Monofunctional Bidentate Research Articles

Synthesis, characterization, antimicrobial and DNA cleavage study of organoantimony(III) and organoarsenic(III) complexes with monofunctional bidentate Schiff base

A series of mononuclear organoantimony(III) and organoarsenic(III) complexes of bidentate Schiff base [2-(2-fluorophenyl)methylene]hydrazinecarbothioamide (LH) have been synthesized by the reaction of Ph3Sb and Ph3As with ligand in 1:1 and 1:2 molar ratios. All the synthesized compounds were characterized by elemental analyses, melting point determinations and a combination of electronic, IR, 1H NMR, 13C NMR and X-ray diffraction spectroscopic studies. These studies showed that the ligand coordinated to the antimony and arsenic in a monobasic bidentate manner through sulfur and nitrogen donor system. Thus, a tetra-coordinated and a penta-coordinated environment around the antimony and arsenic atom has been proposed for 1:1 and 1:2 complexes, respectively. All the complexes and parent ligand have been screened for their antimicrobial activity on several pathogenic fungi and bacteria and were found to possess appreciable fungicidal and bactericidal properties. Further, the ligand and its corresponding metal complexes have been tested for their DNA cleavage activity by the gel electrophoresis and the results revealed that the complexes were better cleaving agents than ligand.

Synthesis, spectroscopic characterization, DFT calculations, and antimicrobial activities of N-arylsalicylaldiminate derivatives of diorganotin(IV)

Equimolar reaction of di-n-butyltin(IV) complexes of bidentate Schiff bases of the type [(n-Bu)2Sn(sb)Cl] with sodium salt of mono-functional bidentate ligands in THF-benzene solution afforded structurally interesting complexes of the type [(n-Bu)2Sn(sb)(L)] (1–6) [where sbH = Schiff bases: N-salicylidene-2-aminopyridine (sapH) I, N-salicylidene-2-methylaminobenzene (o-smabH) II, and N-salicylidene-4-methylaminobenzene (p-smabH) III; LH = mono-functional bidentate ligands, acetylacetone (acacH), ethanolamine (eaH)]. All these colored solid complexes were soluble in common organic solvents and characterized by elemental (C, H, N, and Sn) analysis, spectroscopic techniques [IR, (1H, 13C, and 119Sn) NMR] and mass spectrometry. Thermogravimetric analysis of complexes shows thermal behavior and stability of complexes. Computational studies of the synthesized Schiff bases and their organotin(IV) complexes were carried out using DFT which validate the structure of complexes proposed on the basis of spectroscopic data. The mixed-ligand complexes of diorganotin(IV) and Schiff bases were screened for their antibacterial and antifungal activities.

Microwave Assisted Synthesis, characterization and biological studies of isonicotinoylhydrazones and their Manganese (II) complexes

Among the most promising cleaner and energy efficient technologies, microwave-assisted technique has been popularly used for organic and inorganic synthesis. The use of microwave ovens in chemical synthesis has increasingly grown, due to its ability to dramatically reduce reaction times, improve yields, and simplified procedures. It is, therefore planned to synthesize some new Mn (II) Schiff base complexes using microwave irradiation technique. The Schiff base ligands 1-(2-furanyl) ethanone isonicotinoylhydrazone (L 5 H), 1-(2-thienyl) ethanone isonicotinoylhydrazone (L 6 H), 1-(2- pyridyl) ethanone isonicotinoylhydrazone (L 7 H), 1-(2-naphthyl) ethanone isonicotinoylhydrazone (L 8 H), were prepared by the condensation reaction of isonicotinic acid hydrazide with corresponding ethanons in 1:1 molar ratio, respectively, in ethanol under microwave exposure. The Mn (II) complexes have been prepared by mixing MnCl 2. 4H 2 O in 1:1 and 1:2 molar ratios with monofunctional bidentate ligands. The structure of the ligands and their transition metal complexes were confirmed by the elemental analysis, molecular weight determinations, IR, electronic and EPR spectral studies. On the basis of these studies it is clear that the ligands coordinated to the metal atom in a monobasic bidentate mode, by O ∩ N donor system. Thus a tetrahedral environment around the Mn (II) ionhas been proposed. The antimicrobial activity of Schiff base ligands and their respective Mn (II) complexes were tested against some of pathogenic bacterial and fungal strains. The results indicated that the complexes showed higher activity than the parent ligands.

Syntheses, silylation, characterization, and antimicrobial and antifertility activities of organoboron derivatives of some bioactive monofunctional bidentate semicarbazones

Some new mononuclear organoboron derivatives of the type PhBL1–5(OH) (1a–1e) were synthesized by the reaction of PhB(OH)2 and LH (LH = OC(NH2)NH:NC(CH3)4C6H4R, where R = H (L1H); CH3(L2H); OCH3(L3H); Cl (L4H); Br (L5H)) in 1:1 molar ratio in refluxing tetrahydrofuran (THF). This was followed by the reactions of PhBL1–5(OH) with NH(SiMe3)2 in 2:1 molar ratio in THF to yield new heterodinuclear derivatives of the type PhBL1–5(OSiMe3) (2a–2e). All these newly synthesized complexes were characterized using elemental analyses and their probable structure was proposed on the basis of infrared, 1H NMR, 13C NMR, 11B NMR and 29Si NMR spectral data and mass spectrometry. Semicarbazone ligands and their corresponding mono‐ and heterodinuclear boron derivatives were screened against pathogenic bacteria (E. coli and P. aeruginosa) and fungi (A. niger and P. peniculosum) to examine their antimicrobial activities. Representative compounds of each series of mono‐ and heterodinuclear boron derivatives and a ligand were screened for their antifertility activity on male adult Wistar rats.

Synthesis, Thermal, and Biological Studies of Newly Synthesized Cu(II) Complexes With Ciprofloxacin Based on Bromo-Coumarins Derivatives

The authors describe synthesis, characterization, and biological evaluation of Cu(II) complexes. Characterization of ligands has been carried out by elemental analysis, melting point, mass spectra, (1H & 13C) NMR, and FT-IR, while structure of metal complexes was confirmed by electronic spectra and FAB-mass spectral studies. Spectral studies confirm ligands is mono functional bidentate and octahedral environment around metal ions. Thermal behavior of Cu(II) complexes were investigated by means of TGA and magnetic measurements. The kinetic parameters are reported using the Freeman-Carroll method. Complexes were found significant potent antimicrobial and antioxidant activities compared to parent ligands employed for complexation. Supplemental materials are available for this article. Go to the publisher's online edition of Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry to view the supplemental file.

Greener synthesis and biological application of organosilicon(IV) complexes derived from semicarbazone and thiosemicarbazone of 3-acetyl-2H-chromen-2-one by microwave irradiation

A new series of silicon(IV) complexes have been synthesized by adopting classical thermal- and microwave-irradiated techniques. The complexes are prepared by the reaction of dimethyldichlorosilane and triphenylchlorosilane with the sodium salts of 1-(1-(2-oxo-2H-chromen-3-yl)ethylidene)thiosemicarbazide and 1-(1-(2-oxo-2H-chromen-3-yl)ethylidene)semicabazide in 1:1 and/or 1:2 molar ratios. Characterization of the ligands as well as of the silicon complexes has been carried out on the basis of elemental analysis, melting point determinations, molecular weight determinations, infrared, 1H NMR, 13C NMR, 29Si NMR, and electronic and mass spectral studies. Spectral studies confirm ligands to be monofunctional bidentate and trigonal bipyramidal and octahedral environments around silicon ions. The newly synthesized ligands and their complexes have been screened for antimicrobial, minimum inhibitory concentration, and pesticidal activities. The results obtained from bioassays indicate that this class of compounds can be utilized for the design of new substances with pesticidal activity and promising antimicrobial activity.

Synthesis, characterization, antimicrobial, pesticidal and DNA cleavage activity of germanium(IV) derivatives of 3-(2-methyl-2,3-dihydro-benzthiazo-2-yl)-chromen-2-one and N′-[1-2-oxo-2H-chrome-3yl-ethylidene]-hydrazinecarbodithionic acid benzyl ester ligands

Abstract The new ligands 3-(2-methyl-2,3-dihydro-benzthiazo-2-yl)-chromen-2one (AcBzH) and N′-[1-2-oxo-2H-chrome-3yl-ethylidene]-hydrazinecarbodithionic acid benzyl ester (AcBDTZH) were prepared by the reaction of 3-acetyl-2H-chromen-2-one with 2-aminothiophenol and S-benzyl dithiocarbazate, respectively. The germanium(IV) complexes have been prepared by reacting Ph3GeCl and Me3GeCl in 1:1 molar ratio with these monofunctional bidentate AcBzH and AcBDTZH ligands by using microwave as well as conventional heating methods for comparison purposes. All the synthesized compounds were characterized by elemental analyses, melting point, IR, 1H-NMR 13C-NMR, mass and X-ray powder diffraction techniques. These studies showed that the ligands coordinated to the germanium atom in a monobasic bidentate manner and trigonal bipyramidal environment around the germanium atom have been established for the complexes. To evaluate the effect of metal ion upon chelation, both ligands and their complexes have been screened for their antimicrobial activity against the various pathogenic bacterial and fungal strains. The metal complexes have shown antimicrobial activity as compared to the free ligands. The pesticidal activity and DNA cleavage activity of both ligands and their metal complexes have been tested and discussed.

Synthesis, Spectroscopic Characterization, Antimicrobial, Pesticidal and Nematicidal Activity of Some Nitrogen‐Oxygen and Nitrogen‐Sulfur donor Coumarins based Ligands and their Organotin(IV) Complexes

AbstractSeries of new tin complexes are synthesized by classical thermal and microwave‐irradiated techniques. The biologically potent ligands 3‐formyl‐4‐chlorocoumarin semicarbazone (L1H) and 3‐formyl‐4‐chlorocoumarin thiosemicarbazone (L2H), were prepared by the condensation of semicarbazide hydrochloride and thiosemicarbazide in ethanol with the particular ketone by using microwave as well as conventional methods. The tin(IV) complexes have been prepared by mixing Ph3SnCl/Me3SnCl/Me2SnCl2 in 1:1 and 1:2 molar ratios with monofunctional bidentate ligands. The structures of the ligands and their tin complexes were confirmed by the elemental analysis, melting point determinations, molecular weight determinations, IR, 1H NMR, 13C NMR, 119Sn NMR, UV, mass spectral and X‐ray powder diffraction studies. On the basis of these studies it is clear that the ligands coordinated to the metal atom in a monobasic bidentate mode, by X$^{\cap}$ N donor system. Thus, suitable trigonal bipyramidal geometry for penta‐coordinated state and octahedral geometry for hexa‐coordinated state have been suggested for the 1:1 and 1:2 metal compounds. Both the ligands and their complexes have been screened for their antimicrobial, pesticidal and nematicidal activities. Copyright © 2011 John Wiley & Sons, Ltd.

Structural, spectroscopic, and biological aspects of S∩N donor Schiff-base ligands and their chromium(III) complexes

New chromium(III) complexes are synthesized by classical thermal and microwave (MW)-irradiated techniques. The Schiff bases 2-acetylfuran-S-benzyldithiocarbazate (L1H), 2-acetylthiophene-S-benzyldithiocarbazate (L2H), 2-acetylpyridine-S-benzyldithiocarbazate (L3H), and 2-acetylnaphthalene-S-benzyldithiocarbazate (L4H) were prepared by condensation of -S-benzyldithiocarbazate in ethanol with the respective ketones by using MW as well as conventional methods. The chromium(III) complexes have been prepared by mixing CrCl3 · 6H2O in 1 : 1 and 1 : 2 molar ratios with monofunctional bidentate ketimines. The structure of the ligands and their transition metal complexes were confirmed by elemental analysis, melting point determinations, molecular weight determinations, infrared (IR), electronic and electron paramagnetic resonance (EPR) spectral, and X-ray powder diffraction studies. On the basis of these studies it is clear that the ligands coordinated to the metal atom in a monobasic bidentate mode by S∩N donors. Thus, an octahedral environment around the chromium(III) has been proposed. The growth inhibiting potential of the ligands and complexes has been assessed against a variety of fungal and bacterial strains.

Structural, Spectroscopic and Biological Aspects of O, N‐ Donor Schiff Base Ligand and its Cr(III), Co(II), Ni(II) and Cu(II) Complexes Synthesized through Green Chemical Approach

The monofunctional bidentate Schiff base ligand (o‐vanillin) p‐chloroaniline and its four new complexes of chromium(III), cobalt(II), nickel(II) and copper(II) have been synthesized by classical thermal and microwave‐irradiated techniques. All the new derivatives have been characterized by elemental analysis, molecular weight determinations, molar conductance measurements, UV‐Vis, IR and NMR spectral studies. The IR spectral data suggest the involvement of phenolic oxygen after deprotonation and azomethine nitrogen in coordination to the central metal ion. The growth inhibiting potential of the ligands and complexes has been assessed against a variety of fungal and bacterial strains.

Synthesis, characterization and soft transformation of some bis(cyclopentadienyl) Ti(IV) and Zr(IV) complexes of Schiff's base ligands to nano‐sized titania or zirconia materials

AbstractSome bis(cyclopentadienyl) complexes of Ti(IV)and Zr(IV) have been synthesized by the metathetical reactions of Cp2MCl2 with the sodium salt of monofunctional bidentate Schiff's base ligands in 1:1 and 1:2 stoichiometry in anhydrous THF. All the derivatives of the types Cp2MCl2−n{O(C6H4)CH6H5}n and Cp2MCl2−n{OC(CH3)(R)6H5}n (where R = CH3 or C6H5 and n = 1 or 2) have been characterized by elemental analyses, molecular weight measurements, FT‐IR and ‐NMR [1H and 13C{1H}] studies. The FAB mass spectra of a few representative complexes and the molecular weight measurements in freezing benzene indicate their monomeric nature in solution. Spectral studies appear to indicate mono‐ and bi‐dentate mode of attachment of the ligand in solution and in the solid state, respectively. Thermogravimetric analyses (TGA) of Cp2TiCl{O(C6H4)CH} (1) and Cp2ZrCl{O(C6H4)CH} (7) indicate their low thermal stability. Transformations of some of these complexes to pure titania (TiO2)/zirconia (ZrO2) have been observed at relatively low sintering temperatures. Powder X‐ray diffraction (XRD) and scanning electron micrograph (SEM) studies suggest the nanocrystalline nature of these materials. Copyright © 2007 John Wiley & Sons, Ltd.

Synthesis and characterization of some novel triphenylarsenic(V) derivatives of monofunctional bidentate 2,2‐disubstituted benzothiazoline ligands

AbstractA series of triphenylarsenic(V) derivatives Ph3As(OPri)[SC6H4N:C(R)CH2C(O)R′] have been synthesized by the reactions of triphenylarsenic(V)‐ isoproproxide, Ph3As(OPri)2 with the corresponding 2,2‐disubstituted benzothiazolines of the type ${\rm H\overline{NC_6 H_4 S}C(R)CH_2C(O)R'}$ (where R = CH3, R′ = CH3(1); R = CH3, R′ = C6H5(2); R = CH3, R′ = 4‐CH3C6H4(3); R = CH3, R′ = 4‐ClC6H4(4); and R = CF3, R′ = C6H5(5)) in equimolar ratio in refluxing benzene solution. Molecular weight measurements of these complexes show their monomeric nature in solution. Characterization of these compounds using elemental analyses, molecular weight measurements, and spectral studies (IR as well as NMR (1H and 13C)) shows the monofunctional bidentate nature of the ligands and a hexacoordination around the central arsenic atom in these organoarsenic(V) derivatives. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:76–80, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20233

Structural Studies with Antimicrobial and Antifertility Activity of a Monofunctional Bidentate Ligand with its Boron(III), Palladium(II), and Platinum(II) Complexes

The reaction of the sulfur donor Schiff base ligand, 7-nitro-3-(indolin-2-one) hydrazinecarbo-thioamide, with phenyldihydroxyboron in benzene, palladium(II)chloride, and platinum(II) chloride, in ethanol, gave the mononuclear tetracoordinated and hexacoordinated complexes. The Schiff base ligand coordinated to the boron atom in 1:1 and 1:2 molar ratios and to the palladium and platinum metals in only 1:2 molar ratios in the presence of an acidic and basic medium. Tentative structural conclusions are drawn for reaction products based upon elemental analysis, electrical conductance, and spectral (electronic, infrared, 1 H NMR, 13 C NMR, and 11 B NMR) data. The antifertility activity of the ligand and its nonmetal/metal complexes are discussed with a comparative study in an effective manner.

Heterobimetallic heterocyclic derivatives of indium(III)

AbstractReactions of InCl3 with potassium salts of bifunctional tridentate (L1H2HOC6H4CH NCH2CHMeOH) and monofunctional bidentate (L2HHOC6H4CHN‐i‐Bu) Schiff bases in 1:1 and 1:2 molar ratio in benzene afford complexes In(L1)Cl and In(L2)2Cl, respectively. On reaction with potassium isopropoxymetallates KB(O‐i‐Pr)4, KAl(O‐i‐Pr)4, KTi(O‐i‐Pr)5, and KNb(O‐i‐Pr)6, they produce interes‐ ting heterobimetallic heterocyclic complexes. These are characterized by elemental (N, B, Al, Ti, and Nb) analyses, molecular weight measurements, and spectral [IR, NMR (1H, 13C, 11B, and 27Al)] studies. Probable structures are suggested for them. © 2003 Wiley Periodicals, Inc. 15:21–25, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/.hc10206

Synthesis and Characterization of Some Triphenylantimony(V) Derivatives of Ν, Ο and S Containing Monofunctional Bidentate Ligands

Article Synthesis and Characterization of Some Triphenylantimony(V) Derivatives of Ν, Ο and S Containing Monofunctional Bidentate Ligands was published on February 1, 2004 in the journal Main Group Metal Chemistry (volume 27, issue 1).

Synthesis and Characterisation of Some New Aluminium Derivatives of Schiff Bases Containing N, O and S Donor Atoms and the Anti Fertility Activity of the Derivative Al[SC6H4N:C(CH3)CH2COCH3]3

Some new compounds of aluminium having the general formula AI[SC6H4N:C(R) CH2 C(O)R’]3 where R = CH3, R' = CH3 (1); R' = CH3, R' = C6H5 (2); R = CF3, R’ = -C = CH - CH = CHS (3); R = CF3, R’ = C6H5 (4) have been synthesised by the reactions of Al(OPri)3 and the corresponding ligands in 1:3 molar ratios in benzene. Elemental and spectroscopic (IR, 1H, 13C, and 27AI NMR) characterisation of these monomeric compounds reveals monofunctional bidentate behaviour of ligand moiety and the octahedral geometry around aluminium atom. Compound (1), AI[SC6H4N:C(CH3)CH2COCH3], has been tested for its antifertility activity in male albino rats. The oral administration of this compound at the dose level 6.5 rag/rat/day reduced the weights of testes and epididymides. Significant decrease in sperm motility as well as sperm density resulted in the reduction of male fertility by 100%. Production of primary spermatocytes (preleptotene and pachytene), secondary spermatocytes and step-19 spermatids declined by 56.10%, 44.42 %, 63.35 % and 64.57 % respectively. These results indicate that the administration of compound (1) in male rats brought about an interference with spermatogenesis which ultimately caused infertility.

Synthesis and characterization of some monofunctional bidentate Schiff bases derived from cinnamaldehyde ands-triazoles, and their Co(II), Ni(II), Cu(II) and Zn(II) complexes

A new series of complexes of Co(II), Ni(II), Cu(II) and Zn (II) with Schiff bases derived from the condensation of cinnamaldehyde with 4-amino-5-mercapto-s-triazole and 4-amino-5-mercapto-3-methyl-s-triazole have been synthesized. The complexes are characterized by elemental analyses,1H NMR, IR, electronic spectra and magnetic susceptibility measurements. The spectroscopic studies reveal that Schiff base acts as bidentate ligand with N, S donor set. Thermal studies of the complexes are also reported.

Studies on Heterometallic Binuclear Aldimine Derivatives of Boron(III) and Aluminum(III)

Abstract Synthetic and spectroscopic features of some heterometallic binuclear organoborane derivatives with monofunctional bidentate thiosemicarbazones and semicarbazones derived from the condensation of 2-pyridine carbaldehyde, 2-furfuraldehyde, 2-thiophenecarbaldehyde, 2-cinnamaldehyde and 3-indolecarbaldehyde with thiosemicarbazide and semicarbazide hydrochloride have been carried out in 1:1:1 molar ratio. The resulting derivatives of the types and (where TSCz−1 and SCz−1 represent the anions of thiosemicarbazone and semicarbazone) are coloured solids and non-electrolytic in nature. On the basis of analytical data, IR, 1H, 13C and 11B NMR spectral studies, a tricoordinated environment for boron and a tetra-coordinated environment around aluminum may be assigned to the resulting binculear complexes.

Synthesis to spectroscopy of titanium(IV) and zirconium(IV) chelates with biologically active ON donor systems

A new class of 16 organotitanium(IV) and organozirconium(IV) chelates with biologically active monofunctional bidentate semicarbazones having the O⌢N donor system were prepared by reacting 1∶1 and 1∶2 stoichiometric proportions of bis(cyclopentadienyl)titanium(IV) dichloride and bis(cyclopentadienyl)zirconium(IV) dichloride with the appropriate ligand, prepared by condensing heterocyclic ketones and semicarbazide hydrochlorides in presence of NaOAc. Trigonal bipyramidal and octahedral structures have been suggested for the 1∶1 and 1∶2 (M∶L) complexes of titanium(IV) and zirconium(IV), respectively, on the basis of spectral analyses.

STUDIES ON BINUCLEAR COMPLEXES DERIVED FROM SULFUR CONTAINING ORGANIC MOIETIES

Abstract Synthetic, spectroscopic and biological features of some binuclear complexes with monofunctional bidentate heterocyclic thiosemicarbazones have been described. The resulting derivatives of the type, B(TSCZ) (where TSCZ 1 represents the anion of thiosemicarbazone moiety) are colored solids and non-electrolytic in nature. On the basis of analytical data, IR, 1H, 13C and 11B NMR spectral studies, a tri-coordinated environment for boron and a penta-coordinated environment around arsenic may be assigned to the resulting binuclear complexes. Some representative ligands as well as their binuclear complexes have also been evaluated for their antifungal and antibacterial activities.