Substituents In Ortho Position Research Articles

Aryloxy ‘biometal’ complexes as efficient catalysts for the synthesis of poly(butylene adipate terephthalate)

A comparative study of catalytic activity of aryloxy complexes of Mg, Zn and Al in the synthesis of poly(butylene adipate terephthalate) demonstrated the preference of Al-based catalyst containing two bulky substituents in ortho-position of phenol ligand in terms of higher values of PBAT MW and lower yields of cyclic diester side product.

The synthesis and antiviral activity against yellow fewer virus of 2-(4,6-di(pyrrolidin-1-yl)-1,3,5-triazin-2-yl)-N-(alkyl, aryl)hydrazine-1-carbothioamides

Aim. To synthesize 2-(4,6-di(pyrrolidin-1-yl)-1,3,5-triazin-2-yl)-N-(alkyl, aryl)hydrazine-1-carbothioamides and study their antiviral activity against yellow fever virus (YFV). Results and discussion. The target 2-(4,6-di(pyrrolidin-1-yl)-1,3,5-triazin-2-yl)-N-(alkyl, aryl)hydrazine-1-carbothioamides were obtained in three-step format from cyanuric chloride in good to high yields. The carbothioamides synthesized were estimated to possess the antiviral activity against YFV. The results obtained indicate that most of the compounds studied show the inhibitory activity against YFV in concentrations ≤10 μg/mL. For the most active substances, EC90 was in the range of 0.06 – 2.2 μg/mL. Good effective concentration values were accompanied by low levels of cytotoxicity resulting in excellent selectivity index values. The data obtained also indicate that the presence of an alkyl substituent in ortho-position of the N-aryl fragment is crucial for an effective inhibition of YFV growth. Experimental part. 2-(4,6-Di(pyrrolidin-1-yl)-1,3,5-triazin-2-yl)-N-(alkyl, aryl)hydrazine-1-carbothioamides were synthesized starting from cyanuric chloride in three steps by its successive interaction with two equivalents of pyrrolidine, hydrazine and a series of alkyl-/arylisothiocyanates. The antiviral and cytotoxic activities of the target carbothioamides were studied in the Southern Research Institute (SRI, Birmingham, Alabama) by the viral cytopathic effect reduction assay and the virus yield reduction assay. Conclusions. 2-(4,6-Di(pyrrolidin-1-yl)-1,3,5-triazin-2-yl)-N-(alkyl, aryl)hydrazine-1-carbothioamides synthesized have been proven to be a promising class of compounds for treating such a severe viral disease as yellow fever.

A Triazole-Substituted Aryl Iodide with Omnipotent Reactivity in Enantioselective Oxidations.

A widely applicable triazole‐substituted chiral aryl iodide is described as catalyst for enantioselective oxidation reactions. The introduction of a substituent in ortho‐position to the iodide is key for its high reactivity and selectivity. Besides a robust and modular synthesis, the main advantage of this catalyst is the excellent performance in a plethora of mechanistically diverse enantioselective transformations, such as spirocyclizations, phenol dearomatizations, α‐oxygenations, and oxidative rearrangements. DFT‐calculations of in situ generated [hydroxy(tosyloxy)iodo]arene isomers give an initial rational for the observed reactivity.

Enantioseparation of three isomeric α-(chlorophenyl)propanoic acid by countercurrent chromatography and investigation of chlorine substituent through characterization of inclusion interaction

The influence of chlorine substituents in chiral separation of three racemic 2-(chlorophenyl)propanoic acids by countercurrent chromatography using hydroxypropyl-β-cyclodextrin as a chiral additive were mainly investigated in the present paper, including 2-(2-chlorophenyl)propanoic acids, 2-(3-chlorophenyl)propanoic acids and 2-(4-chlorophenyl)propanoic acids. The influences of chromatographic conditions on the retention behavior were studied by enantioselective liquid-liquid extraction experiments using the methodology of response surface It was found that 2-(3-chlorophenyl)propanoic acids could be successfully chiral separated by countercurrent chromatography, while no resolution was achieved for racemic 2-(2-chlorophenyl)propanoic acids and 2-(4-chlorophenyl)propanoic acids under optimized separation conditions. The formation of 1:1 stoichiometric inclusion compounds between 2-(3-chlorophenyl)propanoic acids and HP-β-CD was determined by UV spectra measurements. The inclusion constants for 2-(3-chlorophenyl)propanoic acids and HP-β-CD were determined by the Benesi-Hildebrand equation. Meanwhile, the inclusion constants of 2-(3-chlorophenyl)-propanoic acid enantiomer and HP-β-CD were obtained by the pesudophase retention equation in countercurrent chromatography. Furthermore, the inclusion interactions of the three racemates with HP-β-CD were also investigated by the molecular docking. The results obtained from UV spectra measurements and molecular docking showed that the racemate with chlorine substituents in meta-position presented the highest enantiorecognition while the racemates with chlorine substituents in ortho-position had the lowest enantiorecognition. The above results further indicated that forming a stable inclusion complex between racemate and chiral selector is a prerequisite for a successful enantioseparation and at the same time, the difference in inclusion capacity between the two enantiomers is also essential for the enantioseparation.

Sterically crowded dimeric diisobutylaluminum aryloxides: Synthesis, characteristics, and application as activators in homo- and copolymerization of olefins

A row of dimeric diisobutylaluminum aryloxides bearing different sterically crowded substituents in ortho-positions of the aryl ligand [(ArO)AliBu2]2 (ArO = 2-tBu-C6H4O (AlTBP), 2-Me,6-tBu-C6H3O (AlMTBP), 2,6-iPr2-C6H3O (AlDIPP), 2-Ph-C6H4O (AlPP), 2,6-Ph2-C6H3O (AlDPP), 1-C10H7O (AlN-1)) was synthesized. The Molecular structures of AlMTBP, AlDIPP, AlPP, AlDPP, and AlN-1 have been determined by X-ray crystallography. All dimeric diisobutylaluminum aryloxides were tested as activators of rac-Et (2-MeInd)2ZrMe2 in homopolymerization of ethylene, propylene, copolymerization of ethylene with propylene and terpolymerization of ethylene/propylene/5-ethylidene-2-norbornene. It was shown that only AlMTBP and AlDPP work as effective activators in all polymerization processes, with activity of AlMTBP system being significantly higher than that of AlDPP. The evaluation of dimerization energies of synthesized aryloxides by means of DFT calculations have shown AlMTBP and AlDPP to form the least stable dimers. The activation of rac-Et (2-MeInd)2ZrMe2 was modeled as bonding of diisobutylaluminum aryloxide with zirconocene followed by the first insertion of ethylene into Zr+–Me bond. As per that model, DFT calculations demonstrated the process to be the most favorable for AlMTBP and AlDPP which well corresponds to experimental observations.

5-HT1A and 5-HT2A receptors affinity, docking studies and pharmacological evaluation of a series of 8-acetyl-7-hydroxy-4-methylcoumarin derivatives

In this work we describe the synthesis, docking studies and biological evaluation of a focused library of novel arylpiperazinyl derivatives of 8-acetyl-7-hydroxy-4-methylcoumarin. The new compounds were screened for their 5-HT1A and 5-HT2A receptor affinity. Among the evaluated compounds, six displayed high affinities to 5-HT1A receptors (4a-0.9 nM, 6a-0.5 nM, 10a-0.6 nM, 3b-0.9 nM, 6b-1.5 nM, 10b-1 nM). Compound 6a and 10a bearing a bromo- or methoxy- substituent in ortho position of the piperazine phenyl ring, were identified as potent antagonists of the 5-HT1A receptors. In the tail suspension test, mice injected with 6a showed a dose-dependent increase in depressive-like behavior that was related to a decrease in locomotor activity. Compound 10a did not decrease or prolong immobility time nor did it affect home cage activity. Molecular docking studies using 5-HT1A and 5-HT2A homology models revealed structural basis of the high affinity of ortho-substituted derivatives and subtle changes in amino acid interactions patterns depending on the length of the alkyl linker.

Highly K+ -Selective Fluorescent Probes for Lifetime Sensing of K+ in Living Cells.

The new K+ -selective fluorescent probes 1 and 2 were obtained by CuI -catalyzed 1,3-dipolar azide alkyne cycloaddition (CuAAC) reactions of an alkyne-substituted [1,3]dioxolo[4,5-f][1,3]benzodioxole (DBD) ester fluorophore with azido-functionalized N-phenylaza-18-crown-6 ether and N-(o-isopropoxy) phenylaza-18-crown-6 ether, respectively. Probes 1 and 2 allow the detection of K+ in the presence of Na+ in water by fluorescence enhancement (2.2 for 1 at 2000 mm K+ and 2.5 for 2 at 160 mm K+ ). Fluorescence lifetime measurements in the absence and presence of K+ revealed bi-exponential decay kinetics with similar lifetimes, however with different proportions changing the averaged fluorescence decay times (τf(av) ). For 1 a decrease of τf(av) from 12.4 to 9.3 ns and for 2 an increase from 17.8 to 21.8 ns was observed. Variation of the substituent in ortho position of the aniline unit of the N-phenylaza-18-crown-6 host permits the modulation of the Kd value for a certain K+ concentration. For example, substitution of H in 1 by the isopropoxy group (2) decreased the Kd value from >300 mm to 10 mm. 2 was chosen for studying the efflux of K+ from human red blood cells (RBC). Upon addition of the Ca2+ ionophor ionomycin to a RBC suspension in a buffer containing Ca2+ , the fluorescence of 2 slightly rose within 10 min, however, after 120 min a significant increase was observed.

Nature of the degradation products of phenol which produce high levels of color in the wastewater oxidized in a photo-Fenton system

This work completes the step of the mechanism of phenol oxidation, where the wastewater shows the maximum color levels, considering the formation of trihydroxybenzene rings and quinoidal compounds of hydroxylated nature as degradation intermediates. They have been determined experimentally by the stoichiometric ratios of oxidant to degrade phenol until the intermediate species generated during the oxidation (R = mol H2O2/mol C6H6O). Hence, catechol forms at R = 1.0, resorcinol at R = 1.3 and hydroquinone at R = 2.0. The addition of these ratios, R = 4.3, corresponds to the minimum dosage required to oxidize the initial phenol contained in the solution. p-benzoquinone is formed at R = 1.0. The formation of trihydroxylated rings with substituents in ortho-position (pyrogallol) and meta-(phloroglucinol), which makes them more unstable, needs a lower dosage of oxidant, R = 4.0, than the para-substituted (hydroxyhydroquinone), that requires R = 5.5. Muconic acid formation reaches its maximum at R = 6.0 while the formation of benzoquinones substituted by hydroxyl groups (dihydroxybenzoquinone) require R = 8.0. These results suggest that oxidation of p-benzoquinone would yield dihydroxybenzoquinone species, whereas muconic acid would be an oxidation byproduct of ortho- and meta-substituted species. The oxidation intermediates generated during the first steps of the oxidation pathway determine the color of oxidized wastewater, although iron species in solution may enhance its intensity. Maximum color is obtained at R = 4.0 and is produced by intermediates that are generated during the oxidation of pyrogallol and phloroglucinol-type compounds. A drastic decrease in color happens between R = 4.0 and 6.0 which corresponds to the formation of muconic acid. Finally, the color increases slightly at R greater than 7.0 which can be related to the formation of dihydroxylated benzoquinones. As the color and toxic compounds are degraded to biodegradable acids of colorless nature, the color intensity diminishes to colorless at R > 13.0.

Novel (2,6-difluorophenyl)(2-(phenylamino)pyrimidin-4-yl)methanones with restricted conformation as potent non-nucleoside reverse transcriptase inhibitors against HIV-1

To elucidate the structure-geometry-activity relationship in diarylpyrimidine family (DAPYs) containing carbonyl linker between the central pyrimidine core and phenyl type B-arm, a series of (2,6-difluorophenyl)(2-(phenylamino)pyrimidin-4-yl)methanones was designed, prepared and tested for their anti-HIV-1 activity. The carbonyl linker bearing B phenyl arm was successfully attached at both C-2 and C-4 positions of the central pyrimidine ring using a new synthetic approach. Further modifications of target compounds are present at C-5 position of the pyrimidine ring. In vitro anti-HIV-1 activity study performed on a series of 22 compounds confirmed the crucial importance of both conformational rigidity between phenyl B arm and the pyrimidine core linked through the carbonyl bridge, as well as presence of fluoro substituents in ortho-positions of phenyl B moiety. The most potent derivative of the series, compound 17, having almost perpendicular angle within the two planes made from the B aromatic arm and the pyrimidine ring, exhibited low nanomolar anti-HIV-1 activity (EC50 = 4 nM) with no significant toxicity (CC50 > 57.1 μM).

OLIGOMERIZATION OF THE ETHYLENE IN THE PRESENCE OF NEW HETEROGENIZED Zr-CONTAINING COMPLEX CATALYTIC SYSTEMS

The new heterogenized zirconium phenolate complexes containing different bulky ionic liquid type amine hydrochloride substituents in ortho-position have been synthesized and characterized. The oligomerization of the ethylene was carried out with use of these complexes activated by aluminum organic compounds in heptane, toluene and chlorobenzene. In the presence of diethyl aluminum chloride these complexes show higher activity than in the presence of ethylaluminum dichloride. The distributions and composition of the obtained oligomer products depend on the nature of aluminum organic compound used. The oligomerization products consist of C4 - C18 oligomers when diethyl aluminum chloride is used as a cocatalyst. In the presence of ethylaluminum dichloride the higher branched structured oligomers (oil fraction with boiling point > 350 °C) is obtained with >75 % yield. The products are easily separated from the catalysts by simple decantation and zirconium complexes may be repeatedly reused in successive ethylene oligomerization.

Effect of the structural factors on reactivity of aryl halides in the copper-catalyzed arylation of aniline in aqueous medium

Arylation of aniline with substituted bromobenzenes in two-phase water–chlorobenzene system catalyzed by Cu(OAc)2–N-phenyloxalyldihydrazide–hexane-2,5-dione system was found to be slightly sensitive to the polar effect of a substituent in the aryl halide. Value of the reaction parameter ρ was 0.55. However the presence of substituent in ortho-position of the benzene ring decreased significantly the reaction rate [krel(2-MeC6H4Br/4-MeC6H4Br) = 0.14.]

An alternative approach to PEPPSI catalysts: from palladium isonitriles to highly active unsymmetrically substituted PEPPSI catalysts.

A series of new pyridine-enhanced precatalyst preparation, stabilization, and initiation (PEPPSI)-type complexes bearing different types of carbene ligands was prepared by the modular and convergent template synthesis strategy. Nitrogen acyclic carbenes, saturated and unsaturated five-membered NHC, saturated six-membered NHCs, and five-membered N-heterocyclic oxo-carbene (NHOC) ligands on palladium were prepared this way. These new organometallic compounds then were tested in Suzuki and Negishi cross-coupling reactions by using substrates with one or two substituents in ortho-position of the new CC bond being formed. Both aryl chlorides and bromides were tested as coupling partners. In some cases, the new ligands gave results similar to Organ's successful IPr-based and IPent-based PEPPSI derivatives, with aryl bromides 0.05 mol % catalyst load still gave satisfactory results, with aryl chlorides 0.5 mol % were needed.

Different electronic and charge-transport properties of four organic semiconductors Tetraazaperopyrenes derivatives

Tetraazaperopyrenes (TAPPs) derivatives are high-performance n-type organic semiconductor material families with the remarkable long-term stabilities. The charge carrier mobilities in TAPPs derivatives crystals were calculated by the density functional theory (DFT) method combined with the Marcus–Hush electron-transfer theory. The existence of considerable C–H…F–C bonding defines the conformation of the molecular structure and contributes to its stability. We illustrated how it is possible to control the electronic and charge-transport parameters of TAPPs derivatives as a function of the positions, a type of the substituents. It is found that the core substitution of TAPPs has a drastic influence on the charge-transport mobilities. The maximum electron mobility value of the core-brominated 2,9-bis (perfluoroalkyl)-substituted TAPPs is 0.521cm2V−1s−1, which appear in the orientation angle 95° and 275°. The results demonstrate that the TAPPs with bromine substituents in ortho positions exhibit the best charge-transfer efficiency among the four different TAPP derivatives.

Identification of vibration characteristics in infrared spectrum of polybrominated diphenyl ethers congeners based on Br substituents

Structure optimization and frequency calculations of 209 kinds of PBDEs homologues were carried out at the B3LYP/6-31G(d) level based on density functional theory, the known experimental parameters of 4 PBDEs congeners were compared with the calculated values, and the average analog coefficient was 0. 989. The main vibration of DE and BDE-209 which contained only H atoms or Br substituent in the benzene ring was assigned due to their less interference for various infrared spectrum vibrations. C-Br bond vibration which was often coupled with other forms of vibration was not easy to distinguish between PBDEs congeners. With the characteristics of universality, strong vibration and identifiable, triangular breathing vibration of the benzene rings in the infrared spectrum was selected as a characteristic vibration among different PBDEs homologues, the analysis results showed that the ortho-substituted and para-substituted Br could significantly improve the vibration frequency of triangular breathing vibration, while the meta-substituted Br played the opposite role; For the low bromide, the more the substituents in ortho position, the higher the frequency, while for the high bromide homologues, simultaneous existence in ortho-position and para-position would have a higher frequency; With the same substituted location, the more the substituent in the same benzene ring, the higher the vibration frequency. SVM regression model was used to verify the relative relationship between Br substituent and triangle breathing vibration frequency of the benzene rings, and the simulation efficiency coefficient of model was 0. 956. The study provided a theoretical basis and guidance for actually testing and identifying PBDEs homologues in the environment.

Structures and Properties of Molecular Torsion Balances to Decipher the Nature of Substituent Effects on the Aromatic Edge‐to‐Face Interaction

Various recent computational studies initiated this systematic re-investigation of substituent effects on aromatic edge-to-face interactions. Five series of Tröger base derived molecular torsion balances (MTBs), initially introduced by Wilcox and co-workers, showing an aromatic edge-to-face interaction in the folded, but not in the unfolded form, were synthesized. A fluorine atom or a trifluoromethyl group was introduced onto the edge ring in ortho-, meta-, and para-positions to the C-H group interacting with the face component. The substituents on the face component were varied from electron-donating to electron-withdrawing. Extensive X-ray crystallographic data allowed for a discussion on the conformational behavior of the torsional balances in the solid state. While most systems adopt the folded conformation, some were found to form supramolecular intercalative dimers, lacking the intramolecular edge-to-face interaction, which is compensated by the gain of aromatic π-stacking interactions between four aryl rings of the two molecular components. This dimerization does not take place in solution. The folding free enthalpy ΔG(fold) of all torsion balances was determined by (1)H NMR measurements by using 10 mM solutions of samples in CDCl3 and C6D6. Only the ΔG(fold) values of balances bearing an edge-ring substituent in ortho-position to the interacting C-H show a steep linear correlation with the Hammett parameter (σ(meta)) of the face-component substituent. Thermodynamic analysis using van't Hoff plots revealed that the interaction is enthalpy-driven. The ΔG(fold) values of the balances, in addition to partial charge calculations, suggest that increasing the polarization of the interacting C-H group makes a favorable contribution to the edge-to-face interaction. The largest contribution, however, seems to originate from local direct interactions between the substituent in ortho-position to the edge-ring C-H and the substituted face ring.

Effect of a bulky lateral substitution by chlorine atom and methoxy group on self-assembling properties of lactic acid derivatives

Several chiral liquid crystalline materials derived from the lactic acid have been studied with the aim to establish the effect of bulky lateral substituents on their self-assembling properties. A chlorine atom and methoxy group have been used as lateral substituents in ortho position to ether group position on phenyl ring far from the chiral centre. All the studied materials possess tilted ferroelectric smectic C* phase in a broad temperature range. In dependence on the molecular structure namely type of lateral substituent and length of the chiral chain, the cholesteric mesophase, orthogonal paraelectric smectic A* and crystal mesophases have been detected. Lateral chlorine substitution results in decrease of both the clearing point and crystallisation temperature as well as in a distinct increase of spontaneous polarization. Bulky methoxy substitution slightly suppresses the spontaneous polarisation but strongly increases the melting point that results in monotropic peculiarity of the SmC* phase. Mesomorphic, spontaneous, structural and dielectric properties of the substituted compounds were established and compared to those of the non-substituted ones in order to contribute to better understanding of the structure–property relationship for such chiral self-assembling materials.

Theoretical investigation on the antioxidative activity of anthocyanidins: A DFT/B3LYP study

Anthocyanidins are an important class of plant pigment, in the present work the antioxidative properties of anthocyanidins have been explored by density functional theory calculations, three main antioxidative mechanisms, which include H atom transfer (HAT), single electron transfer (SET) and sequential proton loss electron transfer (SPLET), have been investigated at B3LYP/6-311G(d,p) level of theory. The O–H bond dissociation enthalpies (BDEs), ionization potentials (IPs), electron affinities (EAs), proton affinities (PAs) and electron transfer enthalpies (ETEs) are investigated in gas phase and aqueous solution. Results show 3-OH and 4′-OH posses lower BDE as compared to other OH groups, the substituents in B-ring influence 4′-OH BDE, but exhibit negligible influence on other OH BDEs. Among all investigated anthocyanidins, pelargonidin has the highest IP and EA in gas phase, substituent in ortho position of 4′-OH leads to remarkable decrease in IP and EA. OH substituent in B-ring almost show no influence on PAs and ETEs of 3-, 5-, and 7-phenolate anions, but OCH3 substituent influence them significantly. For PAs and ETEs of 4′-phenolate anion, two types of substituents both exhibit remarkable influence. Base on the simplest anthocyanidins, pelargonidin, molecular simplification has been performed to explore the necessary pharmacophores responsible for the antioxidative activity of anthocyanidins.

On the Antioxidant Activity of the Tryptophan Derivatives

Abstract The antioxidant activity of ortho- and meta-substituted tryptophan derivatives has been investigated in the gas phase and water. The reaction enthalpies of antioxidant activity of studied derivatives have been calculated and compared with corresponding values of tryptophan. Results show that EWG substituents increase the BDE, IP, and ETE while EDG appendages cause a rise in the PA and PDE. The tryptophan derivatives with lowest BDE, IP, and PA values were identified as the compounds with high antioxidant activity. Results show that the substituents in ortho-position have high potential for synthesis of novel tryptophan derivatives. Results show that EDG-substituted tryptophans can process their protective role via HAT mechanism in gas phase. On the other hand, SPLET mechanism represents the thermodynamically favored process for EWG-substituted tryptophans in water. The calculated reaction enthalpies of the substituted tryptophans have linear dependences with Hammett constants and EHOMO that can be utilized in the selection of suitable substituents for the synthesis novel antioxidants based on tryptophan.

Toward Designed Singlet Fission: Solution Photophysics of Two Indirectly Coupled Covalent Dimers of 1,3-Diphenylisobenzofuran

In order to identify optimal conditions for singlet fission, we are examining the photophysics of 1,3-diphenylisobenzofuran (1) dimers covalently coupled in various ways. In the two dimers studied presently, the coupling is weak. The subunits are linked via the para position of one of the phenyl substituents, in one case (2) through a CH2 linker and in the other (3) directly, but with methyl substituents in ortho positions forcing a nearly perpendicular twist between the two joint phenyl rings. The measurements are accompanied with density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. Although in neat solid state, 1 undergoes singlet fission with a rate constant higher than 10(11) s(-1); in nonpolar solutions of 2 and 3, the triplet formation rate constant is less than 10(6) s(-1) and fluorescence is the only significant event following electronic excitation. In polar solvents, fluorescence is weaker because the initial excited singlet state S1 equilibrates by sub-nanosecond charge transfer with a nonemissive dipolar species in which a radical cation of 1 is attached to a radical anion of 1. Most of this charge transfer species decays to S0, and some is converted into triplet T1 with a rate constant near 10(8) s(-1). Experimental uncertainties prevent an accurate determination of the number of T1 excitations that result when a single S1 excitation changes into triplet excitation. It would be one if the charge-transfer species undergoes ordinary intersystem crossing and two if it undergoes the second step of two-step singlet fission. The triplet yield maximizes below room temperature to a value of roughly 9% for 3 and 4% for 2. Above ∼360 K, some of the S1 molecules of 3 are converted into an isomeric charge-transfer species with a shorter lifetime, possibly with a twisted intramolecular charge transfer (TICT) structure. This is not observed in 2.

Peculiar properties of homoleptic Cu complexes with dipyrromethene derivatives

In view of preparing Cu polynuclear complexes with dipyrromethene ligands, the mononuclear complexes [Cu(II)(dipy)2] (dipyH = 5-phenyldipyrromethene) and [Cu(II)(dpdipy)2] (dpdipyH = 1,5,9-triphenyldipyrromethene) have been prepared and characterized by X-ray crystallography, mass spectrometry and EPR spectroscopy. Their peculiar redox and spectroscopic (absorption/emission) behaviours are discussed. In contrast to Cu(II) complexes of 1,1'-bidypyrrin, the reduction electrolysis of [Cu(II)(dpdipy)2] leads to decomposition products on a time scale of a few hours. Moreover in relation to this observation, [Cu(I)(dpdipy)2](-) could not be synthesized in spite of the Cu(I) core protection by the phenyl substituents in ortho position of the nitrogen atoms. Theoretical calculations provide some explanations for this instability. Interestingly [Cu(II)(dipy)2] and [Cu(II)(dpdipy)2] display weak luminescence at room temperature, attributed to a ligand centered emission.