Substitutions of organopalladium(II) species with benzimidazole derivatives

The [Pd(cod)(cotl)]ClO₄ complex (cod = cycloocta-1,5-diene; cotl = cyclooctenyl, C₁₈H₁₃ ^–) undergoes substitutions with new Schiff base ligands containing benzimidazole L [L = 2-(2-N-n-propylidenephenyl)benzimidazole (L¹); 2-(2-N-i-propylidenephenyl)benzimidazole (L²); 2-(2-N-n-butylidenephenyl)benzimidazole (L³); 2-(2-N-i-butylidenephenyl)benzimidazole (L⁴)]. Facile displacement of cod by L occurs to produce complexes of the type [Pd(cotl)L]ClO₄· nMe₂CO (n= 0; L = L¹, L² or L³; n= 2, L = L⁴). Dihalobridge complexes of the type [Pd(cotl)X]₂(X = Cl or Br) undergo halogen-bridge cleavage with L¹–L⁴ to give mononuclear complexes of the type Pd(cotl)LX · nH₂O (n= 2, X = Cl, L = L¹; n= 0, X = Br, L = L¹; n= 0, X = Cl, L = L²; n= 0, X = Cl or Br, L = L³; n= 0, X = Cl, L = L⁴; n= 2, X = Br, L = L⁴) and a binuclear complex [Pd(cotl)Br]₂L². The complexes were characterised by physical properties, i.r., ¹H- and ¹³C-n.m.r. spectral techniques and by mass spectra. Probable structures have been proposed.     

Neutral and cationic orthopalladated ( ) complexes ( = phenylazophenyl, dimethylbenzylamine, 8-methylquinoline, 2-methoxy-3-N,N-dimetrylaminopropyl)

By reacting [Pd( )(μ-Cl)]₂ with AgClO₄ in NCMe, the corresponding cationic complexes [Pd( )(NCMe)₂]ClO₄ ( = phenylazophenyl-C²,N¹; dimethylbenzylamine-C²,N; 8-methylquinoline-C⁸,N) can be obtained. Solutions containing the cations [Pd( )(S)₂]⁺ are obtained when the reaction is carried out in tetrahydrofuran or acetone (S). The treatment of these solutions with bidentate ligands (L—L) (Ph₂PCH₂PPh₂,Ph₂PNHPPh₂ or Ph₂PCH₂PPh₂CHC(O)Ph) gives the mononuclear [Pd( )(L3l)]ClO₄ complexes, with L3l acting as a chelate ligand. On the other hand [Pd( (μ-Cl)]₂ reacts with L3l (Ph₂PCH₂PPh₂, Ph₂PNHPPh₂) yielding [Pd( )Cl(L3l)] with L3l acting as monodentate. The reactions between [Pd( )(NCMe)₂]ClO₄ and 2,2′-bipyrimidyl give rise to the formation of the mononuclear [Pd( ) (bipym)]ClO₄ or binuclear [Pd₂( )₂(μ-bipym)](ClO₄)₂, [( )Pd(μ-bipym)Pd( )](ClO₄)₂ derivatives. Finally [Pd( )Cldppm] (dppm = Ph₂PCH₂PPh₂) react with NaH producing the neutral complexes [Pd( )(ddppm)] (ddppm = Ph₂PCHPPh₂) which by reaction with HCl lead again to the starting materials [Pd( )Cl(dppm)].     

Cationic palladium(II) complexes involving unprecedented O-coordination of acetylmethylenetriphenylphosphorane

Cationic pentafluorophenyl palladium(II) complexes of the type [Pd(C₆F₅)L₂(APPY)]ClO₄ (L = PPh₃, PBu₃ⁿ; L₂ = bipy and A acetylmethylenetriphenylphosphorane) have been prepared by addition of APPY to the perchlorato complexes [Pd(OClO₃)(C₆F₅)L₂]; the APPY ligand is O-coordinated, which is unprecedented in keto-stabilized ylide complexes of palladium.The neutral complex Pd(C₆F₅)(Cl)(tht)(APPY) has been made by addition of APPY to the binuclear complex Pd₂(μ-Cl)₂(C₆F₅)₂(tht)₂ (tht = tetrahydrothiophene); in which the APPY ligand shows the normal C-coordination.     

Symmetric Ni(II) dithiocarbamates with bidentate phosphines ligands

Ni(II) mononuclear dithiocarbamate complexes with bidentate P,P ligands of composition [Ni(R₂dtc)(P,P)]X {R?=?pentyl (pe), benzyl (bz); dtc?=?S₂CN^?; P,P?=?1,2-bis(diphenylphosphino)ethane (dppe), 1,4-bis(diphenylphosphino)butane (dppb), 1,1′-bis(diphenylphosphino) ferrocene (dppf); X?=?ClO₄, Cl, Br, NCS} and binuclear complexes of composition [Ni₂(μ-dpph)(R₂dtc)₂]X₂ with a P,P-bridging ligand {P,P?=?1,6-bis(diphenylphosphino)hexane (dpph); X?=?Cl, Br, NCS} have been synthesized. The complexes have been characterized by elemental and thermal analysis, IR, electronic and ³¹P{¹H}-NMR spectroscopy, magnetochemical and conductivity measurements. Single crystal X-ray analysis of [Ni(pe₂dtc)(dppf)]ClO₄ confirmed a distorted square planar coordination in the NiS₂P₂ chromophore. For selected samples, the catalysis of graphite oxidation was studied.     

Rhodium(I) complexes with the 2,2′-bipyrimidine ligand

Mono- and dinuclear rhodium(I) complexes of formulae [Rh(L₂)(bipym)]⁺ and [{Rh(L₂)}₂(μ-bipym)]²⁺ [L₂ = diolefin or (CO)₂] have been prepared and their catalytic activity in hydrogen-transfer reactions explored. The heterodinuclear [Cl₂Pd(μ-bipym)Rh(tfb)]ClO₄ complex was obtained by reacting [Rh(tfb)(bipym)]⁺ with [PdCl₂(cod)] or alternatively from [Rh(tfb)(acetone)_x]⁺ with [PdCl₂(bipym)]. Ion-pair complexes of formulae [Rh(diolefin)(bipym)]⁺ [RhCl₂(diolefin)]₋ (diolefin = cod, nbd or tfb) were prepared by adding bipym to acetone suspensions of [RhCl(diolefin)]₂.     

Synthesis,Characterization and SOD Activities of IP-copper（Ⅱ）-L-amino Acid Complexes

Four new ternary complexes： [Cu（IP）（L-Val）（H2O）]ClO4·1.5H2O（1）, [Cu（IP）（L-Leu）（H2O）]ClO4（2）, [Cu（IP）（L-Tyr）（H2O）]ClO4·H2O（3） and [Cu（IP）（L-Trp）（H2O）]ClO4·1.5H2O（4） have been synthesized and character/zed by elementa/analysis, molar conductivity, infrared absorption spectroscopy, electronic absorption spectroscopy and cyclic voltammetry, where IP=imidazo[4,5-f][1,10] phenanthroline, L-Val=L-valinate, L-Leu=L-leucinate, L-Tyr=L-tyrosinate and L-Trp=L-tryptophanate. Complex 3 was structurally characterized by X-ray diffraction method, which crystallizes in orthorhornbic space group P21212 in a unit cell of dimensions a=3.0567（4） nm, b=0.74079（9） nm, c= 1.06198（13） nm, V=2.4047（5） nm^3, Z=4,μ=0.1084 cm^-1. The SOD-like activities of catalytic disrnutation of superoxide anions （O2^-· ） by the complexes were determined by means of modified nitroblue tetrazolium （NBT） photoreduction. The IC50 values of complexes 1, 2, 3 and 4 are 0.072, 0.147, 0.429 and 0.264 μmol·L^-1, respectively     

Synthesis and characterization of Co(II), Ni(II), Zn(II) and Cu(II) complexes with a new tetraazamacrocyclic Schiff base ligand containing a piperazine moiety: X-ray crystal structure determination of the Co(II) complex

Two macrocyclic Schiff base ligands, L¹ [1+1] and L² [2+2], have been obtained in a one-pot cyclocondensation of 1,4-bis(2-formylphenyl)piperazine and 1,3-diaminopropane. Unfortunately, because of the low solubility of both ligands, their separation was unsuccessful. In the direct reaction of these mixed ligands (L¹ and L²) and the appropriate metal ions only [CoL¹(NO₃)]ClO₄, [NiL¹](ClO₄)₂, [CuL¹](ClO₄)₂ and [ZnL¹(NO₃)]ClO₄ complexes have been isolated. All the complexes were characterized by elemental analyses, IR, FAB-MS, conductivity measurements and in the case of the [ZnL¹(NO₃)]ClO₄ complex with NMR spectroscopy.     

Synthesis,characterization and reactivity of electrophilic mono- and binuclear nitrosyls of osmium(II)ketoximates

The reaction of [OsX₂(HL)(L)] (1) {X = Cl or Br; HL = PhC(O)C(=NOH)Ph (HL¹) or PhC(O)C(=NOH)Me (HL2)] with n-BuONO yields mononuclear [OsX(NO)(L¹)₂] (2) or binuclear [OsX₂(NO)(L²)]₂2 (3) nitrosyls depending on L. The complexes are also obtained by reacting (1) with NaNO₂ plus HCl. Molecular weight determinations are in agreement with mono- and binuclear formulations. The diamagnetic orange-red nitrosyls exhibit (NO) at ca. 1890 cm^–1 indicating NO⁺ character of the bound nitrogen monoxide. In ¹H-n.m.r. a single sharp L² methyl signal is in line with the centrosymmetric geometry (4) of the binuclear nitrosyls. The complexes display both spin-allowed and -forbidden charge transfer transitions in the 1000–200 nm range. Both (2) and (3) are electroactive and reductions characteristic of mono- and binuclear compositions are observable on the negative side of s.c.e. They react smoothly with acetylacetone (acacH) in the presence of K2CO3 yielding K[Os(acamo)(L1)2] (5) and K[Os(acac)(acamo)(L2)] (6) [acamo = deprotonated MeC(O)C(=NOH)C(O)Me] respectively.     

Die photochemische synthese von μ-(1-2-η:2-3-η-allen)-octacarbonyldimangan(0)

Novel dihydroiridium(III) complexes containing mono- and bi-dentate sulfur ligands have been isolated. The cationic complexes [Ir(COD)L₂]ClO₄ (COD = 1,5-cyclooctadiene, L = tetrahydrothiophene (tht) or trimethylene sulfide (tms); L₂ = (CH₃S)₂(CH₂)₃ (dth)), [Ir(COD)(L-L)]₂(ClO₄)₂ (L-L = 1,4-dithiacyclohexane (dt) or (t-BuS)₂(CH₂)₂ (tmdto)) and [Ir(CO)₂(tmdto)]₂-(ClO₄)₂ react with H₂ to give the corresponding iridium(III) dihydrides: [IrH₂COD)L₂]ClO₄ (Ia: L = tht, Ib: L = tms, Ic: L₂ = dth), [IrH₂(COD)-(L-L)]₂(ClO₄)₂ (IIa: L-L = tmdto, IIb: L-L = dt) and [IrH₂(CO)₂(tmdto)]₂-(ClO₄)₂ (III). The ¹H NMR chemical shifts and ν(IrH) data are discussed.     

Mixed N-heterocycles/N-heterocyclic carbene palladium(II) allyl complexes as precatalysts for direct arylation of azoles with aryl bromides

A series of mixed N-heterocycles/N-heterocyclic carbene palladium(II) allyl complexes with general formula [(NHC)Pd(η³-allyl)]₂(μ₂-N-heterocycles)(BF₄)₂ were prepared in one pot based on anion metathesis of (NHC)Pd(η³-allyl)Cl complexes and then ligand replacement with N-heterocycles [N-heterocycles?=?pyrazine (pyz), 4,4′-bipyridine (bpy) and trans-4,4′-bipyridylethylene (bpe)]. The solid-state structures shown dinuclear structures with two palladium(II) centers holding together by bridged N-heterocycles. Initially investigation of the obtained complexes as precatalysts for direct CH bond arylation of azoles with aryl bromides was carried out.     

Heterodinukleare Cobalt(II)‐, Nickel(II)‐, Kupfer(II)‐, Zink(II)und Palladium(II)‐Komplexe mit einem makrocyclischen Liganden vom Schiff‐Basen‐Typ: Synthesen und Strukturen

Complexes with Macrocyclic Ligands. IV. Heterodinuclear Cobalt(II), Nickel(II), Copper(II), Zinc(II) and Palladium(II) Complexes with a Macrocyclic Ligand of Schiff‐Base Type: Syntheses and Structures The synthesis and properties of nickel(II), copper(II), and palladium(II) complexes, [ML^Ph] ( 3 ; L^Ph = N,N′‐phenylene‐bis(3‐formyl‐5‐tert.‐butyl‐salicylaldimine)), are described. These neutral mononuclear complexes react with metal(II) perchlorate and 1,3‐propylenediamine to form heterodinuclear, macrocyclic, cationic complexes of the type [MM′(L^Ph,3)]²⁺ ( 4 ; M = Ni, Cu, Pd; M′ = Co, Cu, Zn). The structures of the five new compounds [NiCo(L^Ph,3)](ClO₄)₂, [NiCu(L^Ph,3)](ClO₄)₂, [CuCu(L^Ph,3)](ClO₄)₂, [CuZn(L^Ph,3)](ClO₄)₂, and [PdCu(L^Ph,3)](ClO₄)₂ were determined by X‐ray diffraction.     

Macrocyclic effects upon isomeric CuIIMII and MIICuII cores. Formation with unsymmetric phenol-based macrocyclic ligands

This paper discusses coordination-position isomeric M^IICu^II and Cu^IIM^II complexes, using unsymmetric dinucleating macrocycles (L^m;n)²⁻ ((L^2;2)²⁻, (L^2;3)²⁻ and (L^2;4)²⁻) that comprise two 2-(N-methyl)-aminomethyl-6-iminomethyl-4-bromo-phenonate entities, combined through the ethylene chain (m = 2) between the two amine nitrogens and through the ethylene, trimethylene or tetramethylene chain(n = 2, 3 or 4) between the two imine nitrogens. The macrocycles have dissimilar N(amine)₂O₂ and N(imine)₂O₂ metal-binding sites sharing the phenolic oxygens. The reaction of the mononuclear Cu^II precursors, [Cu(L^2;2)], [Cu(L^2;2)] and [Cu(L^2;2)], with a M^II perchlorate and a M^II acetate salt formed (acetato)M^IICu^II complexes: [CoCu(L^2;2)(AcO)]ClO⁴·0.5H₂O] (1), [NiCu(L^2;2) (AcO)]ClO₄ (2), [ZnCu(L^2;2) (AcO)]ClO₄ (3), [CoCu(L^2;3)(AcO)]ClO₄·0.5H₂O (4), [NiCu(L^2;3)(AcO)]ClO₄ (5), [ZnCu(L^2;3)(AcO)]ClO₄·0.5H₂O (6), [CoCu(L^2;4)(AcO)(DMF)]ClO₄ (7), [NiCu(L^2;4) (AcO)]ClO₄·2DMF (8) and [ZnCu(L^2;4)(AcO)]ClO₄ (9) (the formulation [M_aM_b (L^m;n)]²⁺ means that M_a resides in the aminic site and M_b in the iminic site). The site selectivity of the metal ions is demonstrated by X-ray crystallographic studies for 2·MeOH,3,5,7, and9. An (acetato)Cu^IIZn^II complex, [CuZn(L^2;3)(AcO)]ClO₄ (10), was obtained by the reaction of [PbCu(L^2;3)]-(ClO₄)₂ with ZnSO₄·4H₂O, in the presence of sodium acetate. Other complexes of the Cu^IIM^II type were thermodynamically unstable to cause a scrambling of metal ions. The Cu migration from the iminic site to the aminic site in the synthesis of10 is explained by the ‘kinetic macrocyclic effect’. The coordination-position isomers,6 and10, are differentiated by physicochemical properties.     

Chiral Recognition of Racemic Proline based on Chiral Macrocyclic Nickel(II) Complex: Synthesis and Crystal Structures

The reactions of dl‐proline with chiral macrocyclic Ni^II complex [Ni(SS‐L)](ClO₄)₂ in acetonitrile/water gave a six‐coordinate enantiomer formulated as [Ni(SS‐L)(l‐Pro)](ClO₄)₂ · H₂O ( 1 ). Another enantiomer of [Ni(RR‐L)(d‐Pro)](ClO₄)₂ · H₂O ( 2 ) was obtained when [Ni(RR‐L)](ClO₄)₂ was used (L = 5,5,7,12,12,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane, Pro = proline). Single‐crystal X‐ray diffraction analyses of complexes 1 and 2 revealed that the Ni^II atom has a distorted octahedral coordination arrangement, being coordinated by four nitrogen atoms of L in a folded configuration, plus two carboxylate oxygen atoms of proline in mutually cis positions. Complexes 1 and 2 are supramolecular stereoisomers, which are constructed with hydrogen bonding linking of [Ni(SS‐L)(l‐Pro)]²⁺ and [Ni(RR‐L)(d‐Pro)]²⁺ monomers to form one‐dimensional zigzag chains. The homochiral natures of complexes 1 and 2 were confirmed by solid CD spectroscopy.     

Syntheses and characterization of some new 2-picolylpalladium(II) complexes

The 2-picolylpalladium(II) complex [{Pd(CH₂Py)Cl(PPh₃)}₂] (CH₂Py=2-picolyl) (I), prepared from 2-picolyl chloride and [Pd(PPh₃)₄], was treated with lithium bromide, silver acetate, 4-picoline (pic) and silver perchlorate, thallium acetylacetonate{Tl(acac)}, sodium dimenthyldithiocarbamate-water-(1/2) {Na(dmdc). 2 H₂O}, and 1,2-bis(diphenylphospino)ethane (dppe) to yield [{PdBr(CH₂Py)(PPh₃)}₂] (II), [{Pd(CH₂Py)OAc(PPh₃)}₂] (III), [{Pd(Ch₂Py)(pic)(PPh₃)}₂](ClO₄)₂ (IV), [Pd(CH₂Py)(acac)(PPh₃)] (V), [Pd(CH₂Py)(dmdc)(PPh₃)] (VI), and [Pd(Ch₂Py)Cl(dppe)] (VII), respectively. Halogen abstraction from VII using silver perchlorate afforded an ionic complex [{Pd(CH₂Py)(dppe)}₂](ClO₄)₂ (VIII). It was concluded that the 2-picolyl groups in these eight complexes are σ-bonded to palladium, and that in the dinuclear complexes I, II, III, IV, and VIII, they serve as bridging ligands.     

Cyclopalladated ethylenediamine complexes on the basis of 4-phenylpyrimidine and 4,6-diphenylpyrimidine

Mono-and binuclear cyclopalladated complexes [Pd(ppm)En]ClO₄, [Pd(Hdphpm)En]ClO₄, and [(PdEn)₂(μ-dphpm)]ClO₄ (ppm^? is the deprotonated form of 4-phenylpyridine, Hdphpm^? and dphpm^2? are the mono-and bisdeprotonated forms of 4,6-diphenylpyrimidine, En is 1,2-diaminoethane) were prepared and characterized by means of ¹H NMR and electronic absorption and emission spectroscopy, and cyclic voltammetry. It was shown that cyclopalladation leads to a bathochromic shift of intraligand absorption and phosphorescence bands, appearance of new absorption band associated with metal-to-ligand charge transfer, and an anodic potential shift of the ligand-centered electroreduction Hppm ≈ H₂dphpm < [Pd(ppm)En]⁺ ≈ [Pd(Hdphpm)En]⁺ < [(PdEn)₂(μ-dphpm)]²⁺.     

Synthesis,crystal structure and physicochemical properties of copper(II) complexes containing bis[(benzimidazol-2-yl)methyl] ether derivatives

A new benzimidazoyl ligand bis[(N-ethylbenzimidazol-2-yl)methyl]ether (EDGB) and Cu^II complexes [Cu(L¹) (L²)](ClO₄)·mEt₂O·nH₂O [L¹ = bis[(benzimidazol-2-yl)methyl]ether (DGB) or EDGB, L² = 2,2-bipyridine (bipy) or 1,10-phenanthroline (phen)] have been synthesized and characterized by elemental analyses and i.r. spectra. The single-crystal structure of the [Cu(phen)(DGB)(OClO₃)]ClO₄·Et₂O·0.5H₂O complex was determined by X-ray diffraction. The geometry around Cu is best described as a distorted octahedron with four nitrogen atoms from phen and DGB ligands forming the equatorial plane. The oxygen atoms of DGB and one perchlorate group are in the axial positions with semi-coordinated bonding modes. The electrochemical behavior of the complexes is described.     

Bidentate amine N-oxides and phosphine oxides as ligands in rhodium(I) chemistry

Cationic rhodium(I) complexes of the general formula [Rh(COD)L₂]ClO₄ (L₂ = bipyO₂, phenO, dpeO₂ and dpmO₂) are prepared from the solvated species [Rh(COD)(Me₂CO)_x]⁺ and the appropriate ligand. Complexes of the type [Rh_n(COD)_n](ClO₄)_n (CNPyO = 4-cyano and 2-cyanopyridine N-oxide) are obtained similarly. Reaction of [RhCl(COD)]₂ with the potassium salt of 2-picolinic acid N-oxide leads to the neutral complex Rh(COOPyO)(COD). The mononuclear rhodium diolefinic compounds react with carbon monoxide to give complexes of the type [Rh(CO)₂L₂]ClO₄ and Rh(COOPyO)(CO)₂, which on treatment with triphenylphosphine yield monocarbonyl derivatives.The catalytic activities of the diolefin complexes and related derivatives in hydrogen-transfer catalytic reactions have been studied.     

Speciation studies of mono- and binuclear Pd(II) complexes involving mixed nitrogen–sulfur donor ligand and 4,4′-bipiperidine as a linker

Pd(MME)Cl₂ complex, where MME = methionine methyl ester, was synthesized and characterized by elemental analysis and spectroscopic techniques. [Pd(MME)(H₂O)₂]²⁺ interacts with some DNA constituents giving 1 : 1 and 1 : 2 complexes. The binuclear complexes having 4,4′-bipiperidine as a linker and involving [Pd(MME)(H₂O)₂]²⁺ and DNA constituents were investigated. The results show formation of [(H₂O)(MME)Pd(Bip)Pd(MME)(H₂O)]⁴⁺. Inosine, uracil, and thymine interact with the previously mentioned complex by substitution of the two coordinated water molecules. Formation constants of all possible mono- and binuclear complexes were determined and their speciation diagrams were evaluated.     

Palladium(II) and platinum(II) complexes of dithiocarbamates and L-methioninol

The [M(dithiocarbamato)(Mol)]Cl complexes [M = Pd or Pt; dithiocarbamato = DMDT (Me₂NCS^– ₂) or ESDT (EtO₂CCH₂MeNCS^– ₂); Mol = L-methioninol (L-2-amino-4-methylthio-1-butanol)] have been prepared by reacting methioninol with the appropriate [M(dithiocarbamato)Cl] _n complex in a 1:1 molar ratio in chlorinated hydrocarbons. By operating at a 1:2 molar ratio, the binuclear species [M₂(dithiocarbamato)₂(Mol)Cl₂] were obtained. The complexes were characterized by i.r., n.m.r. and electrospray ionisation (ESI) mass spectra and by t.g.a. The [M(dithiocarbamato)(Mol)]Cl species are ionic and contain S,N-chelated methioninol. The ligand forms an S,N bridge between two metal atoms in the binuclear species, whose formation is confirmed by the presence of the deprotonated molecular ion in the ESI negative ion mode.     

Potential inhibitors of DNA topoisomerase II: ruthenium(II) poly-pyridyl and pyridyl-azine complexes

In search of new DNA probes a series of new mono and binuclear cationic complexes [RuH(CO)(PPh₃)₂(L)]⁺ and [RuH(CO)(PPh₃)₂(-μ-L)RuH(CO)(PPh₃)₂]²⁺ [L=pyridine-2-carbaldehyde azine (paa), p-phenylene-bis(picoline)aldimine (pbp) and p-biphenylene-bis(picoline)aldimine (bbp)] have been synthesized. The reaction products were characterized by microanalyses, spectral (IR, UV-Vis, NMR and ESMS and FAB-MS) and electrochemical studies. Structure of the representative mononuclear complex [RuH(CO)(PPh₃)₂(paa)]BF₄ was crystallographically determined. The crystal packing in the complex [RuH(CO)(PPh₃)₂(paa)]BF₄ is stabilized by intermolecular π-π stacking resulting into a spiral network. Topoisomerase II inhibitory activity of the complexes and a few other related complexes [RuH(CO)(PPh₃)₂(L)]⁺ {L=2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) and 2,3-bis(2-pyridyl)-pyrazine (bppz)} have been examined against filarial parasite Setaria cervi. Absorption titration experiments provided good support for DNA interaction and binding constants have also been calculated which were found in the range 1.2 × 10³-4.01 × 10⁴ M⁻¹.