Dicyanamide Ions Research Articles

Sporadic binding of perchlorate and dicyanamide ions in trinuclear CuII2NiII complexes with a reduced di-Schiff base ligand: Synthesis, structures and spectral properties

Two new unusual trinuclear linear heterometallic complexes, [(CuLR)2Ni(ClO4)2{CO(CH3)2}2]·0.17H2O (1) and [(CuLR)2Ni(N3C2)2(0.5CH3OH)2] (2) have been synthesized by using [CuLR] as a “metalloligand” (where H2LR=N,N′-bis(2-hydroxybenzyl)-1,3-propanediamine) in presence of anions perchlorate and dicyanamide, respectively. Both the complexes have been diagnosed by elemental analysis, spectroscopic investigations, and single crystal XRD study. In these complexes, the terminal “ligand complex” [CuLR] coordinates to the central nickel atom via double phenoxido oxygen atoms bridge, resulted in a linear trinuclear structures. In both structures, the anions (perchlorate for 1 and dicyanamide for 2) coordinate to the terminal Cu(II) centers of the trinuclear unit (Cu(II)-Ni(II)-Cu(II)) to complete the distorted octahedral geometry around Cu(II); whereas the central Ni(II) metal ion remains in square planar geometry. The binding of perchlorate or dicyanamide to the terminal Cu(II) instead of central Ni(II) ion is rather unusual compared to the complexes of analogous unreduced species.

Chromone-Based Cd(II) Fluorescent Coordination Polymer Fabricated to Study Optoelectronic and Explosive Sensing Properties.

Here, electrical conductivity and explosive sensing properties of multifunctional chromone-Cd(II)-based coordination polymers (CPs) (1-4) have been explored. The presence of different pseudohalide linkers, thiocyanate ions, and dicyanamide ions resulted in 1D and 3D architecture in the CPs. Thin film devices developed from CPs 1-4 (complex-based Schottky devices, CSD1, CSD2, CSD3, and CSD4, respectively) showed semiconductor behavior. Their conductivity values increased under photo illumination (1.37 × 10-5, 1.85 × 10-5, 1.61 × 10-5, and 2.01 × 10-5 S m-1 under dark conditions and 5.06 × 10-5, 8.78 × 10-5, 7.26 × 10-5, and 10.21 × 10-5 S m-1 under light). The nature of the I-V plots of these thin film devices under light irradiation and dark are nonlinear rectifying, which has been observed in Schottky barrier diodes (SBDs). All four CPs (1-4) exhibited highly selective fluorescence quenching-based sensing properties toward well-known explosives, 2,4-dinitrophenol (DNP) and 2,4,6-trinitrophenol (TNP). The limit of detection (LOD) values are 55, 28, 27, and 31 μM for TNP and 78, 44, 32, and 41 μM for DNP for complexes 1-4, respectively. A structure property correlation has been established to explain optoelectronic and explosive sensing properties.

A new trinuclear Cd(II)-based coordination polymer with Salen ligand building blocks: Synthesis, crystallographic aspects, and optimistic photosensitive Schottky barrier diode behaviour

A new X-ray-characterized Cd(II)-based coordination polymer has been synthesized using Salen ligand (H2L1) and dicyanamide ion (dca) [N(CN)2]−, and characterized using elemental analysis, spectroscopy, SEM/EDX, TEM, and powder X-ray diffraction techniques. According to SCXRD, the complex crystallizes in the triclinic space group P-1. The asymmetric unit includes de-protonated ligands [L]2−, Cd(II) centres, and dca ions. The complex binuclear parts are connected by two μ1,5-dca bridges, resulting in the creation of a one-dimensional coordination polymer [(L1Cd)2(μ1,5-dca)2Cd]n. The polymer undergoes supramolecular aggregation via hydrogen bonding, CH···π(dca), and CH···π(arene) interactions. Hirshfeld surfaces (HS) and 2D fingerprint plots have been deployed to visualize the supramolecular interactions. The analysis shows that N…H interactions (18.2%) are more common in the crystal packing than Cd···O/O···H. This complex displays electrical conductivity and photosensitivity properties, making it a promising material for optoelectronic applications. Experimental and DFT studies have confirmed that it is a direct semiconductor with a specific optical band gap (3.54 eV) and is also used to construct a photosensitive Schottky barrier diode (SBD). The DFT calculated optical conductivity was used to analyse how the material's conductivity changes upon illumination. Due to the photon absorption, the material's electrical conductivity and photoconductivity change were concomitantly observed. Finally, the DOS analysis explains the complex's conductivity behaviour in a better logistic way.

Electrosynthesis and characterization of copper dicyanamide materials

X-ray diffraction and infrared reflection spectroscopy data have confirmed the electrosynthesis of copper dicyanamide films by cyclic voltammetry and potentiostatic electrolysis. An insoluble Cu(I)dca film can be synthesized on a gold or copper electrode by the reduction of Cu(II) or oxidation of Cu(0) in aqueous or methanolic solutions containing dicyanamide ions. By resorting to the use of the ruthenium hexaammine redox probe the Cu(I)dca film was shown to be electronically conductive although the deposition rate decreases when the film formation proceeds.Depending on the applied potential, not only Cu(I)dca but also Cu(II)dca can be formed by oxidation of a copper electrode in presence of dicyanamide ions dissolved in methanol. The powder obtained by electrolysis at 1 V vs Hg/Hg2SO4 made essentially of Cu(II)dca presents a specific surface area of (183 ± 59) m2/g. This material can adsorb preferentially methyl orange and Congo red dyes compared to methylene blue whereas no marked difference is obtained between CO and CO2 adsorption.

Investigation uncovered the impact of anions on CO2 absorption by low viscous ether functionalized pyridinium ionic liquids

Ionic liquids, which are designable and nonvolatile, have become a hot topic in the field of CO2 separation from industrial gases. In order to utilize the nonvolatile and low heat capacity of ionic liquids, it is necessary to solve the problem of high viscosity of pure ionic liquids. In the present study, ether functionalized pyridinium ion [E1Py]+ with good biodegradability and low viscosity was selected as cation. Ions containing cyano groups were used as anions, such as thiocyanate ion [SCN]-, dicyanamide ion [N(CN)2]-, tricyanomethanide ion [C(CN)3]-. Three ionic liquids with low viscosity were synthesized and characterized by 1HNMR, 13CNMR and FTIR. The physiochemical properties of ionic liquids such thermal decomposition temperature, density and viscosity were tested. The CO2 absorption capacity was systematically studied by using intelligent gravimetric analyzer at the pressure range between 0 and 15 bars and the temperature range from 303.15 to 333.15 K. The results showed that the order of CO2 absorption capacity of these three ionic liquids is [E1Py][C(CN)3] > [E1Py] [N(CN)2] > [E1Py][SCN], which showed that the solubility increased by increasing more cyano groups in ionic liquids. Thermodynamic properties such as enthalpy, entropy, and Gibbs free energy were also calculated for CO2 absorption.

Synthesis, characterization and thermal properties of 1,10-phenanthroline mixed-ligand complexes of cobalt(II) and copper(II): metal-mediated transformations of the dicyanamide ion

The reaction of 1,10-phenanthroline and dicyanamide ligands with Cu(II) and Co(II) nitrates afforded the complexes [Cu(phen)(BMCA)](NO3)] (1) and [Co(phen)2(NO3)](dcg-)·(H2O) (2). The dicyanamide anion was transformed in 1 and 2 to bis(methoxycarbimido)aminato (BMCA) and dicyanoguanidinate (dcg) anions, respectively. The complexes were characterized by elemental analysis, infrared spectroscopy and ultraviolet–visible spectroscopy, magnetic susceptibility measurement and X-ray crystallography. Both complexes crystallize in the monoclinic crystal system, and the structures are stabilized by extended hydrogen bonding networks as well as aromatic π–π stacking interactions. The thermal and antimicrobial properties of the complexes have also been evaluated. Density functional theory calculations were also performed in order to gain insights into the molecular interactions in the synthesized compounds and to predict some of their electronic properties.

Syntheses, X-ray crystal structures of two new Zn(II)-dicyanamide complexes derived from H2vanen-type compartmental ligands: Investigation of thermal, photoluminescence, in vitro cytotoxic effect and DFT-TDDFT studies

Two new dicyanamide modulated zinc metal complexes [Zn4(LOMe)2(µ1-dca)2(µ1,5-dca)2] (1) and [Zn3(LOEt)2(H2O)(µ1-dca)(µ1,5-dca)] (2) have been synthesized using H2vanen-type compartmental ligands. Schiff base ligands and the complexes were characterized by means of elemental analyses, FT-IR, FT-Raman, UV–Visible, powder X-ray diffraction, TGA and fluorescence spectroscopy. Dicyanamide modulated Zn4/Zn3-nuclear metal complexes were structurally characterized by single crystal X-ray diffraction studies. In 1, the asymmetric Zn2-nuclear unit was ensembled with one fully deprotonated Schiff base ligand [LOMe]2− along with two dicyanamide ions where two structurally independent Zn(II) metal centers are found in the X-ray crystal structure. Single X-ray crystal structure confirmed the environment of Zn1 is distorted square pyramidal whereas Zn2 acquires distorted tetrahedral geometry. Unlike 1, in 2 three independent zinc metal centers have been identified as square pyramidal (Zn1), distorted trigonal bipyramidal (Zn2) and distorted tetrahedral (Zn3). 1 and 2 geometry were optimized using hybrid B3LYP functional with DGDZVP basis set to explain frontier molecular orbitals, molecular electrostatic potential and Hirshfeld surface (dnorm surfaces and 2D fingerprint plots). The electronic UV–Vis properties were determined by TD-DFT approach. The steady state and time-resolved fluorescence properties have been explored in DMSO solution. 1 and 2 exhibit bi-exponential decay and intra-ligand (π → π*) fluorescence behaviors with lifetimes in the range (2.45–5.71 ns). In addition, complexes solid-state and different solvent-dependent absorption and fluorescence spectra have been reported. Finally, the cytotoxic effect of the investigated dicyanamide complexes against breast cancer cell line (MCF7) shows promising results which makes them prospective complexes for anticancer medicament studies.

Demulsification of water-in-oil emulsions using ionic liquids: Effects of counterion and water type

Demulsification of crude oil emulsions is of significant interest in the petroleum industry. This study aims to investigate the effect of ionic liquid (IL) counterions and water type (distilled water (DW) and laboratory formulated seawater (SW)) on the demulsification of water-in-oil (W/O) emulsions. Three ILs belonging to the phosphonium compounds with different counterions were used. These ILs were designated as THPC (contains chloride ion), THPD (contains decanoate ion), and THPDc (contains dicyanamide ion). Emulsions were formed using DW and SW while demulsification tests were conducted at temperatures of 60 °C and 80 °C. According to the demulsification outcomes at 60 °C, THPC was the best candidate for breaking W/O emulsions produced from DW while THPD and THPDc were excellent candidates for destabilizing emulsions produced from SW. The optimal percentage demulsification efficiency (DE) achieved for emulsions from DW was 99% with just 1000 ppm THPC while 1000 ppm THPD and 700 ppm THPDc are adequate to bring about excellent water separation in emulsions formulated from SW. THPD and THPDc also attained the maximum percentage DE of 99%.On the other hand, at elevated temperature (80 °C), THPC, THPD, and THPDc attained nearly the same water separation in the W/O emulsions produced from DW and SW with a demulsifying capacity of 99%. However, demulsification activities at this temperature (80 °C) in the W/O emulsions formed using SW were very fast as compared to what was observed in the case of emulsions obtained from DW. Thus, salts present in SW have propensities to accelerate the destabilization of crude oil emulsions. Viscosity and elastic modulus time sweep measurements reveal that the tested ILs can collapse the natural emulsifiers (asphaltenes and resins) existing at the water-oil interfaces.

Dicyanamide Ions as Complexing Agents of Co(II): From Weak Ligands in Water to Strong Ones in an Ionic Liquid

ABSTRACTThe complexation of cobalt cations (Co(II)) by dicyanamide (DCA–) in water and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([C1C4Pyrr][NTf2]) has been investigated by recording UV–vis spectra at 20 °C for solutions containing different ratios for the concentrations of DCA– vs. Co(II) (R = [DCA–]/[Co(II)]). The variation of the absorbance at a fixed wavelength as a function of R was expressed using the Beer Lambert law, based on a chemical model assuming the formation of up to four successive cobalt–dicyanamide complexes. This allowed us to determine the speciation of cobalt and the complexation constants of all complexes in both aqueous and ionic liquid media. In water, a unique complex of [Co(H2O)5(DCA)]+ exhibiting a weak complexation constant (K = 20.5) is observed. In the ionic liquid, cobalt is shown to coordinate with up to four dicyanamide anions. All species coexist until the ratio R reaches 5000, where more than 90% of the fourth and last complex [Co(NTf2)(3–x)(DCA)4](x–5) is formed. In addition, the extraction of cobalt towards hydrophobic ionic liquids trihexyltetradecylphosphonium dicyanamide ([P66614][DCA]) and trihexyltetradecylphosphonium bis(trifluoromethanesulfonyl)imide ([P66614][NTf2]) was carried out using various concentrations of DCA both in the aqueous and ionic liquid phases. Results were found to correlate very well with the speciation of Co(II) obtained in this work.

Pressure-Induced Polymerization of LiN(CN)2.

The high-pressure behavior of lithium dicyanamide (LiN(CN)2) was studied with in situ Raman and infrared (IR) spectroscopies, and synchrotron angle-dispersive powder X-ray diffraction (PXRD) in a diamond anvil cell (DAC) to 22 GPa. The fundamental vibrational modes associated with molecular units were assigned using a combination of experimental data and density functional perturbation theory. Some low-frequency modes were observed for the first time. On the basis of spectroscopic and diffraction data, we suggest a polymorphic phase transformation at ∼8 GPa, wherein dicyanamide ions remain as discrete molecular species. Above ca. 18 GPa, dicyanamide units polymerize, forming a largely disordered network, and the extent of polymerization may be increased by annealing at elevated temperature. The polymerized product consists of tricyanomelaminate-like groups containing sp2-hybidized carbon-nitrogen bonds and exhibits a visible absorption edge near 540 nm. The product is recoverable to ambient conditions but is not stable in air/moisture.

Synthesis, characterization, and structures of two new tetranuclear copper complexes with azido/dicyanamide bridges containing chiral Schiff base ligand

Two new copper complexes [Cu4(μ-L)2(μ1,1-N3)2(N3)2] (I) and [Cu4(μ-L)2(μ1,5-Dca)2(Dca)2] (II) (H2L = (1R,3S)-N′,N″-bis[5-methoxysalicylidene]-1,3-diamino-1,2,2-trimethylcyclopentane, Dca = dicyanamide ions) were synthesized and structurally characterized by elemental analyses, IR spectroscopy and single-crystal X-ray diffraction (CIF files CCDC nos. 1013673 (I), 1013672 (II)). The two complexes crystallize in monoclinic P21/c and triclinic $P\bar 1$ space group, respectively. Both the complexes consist of two crystallographically independent copper ions connected by a double phenoxo bridges, which are further linked to the other symmetry-related half of the molecule by two end-on azido bridges or μ1,5-dca groups.

Dicynamide bridged two new zig-zag 1-D Zn(II) coordination polymers of pyrimidine derived Schiff base ligands: Synthesis, crystal structures and fluorescence studies

Two new zigzag 1-D polymeric Zn(II) coordination polymers {[Zn(L1)(μ1,5-dca)](H2O)}n (1), {[Zn(L2)(μ1,5-dca)](ClO4)}n (2) of two potentially tridentate NNO-, NNN-, donor Schiff base ligands [2-(2-(4,6-dimethylpyrimidin-2-yl)hydrazono)methyl)phenol] (L1), [1-(4,6-dimethylpyrimidin-2-yl)-2-(dipyridin-2ylmethylene)hydrazine] (L2) have been synthesized and characterized by elemental analyses, IR and 1H NMR, fluorescence spectroscopy and single crystal X-ray crystallography. The dicyanamide ions act as linkers (μ1,5 mode) in the formation of these coordination polymers. Both the complexes 1 and 2 have same distorted square pyramidal geometry around the Zn(II) centres. The weak forces like π⋯π, CH⋯π, anion⋯π interactions lead to various supramolecular architectures. Complex 1 shows high chelation enhanced fluorescence compared to that of 2. The fluorescence spectral changes observed high selectivity towards Zn(II) over other metal ions such as Mn(II), Co(II), Ni(II), Cu(II).

An unprecedented 2D Cd(II) coordination polymer with 3,6 connected binodal net of pyrimidine derived schiff base ligand: Synthesis, crystal structure and spectral studies

An unprecedented 2D cadmium(II) coordination polymer {[Cd3(L)2(μ1,5-dca)6](H2O)}n (1) of potentially tridentate NNN donor Schiff base ligand (L) [L=1-(4,6-dimethylpyrimidin-2-yl)-2-(dipyridin-2ylmethylene)hydrazine] with the point symbol {43}2{46·66·83} has been synthesized and characterized by elemental analyses, IR, 1H NMR, emission spectroscopy and single crystal X-ray crystallography. The dicyanamide ions act as linker in the formation of the said coordination polymer. Complex 1 has distorted octahedral geometry around the Cd(II) centers. Interestingly, two different ligand environments are observed around Cd(II) center. Each Cd(L) fragment is connected by three six connecting nodes of [Cd(NCN)6] units to form the 2D coordination polymer of 3,6 connecting binodal system. In addition, the complex molecule gains extra stability by π⋯π interaction.

Pseudohalide manganese(II) complexes of 2-hydroxymethylbenzimidazole – Synthesis, spectroscopy, X-ray structure and magnetic properties

Three new manganese(II) complexes of 2-hydroxymethylbenzimidazole [Mn(hmbzim)2(NCS)2] (1), [Mn2(hmbzim)4(μ1,1-N3)2](NO3)2 (2) and [Mn(hmbzim)2(dca)2]n (3) were synthesized and characterised. On the basis of structural data, the influence of pseudohalide ions on a final complex structure and role of weak intermolecular interactions in creation of molecular architecture have been discussed. The structure 1 consists of the mononuclear molecules [Mn(hmbzim)2(NCS)2] assembled via O–H⋯S and N–H⋯S hydrogen bonds into three dimensional supramolecular network The reaction with using of sodium azide resulted in formation of 0D dimeric structure of 2, whereas the complex 3 incorporating dicyanamide ions displays two-dimensional coordination framework. Magnetic measurements revealed ferromagnetic coupling (J=0.82(1)cm−1) inside the dimer of 2 and weak antiferromagnetic coupling (J=−0.37(1) cm−1) in 2D lattice of 3. The complex 1 indicated a very small antiferromagnetic interaction between MnII ions transmitted in the crystal lattice.

Effect of steric congestion and non-covalent interaction on the self-organization of two isostructural 1D chiral coordination polymers

Two isostructural 1D chiral coordination polymers namely, [M(L)(N(CN)2)]n have been synthesized using a racemic mixture of chiral tridentate Schiff base ligand, LH (LH=2-((phenyl(2-pyridyl)methylimino)methyl)phenol), M(II) ions (M=Cu (1), Zn (2)) and dicyanamide ion. Structural characterization reveals that dicyanamide ion links two mononuclear units having same enantiomer of ligand L (either R or S) though it’s end-on-end bridging mode and extends further towards the formation of 1D homochiral self-assembly in a chiral self-recognition manner. The effects of different non-covalent interactions on the arrangement of 1D chiral coordination polymers into 2D sheet have been studied. The results demonstrate the effect of dicyanamide ion, steric congestion and non-covalent interactions on the homochiral self-assembly of the synthesized complexes.

Supramolecular 2D/3D Isomerism in a Compound Containing Heterometallic CuII2CoII Nodes and Dicyanamide Bridges

Three new heterometallic copper(II)-cobalt(II) complexes [(CuL(2))2Co{dca}2]·H2O(1), [(CuL(1))2Co{dca}2]n (2a), and [(CuL(1))2Co{dca}2]n (2b) [dca(-) = dicyanamide = N(CN)2(-)] have been synthesized by reacting the "metallo-ligand" [CuL(1)] or [CuL(2)] with cobalt(II) perchlorate and sodium dicyanamide in methanol-water medium (where H2L(1) = N,N'-bis(salicylidene)-1,3-propanediamine and H2L(2) = N,N'-bis(α-methylsalicylidene)-1,3-propanediamine). The three complexes have been structurally and magnetically characterized. Complex 1 is a discrete trinuclear species in which two metallo-ligands coordinate to a cobalt(II) ion through the phenoxido oxygen atoms along with two terminally coordinated dicyanamide ions. On the other hand, complexes 2a and 2b are one of the very scarce examples of supramolecular isomers since they present the same [(CuL(1))2Co{dca}2] trinuclear units (very similar to the trinuclear core in 1) and differ only in their superstructures. Thus, although each Cu2Co trimer in 2a and 2b is connected to four other Cu2Co trimers through four μ1,5-dca(-) bridges, 2a presents a square two-dimensional structure (each Cu2Co trimer is connected to four in-plane Cu2Co trimers); whereas, 2b shows a triangular three-dimensional lattice (each Cu2Co trimer is connected to three in-plane and one out-of-plane trimers). Variable-temperature magnetic susceptibility measurements show the presence of moderate antiferromagnetic exchange interactions (ferrimagnetic) in all the cases mediated through the double phenoxido bridges that have been fitted with an anisotropic model including spin-orbit coupling in the central Co(II) ion.

Catena-Poly[[[{1-[(E)-phenyl(pyridin-2-yl-κN)methylidene]semicarbazidato-κ2N1,O}copper(II)]-μ-dicyanamido-κ2N1:N5] monohydrate

The CuII atoms in the title coordination polymer, {[Cu(C13H11N4O)(C2N3)]·H2O}n, are N,N′,O-chelated by the deprotonated Schiff base ligands, and adjacent metal atoms are bridged by the dicyanamide ions, generating a polymeric chain that propagates along the b axis. The two independent metal atoms show a square-pyramidal N4O coordination. The two independent water mol­ecules are disordered over two positions; each water mol­ecule is a hydrogen-bond donor to a carbonyl O atom. Weak N—H⋯N hydrogen bonding is also observed.

One‐Pot Synthesis of Metal‐Doped Mesoporous Materials from (Dicyanamido)metallate Precursors

AbstractMetal‐doped mesoporous composites were synthesised by using a facile one‐pot sol–gel approach. Special multifunctional surfactants were designed and used simultaneously as structure‐directing agents, N‐doped carbon source and metal dopant. This versatile profile of properties is obtained by combining complex metallate anions carrying dicyanamide ions as ligands with nitrogen‐containing amphiphilic counteranions. Furthermore, also the use of nonamphiphilic countercations yields interesting precursors that can be converted into carbon materials with submicron‐sized morphologies by simple annealing. We therefore present herein a novel precursor system enabling immediate pathways to new materials that are of significant interest for sustainable catalysis and energy applications.

Molecular structures of nickel(II) monochelates of a racemic tridentate ligand and co-ligand induced structural variations

Using a racemic mixture of the tridentate ligand, (((2-pyridyl)ethylamine)methyl)phenolate ion ( L −) and N 3 - , NCS −, (NC) 2N −, OAc − as coligands, complexes having the formula [Ni( L)(N 3)] ( 1), [Ni( L)(NCS)] 2 ( 2), [Ni 2( L) 2(OAc)(N(CN) 2)] n ( 3) were prepared and structurally characterized. In 1, Ni(II) has a square planar geometry and phenolate oxygen is involved in dipolar O P δ - ⋯N δ+ interaction with electrophilic central nitrogen atom of coordinated azide ion. Complex 2 is dimeric in nature and nickel(II) is penta-coordinated. Compounds 1 and 2 exist as centrosymmetric dimers made up of a pair of R and S enantiomers of L. In 3, an acetate and phenoxo bridged dinickel complex is present which is further linked to a zig-zag coordination polymer by the dicyanamide ion. In a given chain of 3, both L have same enantiomeric form and either RR or SS dimers are repeated along the chain. The magnetic properties are described.

Designing dicyanamide bridged 1D molecular architecture from a mononuclear copper(II) Schiff base precursor: Syntheses, structural variations and magnetic study

A new tridentate N 2O donor Schiff base ligand [(C 6H 5C(OH) CHC(CH 3) NCH 2C 5H 4N) LH] was obtained by 1:1 condensation of benzoylacetone with 2-picolylamine and has been used to synthesise a mononuclear [CuLCl] ( 1) and an end-to-end dicyanamide bridged polynuclear {[Cu 2(μ-L) 2(μ 2-1,5-(CN) 2N)]ClO 4} n ( 2) copper(II) complexes. The ligand, 1 and 2 were clearly characterised by elemental analysis, FT-IR, 1H NMR, UV–Vis spectral studies, electrochemical studies and in addition single crystal X-ray diffraction studies were performed for 1 and 2. The Schiff base ligand [ LH] shows a significant variation in its coordination behaviour with copper(II) ion in absence and in presence of dicyanamide ion in 1 and 2 respectively. In absence of dicyanamide the deprotonated enolato oxygen of the tridentate Schiff base ligand [ L] − coordinates the copper(II) ion in a monodentate fashion generating a mononuclear species ( 1) whereas in presence of the dicyanamide ion, the deprotonated enolato oxygen of [ L] − bridges two adjacent [CuL(CN) 2N] units through μ-OL bridges, forming dimers. The dimeric units are further linked to adjacent dimeric units through μ 2-1,5-dicyanamide bridges to produce 1D polymeric chains in 2. Variable temperature magnetic susceptibility measurements for 2 in the temperature range 2-300 K reveal the presence of weak antiferromagnetic exchange interactions in the polymeric chain.