Syntheses and studies of electron/energy transfer of new dyads based on an unsymmetrical perylene diimide incorporating chelating 1,10-phenanthroline and its corresponding square-planar complexes with dichloroplatinum(ii) and dichloropalladium(ii )

2018 ◽  
Vol 47 (22) ◽  
pp. 7422-7430 ◽  
Author(s):  
Sebile Işık Büyükekşi ◽  
Ahmet Karatay ◽  
Nursel Acar ◽  
Betül Küçüköz ◽  
Ayhan Elmali ◽  
...  

Photophysical properties of new dyads have been studied with steady-state absorption and TDDFT.

2016 ◽  
Vol 7 ◽  
pp. 1018-1027 ◽  
Author(s):  
Irina V Martynenko ◽  
Anna O Orlova ◽  
Vladimir G Maslov ◽  
Anatoly V Fedorov ◽  
Kevin Berwick ◽  
...  

The formation of nonluminescent aggregates of aluminium sulfonated phthalocyanine in complexes with CdSe/ZnS quantum dots causes a decrease of the intracomplex energy transfer efficiency with increasing phthalocyanine concentration. This was confirmed by steady-state absorption and photoluminescent spectroscopy. A corresponding physical model was developed that describes well the experimental data. The results can be used at designing of QD/molecule systems with the desired spatial arrangement for photodynamic therapy.


Author(s):  
Sebile Işık Büyükekşi ◽  
Ahmet Karatay ◽  
Nursel Acar ◽  
Betül Küçüköz ◽  
Ayhan Elmali ◽  
...  

2021 ◽  
Vol 12 (2) ◽  
pp. 2462-2472

The detection of various biologically important cationic and anionic species has led to the synthesis of various Zinc (II) Schiff base complexes, which bear a large application in catalysis and sensors. A recently reported study has indicated a synthesis of a 48 membered macrocyclic Zn(II) Schiff base complex, which functions as a dual anion sensor (DAS) containing a protonated amine group. In the present investigation, an attempt has been made to study the interaction of the Zn tetranuclear complex (Zn-TCom), a neutral complex, with a cationic surfactant cetyltrimethylammonium bromide (CTAB), employing steady-state absorption and fluorescence studies. The change in the photophysical properties of the fluorophore is studied on binding with the surfactant. The steady-state absorption and emission studies reveal that the polarity of the surrounding of the fluorophore has been modified upon binding with CTAB. A study on the alteration of polarity during the interaction of Zn-TCom with the surfactant is studied by comparing the fluorescence behavior of the probes in a micro heterogeneous environment in a mixture of dioxane and water of varying composition. The binding constant magnitude (analyzed using the Hildebrand equation) manifests that the Schiff base binds to the micellar compartment. These results are manifested to enhance the potential application of the macrocyclic complex in the field of biochemistry. Furthermore, quantum chemical calculations are undertaken to correlate the molecular structure of Zn-TCom with the associated frontier molecular orbitals. The parameters like the energy of HOMO, LUMO and the associated Mulliken charges with respect to individual elements are computed using the single point geometry. The studied reports are correlated with the feasibility of binding with bio mimicking environment or bio proteins for selective application as drug carriers.


2005 ◽  
Vol 77 (6) ◽  
pp. 1035-1050 ◽  
Author(s):  
A. D’Aléo ◽  
S. Welter ◽  
E. Cecchetto ◽  
L. De Cola

The synthesis and photophysical properties of heterometallic dinuclear complexes based on ruthenium and osmium trisbipyridine units, Ru-mPh3-Os and Ru-mPh5-Os, in which the metal complexes are linked via an oligophenylene bridge centrally connected in the meta position, are described. Electronic energy transfer from the excited ruthenium-based component (donor) to the osmium moiety (acceptor) has been investigated using steady-state and time-resolved spectroscopy. The results obtained for the meta-substituted compounds are compared with the analogous systems in which the phenylene spacers are substituted in the para position. The mechanism of energy transfer is discussed.


1971 ◽  
Vol 24 (10) ◽  
pp. 1993 ◽  
Author(s):  
DE Scaife

Nuclear quadrupole resonance for the 35Cl nucleus has been observed in some chloro complexes of divalent copper. Square-planar complexes each show two resonance lines, with the following frequencies (at 77�K): (CH3NH3)2CuCl4, 10.780, 12.157 MHz; (C2H5NH3)2CuCl4, 10.817, 12.074 MHz; (enH2)CuCl4, 10.271, 11.901 MHz; and (C3H7NH3)2CuCl4 at 223�K, 11.290 and 11.781 MHz. NH4CuCl3, containing dimeric Cu2Cl62- units, has resonances, at 77�K, at 11.907, 11.993, and 12.448 MHz. The trigonal pyramidal anion in Co(NH3)6CuCl5 has two resonances at 9.642 and 10.352 MHz at 77�K. ��� These results are compared with previous results for copper chloro complexes, and the implications of covalent bonding are discussed. In particular, it is suggested that the long-bond interaction between units in square-planar complexes amounts to 7-16% of the bonding interaction within the units.


2009 ◽  
Vol 62 (7) ◽  
pp. 692 ◽  
Author(s):  
Toby D. M. Bell ◽  
Sheshanath V. Bhosale ◽  
Kenneth P. Ghiggino ◽  
Steven J. Langford ◽  
Clint P. Woodward

The synthesis of a porphyrin star-pentamer bearing a free-base porphyrin core and four zinc(ii) metalloporphyrins, which are tethered by a conformationally flexible linker about the central porphyrin’s antipody, is described. The synthetic strategy is highlighted by the use of olefin cross metathesis to link the five chromophores together in a directed fashion in high yield. Photoexcitation into the Soret absorption band of the zinc porphyrin chromophores at 425 nm leads to a substantial enhancement of central free-base porphyrin fluorescence, indicating energy transfer from the photoexcited zinc porphyrin (outer periphery) to central free-base porphyrin. Time-resolved fluorescence decay profiles required three exponential decay components for satisfactory fitting. These are attributed to emission from the central free-base porphyrin and to two different rates of energy transfer from the zinc porphyrins to the free-base porphyrin. The faster of these decay components equates to an energy-transfer rate constant of 3.7 × 109 s–1 and an efficiency of 83%, whereas the other is essentially unquenched with respect to reported values for zinc porphyrin fluorescence decay times. The relative contribution of these two components to the initial fluorescence decay is ~3:2, similar to the 5:4 ratio of cis and trans geometric isomers present in the pentamer.


2015 ◽  
Vol 22 (1) ◽  
pp. 124-129 ◽  
Author(s):  
Weiwei Gu ◽  
Hongxin Wang ◽  
Kun Wang

A series of Ni dithiolene complexes Ni[S2C2(CF3)]2n(n= −2, −1, 0) (1,2,3) and a 1-hexene adduct Ni[S2C2(CF3)2]2(C6H12) (4) have been examined by NiK-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectroscopies. Ni XANES for1–3reveals clear pre-edge features and approximately +0.7 eV shift in the NiK-edge position for `one-electron' oxidation. EXAFS simulation shows that the Ni—S bond distances for1,2and3(2.11–2.16 Å) are within the typical values for square planar complexes and decrease by ∼0.022 Å for each `one-electron' oxidation. The changes in NiK-edge energy positions and Ni—S distances are consistent with the `non-innocent' character of the dithiolene ligand. The Ni—C interactions at ∼3.0 Å are analyzed and the multiple-scattering parameters are also determined, leading to a better simulation for the overall EXAFS spectra. The 1-hexene adduct4presents no pre-edge feature, and its NiK-edge position shifts by −0.8 eV in comparison with its starting dithiolene complex3. Consistently, EXAFS also showed that the Ni—S distances in4elongate by ∼0.046 Å in comparison with3. The evidence confirms that the neutral complex is `reduced' upon addition of olefin, presumably by olefin donating the π-electron density to the LUMO of3as suggested by UV/visible spectroscopy in the literature.


Sign in / Sign up

Export Citation Format

Share Document