Polarographic study of mixed ligand complexes of Pb(II) with carboxylate ions and imidazole

Mixed complexes of Pb(II) with some carboxylate ions, viz. tartrate (tart^2?), malonate (mal^2?) and citrate (citr^3?); and imidazole (im) have been studied polarographically at 25°C and at constant ionic strength μ = 2.0 (NaNO₃) and at pH 6. The polarographic reduction of the complexes in each case is reversible and diffusion-controlled. Pb(II) forms a single mixed complex with tartrate and imidazole, viz [Pb(tart)(im)] with stability constant log β₁₁ = 4.19; with mal^2? and im, three mixed complexes, [Pb(mal)(im)], [Pb(mal)(im)₂] and [Pb(mal)₂(im)]^2? with stability constants log β₁₁ = 4.3, log β₁₂ = 7.3 and log β₂₁ = 5.5 respectively are formed. With citr^3? and im a single mixed species, [Pb(citr)(im)]^? with stability constant log β₁₁ = 8.0 is formed. Various equilibria involved in the mixed systems have been discussed.     

Polarographic study of Eu(III)-succinate-ethylenediamine and Eu(III)-malonate-ethylenediamine mixed systems

The mixed complexes of Eu(III) with succinate (succ^2?) and malonate (mal^2?) and ethylenediamine (en) have been studied polarographically at 25°C and at constant ionic strength, μ = 0.1 (NaNO₃) and pH 6. The reduction of the complexes in each case is quasi-reversible and diffusion-controlled. In each system three mixed complexes are formed, viz. [Eu(succ)(en)]⁺, [Eu(succ)(en)2]⁺ and [Eu(succ)₂(en)]^? with stability constants log β₁₁ = 9.2, log β₁₂ = 17.5 and log β₂₁ = 11.7; and [Eu(mal)(en)]⁺, [Eu(mal)₂(en)₂]^? and [Eu(mal)₃(en)]^3? with stability constants log β₁₁ = 11.4, log β₂₂ = 19.08 and log β₃₁ = 13.5 respectively.     

Polarographic Determination of the Formation Constants of the Mixed Ligand Complexes of Cd(II) and Pb(II) with Thiosulphate and Halide Ions

The mixed ligand complexes of Cd(II) and Pb(II) with thiosulphate as a primary ligand and chloride, bromide of iodide (individually) as a secondary ligand have been polarographically, investigated at 30°C and at a constant ionic strength of μ = 1.0 M (NaClO₄). Two mixed ligand complexes were formed with the Cd(II) ion: log β₁₂ = 4.77, 5.30 and 6.78 for the chloride, bromide and iodide ions, respectively; and log β₂₁ = 5.36, 5.04 and 6.22 for the same ions. For the Pb(II)-Ts-Cl system, only one mixed ligand complex was formed with a log stability constant log β₂₁ =4.35. For the Pb(II)-Ts-Br system, three mixed ligand complexes are obtained with log β₁₁ = 3.63, log β₁₂ = 4.51 and log β₂₁ = 4.85.     

Synthesis,spectral and thermal studies of monomeric,homobimetallic and polymeric complexes containing benzoyldithiocarbazate

New mixed ligand complexes of benzoyldithiocarbazate (H₂BDT) have been synthesized and characterized by elemental analyses, spectral studies (i.r., u.v.–vis., mass), thermal analysis and electrical conductivity measurements. The complexes have the general formulae: [M₂(BDT)(OX)₂] · xH₂O; [Co₂(BDT)(OX)₂(H₂O)₄]; [M(HBDT)(OX)-(H₂O)], [Ni(BDT)(py)₂] _n and [Ni(BDT)(L)] _n where M = Mn^II, Ni^II and Cu^II; BDT = dithiocarbazate dianion; OX = 8-hydroxyquinolinate; x = 1 or 2; M = Zn^II or Cd^II; HBDT = dithiocarbazate anion and L = 2,2-bipyridyl or 1,10-o-phenanthroline. For the [M₂(BDT)(OX)₂] · xH₂O, [Co₂(BDT)(OX)₂(H₂O)₄], [Ni(BDT)(py)₂] _n and [Ni(BDT)(L)] _n complexes, benzoyldithiocarbazate acts as a dibasic-tetradentate ligand in the enol form via the enolic oxygen, the hydrazide nitrogens and the thiolate sulphur, while it acts as a monobasic-tridentate ligand in the keto form in the [M(HBDT)(OX)(H₂O)] complexes. The thermal behaviour of the complexes has been studied by t.g.–d.t.g. techniques. Kinetic parameters of the thermal decomposition process have been computed by Coats–Redfern and Horowitz–Metzger methods. It is obvious that the thermal decomposition in the complexes occurs directly at the metal–ligand bonds except for the Zn^II and Cd^II complexes in which decomposition seems to be at a point in the benzoyldithiocarbazate moiety. From the calculated kinetic data it can be concluded that the dehydration processes in all complexes have been described as phase-boundary controlled reactions. The activation energy values reveal that the thermal stabilities of the homobimetallic complexes lie in the order: Mn^II < Ni^II < Co^II, while the monomeric Cd^II complex has more enhanced thermal stability than the Zn^II complex.     

A potentiometric study on complex formation of cadmium(II) ion with 2-mercaptoacetic and 2-mercaptopropionic acids

Complex equilibria between cadmium ions and 2-mercaptoacetic acid (H₂maa) or 2-mercaptopropionic acid (H₂mpa) have been studied in aqueous solutions containing 3 mol dm^?3 LiClO₄ as a constant ionic medium at 25°C by potentiometric titration. Formation constants of mono-η and bis-2-mercaptoalkanoato)cadmium complexes were found to ge log K₁₁ = 4.34 and log K₁₂ = 2.15 for the cadmium-H₂maa complexes, and log K₁₁ = 5.66 and log K₁₂ = 2.85 for the cadmium-H₂mpa complexes, respectively. The protonated complexes, CdHmaa⁺ and CdHmpa⁺, and a mixed ligand complex, Cd(maa)(mpa)²- were also detected.     

Synthesis and spectral studies on mixed ligand complexes of Cd(II) dithiocarbamates with nitrogen donors: single crystal X-ray structure of bis (4-methylpiperidinecarbodithioato-S,S′)(1,10-phenanthroline)cadmium(II)

The current article describes the synthesis and characterization of the following adducts: [Cd(2-mpipdtc)₂(1,10-phen)], [Cd(2-mpipdtc)₂(bipy)], [Cd(4-mpipdtc)₂(1,10-phen)], [Cd(4-mpipdtc)₂(bipy)] (where 2-mpipdtc^? = 2-methylpiperidinecarbodithioate anion, 4-mpipdtc^? = 4-methylpiperidinecarbodithioate anion, 1,10-phen = 1,10-phenanthroline and bipy = 2,2′-bipyridine). A single crystal X-ray structural analysis was carried out for [Cd(4-mpipdtc)₂(1,10-phen)]. IR spectra of the complexes show the contribution of the thioureide form to the structures. Reduction in ν_C–N(thioureide) for the mixed ligand complexes is attributed to the change in coordination number from four to six and the steric effect exerted by 1,10-phenanthroline or 2,2′-bipyridine. Deshielding of the protons adjacent to nitrogen in the ¹H NMR spectra is attributed to drift of electrons from the nitrogen of NR₂, forcing electron density towards sulfur via the thioureide π-system. Single crystal X-ray structural analysis of [Cd(4-mpipdtc)₂(1,10-phen)] showed that the cadmium is in a distorted octahedral environment with a CdS₄N₂ chromophore. The presence of 1,10-phenanthroline in the coordination sphere of Cd(dtc)₂ increases the Cd–S distances and decreases the S–Cd–S angles. VBS analysis supports the determined structure.     

Mixed ligand complexes with 2-piperidine-carboxylic acid as primary ligand and ethylene diamine, 2,2′-bipyridyl, 1,10-phenanthroline and 2(2′-pyridyl)quinoxaline as secondary ligands: preparation,characterization and biological activity

Synthesis procedures are described for the new stable mixed ligand complexes, [Pd(Hpa)(pa)]Cl, [Pd(pa)(H₂O)₂]Cl, [Pd(pa)(en)]Cl, [Pd(pa)(bpy)]Cl, [Pd(pa)(phen)Cl], [Pd(pa)(pyq)Cl], cis-[MoO₂(pa)₂], [Ag(pa)(bpy)], [Ag(pa)(pyq)], trans-[UO₂(pa)(pyq)](BPh₄) and [ReO(PPh₃)(pa)₂]Cl (Hpa = 2-piperidine-carboxylic acid, en = ethylene diamine, bpy = 2,2′-bipyridyl, phen = 1,10-phenanthroline, pyq = 2(2′-pyridyl)quinoxaline). Their elemental analyses, conductance, thermal measurements, Raman, IR, electronic, ¹H-n.m.r. and mass spectra have been measured and discussed. 2-Piperidine-carboxylic acid and its palladium complexes have been tested as growth inhibitors against Ehrlich ascites tumour cells (EAC) in Swiss albino mice.     

Trace metal speciation in sea water — a paper electrophoretic approach

Stability constants of individual trace metal complexes form the basis for calculations predicting the distribution of trace metal species in complexing media, such as sea water. In this study, the electrophoretic mobility of radiotracer ²¹⁰Pb is measured as a function of ligand concentration in chloride and sulfate solutions of constant ionic strength and temperature. A theoretically-derived expression, relating mobility to ligand concentration and complex stability constants, is fitted by the method of least squares to the experimental data to obtain estimates of the conditional stability constants of lead(II) chloro and sulfato complexes at 23°C and ionic strength 0.7 i.e., under conditions resembling those of ocean water. The values obtained are: log β₁ = 0.999 ± 0.014, log β₂ = 1.037± 0.032, log β₃ = 1.250 ± 0.015 for lead(II) chloro complexes, and log β₁ = 1.048 ± 0.015 and log β₂ = 1.183 ± 0.025 for lead(II) sulfato complexes. Experiments with eight other metal ions [Au(III), Bi(III), Cd(II), Co(II), Cu(II), Hg(II), Ni(II), and Po(IV)] and with sea water as electrolyte indicate the general applicability of the method.     

Study of Equilibria in the Aluminium(III)-Glycine and -Alanine Systems

The formation of various hydrolytic and mixed hydrolytic complexes of the aluminium(III) ion in the presence of glycine and L-alanine, has been studied in 0.5 mol dm^?3 (Na)NO₃ medium at 25deg;C, by emf method. The concentration ratios of amine acids to aluminium(III) were varied from 1 : 1 to 10 : 1. The least-squares treatment of the data obtained, in the absence of the amino acids, indicates the formation of the dimer, [Al₂(OH)₂]⁴⁺, and monomer, [AlOH]²⁺, with the stability constants log β₂₂ = ?7.03 ± 0.03 and log β₁₁ = ?5.65 ± 0.09, respectively. At pH values higher then ～4.0 formation of the trimer [Al₃(OH)₄]⁵⁺ (log β₃₄ = ?12.60 ± 0.08) becomes significant. In the presence of amino acids the evidence has been found for the formation of [Al₂(OH)₄]²⁺ (log β₂₄ = ?15.65 ± 0.09). Besides the formation of the pure hydrolytic complexes, equilibria in the title systems can be explained by assuming the main reaction products to have the compositions [Al(OH)₃Gly] (log β₁₃₁ = ?7.53 ± 0.04), [Al₂(OH)₂(Gly)₂] (log β₂₂₂ = 6.56 ± 0.09) and [Al(OH)₃Ala] (log β₁₃₁ = ?7.70 ± 0.03), [Al₂(OH)₂Ala₂] (log β₂₂₂ = 7.23 ± 0.07).     

Stability constants for aqueous silver/bromide/thiocyanate complexes

Stability constants for aqueous Ag⁺/Br^?, Ag⁺/SCN^?, and mixed Ag⁺/Br^?/SCN^? complexes are determined at 25° C by using data generated potentiometrically in solutions having ionic strengths of 0.4, 1.0, and 2.0 m. Monte Carlo numerical methods which yield apparent stability constants for these complexes as well as confidence limits are described in detail. Explicit consideration of speciation shows that under useful precipitation conditions (high bromide and low thiocyanate), a significant fraction of soluble silver is present as AgBr_n (SCN)^1?n?m_m complexes. The most prevalent mixed complexes under these conditions are AgBr (SCN)^? (log β₁₁=8.0 ± 0.5) and AgBr₂(SCN)^2? (log β₂₁=9.2 ± 0.3). The free energies of formation of the other tri- and tetra-coordinate mixed complexes are nearly indistinguishable (log β₁₂=9.3 ± 0.5; log β₃₁=9.0 ± 0.6; log β₂₂=9.6 ± 0.9; log β₁₃=10.3 ±0.5).     

Synthesis and antibacterial activity of copper(II) complexes with sulphathiazole and cephalosporin ligands

Copper(II) reacts with cephalosporins plus sulphathiazole (Hstz) to form the following mixed complexes: [Cu(cefazol)(stz)(H₂O)], [Cu(cephalot)(stz)(H₂O)₂], [Cu(cefotax)(stz)], [Cu(ceftria)(Hstz)] and [Cu(cefepime)(stz)Cl] (Hcefazol = cefazolin, Hcephalot = cephalothin, Hcefotax = cefotaxime and H₂ceftria = ceftriaxone) which were characterized by physicochemical and spectroscopic methods. The spectra indicated that most of the cephalosporins are probably acting as monoanionic multidentate chelating agents, the exception being ceftriaxone which is dianionic. The complexes are insoluble in water and common organic solvents and probably have polymeric structures. They have been screened for activity against several bacteria, and the results are compared with the activity of cephalosporins.     

Synthesis,Characterization, and Thermostability of Four Novel Cadmium(II) Coordination Polymers with Mixed Ligands

Four novel mixed‐ligand complexes were obtained from the reaction of maleic acid, diimine chelating ligands and Cd(OH)₂ or CdO in a mixed solvent of water and methanol. The complexes were characterized by IR spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction. The results show that all the four complexes are coordination polymers. [Cd(phen)(H₂O)(male)]_n · 2nH₂O ( 1 ) and [Cd(bipy)(H₂O)(male)]_n · 2nH₂O ( 2 ) (male = maleate; phen = 1, 10‐phenanthroline, bipy = 2, 2′‐bipyridine) are isomorphic, and the asymmetric unit is constructed by one Cd^II atom, a maleate group, a diimine ligand and two crystal water molecules. Each maleate group links two Cd^II atoms in a bis(bidentate) chelating mode, resulting in a 1D helical chain. Within [Cd(phen)(H₂O)₂(male)]_n · 2nH₂O ( 3 ), the maleate group bridges two Cd^II atoms in a bis(monodentate) chelating mode into a 1D helical chain along the [100] direction. The helical chain is decorated by phen groups alternatively at the two sides, and each phen plane of one chain is inserted in the void space between two adjacent phen ligands from an adjacent chain, resulting in a double zipper‐like chain. The asymmetric unit of [Cd₂(phen)₂(male)₂]_n ( 4 ) contains a Cd^II cation, one phen molecule, and a maleate group, and one bridging maleate group links three Cd^II atoms resulting in a 2D layer extending in [011] plane. The 2D networks are constructed by four kinds of rings formed by the central metal atom and maleate dianion. The thermostabilities of the four complexes were investigated.     

Homogeneous Catalytic Hydrogenation of Amides to Amines

Hydrogenation of amides in the presence of [Ru(acac)₃] (acacH=2,4‐pentanedione), triphos [1,1,1‐tris‐ (diphenylphosphinomethyl)ethane] and methanesulfonic acid (MSA) produces secondary and tertiary amines with selectivities as high as 93 % provided that there is at least one aromatic ring on N. The system is also active for the synthesis of primary amines. In an attempt to probe the role of MSA and the mechanism of the reaction, a range of methanesulfonato complexes has been prepared from [Ru(acac)₃], triphos and MSA, or from reactions of [RuX(OAc)(triphos)] (X=H or OAc) or [RuH₂(CO)(triphos)] with MSA. Crystallographically characterised complexes include: [Ru(OAc‐κ¹O)₂(H₂O)(triphos)], [Ru(OAc‐κ²O,O′)(CH₃SO₃‐κ¹O)(triphos)], [Ru(CH₃SO₃‐κ¹O)₂(H₂O)(triphos)] and [Ru₂(μ‐CH₃SO₃)₃(triphos)₂][CH₃SO₃], whereas other complexes, such as [Ru(OAc‐κ¹O)(OAc‐κ²O,O′)(triphos)], [Ru(CH₃SO₃‐κ¹O)(CH₃SO₃‐κ²O,O′)(triphos)], H[Ru(CH₃SO₃‐κ¹O)₃(triphos)], [RuH(CH₃SO₃‐κ¹O)(CO)(triphos)] and [RuH(CH₃SO₃‐κ²O,O′)(triphos)] have been characterised spectroscopically. The interactions between these various complexes and their relevance to the catalytic reactions are discussed.     

Synthesis and characterization of mixed ligand complexes of cobalt(II) with some nitrogen and sulfur donors

Mixed ligand complexes of Co(II) with nitrogen and sulfur donors, Co(OPD)(S–S) · 2H₂O and Co(OPD)(S–S)L₂ [OPD = o-phenylenediamine; S–S = 1,1-dicyanoethylene-2,2-dithiolate (i-MNT^2?) or 1-cyano-1-carboethoxyethylene-2,2-dithiolate (CED^2?); L = pyridine (py), α-picoline (α-pic), β-picoline (β-pic), or γ-picoline (γ-pic)], have been isolated and characterized by analytical data, molar conductance, magnetic susceptibility, electronic, and infrared spectral studies. The molar conductance data reveal non-electrolytes in DMF. Magnetic moment values suggest low-spin and high-spin complexes. The electronic spectral studies suggest distorted octahedral stereochemistry around Co(II) in these complexes. Infrared spectral studies suggest bidentate chelating behavior of i-MNT^2?, CED^2?, or OPD while other ligands are unidentate in their complexes.     

Spectroscopic studies and biological evaluation of some transition metal complexes of Schiff-base ligands derived from 5-arylazo-salicylaldehyde and thiosemicarbazide

Synthesis and spectroscopic characterization of Schiff-base complexes of Cu(II), Ni(II), and Mn(II) resulting from condensation of salicylaldehyde derivatives with thiosemicarbazide [PHBT = 1-(5-(2-phenyldiazenyl)-2-hydroxybenzylidene)thiosemicarbazide, CHBT = 1-(5-(2-(2-chlorophenyl)diazenyl)-2-hydroxybenzylidene)thiosemicarbazide, and MHBT = 1-(5-(2-p-tolyldiazenyl)-2-hydroxybenzylidene)thiosemicarbazide] are discussed. The solid complexes were confirmed by elemental analysis (CHN), molar conductance, and mass spectra. Important infrared (IR) spectral bands corresponding to the active groups in the three ligands, ¹H-NMR and UV-Vis spectra and thermogravimetric analysis were performed. The dehydration and decomposition of [Cu(PHBT)(H₂O)], [Ni(PHBT)(H₂O)] · 2H₂O, [Mn(PHBT)(H₂O)] · H₂O, [Cu(CHBT)(H₂O)], [Ni(CHBT)(H₂O)] · H₂O, [Mn(CHBT)(H₂O)] · H₂O, [Cu(MHBT)(H₂O)], [Ni(MHBT)(H₂O)] · 2H₂O, and [Mn(MHBT)(H₂O)] · 2H₂O complexes were studied. The ligands are tridentate forming chelates with 1 : 1 (metal : ligand) stoichiometry. The molar conductance measurements of the complexes in DMSO indicate non-electrolytes. The biological activities of the metal complexes have been studied against different gram positive and gram negative bacteria.     

Complex Formation of PdII Ion with the Tripodal Ligand Tris[2-(dimethylamino)ethyl]amine

The complex formation of Pd^II with tris[2-(dimethylamino)ethyl]amine (N(CH₂CH₂N(CH₃)₂)₃, Me₆tren) was investigated at 25° and ionic strength I = 1, using UV/VIS, potentiometric, and NMR measurements. Chloride, bromide, and thiocyanate were used as auxiliary ligands. The stability constant of [Pd(Me₆tren)]²⁺ in various ionic media was obtained: log β([Pd(Me₆tren)] = 30.5 (I = 1(NaCl)) and 30.8 (I = 1(NaBr)), as well as the formation constants of the mixed complexes [Pd(HMe₆tren)X]²⁺ from [Pd(HMe₆tren)(H₂O)]³⁺:log K = 3.50 = Cl^?) and 3.64 (X^? = Br^?) and [Pd(Me₆tren)X]⁺ from [Pd(Me₆tren)(H₂O)]²⁺: log K = 2.6 (X^? = Cl^?), 2.8(Br^?) and 5.57 (SCN^?) at I = 1 (NaClO₃). The above data, as well as the NMR measurements do not provide any evidence for the penta-coordination of Pd^II, proposed in some papers.     

Differential Pulse Voltammetric Study of Complexes of Rare Earth Ion(Eu3+) with Glutarate and 1,2-Diminopropane

Abstract

The mixed complexes of Eu (III) with glutarate (Gluta) and 1,2-diaminopropane (DMPA) have been studied at 25°C, μ=0.12(NaClO₄) by differential pulse voltammetry(DPV). The reduction process in each case appears to be quasi-reversible and diffusion-controlled. The stability constants have been measured by Schaap and McMasters′ method. The stability constants of three mixed complexes formed are logβ₁₁=7. 414 for [Eu(Gluta) (DMPA)]⁺, logβ₂₁ = 8. 506 for [Eu(Gluta)₂ (DMPA)]^? and logβ₁₂ = 9. 984 for [Eu(Gluta) (DMPA)₂]⁺.     

The mer-[RuCl3(dppb)(H2O)] complex: A versatile tool for synthesis of Ru compounds

The complex mer-[RuCl₃(dppb)(H₂O)] [dppb = 1,4-bis(diphenylphosphino)butane] was used as a precursor in the synthesis of the complexes tc-[RuCl₂(CO)₂(dppb)], ct-[RuCl₂(CO)₂(dppb)], cis-[RuCl₂(dppb)(Cl-bipy)], [RuCl(2Ac4mT)(dppb)] (2Ac4mT = N(4)-meta-tolyl-2-acetylpyridine thiosemicarbazone ion) and trans-[RuCl₂(dppb)(mang)] (mang = mangiferin or 1,3,6,7-tetrahydroxyxanthone-C2-β-D-glucoside) complexes. For the synthesis of Ru^II complexes, the Ru^III atom in mer-[RuCl₃(dppb)(H₂O)] may be reduced by H₂(g), forming the intermediate [Ru₂Cl₄(dppb)₂], or by a ligand (such as H2Ac4mT or mangiferin). The X-ray structures of the cis-[RuCl₂(dppb)(Cl-bipy)], tc-[RuCl₂(CO)₂(dppb)] and [RuCl(2Ac4mT)(dppb)] complexes were determined.     

Structural models of vanadate-dependent haloperoxidases and their reactivity

Vanadium(V) complexes with hydrazone-based ONO and ONN donor ligands that partly model active-site structures of vanadate-dependent haloperoxidases have been reported. On reaction with [VO(acac)₂] (Hacac = acetylacetone) under nitrogen, these ligands generally provide oxovanadium(IV) complexes [VO(ONO)X] (X = solvent or nothing) and [VO(acac)(ONN)], respectively. Under aerobic conditions, these oxovanadium(IV) species undergo oxidation to give oxovanadium(V), dioxovanadium (V) or μ-oxobisoxovanadium(V) species depending upon the nature of the ligand. Anionic and neutral dioxovanadium(V) complexes slowly deoxygenate in methanol to give monooxo complexes [VO(OMe)(MeOH)(ONO)]. The anionic complexes [VO₂(ONO)]^- can also be convertedin situ on acidification to oxohydroxo complexes [VO(OH)(HONO)]⁺ and to peroxo complexes [VO(O₂)(ONO)]^-, and thus to the species assumed to be intermediates in the haloperoxidases activity of the enzymes. In the presence of catechol (H₂cat) and benzohydroxamic acid (H₂bha), oxovanadium (IV) complexes, [VO (acac)(ONN)] gave mixed-chelate oxovanadium(V) complexes [VO(cat)(ONN)] and [VO(bha)(ONN)] respectively. These complexes are not very stable in solution and slowly convert to the corresponding dioxo species [VO₂(ONN)] as observed by⁵¹V NMR and electronic absorption spectroscopic studies.     

Spectral, magnetic and biological studies of 1,4-dibenzoyl-3-thiosemicarbazide complexes with some first row transition metal ions

The ligand 1,4-dibenzoyl-3-thiosemicarbazide (DBtsc) forms complexes [M(DBtsc-H)(SCN)] [M = Mn(II), Co(II) or Zn(II)], [M(DBtsc-H) (SCN)(H₂O)] [M = Ni(II) or Cu(II)], [M(DBtsc-H)Cl] [M = Co(II), Ni(II), Cu(II) or Zn(II)] and [Mn(DBtsc)Cl₂], which have been characterized by elemental analyses, magnetic susceptibility measurements, UV/Vis, IR,¹H and¹³C NMR and FAB mass spectral data. Room temperature ESR spectra of the Mn(II) and Cu(II) complexes yield <g> values, characteristic of tetrahedral and square planar complexes respectively. DBtsc and its soluble complexes have been screened against several bacteria, fungi and tumour cell lines.