Luminescent coordination polymers (CPs) of Zn2+ or Cd2+ and bis-9,10-(pyridine-4-yl)-anthracene (BA) show different 1D and 2D topologies depending on the anion used in the precursor. Compounds ...{Zn(μ2-BA)(MeOH)2(p-Tos)2} n (1) and {Zn(μ2-BA)(MeOH)2(CF3CO2)2} n (2) form linear structures and {BA@Zn(μ2-BA)(MeOH)2(H2O)2(CF3SO3)2} n (3) featuring intercalation of uncoordinated BA molecules into linear ribbons. Cd-based CPs {Cd(μ2-BA)2(ClO4)2·n(DCM)} n (4) and {Cd(μ2-BA)(MeOH)2(Dioxane)(η2-SiF6)·mDioxane} n (5) form porous structures with 2D lattices. All complexes exhibit strong blue emission in the solid state with average lifetimes between 8 and 13 ns. The emission of compound 4 is sensitive to the presence of nitro aromatics, simazine, and trichloroanisole (TCA) and demonstrates nonlinear Stern–Volmer quenching kinetics. Limits of detection (LOD) of 15 and 16 ppb for picric acid and TCA were achieved, respectively.
A benzo
rst
pentaphene (BPP) substituted by two bis(methoxyphenyl)amino (MeOPA) groups (BPP-MeOPA) was synthesized and clearly characterized by NMR and single-crystal X-ray analysis. Detailed ...investigations of its photophysical properties, including transient absorption spectroscopy analyses, revealed that the introduction of the MeOPA groups breaks the symmetry of the BPP core, improving its absorption and emission from an S
1
state with both excitonic and charge-transfer character.
A benzo
rst
pentaphene (BPP) substituted by two bis(methoxyphenyl)amino (MeOPA) groups (BPP-MeOPA) was synthesized and its structural and photophysical properties clearly characterized.
We report an anthracene-based Ni-MOF Ni(II) metal-organic framework, {Ni(μ
-
)
Cl
·
(C
H
)·
(MeOH)}
(
),
= anthracene-9,10-diylbis(methylene)diisonicotinate whose crystal structure reveals the ...presence of hexagonal channels with a pore size of 1.4 nm that can accommodate guests such as C
and C
. Both confocal fluorescence and Raman microscopy results are in agreement with a homogeneous distribution of fullerenes throughout the single crystals of
. Efficient energy transfer from
to the fullerenes was observed, which emitted partially polarized fluorescence emission. Stronger binding between
and C
versus C
was confirmed from HPLC analysis of the dissolved material and provides a basis for the selective retention of C
in liquid chromatography columns packed with
.
We report in situ generation of a 6,6′-biindeno1,2-banthracene (BIA) derivative as an open-shell biaryl with high diradical character, which could be identified by mass spectrometry, NMR ...spectroscopy, single-crystal X-ray analysis, UV–vis–NIR absorption spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy. Theoretical calculations by various methods and variable-temperature EPR analyses were performed to tackle the elusive ground state of BIA diradical, suggesting a singlet ground state with a nearly degenerate triplet state. These results provide insight into the design of unique open-shell biaryls.
Abstract
We report a series of heterobimetallic Pt/Zn and Pt/Ca complexes to study the effect of proximity of a dicationic base metal on the organometallic Pt species. Varying degrees of Pt⋅⋅⋅Zn and ...Zn interaction with the bridging Me group are achieved, showcasing snapshots of a hypothetical process of retrotransmetalation from Pt to Zn. In contrast, only weak interactions were observed for Ca with a Pt‐bound Me group. Activation of H
2
, B−H and Si−H bonds leads to the formation of hydride‐bridged Pt−H−Zn complexes, which is not observed in the absence of Zn, pointing out the importance of metal‐metal cooperation. Reactivity of PtMe
2
/M
2+
with terminal acetylene, water and methanol is also studied, leading to facile protonation of one of the Me groups at the Pt center only when Zn is present. This study sheds light on various ways in which the presence of a 2+ metal cation significantly affects the reactivity of a common organoplatinum complex.
We describe a "ligand-free" Ni-catalyzed perfluoroalkylation of heteroarenes to produce a diverse array of trfiluoromethyl, pentafluoroethyl and heptafluoropropyl adducts. Catalysis proceeds at room ...temperature
via
a radical pathway. The catalytic protocol is distinguished by its simplicity, and its wide scope demonstrates the potential in the late-stage functionalization of drug analogues and peptides.
A ligand-free, room temperature, Ni-catalyzed perfluoroalkylation of heteroarenes produced a diverse array of polyfluorinated adducts; potential in the late-stage functionalization of drugs and peptides is also demonstrated.
The reduction of Ag+ ions to Ag0 atoms is a highly endergonic reaction step, only the aggregation to Agn clusters leads to an exergonic process. These elementary chemical reactions play a decisive ...role if Ag nanoparticles (AgNPs) are generated by electron transfer (ET) reactions to Ag+ ions. We studied the formation of AgNPs in peptides by photoinduced ET, and in c‐cytochromes by ET from their Fe2+/hemes. Our earlier photoinduced experiments in peptides had demonstrated that histidine prevents AgNP formation. We have now observed that AgNPs can be easily synthesized with less‐efficient Ag+‐binding amino acids, and the rate increases in the order lysine<asparagine<aspartate<serine. The ability of Fe2+/hemes of c‐cytochromes to reduce Ag+ to AgNPs was studied in an enzymatic experiment and with living bacteria Geobacter sulfurreducens (Gs).
The reduction of Ag+ ions is an endergonic process therefore Fe2+ ions in isolated cytochromes are not oxidized to Fe3+. Nevertheless, this reaction occurs in G. sulfurreducens and leads to the formation of silver nanoparticles. Intermediates are Fe3+/hemes that are re‐reduced by the electron flow maintained by the bacterial respiration processes.
New functional coordination polymers based on the semi-flexible 9,10-di(1H-imidazol-1-yl)-anthracene ligand (L) with Zn
and Cd
, namely {Zn(μ
-L)
(ClO
)
·m(MeOH)·n(DCM)}
(1), {Zn(μ
-L)
(BF
)
...·m(MeOH)·n(DCM)}
(2), {Zn(μ
-L)
(p-Tos)
·m(DCM)·n(MeOH)}
(3), {Cd(μ
-L)
(p-Tos)
·m(DCM)}
(4) {Cd(μ
-L)
(p-Tos)
·m(MeOH)·n(Dioxane)}
(5) and {Zn(μ
-L)
(CF
CO
)
·2(Dioxane)}
(6), were obtained. Dissolving L in polar solvent mixtures MeOH-DCM (4 : 1) or MeOH-dioxane (1 : 1) with Zn
and Cd
salts resulted in the formation of complexes 1, 2, and 5 adopting a cis-conformation of the imidazole groups with respect to anthracene. In less polar mixtures of solvents such as MeOH-DCM (1 : 4) trans-L is observed, leading to the coordination polymers 3-4 with Zn
and Cd
. In an intermediate solvent mixture such as MeOH-dioxane (1 : 4), the cis- and trans-conformation coexist as exemplified in complex 6 with Zn
. In the solid state, complexes 1-5 assemble as supramolecular 2-D coordination polymers with a (4,4) topology, while 6 forms a tridimensional porous network with a cds topology. All compounds reveal strong blue emission in the solid state at room temperature.
Nickel perfluoroethyl and perfluoropropyl complexes supported by naphthyridine-type ligands show drastically different aerobic reactivity from their trifluoromethyl analogs resulting in facile oxygen ...transfer to perfluoroalkyl groups or oxygenation of external organic substrates (phosphines, sulfides, alkenes and alcohols) using O
2
or air as a terminal oxidant. Such mild aerobic oxygenation occurs through the formation of spectroscopically detected transient high-valent Ni
III
and structurally characterized mixed-valent Ni
II
-Ni
IV
intermediates and radical intermediates, resembling O
2
activation reported for some Pd dialkyl complexes. This reactivity is in contrast with the aerobic oxidation of naphthyridine-based Ni(CF
3
)
2
complexes resulting in the formation of a stable Ni
III
product, which is attributed to the effect of greater steric congestion imposed by longer perfluoroalkyl chains.
Aerobic oxidation of long-chain perfluoroalkyl Ni complexes results in O-atom transfer to form perfluorocarboxylates
via
high valent Ni; in the presence of external substrate, oxygenation of phosphines, sulfides, stilbenes or alcohols occurs.
We report the synthesis of a dibenzodinaphthocoronene (DBDNC) derivative as a novel nanographene with armchair, zigzag, and fjord edges, which was characterized by NMR and X-ray crystallography as ...well as infrared (IR) and Raman spectroscopies. Ultrafast transient absorption (TA) spectroscopy revealed the presence of stimulated emission signals at 655 nm and 710 nm with a relatively long lifetime, which resulted in dual amplified spontaneous emission (ASE) bands under ns-pulsed excitation, indicating the promise of DBNDC as a near-infrared (NIR) fluorophore for photonics. Our results provide new insight into the design of nanographene with intriguing optical properties by incorporating fjord edges.
Dibenzo
a
,
m
dinaphtho
ef
,
hi
coronene with zigzag and fjord edges was synthesized and characterized, demonstrating a nonplanar structure with near-infrared stimulated emission with a relatively long lifetime and dual-amplified spontaneous emission.
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![6,6′-Biindeno[1,2‑b]anthrac...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0002-7863_1943-2984_1520-5126/small "6,6′-Biindeno[1,2‑b]anthracene: An Open-Shell Biaryl with High Diradical Character")
