Three cadmium(II) complexes of N-(2-aminoethyl)-1, 2-ethanediamine (DETA) (1), N-(3-aminopropyl)-1, 3-propanediamine (DPTA) (2) and N,N'-(ethane-1,2-diyl)bis(propane-1,3-diamine) (DPETA) (3) have been synthesized and characterized by single crystal X-ray crystallography, UV-visible spectroscopy, IR and conductivity measurements. Complexes 1 and 3 show octahedral geometry while complex 2 show five coordinated square pyramidal geometry. Two molecules of DETA ligand are coordinated to the Cd(II) ion in complex 1. But one molecule each of DPTA and DPETA ligands and two bromide ions are coordinated to the Cd(II) ions to form square pyramidal (2) and octahedral structure (3). DFT results show that complex 3 is the most favoured complex thermodynamically while complex 1 is the least. The complexes exhibit good photocatalytic activity with reference to the intensity of organic dye methylene blue. The complexes were investigated for DNA interaction by absorption and fluorescence spectroscopy suggesting both hypochromism (internal contact or intercalative interaction) and hyperchromism (external contact or electrostatic binding). The cadmium (II) complexes show growth inhibitory activity against four pathogenic bacteria, two gram +ve, viz., Staphyloccus aureus, Bacillus subtilis and two gram -ve, viz., Escherichia coli, Salmonella typhi. Albumin denaturation assay and Heat Induced Haemolysis were studied for the complexes for anti-inflammatory activity.

The synthesis and characterization on four rhodium(II) complexes with the formula [Rh-2(CH3COO)(2)(AMUH)(2)(dcda)(2)](CH3COO)(2)(1),[Rh-2(CH3COO)(2)(AEUH)(2)(dcda)(2)](CH3COO)(2)(2),[Rh-2(CH3COO)(2)(APr(n)UH)(2)(dcda)(2)](CH3COO)(2)(3),[Rh-2(CH3COO)(2)(AB(n)UH)(2)(dcda)(2)](CH3COO)(2)(4), where AMUH = 1-amidino-O-methylurea, AEUH = 1-amidino-O-ethylurea, APr(n)UH = 1-amidino-O-n-propylurea, AB(n)UH = 1-amidino-O-n-butylurea, dcda = dicyandiamide are reported. The complexes were prepared by the reaction of dicyandiamide with rhodium(II) acetate in methanol (1), ethanol (2), n-propanol (3) and n-butanol (4) respectively and characterized by various techniques such as C, H, N analysis, FTIR, UV-Visible, EPR, conductance, SEM, EDX, powder XRD pattern and mass spectral studies. The interaction studies of the complexes with CT-DNA suggested the non-intercalative mode of binding for these complexes. The antimicrobial activity of the complexes against the tested microorganisms viz. Bacillus subtilis, Enterococcus faecium, Staphylococcus aureus and Escherichia coli, using the standard antibiotics streptomycin as positive control is also reported.

Mixed ligand copper(II) complexes of dicyanamide with different polyamines, viz. ethylenediamine (1) and 1,3-diaminopropane (2), have been synthesized and characterized. The crystal structure of complex 1 contains a five-coordinated copper in a distorted square-pyramidal environment and forms 1D zig-zag polymeric chain via the bridging ligand dicyanamide. Hydrogen bonding contributes supramolecular architecture in the crystal. Electronic spectral studies suggest the distorted square-pyramidal structure of the complexes. The interaction of the copper(II) complexes with calf-thymus DNA reveals nonintercalative binding mode. The two complexes have antimicrobial activity against the bacteria (viz. Salmonella paratyphi), which is responsible for paratyphoid fever.

Three new copper(II) complexes, [(CuL)(2)Cl{N(CN)(2)}(3)]n, where L=1-amidino-O-methylurea (1), 1-amidino-O-ethylurea (2), or 1-amidino-O-propylurea (3), have been synthesized and characterized. The single crystal X-ray structure of 2 and X-ray powder diffraction analysis on 1 and 3 show that they crystallize in the monoclinic system. The neutral dinuclear entity of 2 contains a crystallographic 2-fold axis passing through the amido nitrogen of a bridging dicyanamido ligand. The dinuclear units are bridged by weak Cu ... Cl interactions through the axial position of both copper ions to form a 1D polymer. The interaction of 1-3 with calf-thymus DNA (CT-DNA) has been explored by using absorption, emission, thermal denaturation, cyclic voltammetric studies, and viscosity experiments. The complexes bind to CT-DNA by non-intercalative mode and the order of binding ability is 1>2>3.

Three new [Cu-2(mu-Cl)(2)(O-2-alkoxyethylpyridine-2-carboximidate)(2)Cl-2] complexes, where alkoxy = methoxy, ethoxy, and butoxy, were synthesized and characterized by elemental analyses, FTIR spectra, electronic spectra, EPR, conductance, magnetic moment, powdered X-ray powder diffraction, and X-ray single-crystal diffraction. The three complexes contain chloride as a bridging ligand and in each complex the planar bidentate ligand binds the metal ion via the pyridine-N and the NH of the imino ether group. The X-ray crystal structure of [Cu-2(mu-Cl)(2)(O-2-butoxyethylpyridine-2-carboximidate)(2)Cl-2] shows that it crystallizes as a centrosymmetric dinuclear species in which each copper(II) is in a distorted square pyramid. Magnetic field-induced partial molecular alignment has been observed in polycrystalline samples of 2 and 3 when cooled in a magnetic field of 1 T at 77 K. The interaction of these complexes with Calf thymus DNA has been explored and the values of binding constant, K-b for 1, 2, and 3 are 1.524 x 10(3), 5.587 x 10(3), and 6.362 x 10(3) (ML-1)(-1), respectively. Complexes were screened for antimicrobial activities by the agar well diffusion technique.

Three new solid lanthanide(III) complexes, [Ln(1-AMUH)3] · (NO3)3 (1-AMUH = 1-amidino-O-methylurea; Ln = Eu(III), Gd(III), or Tb(III)) were synthesised and characterised by elemental analysis, infrared spectra, magnetic moment measurement, and electron paramagnetic resonance (EPR) spectra for Gd(III) complex. The formation of lanthanide(III) complexes is confirmed by the spectroscopic studies. The photophysical properties of Gd(III), Eu(III), and Tb(III) complexes in solid state were investigated. The Tb(III) complex exhibits the strongest green emission at 543 nm and the Eu(III) complex shows a red emission at 615 nm while the Gd(III) complex shows a weak emission band at 303 nm. Under excitation with UV light, these complexes exhibited an emission characteristic of central metal ions. The powder EPR spectrum of the Gd(III) complex at 300 K exhibits a single broad band with g = 2.025. The bi-exponential nature of the decay lifetime curve is observed in the Eu(III) and Tb(III) complexes. The results reveal them to have potential as luminescent materials.

Three new copper(II) complexes, bis(1-amidino-O-2-alkoxyethylurea)Cu(II)nitrate, where alkoxy = methoxy (1), ethoxy (2) or butoxy (3) have been synthesized and characterized. Electron paramagnetic resonance (EPR) spectra of complexes 2 and 3 gave half-field signal (ΔMs = ±2) ca. 1600 G, in addition to fine structure due to zero field splitting (ZFS) characteristics of the S = 1 system suggesting the formation of binuclear copper(II) complexes. Single crystal X-ray diffraction studies of complex 1 revealed that the copper atoms have tetra-coordinated square planar environments formed by two N atoms derived from two different ligands. The interaction of the copper(II) complexes with DNA were investigated by absorption spectroscopy, fluorescence spectroscopy, viscosity measurements and thermal denaturation studies. The values of binding constant (Kb) and the apparent binding constant (Kapp) calculated from the absorption and fluorescence spectral studies suggest that the binding strength of the three complexes are in the order 3 > 2 > 1. The three complexes interact with CT-DNA primarily by partial or non-intercalative modes.

Three complexes, namely, [Cu(salbn)] ( 1 ), [Cu(salbn)Gd(NO 3 ) 3 ·H 2 O] ( 2 ), and [Cu(salbn)Eu(NO 3 ) 3 ·H 2 O] ( 3 ) where salbn = N,N′-1,3-propylenebis (salicylaldiminato) have been synthesized and characterized by elemental analyses, ICP-AES, IR, UV, NMR, MS, EDX, powder XRD, and EPR spectroscopies. The EDX results suggest the presence of two different metal ions in heteronuclear complexes ( 2 ) and ( 3 ). The ligand(salbn), complex ( 1 ), and complex ( 3 ) crystallize in triclinic system while complex ( 2 ) crystallizes in monoclinic system. The EPR studies suggest that [Cu(salbn)] complex is tetragonally coordinated monomeric copper(II) complex with unpaired electron in the dx2-y2 orbital and spectral features that are the characteristics of axial symmetry while complex ( 2 ) in DMF solution at liquid nitrogen temperature exhibits an anisotropic broad signal around g ~ 2.03 which may suggest a weak magnetic spin-exchange interaction between Gd(III) and Cu(II) ions. The fluorescence intensity of Eu(III) decreased markedly in the complex ( 3 ).

Five New Cu(II) complexes, [bis(1-amidino-O-alkylurea) Cu(II) tartrate], where alkyl=methyl (1), ethyl (2), n-propyl (3), n-butyl (4), or iso-butyl (5) have been synthesized and characterized. The electron paramagnetic resonance spectra of complexes 1 and 2 showed features of mononuclear species whereas complexes 3, 4, and 5 in frozen DMSO solution show the existence of mononuclear and binuclear species in these complexes. Complexes crystallize in a monoclinic structure. The binding of these complexes with calf thymus DNA suggested that these complexes interact with DNA by electrostatic or groove binding, not by intercalation. These complexes are also found to have good antimicrobial activity.

Three new copper(II) complexes, viz. [Cu(II)(1-amidino-O-2-methoxyethylurea)(2)](ClO4)(2)center dot H2O (1). [Cu(II)(1-amidino-O-2-ethoxyethylurea)(2)](ClO4)(2)center dot 2/3H(2)O (2) and [Cu(II)(1-amidino-O-2-butoxyethylurea)(2)](ClO4)(2) (3), have been synthesized and characterized by means of analytical and spectroscopic techniques. The single crystal X-ray structure of complex 2 and X-ray powder diffraction studies on complexes 1 and 3 show that they crystallize in the triclinic system. The asymmetric unit of complex 2 contains one and half [Cu(II)(1-amidino-O-2-ethoxyethylurea)(2)](2+) units, three perchlorate anions to balance the charge and a water molecule. The binding of these complexes with CT-DNA suggested that these complexes interact with CT-DNA by partial or non-intercalative modes. (C) 2012 Elsevier Ltd. All rights reserved.

Copper(II) complexes of [Cu(II)(1-amidino-O-2-methoxyethylurea)2]Cl2 (1) and [Cu(II)(1-amidino-O-2-ethoxyethylurea)2]Cl2 (2) have been synthesized and characterized by elemental analysis, magnetic moment, conductance, thermal analysis, IR, UV, powdered XRD and EPR spectral studies. The trend in g values g || > g ⊥ > 2.0023 in the EPR spectra of the complexes suggest that the unpaired electron on copper(II) ion has \({d_{x}}^2 - {{}_{y}}^2\) character and the complexes have square planar structure which is also supported by electronic absorption spectral studies. The bonding parameters of these complexes in DMF have been calculated based on the EPR and electronic spectral data. The complexes (1) and (2) exhibit K || > K ⊥ which indicates the presence of significant out-of-plane π bonding. Powdered XRD spectral patterns show that complexes crystallize in a monoclinic system. The binding of the complexes with calf thymus DNA was investigated by absorption and emission spectroscopy, viscosity measurements, DNA melting and cyclic voltammetric studies. DNA interaction studies show that the complexes bind to calf thymus DNA in a non-intercalative mode. The two complexes exhibit growth inhibitory activity against pathogenic bacteria, viz., Escherichia coli, Klebsiella pneumoniae sub sp. Pneumoniae, Proteus mirabilis.

Four new Cu(II) complexes of 4,4′-diaminodiphenyl sulfone (DDS) with different anions (chloride, sulfate, nitrate or acetate) were synthesized and characterized by elemental analysis, electronic absorption, IR, magnetic moment, thermal analysis and powder X-ray diffraction studies. It was found that the pure DDS and complex [Cu2(DDS)2(NO3)2].(NO3)2 (3) crystallize in orthorhombic system while the complexes [Cu2(DDS)2].Cl4 (1), [Cu2(DDS)2].(SO4)2 (2), and [Cu2(DDS)2].(CH3COO)4 (4) crystallize in monoclinic system. The crystallite sizes of complexes have smaller values as compared to pure DDS. Infrared studies suggest that the coordination of NH2 of DDS with Cu(II) ion. The binding of the complexes with calf thymus (CT) DNA was investigated by electronic absorption titration, fluorescence measurements and DNA thermal denaturation. The spectroscopic studies together with the DNA melting studies indicated that the complexes may bind to CT-DNA in a non-intercalative mode.

A new oxovanadium (IV) complex [VO(acac)(2)DCDA]H2O (where acac = acetylacetonate; DCDA = dicyandiamide) was synthesized and characterized by elemental analysis, IR, UV, ESR, TG-DTA analysis and powdered XRD. The electronic and ESR spectral studies indicate the monomeric nature of the complex having distorted octahedral structure. The complex shows prominent emission peak at 485nm and excitation peak at 355nm. The cyclic voltammetry study shows irreversible process. DNA binding study of the complex with CT-DNA indicates nonintercalative mode with binding constant 2.063 x 10(2) M-1.

EPR spectra of two copper(II) binuclear complexes, [Cu(II)(1-phenylamidino-O-methylurea) 2(H2O)](2)(Cl-2)(2) (1) and [Cu(II)(1-phenylamidino-O-i-butylurea) tmen](2)(Cl-2)(2) center dot 2H(2)O (2), at room temperature showed fine structure transitions (Delta Ms = +/- 1) and a very weak halffield signal corresponding to forbidden transitions (Delta Ms = +/- 2). The spectrum of 1 showed disappearance of normal and half-field transitions when cooled to 77 K, suggesting antiferromagnetical coupling dicopper complex which is also supported by the low magnetic moments (mu(eff) = 1.64 B.M.). The isotropic exchange interaction constant J (41 cm(-1)) for 2 indicated that interaction between the two spins of the binuclear complex is ferromagnetic, confirmed from the high magnetic moment value (mu(eff) = 2.25 B.M.). The binding of these complexes with calf thymus DNA suggested that these complexes interact with DNA by electrostatic or groove binding, not by intercalation. The two complexes have good antibacterial activity against tested bacteria responsible for urinary tract infection.

Five novel lanthanide (Tb, Eu, Gd, Sm and Dy ) complexes with dicyandiamide in 2ethoxyethanol were synthesized and characterized. The spectroscopic studies indicate the formation of lanthanide complexes. The thermal analysis data indicate a series of wt. loss of the ligand at different temperatures. The photophysical properties of these complexes were studied using ultraviolet-visible absorption spectra, fluorescence excitation and emission, and phosphorescence spectra. The ligand acts as the main energy donor and luminescence sensitizer of the Ln ions. The luminescence intensities of Tbcomplex show the strongest luminescence and Sm species show the weakest emission. Life-time studies on (Tb and Eu) complexes indicate biexponential nature of the luminescence decay.

Five new complexes of bis(1-amidino-O-alkylurea)Cu(II) vanadate where alkyl methyl, ethyl, n-propyl, n-butyl or i-butyl have been synthesized by reaction of ammonium metavanadate with bis(1-amidino-O-alkylurea)Cu(II) perchlorate complexes. Electron paramagnetic resonance (EPR) spectra of bis(1-amidino-O-n-propylurea)Cu(II) vanadate (1), bis(1-amidino-O-nbutylurea)Cu(II) vanadate (2) and bis(1-amidino-O-i-butylurea)Cu(II) vanadate (3) gave halffield signal (Delta M-s=+/- 2) ca 1623G, in addition to fine structure due to zero field splitting (ZFS) characteristics of the S 1 system. From the observed ZFS the average Cu-Cu distance was estimated. The isotropic exchange constant J was evaluated by recording EPR spectra at different temperatures. The photoacoustic signal of the complexes indicated square-planar geometry around Cu2+. X-ray powder diffraction studies on 2 suggested orthorhombic structure with unit cell dimensions a = 21.11 angstrom, b = 24.11 angstrom, c = 27.11 angstrom, alpha = beta = gamma = 90 degrees. The crystal structure of bis(1-amidino-O-n-butylurea) Cu(II) perchlorate is also reported.

Four new Cu(II) complexes of 4,4□‐diaminodiphenyl sulfone(DDS) with different anions(chloride, sulphate or acetate) were synthesized and characterized by X‐ray diffraction studies. It is observed that all the complexes crystallize in monoclinic system unlike the pure DDS which crystallizes in orthorhombic system. Complexes of DDS with CuSO4 in 1:1 and 2:1 stoichiometric ratio crystallize in monoclinic system with much larger volume compared to other DDS complexes.

Ni(II) and Co(III) complexes of dicyandiamide in alkoxyethanols (alkoxy = methoxy, ethoxy or butoxy) were synthesized and characterized by elemental analysis. magnetic moment, conductance, IR. UV and H-1 NMR spectral studies. In the H-1 NMR spectra appearance of new multiplet peaks at 3.25-3.50 ppm assignable to CH3-O-CH2-CH2-O- for complex [Ni(II)(1-amidino-O-methoxyethylurea)(2)](NO3)(2) and 3.30-3.45 ppm due to CH3-CH2-O-CH2-CH2-O- for complex [Ni(II)(1-amidino-O-2-ethoxyethyl-urea)(2)](NO3)(2), respectively suggests the addition of alkoxyethanols in complexation which is also supported by IR studies. The electronic spectral studies on Ni(II) and Co(III) complexes indicate square planar and octahedral structures, respectively. Fluorescence, UV absorption as well as thermal denaturation studies revealed that [Ni(II)(1-amidino-O-methoxyethylurea)(2)](NO3)(2) and [Ni(II)(1-amidino-O-2-ethoxyethylurea)(2)](NO3)(2) complexes are avid binder to calf thymus DNA (CT-DNA).

Four new Cu(II) Complexes viz. [Cu(II)(1-amidino-O-methylurea)2]SO4·2H2O (1), [Cu(II)(1-amidino-O-ethylurea)2](SO4)2·2H2O (2), [Cu(II)(1-amidino-O-n-propylurea)2] SO4·2H2O (3), [Cu(II)(1-amidino-O-n-butylurea)2]2(SO4)2·2H2O (4) have been synthesized and characterized. EPR spectrum of complex 4 at RT consisted of fine-structure transitions (ΔMs=±1) with zero-field splitting (ZFS) of 0.0485cm−1 and a half-field signal (ΔMs=±2) at ca. 1600G, revealed formation of binuclear complex (S=1). Whereas EPR spectrum of complex 2 in DMSO showed a mixture of mononuclear and binuclear complex in the ratio 0.75:1.0 with ZFS of 0.0385cm−1. From the temperature dependence of the EPR signal intensity, the isotropic exchange-interaction constant J was evaluated.

Copper(II) complexes of the type [Cu(1-AAAUH)(2)]X-2 where 1-AAAUH = 1-alkylamidino-O-alkylurea, X = Cl, Br, 1, have been synthesized and characterized by elemental analyses, magnetic moments, electronic absorption, IR and EPR spectroscopy. EPR spectra of two complexes [Cu(II)(1-methylamidino-O-methylurea)(2)]Cl, and [Cu(II)(1-ethylamidino-O-methylurea)(2)]Cl-2 were recorded in solid state and in DMF and bonding parameters alpha(2), beta(2) and gamma(2) were calculated. The orbital factors K-II and K-perpendicular to were also calculated. The trend K-II < K-perpendicular to indicates the presence of significant in plane pi-bonding. The bis(1-alkylamidino-O-alkylurea)copper(II) complexes show growth inhibitory against pathogenic fungus Ceratocystis paradoxa.