa and Escherichia coli have been found compared to its free ligands.

Synthesis, Structure, and Anticancerous Properties of Silver Complexes

Although the “war on cancer” is now in its fourth decade and much progress has been made in categorizing the environmental causes and cellular and molecular biological basis for this dreaded disease, we still do not have a precise understanding of the differences between a cancer cell and its normal counterpart. The completion of the human genome sequence and its subsequent improvements in the sequence data are important steps to fully comprehend cancer cell biology. Ag(I) is being used as an anticancer agent in several human cancers. The anticancer activity of these complexes against Ehrlich’s ascites tumor cells (EACs) has been reported. The aim of the present study is to synthesize some new water soluble Ag(I) mixed ligand complexes containing nitrogen and sulfur base and to evaluate their biomedicinal properties. Mixed ligand complexes of Ag(I) metal derived from L‐lysine and thiouracil with 2,2′‐bipyridyl; 2‐aminopyridine with thiouracil have been synthesized. The composition of the prepared complexes was discussed on the basis of microanalysis, FAB‐mass, and FT‐ir, measurements. Molecular weight was confirmed by FAB‐mass spectra. The elemental analysis data suggest the stoichiometry to be M : L : L′ (1 : 1 : 1) ratio. These Ag(I) mixed ligand complexes showed excellent anticancer activity against Ehrlich’s ascites tumor cells (EACs).

Synthesis and spectral characterization of trinuclear, oxo-centered, carboxylate-bridged, mixed-valence iron complexes with Schiff bases

Some novel trinuclear, oxo-centered, carboxylate-bridged, mixed-valence iron complexes of the general formula [Fe3O(OOCR)3(SB)3L3] (where R=C13H27, C15H31 or C17H35, HSB=Schiff bases and L=Ethanol) have been synthesized by the stepwise substitutions of acetate ions from μ3-oxo-hexa(acetato)tri(aqua)iron(II)diiron(III), first with straight chain carboxylic acids and then with Schiff bases. The complexes were characterized by elemental analyses, molecular weight determinations and spectral (electronic, infrared, FAB mass, Mössbauer and powder XRD) studies. Molar conductance measurements indicated the complexes to be non-electrolytes in nitrobenzene. Bridging nature of carboxylate and Schiff base anions in the complexes was established by their infrared spectra. Mössbauer spectroscopic studies indicated two quadrupole-split doublets due to Fe(II) and Fe(III) ions at 80, 200 and 295K, confirming the complexes are mixed-valence species. This was also supported by the observed electronic spectra of the complexes. Magnetic susceptibility measurements displayed octahedral geometry around iron in mixed-valence state and a net antiferromagnetic exchange coupling via μ-oxo atom. Trinuclear nature of the complexes was confirmed by their molecular weight determination and FAB mass spectra. A plausible structure for these complexes has been established on the basis of spectral and magnetic moment data.

Synthesis and pharmaceutical importance of 2-azetidinone derivatives of phenothiazine

A new series of N-[3-(10H-phenothiazin-1-yl)propyl]-4-(substituted phenyl)-3-chloro-2-oxo-1-azetidinecarboxamide 4(a–m) have been synthesized from phenothiazine in four steps. Phenothiazine on reaction with Cl(CH2)3Br at room temperature gave 1-(3-chlorophenyl)-10H-phenothiazine, 1. The compound 1 yielded the condensation product with urea at room temperature, N-[3-(10H-phenothiazin-1-yl)propyl]urea 2. The compound 2 on further reaction with several substituted aromatic aldehydes produced N-[3-(10H-phenothiazin-1-yl)propyl]-N′-[(substituted phenyl)methylidene]-urea 3(a–m). The compounds 3(a–m) on treatment with ClCH2COCl in the presence of Et3N furnished final products 4(a–m). The structures of all the newly synthesized compounds were confirmed by IR, 1H NMR, 13C NMR and FAB-Mass spectra and chemical methods. All the final synthesized compounds were evaluated for their antibacterial, antifungal and antitubercular activities which displayed acceptable activities.

Synthesis and Characterization of Organotin(IV) Thiobiurets

Some triphenyltin and dibutyltin thiobiurets of the type Ph3SnL and Bu2SnL2 [where LH = 1,5 diphenyl-2-thiobiuret (PPTBH), 1-(4-ethoxyphenyl)-5-phenyl-2-thiobiuret (EtOPPTBH), or 1-naphthyl-5-phenyl-2-thiobiuret (naphPTBH)], have been synthesized and characterized by elemental analysis and various physicochemical techniques. Molar conductance measurements show the non-ionic behavior of the complexes. FAB mass spectra exhibit their monomeric nature. 1H and 13CNMR spectra support the proposed stoichiometry of the complexes. Infrared spectra suggest monoanionic bidentate mode of bonding of the ligands. The powder XRD patterns of the complex Bu2Sn (PPTB)2 are indicative of triclinic crystal system.

Complexes of some rare earth metal ions of the mesogenic Schiff-base, N,N′-di-(4′-octyloxybenzoatesalicylidene)-l″,8″-diamino-3″,6″-dioxaoctane: Synthesis and spectral studies

A mesogenic Schiff-base, N,N′-di-(4′-octyloxybenzoatesalicylidene)-l″,8″-diamino-3″,6″-dioxaoctane; H2dobsdd (H2L3), that nematogenic mesophase was synthesized and its structure studied by elemental analysis and FAB mass, NMR and IR spectra. The Schiff-base, H2L3, upon condensation with hydrated lanthanide(III) nitrates, yields LnIII complexes of the general composition [Ln2(L3H2)3(NO3)4](NO3)2, where Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Ho. The IR and NMR spectral data imply a bi-dentate of the Schiff-base through two phenolate oxygens in its zwitterionic form (as L3H2) to the LnIII ions, rendering the overall geometry of the complexes to seven-coordinated polyhedron — possibly distorted mono-capped octahedron. Among the metal complexes, only that of LaIII and GdIII are found to be mesogenic.

Synthesis and characterization of some novel copper(II) complexes with an optically active Betti base

Novel Cu(II) complexes with racemic as well as optically pure 1-(α-amino benzyl)-2-napthol, commonly known as Betti base, and its derivative 1-(α-pyrrolidinyl benzyl)-2-napthol have been synthesized. The general composition of all the isolated complexes, as determined by elemental analysis, thermal analysis and FAB mass spectra, is found to be Cu(L-H)2. The coordination of the ligand with metal has been confirmed by IR and ESR spectra of the complexes. The CD spectra of complexes with the S-form of the ligands exhibit a mirror image relationship with the CD spectra of the complexes with the corresponding R-form of the ligands. The Cu(II) complex with racemic Betti base has been characterized structurally. It crystallizes in the monoclinic space group P21/c. The complexes display quasi reversible redox behavior due to the Cu(II)/Cu(I) reduction process.

Binary Titanium (IV) Metal-organic Frameworks with Multidentate Ligands

Some volatile binary metal-organic frameworks of titanium (IV), [Ti(OOCR) 4 ] (where R = C 13 H 27, C 15 H 31, C 17 H 35 or C 21 H 43 ) were synthesized by the reaction of titanium tetrachloride and sodium salts of the straight chain fatty acids (prepared in situ) in 1:4 molar ratio. The isolated solid products were showing poor crystallinity and were characterized by their elemental analyses, molecular weight determinations, conductance, spectral (infrared, 1 H NMR, 13 C NMR, FAB mass and powder XRD) and TEM studies. Their monomeric nature was confirmed by molecular weight determinations and FAB mass spectra. Eight coordination number of titanium (IV) have been assigned in the isolated compounds. TEM indicated the particles are spherical in shape having ~200 nm diameter.

Molecular precursors for the preparation of homogenous zirconia–silica materials by hydrolytic sol–gel process in organic media. Crystal structures of [Zr{OSi(OtBu)3}4(H2O)2]·2H2O and [Ti(OtBu){OSi(OtBu)3}3

[Zr(OPr(i))(4)·Pr(i)OH] reacts with [HOSi(O(t)Bu)(3)] in anhydrous benzene in 1:1 and 1:2 molar ratios to afford alkoxy zirconosiloxane precursors of the types [Zr(OPr(i))(3){OSi(O(t)Bu)(3)}] (A) and [Zr(OPr(i))(2){OSi(O(t)Bu)(3)}(2)] (B), respectively. Further reactions of A or B with glycols in 1:1 molar ratio afforded six chemically modified precursors of the types [Zr(OPr(i))(OGO){OSi(O(t)Bu)(3)}] (1A-3A) and [Zr(OGO){OSi(O(t)Bu)(3)}(2)] (1B-3B), respectively [where G = (-CH(2)-)(2) (1A, 1B); (-CH(2)-)(3) (2A, 2B) and (-CH(2)CH(2)CH(CH(3)-)} (3A, 3B)]. The precursors A and B are viscous liquids, which solidify on ageing whereas the other products are all solids, soluble in common organic solvents. These were characterized by elemental analyses, molecular weight measurements, FAB mass, FTIR, (1)H, (13)C and (29)Si-NMR studies. Cryoscopic molecular weight measurements of all the products, as well as the FAB mass studies of 3A and 3B, indicate their monomeric nature. However, FAB mass spectrum of the solidified B suggests that it exists in dimeric form. Single crystal structure analysis of [Zr{OSi(O(t)Bu)(3)}(4)(H(2)O)(2)]·2H(2)O (3b) (R(fac) = 11.9%) as well as that of corresponding better quality crystals of [Ti(O(t)Bu){OSi(O(t)Bu)(3)}(3)] (4) (R(fac) = 5.97%) indicate the presence of a M-O-Si bond. TG analyses of 3A, B, and 3B indicate the formation of zirconia-silica materials of the type ZrO(2)·SiO(2) from 3A and ZrO(2)·2SiO(2) from B or 3B at low decomposition temperatures (≤200 °C). The desired homogenous nano-sized zirconia-silica materials [ZrO(2)·nSiO(2)] have been obtained easily from the precursors A and B as well as from the glycol modified precursors 3A and 3B by hydrolytic sol-gel process in organic media without using any acid or base catalyst, and these were characterized by powder XRD patterns, SEM images, EDX analyses and IR spectroscopy.

Effect of substituent of terpyridines on the DNA-interaction of polypyridyl ruthenium(II) complexes

An octahedral complexes of ruthenium with 2,9-dimethyl-1,10-phenanthroline (dmphen) and substituted terpyridine have been synthesized. The Ru II complexes have been characterized by elemental analyses, thermogravimetric analyses, magnetic moment measurements, FT-IR, electronic, 1H NMR and FAB mass spectra. The binding strength and mode of interaction of the complexes with Herring Sperm DNA has been investigated using absorption titration and viscosity measurement studies. Results suggest that the substituent on terpyridine ligand affects the binding mode and binding ability of the complexes. Effect of time and ionic strength on DNA cleavage ability of complex has also been studied by gel electrophoresis. Results suggest that more than 200 mM concentration of NaCl decreases the cleavage ability of complex.

Synthesis, characterization and catalytic property of ruthenium–terpyridyl complexes

The known compound 4′-(carboxyphenyl)-2,2′:6,2″-terpyridine (LH) was prepared and complexed with RuCl 3.3H 2O. The resulting complex [Ru(LH)Cl 3] was then allowed to react separately with 2,2′-bipyridine (bpy), 1,10-phenanthroline (phen), triphenylphosphine (PPh 3) and 1,2-bis-(diphenylphosphino)ethane (dppe). The compositions of corresponding complexes [Ru(LH)bpyCl](BF 4) 1, [Ru(LH)phenCl](BF 4) 2, [Ru(LH)(PPh 3)(CH 3CN) 2] (BF 4) 2 3 and [Ru(LH)(dppe)Cl](BF 4) 4 were assigned on the basis of their FAB-mass spectra, elemental analysis, spectroscopic (IR, NMR) data and X-ray diffraction measurements. The diamagnetic, cationic complexes displayed strong MLCT transitions in the visible region with significant shift in MLCT band energy corresponding to the strength of substituted ligands. The redox behaviour of the complexes was investigated using cyclic voltammetry measurements. Among all the complexes, 3 efficiently catalyzed the synthesis of propargylamine via three components coupling reaction.

Vanadyl(IV) complexes of 4-alkoxy substituted [N,O] donor salicylaldimine Schiff bases derived from chloro-/nitro-aniline: synthesis, mesomorphism, and DFT study

Oxovanadium(IV)-Schiff-base complexes, [VOL2] {L = N,N′-bis-(4-X-amino phenyl (4′-n-alkoxy)-salicylaldiminato), n = 10, 18; X = Cl, NO2}, have been synthesized from the interaction of vanadyl (VO2+) and the bidentate [N,O] donor in methanol/ethanol. The compounds were characterized by FT–IR, 1H- and 13C-NMR, FAB-mass spectra, elemental analyses, and solution electrical conductivity. Mesomorphic behavior of the ligands and their vanadyl complexes were probed by polarizing optical microscopy and differential scanning calorimetry. The compounds are thermally stable and exhibit enantiotropic smectic A mesomorphism over the temperature range of 57–231°C. The mesophase–isotropic transition temperatures for the complexes are much higher than the ligands. Melting and clearing points of the compounds did not show any definitive trend with regards to alkoxy chain length or electronegative substituent. Variable temperature magnetic susceptibility measurements of the vanadyl complexes clearly show the absence of exchange interactions among the vanadyl spin centers. Non-electrolytic natures of the complexes were shown by conductometric measurements. A ν(V=O) of ∼970 cm−1 corroborated the absence of any V=O ··· V=O interactions. Density functional theory study carried out using DMol3 at BLYP/DNP level to determine the energy-optimized structure revealed a distorted square pyramidal geometry for the vanadyl complexes.