Efficient Intramolecular Energy Transfer between Two Fluorophores in a Bis‐Branched [3]Rotaxane

A bis‐branched [3]rotaxane, with two [2]rotaxane arms separated by an oligo(para‐phenylenevinylene) (OPV) fluorophore, was designed and investigated. Each [2]rotaxane arm employed a difluoroboradiaza‐s‐indacene (BODIPY) dye‐functionalized dibenzo[24]crown‐8 macrocycle interlocked onto a dibenzylammonium in the rod part. The chemical structure of the [3]rotaxane was confirmed and characterized by ¹H and ¹³C NMR spectroscopy and high‐resolution ESI mass spectrometry. The photophysical properties of [3]rotaxane and its reference systems were investigated through UV/Vis absorption, fluorescence, and time‐resolved fluorescence spectroscopy. An efficient energy‐transfer process in [3]rotaxane occurred from the OPV donor to the BODIPY acceptor because of the large overlap between the absorption spectrum of the BODIPY moiety and the emission spectrum of the OPV fluorophore; this shows the important potential of this system for designing functional molecular systems.     

Co‐Conformational Isomerism in a Neutral Ion‐Paired Supramolecular System

Two different counter‐ion‐free host–guest complexes have been prepared and isolated. These compounds were formed from two equally and opposite doubly‐charged species, the viologen guests 1 a ²⁺ and 1 b ²⁺ and the anti‐disulfodibenzo[24]crown‐8 [ DSDB24C8] ^2? host, which gave rise to the 1:1 neutral complexes [ 1 a?DSDB24C8 ] and [ 1 b?DSDB24C8 ]. These species are held together by hydrogen bonding and π stacking, as well as strong electrostatic interactions. The investigation of these neutral ion‐paired supramolecular systems in solution and in the solid state allowed us to establish their co‐conformational preferences. Compound [ 1 a?DSDB24C8 ], with small methyl groups as substituents on the viologen unit, may adopt three different geometries, 1) an exo nonthreaded, 2) a partially threaded, and 3) a threaded arrangement, depending on the relative spatial orientation between the host and guest: The partially‐threaded structure is preferred in solution and in the solid state. The presence of bulky tert‐butylbenzyl groups in the viologen moiety in compound [ 1 b?DSDB24C8 ] restricts the possible geometrical arrangements to one: The exo nonthreaded arrangement. This structure was confirmed in the solid state by X‐ray crystallography. The stability of the neutral complexes in solution was determined by UV/Vis spectrophotometry. The stoichiometry of the complexes was established by continuous variation experiments, and overall equilibrium constants and ΔG° values were determined on the basis of dilution experiments. The results observed are a consequence of only the intrinsic stability of the complexes as there are no additional contributions from counter ions.     

Planar and Nonplanar Free‐Base Tetraarylporphyrins: β‐Pyrrole Substituents and Geometric Effects on Electrochemistry,Spectroelectrochemistry, and Protonation/Deprotonation Reactions in Nonaqueous Media

A series of planar and nonplanar free‐base β‐pyrrole substituted meso‐tetraarylporphyrins were characterized by electrochemistry, spectroelectrochemistry, and protonation or deprotonation reactions in neutral, acidic, and basic solutions of CH₂Cl₂. The neutral compounds are represented as H₂(P), in which P represents a porphyrin dianion with one of several different sets of electron‐withdrawing or ‐donating substituents at the messo and/or β‐pyrrole positions of the macrocycle. The conversion of H₂(P) to [H₄(P)]²⁺ in CH₂Cl₂ was accomplished by titration of the neutral porphyrin with trifluoroacetic acid (TFA) while the progress of the protonation was monitored by UV/Vis spectroscopy, which was also used to calculate logβ₂ for proton addition to the core nitrogen atoms of the macrocycle. Cyclic voltammetry was performed after each addition of TFA or TBAOH to CH₂Cl₂ solutions of the porphyrin and half‐wave potentials for reduction were evaluated as a function of the added acid or base concentration. Thin‐layer spectroelectrochemistry was used to obtain UV/Vis spectra of the neutral and protonated or deprotonated porphyrins under the application of an applied reducing potential. The magnitude of the protonation constants, the positions of λ_max in the UV/Vis spectra and the half‐wave or peak potentials for reduction are then related to the electronic properties of the porphyrin and the data evaluated as a function of the planarity or nonplanarity of the porphyrin macrocycle. Surprisingly, the electroreduction of the diprotonated nonplanar porphyrins in acid media leads to H₂(P), whereas the nonplanar H₂(P) derivatives are reduced to [(P)]^2? in CH₂Cl₂ containing 0.1 M tetra‐n‐butylammonium perchlorate (TBAP). Thus, in both cases an electrochemically initiated deprotonation is observed.     

Highly Pure Synthesis,Spectral Assignments,and Two‐Photon Properties of Cruciform Porphyrin Pentamers Fused with Benzene Units

Tetrameric porphyrin formation of 2‐hydroxymethylpyrrole fused with porphyrins through a bicyclo[2.2.2]octadiene unit gave bicyclo[2.2.2]octadiene‐fused porphyrin pentamers. Thermal conversion of the pentamers gave fully π‐conjugated cruciform porphyrin pentamers fused with benzene units in quantitative yields. UV/Vis spectra of fully π‐conjugated porphyrin pentamers showed one very strong Q absorption and were quite different from those of usual porphyrins. From TD‐DFT calculations, the HOMO level is 0.49 eV higher than the HOMO?1 level. The LUMO and LUMO+1 levels are very close and are lower by more than 0.27 eV than those of other unoccupied MOs. The strong Q absorption was interpreted as two mutually orthogonal single‐electron transitions (683 nm: 86 %, HOMO→LUMO; 680 nm: 86 %, HOMO→LUMO+1). The two‐photon absorption (TPA) cross section value (σ⁽²⁾) of the benzene‐fused porphyrin pentamer was estimated to be 3900 GM at 1500 nm, which is strongly correlated with a cruciform molecular structure with multidirectional π‐conjugation pathways.     

Heteroleptic [n]Chromoarenophanes: ansa Complexes Derived from [Cr(η5‐C5H5)(η6‐C6H6)]

The synthesis of ansa complexes has been studied intensively owing to their importance as homogeneous catalysts and as precursors of metal‐containing polymers. However, paramagnetic non‐metallocene derivatives are rare and have been limited to examples with vanadium and titanium. Herein, we report an efficient procedure for the selective dilithiation of paramagnetic sandwich complex [Cr(η⁵‐C₅H₅)(η⁶‐C₆H₆)], which allows the preparation of a series of [n]chromoarenophanes (n=1, 2, 3) that feature silicon, germanium, and tin atoms at the bridging positions. The electronic and structural properties of these complexes were probed by X‐ray diffraction analysis, cyclic voltammetry, and by UV/Vis and EPR spectroscopy. The spectroscopic parameters for the strained and less strained complexes (i.e., with multiple‐atom linkers) indicate that the unpaired electron resides primarily in a d orbital on chromium(I); this result was also supported by density functional theory (DFT) calculations. We did not observe a correlation between the experimental UV/Vis and EPR data and the degree of molecular distortion in these ansa complexes. The treatment of tin‐bridged complex [Cr(η⁵‐C₅H₄)(η⁶‐C₆H₅)SntBu₂] with [Pt(PEt₃)₃] results in the non‐regioselective insertion of the low‐valent Pt⁰ fragment into the C_ipso? Sn bonds in both the five‐ and six‐membered rings, thereby furnishing a bimetallic complex. This observed reactivity suggests that ansa complexes of this type are promising starting materials for the synthesis of bimetallic complexes in general and also underline their potential to undergo ring‐opening processes to yield new metal‐containing polymers.     

Ruthenium‐Grafted Vinylhelicenes: Chiroptical Properties and Redox Switching

The properties of mono‐ and bis‐Ru–vinyl[6]helicene complexes ( 2 a and 2 b , respectively), recently synthesized by using molecular engineering of helicenes based on the grafting of lateral organometallic substituents on the π‐helical backbone through a vinyl bridge, are presented. These helicene derivatives are thoroughly characterized, with special attention given to their chiroptical properties and redox switching activity. The UV/Vis and electronic circular dichroism (ECD) spectra of P and M enantiopure species, both in the neutral and oxidized states ([ 2 a ] ^{. +}, [ 2 b ] ^{. +}, and [ 2 b ]²⁺), are analyzed with the aid of quantum‐chemical calculations. The extended π‐conjugation facilitated by the vinyl moiety, clearly visible in the electronic structures of 2 a , b , introduces new active bands in the ECD spectra that consequently lead to a significant increase in optical rotation of Ru–vinylhelicenes compared with the organic precursors. The vibrational circular dichroism (VCD) spectra were measured and calculated for both the organic and organometallic species and constitute the first examples of VCD for metal‐based helicene derivatives. Finally, the redox‐triggered chiroptical switching activity of 2 a , b is examined in detail by using ECD spectroscopy. The modifications of the ECD spectra in the UV/Vis and NIR region are well reproduced and rationalized by calculations.     

An Adaptable N‐Heterocyclic Carbene Macrocycle Hosting Copper in Three Oxidation States

A neutral hybrid macrocycle with two trans‐positioned N‐heterocyclic carbenes (NHCs) and two pyridine donors hosts copper in three oxidation states (+I–+III) in a series of structurally characterized complexes ( 1 – 3 ). Redox interconversion of [LCu]^+/2+/3+ is electrochemically (quasi)reversible and occurs at moderate potentials (E_1/2=?0.45 V and +0.82 V (vs. Fc/Fc⁺)). A linear C^NHC‐Cu‐C^NHC arrangement and hemilability of the two pyridine donors allows the ligand to adapt to the different stereoelectronic and coordination requirements of Cu^I versus Cu^II/Cu^III. Analytical methods such as NMR, UV/Vis, IR, electron paramagnetic resonance, and Cu Kβ high‐energy‐resolution fluorescence detection X‐ray absorption spectroscopies, as well as DFT calculations, give insight into the geometric and electronic structures of the complexes. The XAS signatures of 1 – 3 are textbook examples for Cu^I, Cu^II, and Cu^III species. Facile 2‐electron interconversion combined with the exposure of two basic pyridine N sites in the reduced Cu^I form suggest that [LCu]^+/2+/3+ may operate in catalysis via coupled 2 e^?/2 H⁺ transfer.     

Assembly of π‐Conjugated Phosphole Azahelicene Derivatives into Chiral Coordination Complexes: An Experimental and Theoretical Study

Aza[n]helicene phosphole derivatives have been prepared from aza[n]helicene diynes by the Fagan–Nugent route. Their photophysical properties (UV/Vis absorption and emission behavior) have been evaluated. Their behavior as P,N chelates towards coordination to Pd^II and Cu^I has been investigated: metal–bis(aza[n]helicene phosphole) assemblies are formed by a highly stereoselective coordination process, as demonstrated by X‐ray crystallography. An aza[6]helicene phosphole bearing an enantiopure helicene part has been obtained, which allows the preparation of enantiopure Pd^II and Cu^I complexes with original topologies and high molar rotation (MR) and circular dichroism (CD). The structure–property relationship established from the experimental data has been studied in detail by theoretical studies (TDDFT calculations of UV/Vis, CD, and MR). Aza[n]helicene phosphole derivatives show π conjugation extended over the entire molecule, and its influence on the MR of aza[6]helicene phosphole 5 c has been demonstrated. Finally, it has been shown that the nature of the metal (coordination geometry and electronic interaction) can have a great impact on the amplitude of the chiroptical properties in metal–bis(aza[n]helicene phosphole) assemblies.     

Stereodynamics of Metal–Ligand Assembly: What Lies Beneath the “Simple” Spectral Signatures of C2‐Symmetric Chiral Chelates

A series of C₂‐symmetric chiral tetra‐dentate ligands were prepared by using [4,5]‐ or [5,6]‐pinene‐fused 2,2′‐bipyridyl units that are supported across a rigid arylene–ethynylene backbone. These conformationally pre‐organised chelates support stable 1:1 metal complexes, which were fully characterised by UV/Vis, fluorescence, circular dichroism (CD), and ¹H NMR spectroscopy. A careful inspection of the exciton‐coupled circular dichroism (ECCD) and ¹H NMR spectra of the reaction mixture in solution, however, revealed the evolution and decay of intermediate species en route to the final 1:1 metal–ligand adduct. Consistent with this model, mass spectrometric analysis revealed the presence of multiple metal complexes in solution at high ligand‐to‐metal ratios, which were essentially unobservable by UV/Vis or fluorescence spectroscopic techniques. Comparative studies with a bi‐dentate model system have fully established the functional role of the π‐conjugated ligand skeleton that dramatically enhances the thermodynamic stability of the 1:1 complex. In addition to serving as a useful spectroscopic handle to understand the otherwise “invisible” solution dynamics of this metal–ligand assembly process, temperature‐dependent changes in the proton resonances associated with the chiral ligands allowed us to determine the activation barrier (ΔG^≠) for the chirality switching between the thermodynamically stable but kinetically labile (P)‐ and (M)‐stereoisomers.     

Effect of Solvent and Protonation/Deprotonation on Electrochemistry,Spectroelectrochemistry and Electron‐Transfer Mechanisms of N‐Confused Tetraarylporphyrins in Nonaqueous Media

A series of N‐confused free‐base meso‐substituted tetraarylporphyrins was investigated by electrochemistry and spectroelectrochemistry in nonaqueous media containing 0.1 M tetra‐n‐butylammonium perchlorate (TBAP) and added acid or base. The investigated compounds are represented as (XPh)₄NcpH₂, in which “Ncp” is the N‐confused porphyrin macrocycle and X is a OCH₃, CH₃, H, or Cl substituent on the para position of each meso‐phenyl ring of the macrocycle. Two distinct types of UV/Vis spectra are initially observed depending upon solvent, one corresponding to an inner‐2H form and the other to an inner‐3H form of the porphyrin. Both forms have an inverted pyrrole with a carbon inside the cavity and a nitrogen on the periphery of the π‐system. Each porphyrin undergoes multiple irreversible reductions and oxidations. The first one‐electron addition and first one‐electron abstraction are located on the porphyrin π‐ring system to give π‐anion and π‐cation radicals with a potential separation of 1.52 to 1.65 V between the two processes, but both electrogenerated products are unstable and undergo a rapid chemical reaction to give new electroactive species, which were characterized in the present study. The effect of the solvent and protonation/deprotonation reactions on the UV/Vis spectra, redox potentials and reduction/oxidation mechanisms is discussed with comparisons made to data and mechanisms for the structurally related free‐base corroles and porphyrins.     

meso‐3,5‐Bis(trifluoromethyl)phenyl‐Substituted Expanded Porphyrins: Synthesis,Characterization, and Optical,Electrochemical, and Photophysical Properties

Trifluoroacetic acid‐catalyzed condensation of pyrrole with electron‐deficient and sterically hindered 3,5‐bis(trifluoromethyl)benzaldehyde results in the unexpected production of a series of meso‐3,5‐bis(trifluoromethyl)phenyl‐substituted expanded porphyrins including [22]sapphyrin 2 , N‐fused [22]pentaphyrin 3 , [26]hexaphyrin 4 , and intact [32]heptaphyrin 5 together with the conventional 5,10,15,20‐tetrakis(3,5‐bis(trifluoromethyl)phenyl)porphyrin 1 . These expanded porphyrins are characterized by mass spectrometry, ¹H NMR spectroscopy, UV/Vis/NIR absorption spectroscopy, and fluorescence spectroscopy. The optical and electrochemical measurements reveal a decrease in the HOMO–LUMO gap with increasing size of the conjugated macrocycles, and in accordance with the trend, the deactivation of the excited singlet state to the ground state is enhanced.     

On the Tacticity of Polynorbornenes with 5,6‐endo Pendant Groups That Contain Substituted Aryl Chromophores

Two dimers and a series of polymers with 5,6‐endo pendant aryl groups that contain different substituents at the para positions were synthesized. The conformation and stereochemistry of the dimers and polymers were determined by nonlinear optical analysis (EFISH) as well as UV/Vis and ¹³C NMR spectroscopy. The chemical shifts of C7 for the polymers appeared as two peaks in the ¹³C NMR spectra when the substituents are electron‐withdrawing groups. The percentage decrease in the relative extinction coefficient of the polymers, ε_d, was linearly related to the Hammett constant σ. Polynorbornenes with electron‐withdrawing substituents may adopt isotactic stereochemistry with all pendant groups aligned in one direction. The nature of the interactions between neighboring chromophores may be one of the most important factors in directing the stereoregularity and conformation of these polymers. The corresponding polymers derived from the exo isomers appeared to be less stereoregular.     

Strain‐Induced Reactivity in the Dynamic Covalent Chemistry of Macrocyclic Imines

The displacement of molecular structures from their thermodynamically most stable state by imposition of various types of electronic and conformational constraints generates highly strained entities that tend to release the accumulated strain energy by undergoing either structural changes or chemical reactions. The latter case amounts to strain‐induced reactivity (SIR) that may enforce specific chemical transformations. A particular case concerns dynamic covalent chemistry which may present SIR, whereby reversible reactions are activated by coupling to a high‐energy state. We herewith describe such a dynamic covalent chemical (DCC) system involving the reversible imine formation reaction. It is based on the formation of strained macrocyclic bis‐imine metal complexes in which the macrocyclic ligand is in a high energy form enforced by the coordination of the metal cation. Subsequent demetallation generates a highly strained free macrocycle that releases its accumulated strain energy by hydrolysis and reassembly into a resting state. Specifically, the metal‐templated condensation of a dialdehyde with a linear diamine leads to a bis‐imine [1+1]‐macrocyclic complex in which the macrocyclic ligand is in a coordination‐enforced strained conformation. Removal of the metal cation by a competing ligand yields a highly reactive [1+1]‐macrocycle, which then undergoes hydrolysis to transient non‐cyclic aminoaldehyde species, which then recondense to a strain‐free [2+2]‐macrocyclic resting state. The process can be monitored by ¹H NMR spectroscopy. Energy differences between different conformational states have been evaluated by Hartree–Fock (HF) computations. One may note that the stabilisation of high‐energy molecular forms by metal ion coordination followed by removal of the latter, offers a general procedure for producing out‐of‐equilibrium molecular states, the fate of which may then be examined, in particular when coupled to dynamic covalent chemical processes.     

Alkali‐Metal Trichloroacetates for Dichloromethylenation of Fullerenes: Nucleophilic Addition‐Substitution Route

The first experimental evidence that fullerenes react with alkali‐metal trichloroacetates through a nucleophilic addition‐substitution route, yielding dichloromethylenefullerenes as the final products, is reported. The intermediates, C₆₀(CCl₃)^? and C₇₀(CCl₃)^? anions, have been isolated in their protonated forms as ortho‐C₆₀(CCl₃)H, as well as three ortho and one para isomer of C₇₀(CCl₃)H. The structures were unambiguously determined by means of ¹H, ¹³C, and ¹H–¹³C HMBC NMR spectroscopy along with UV/Vis spectroscopy. The observed regiochemistry was analyzed with the aid of quantum chemical calculations. Conversion of the protonated compounds into the [6,6]‐closed C_60/70(CCl₂) cycloadducts under basic conditions can be effected only for the ortho isomers, whereas para‐C₇₀(CCl₃)H decomposes back into pristine C₇₀.     

Macrocyclic Dinuclear Palladium Complex as a Novel Doubly Threaded [3]Rotaxane Scaffold and Its Application as a Rotaxane Cross‐Linker

A dinuclear Pd^II complex possessing a cyclic ligand was developed as a novel doubly threaded [3]rotaxane scaffold and applied as a rotaxane cross‐linker reagent. The dinuclear complex (PdMC)₂ was prepared by one‐step macrocyclization followed by the double palladation reaction. ¹H NMR analysis and UV/Vis measurements revealed the formation of a doubly threaded pseudo[3]rotaxane by the complexation of (PdMC)₂ with 2 equivalents of 2,6‐disubstituted pyridine 3 through double metal coordination. The treatment of (PdMC)₂ with 2 equivalents of 4‐vinylpyridine (VP) afforded a doubly threaded [3]rotaxane cross‐linker (PdMC‐VP)₂ . Radical co‐polymerization of VP and t‐butylstyrene in the presence of (PdMC‐VP)₂ afforded a stable rotaxane cross‐linked polymer (RCP). An elastic RCP was also prepared by using n‐butyl acrylate as a monomer. The obtained RCPs exhibited higher swelling ability and higher mechanical toughness compared with the corresponding covalent cross‐linked polymers.     

Protonation Behaviour of Chiral Tetradentate Polypyridines Derived from α‐Pinene

Detailed protonation experiments of the [5,6]‐pinenebipyridine molecule and the unsubstituted [4,5]‐ and [5,6]‐CHIRAGEN[0] ligands in various solvents indicate a variety of structures of the protonated species. UV‐visible and NMR measurements (including ¹⁵N chemical shifts) show the transition from trans to cis conformation of [5,6]‐pinenebipyridine upon protonation. The [4,5]‐CHIRAGEN[0] ligand, in which the protonation sites of the nitrogen atom donors are at opposite sides of the molecule, behave essentially like two independent bipyridine moieties; this behaviour was monitored by UV‐visible, CD and NMR spectroscopy (including ¹⁵N data). In the case of the [5,6]‐CHIRAGEN[0], a pocket of donor atoms provides a chiral environment for two protons per ligand.     

Synthesis of [n]Cyclo‐5,15‐porphyrinylene‐4,4′‐biphenylenes Displaying Size‐Dependent Excitation‐Energy Hopping

A set of 5,15‐biphenylene‐bridged porphyrin wheels, namely, [n]cyclo‐5,15‐porphyrinylene‐4,4′‐biphenylenes [n]CPB , have been synthesized through the platination of 5,15‐bis(4‐(pinacolboranyl)phenyl) nickel(II) porphyrin and subsequent reductive elimination of Pt^II(cod)‐bridged cyclic porphyrin intermediates. The calculated strain energies for [3]CPB , [4]CPB , [5]CPB , and [6]CPB are 49.3, 32.9, 23.5, and 16.0 kcal mol^?1, respectively. UV/Vis absorption spectra and cyclic voltammetry indicated characteristic ring‐size‐dependent absorption‐peak shifts and redox‐potential shifts, which presumably reflect the degree of strain in the π‐systems. Excitation‐energy hopping (EEH) times were determined to be 5.1, 8.0, 8.0, and 9.6 ps for [3]CPB , [4]CPB , [5]CPB , and [6]CPB , respectively, in a pump‐power‐dependent TA experiment.     

Photoresponsive Formation of an Intermolecular Minimal G‐Quadruplex Motif

The ability of three different bifunctional azobenzene linkers to enable the photoreversible formation of a defined intermolecular two‐tetrad G‐quadruplex upon UV/Vis irradiation was investigated. Circular dichroism and NMR spectroscopic data showed the formation of G‐quadruplexes with K⁺ ions at room temperature in all three cases with the corresponding azobenzene linker in an E conformation. However, only the para–para‐substituted azobenzene derivative enables photoswitching between a nonpolymorphic, stacked, tetramolecular G‐quadruplex and an unstructured state after E–Z isomerization.     

Two‐Dimensional Acetylenic Scaffolding: Extended Donor‐Substituted Perethynylated Dehydroannulenes

Starting from (Z)‐bis(N,N‐diisopropylanilino)‐substituted tetraethynylethene (TEE), perethynylated octadehydro[12]‐ and dodecadehydro[18]annulenes were prepared by oxidative Hay coupling. The dodecadehydro[18]annulene with six peripheral N,N‐diisopropylanilino substituents was characterized by X‐ray crystallography. Elongation of the Z‐bisdeprotected TEE by Cadiot–Chodkiewicz coupling with 1‐bromo‐2‐(triisopropylsilyl)ethyne provided a Z‐configured bis(butadiyne), which after alkyne deprotection afforded under Hay coupling conditions N,N‐diisopropylanilino‐substituted perethynylated hexadecadehydro[20]‐ and tetracosadehydro[30]an‐nulenes. The diisopropylanilino substituents enhance the properties of these unprecedented all‐carbon perimeters in several distinct ways. They ensure their solubility, increase their stability, and importantly, engage in strong intramolecular charge‐transfer interactions with the electron‐accepting all‐carbon cores, resulting in intense, bathochromically shifted charge‐transfer bands in the UV/Vis spectra. The charge‐transfer character of these bands was confirmed by protonation‐neutralization experiments. The redox properties of the new carbon‐rich chromophores were investigated by cyclic voltammetry and rotating disk voltammetry, which indicated different redox behavior for aromatic (4n+2 π electrons) and antiaromatic (4n π electrons) dehydroannulenes.     

Syntheses,Physico‐Chemical Studies and Antioxidant Activities of Transition Metal Complexes with a Perimidine Ligand

A series of mononuclear complexes of the type, [MLCl₂] [M = Co^II, Ni^II, Cu^II, and Zn^II] with a pyrimidene‐type ligand, which was synthesized by the reaction of 2‐furaldehyde and 1, 8‐diaminonaphthalene, was obtained. The ligand and its complexes were characterized by elemental analysis, IR, NMR, EPR, and UV/Vis spectroscopy, ESI‐mass spectrometry, magnetic susceptibility, molar conductivity, and thermogravimetric analyses. On the basis of UV/Vis spectroscopic and magnetic susceptibility data, an octahedral arrangement was assigned around all metal ions. The low molar conductivity data for all the complexes show their non‐electrolytic nature. The thermal behavior of the complexes was studied by TGA analyses. The electrochemical study carried out on the Cu^II complex exhibits a quasi reversible redox process. The ligand and its complexes showed potential antioxidant and antimicrobial activities.