Functionalizing tetraphenylpyrazine with perylene diimides (PDIs) as high-performance nonfullerene acceptors

Perylene diimide (PDI)-based small molecular acceptors with a three-dimensional structure are thought to be essential for efficient photocurrent generation and high power conversion efficiencies (PCEs). Herein, a couple of new perylene diimide acceptors (PPDI-O and PPDI-Se) have been designed and successfully synthesized using pyrazine as the core-flanking pyran and selenophene-fused PDIs, respectively. Compared to PPDI-O, PPDI-Se exhibits a blue-shifted absorption in the 400–600 nm range, a comparable LUMO level, and a more distorted molecular geometry. The PPDI-Se-based organic solar cell device with PDBT-T1 as the donor achieved the highest PCE of 7.47% and a high open-circuit voltage (Voc) of up to 1.05 V. The high photovoltaic performance of PPDI-Se-based devices can be attributed to its high LUMO energy level, complementary absorption spectra with donor materials, favorable morphology and balanced carrier transport. The results demonstrate the potential of this type of fullerene-free acceptor for high efficiency organic solar cells

Luminescent metal-organic frameworks (MOFs) as a chemopalette: Tuning the thermochromic behavior of dual-emissive phosphorescence by adjusting the supramolecular microenvironments

Two classical copper(I)-cluster-based luminophores, namely, Cu 4I4 and [Cu3Pz3]2 (Pz=pyrazolate), are immobilized in a supramolecular system through the formation of metal-organic framework (MOF) materials. This series of luminescent MOF materials, namely, [Cu4I4(NH3)Cu 3(L1)3]n, [Cu4I4(NH 2CH3)Cu3(L1)3]n, and [Cu4I4Cu3(L2)3]n (L1=3-(4-pyridyl)-5-(p-tolyl)pyrazolate; L2=3-(4-pyridyl)-5-(2,4-dimethylphenyl) pyrazolate), exhibit diverse thermochromism attributed to the relative functioning efficacy of the two coordination luminophores. Such an intriguing chemopalette effect is regulated by the different supramolecular microenvironments between the two-dimensional layers of these MOFs, and in particular, by the fine-tuned Cu-Cu distances in the excimeric [Cu 3Pz3]2 luminophore. The structure-property elucidation of the thermochromic behavior allows one to understand these optical materials with unusual dual-emissive properties. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Excimer and exciplex formation in a pair of bright phosphorescent isomers constructed from Cu3(pyrazolate)3 and Cu3I3 coordination luminophores

Reported herein are a pair of supramolecular pseudo-isomers, namely, (Cu 3I 3)(Cu 3L 3) 2· H 2O (1) and (Cu 3I 3)(Cu 3L 3) 2 (2) (L = 3-(4-pyridyl)-5-isobutyl-pyrazolate), both of which incorporate Cu 3Pz 3 (Pz = pyrazolate) and Cu 3I 3 clusters as luminophores. The two complexes show distinct yellow (570 nm) and orange (638 nm) emissions, which are ascribed to the formation of the excimer and exciplex involving the same or different copper(i)-cluster-based luminophores. © 2011 The Royal Society of Chemistry

An unprecedented 2-D CuSCN coordination network containing both regular and irregular [Cu3(SCN)3] rings supported by a tridentate N-donor ligand

A neutral 2-D (CuSCN)∞ containing both regular and irregular [Cu3(SCN)3] six-membered rings supported by an asymmetrical tridentate ligand 3,5-bis(3-pyridyl)-1H-pyrazole (Hbppz) were prepared with the formula [Cu3(SCN)3(Hbppz)] ∞. The compound gives strong green luminescence with an emission maximum at 536 nm. © 2010 The Royal Society of Chemistry

A luminescent edge-interlocked prismatic heteroleptic metallocage assembled through a ligand replacement reaction

A luminescent edge-interlocked heteroleptic metallocage based on Cu3(pyrazolate)3 was prepared through a ligand replacement reaction from a homoleptic metallocage and a new ligand. Its structure was confirmed by XRD and MALDI-TOF mass spectrometry. Theoretical calculations revealed the new ligand was evidently responsible for the bathochromic shift of the optimal excitation. This work provides a heteroleptic strategy to regulate the interlocking fashion and photophysical mechanism of metallocages based on Cu3(pyrazolate)3

Mechanically Triggered Fluorescence/Phosphorescence Switching in the Excimers of Planar Trinuclear Copper(I) Pyrazolate Complexes

Luminescence mechanochromism of the well-known Cu₃Pz₃-type (Pz = pyrazolate) complexes is reported here, which is unusual for this family. Two types of new Cu₃Pz₃ complexes, namely Cu₃(EBPz)₃ (<b>1</b>; EBPz = ethyl-4′-benzoate-3,5-dimethylpyrazolate) and Cu₃(MBPz)₃ (polymorphs <b>2a</b>–<b>c</b>; MBPz = methyl-4′-benzoate-3,5-dimethylpyrazolate), have been synthesized and characterized. Their crystal structures exhibit a similar chairlike dimer stacking supported by short Cu···Cu contacts, which would facilitate the formation of photoinduced excimers. The dual emission from the organic fluorophore and excimeric copper cluster phosphor is found to undergo mechanically induced intensity switching between their high-energy (HE) and low-energy (LE) bands. Specifically, the relative intensities of crystalline samples are HE > LE, while the ground solid samples show LE > HE, resulting in the overall emission color interchanging between bluish violet and red. This switching can be reversed by application of solvent to the ground samples, presumably due to recrystallization, and also by heating. TD-DFT calculations reveal that the emissive singlet ligand localized state (S₁) and triplet cluster centered state (T₈) lie close in energy (separated by a gap of 0.1788 eV), suggesting the feasibility of dual emission and the possibility of reverse intersystem crossing, consistent with the long fluorescent lifetimes (10² ns scale) of the HE bands

Mechanically Triggered Fluorescence/Phosphorescence Switching in the Excimers of Planar Trinuclear Copper(I) Pyrazolate Complexes

Luminescence mechanochromism of the well-known Cu₃Pz₃-type (Pz = pyrazolate) complexes is reported here, which is unusual for this family. Two types of new Cu₃Pz₃ complexes, namely Cu₃(EBPz)₃ (<b>1</b>; EBPz = ethyl-4′-benzoate-3,5-dimethylpyrazolate) and Cu₃(MBPz)₃ (polymorphs <b>2a</b>–<b>c</b>; MBPz = methyl-4′-benzoate-3,5-dimethylpyrazolate), have been synthesized and characterized. Their crystal structures exhibit a similar chairlike dimer stacking supported by short Cu···Cu contacts, which would facilitate the formation of photoinduced excimers. The dual emission from the organic fluorophore and excimeric copper cluster phosphor is found to undergo mechanically induced intensity switching between their high-energy (HE) and low-energy (LE) bands. Specifically, the relative intensities of crystalline samples are HE > LE, while the ground solid samples show LE > HE, resulting in the overall emission color interchanging between bluish violet and red. This switching can be reversed by application of solvent to the ground samples, presumably due to recrystallization, and also by heating. TD-DFT calculations reveal that the emissive singlet ligand localized state (S₁) and triplet cluster centered state (T₈) lie close in energy (separated by a gap of 0.1788 eV), suggesting the feasibility of dual emission and the possibility of reverse intersystem crossing, consistent with the long fluorescent lifetimes (10² ns scale) of the HE bands

Формирование адаптивной системы контроллинга в банке

У статті досліджено можливість формування адаптивної системи контролінгу в банку, визначено мету та основні етапи її здійснення, наведено характеристику принципів.This article explores the possibility of forming adaptive system controlling a bank specified purpose and main stages of its implementation, the characteristics of principles

Metallophilicity-Driven Dynamic Aggregation of a Phosphorescent Gold(I)–Silver(I) Cluster Prepared by Solution-Based and Mechanochemical Approaches

We observed an unusual reversible aggregation process showing stimuli-responsive structural dynamics and optical changes attributed to the formation of a sandwich-like Au₃–Ag–Au₃ cluster, which can be synthesized through both solution and mechanochemical methods. Unlike many other heteronuclear gold–silver clusters, the affinity of two cyclic Au₃ complexes and a Ag^I ion is solely bound by ligand unsupported Au–Ag bonding. The assembly/disassembly behavior, further forming nanoaggregates, is controllable by adjusting the concentration of the solution. In the solid state, the insertion of Ag^I ion can be implemented through a mechanochemical approach, accompanied by visual color changes and reversible luminochromism. Furthermore, an uncommon solid–liquid extraction is demonstrated, showing the uniqueness of this labile Au–Ag metallophilicity and hinting at the possibility of manipulating a bonding process through a heterogeneous route