Luminescent
-heterocyclic carbene chloride copper (I) complexes incorporating pyrene chromophore (1-Pyrenyl-NHC-R)-Cu-Cl, (
,
) have been prepared and fully characterized. Two complexes were prepared ...with R = methyl (
) and R = naphthyl groups (
) at the nitrogen center of the carbene unit to tune their electronic properties. The molecular structures of
and
have been elucidated by X-ray diffraction and confirm the formation of the target compounds. Preliminary results reveal that all compounds including the imidazole-pyrenyl ligand
are emissive in the blue region at room temperature in solution and in solid-state. All complexes display quantum yields comparable or higher when compared to the parent pyrene molecule. Interestingly replacement of the methyl by naphthyl group increases the quantum yield by almost two-folds. These compounds might show promise for applications as optical displays.
A novel
3+2-cycloaddition reaction of
3-arylidene-1-phenyl-succinimides, cyclic 1,2-diketones (isatin, 5-chloro-isatin and acenaphtenequinone), and diverse
aminoacids such as 2-phenylglycine or ...sarcosine is reported. The reaction provides succinimide-substituted dispiropyrrolidine derivatives with high regio- and diastereoselectivities under mild reaction conditions. The stereochemistry of these
heterocycles has been confirmed by four X-ray diffraction studies. Several synthetized compounds show higher inhibition on acetylcholinesterase (AChE) than butyrylcholinesterase (BChE). Of the 17 synthesized compounds tested, five exhibit good AChE inhibition with IC
of 11.42 to 22.21 µM. A molecular docking study has also been undertaken for compound
possessing the most potent AChE inhibitory activity, disclosing its binding to the peripheral anionic site of AChE enzymes.
The parent compound 1,3-dithiane (L1) was reacted with CuI providing the 1D coordination polymer {Cu(μ2-I)2Cu}(μ2-L1)2 n (CP1), an isostructural compound {Cu(μ2-Br)2Cu}(μ2-L1)2 n (CP2) was ...isolated upon treatment of CuBr with L1. In contrast, treatment of L1 with CuCl results in the formation of 2D polymeric {Cu(μ2-Cl)2Cu}(μ2-L1) n (CP3), in which each sulfur atom acts as a 4-electron donor. The 1D compounds {Cu(μ2-X)2Cu}(μ2-L2)2 n (CP7, X = Br, and CP8, X = Cl) resulting from treatment of 2-methyl-1,3 dithiane (L2) with CuBr and CuCl are isostructural with their CuI homologue {Cu(μ2-I)2Cu}(μ2-L2)2 n (CP5), reported previously. Using CuCN, a 2D CP of composition {Cu(μ2-CN)2Cu}(μ2-L2)2 n (CP9) has been isolated. Complexation of 2-isobutyl-1,3-dithiane (L3) on CuI generates a 2D material {Cu3(μ3-I)(μ2-I)2(μ2-L3)2} n (CP10), incorporating the usual trinuclear μ3-I-capped Cu clusters as SBUs, whereas 2D-polymeric compounds {Cu(μ2-Br)2Cu}(μ2-L3)2 n (CP11) and {Cu(μ2-Cl)2Cu}(μ2-L3)2 n (CP12) were obtained with CuBr and CuCl. Treatment of 2-Me3Si-1,3-dithiane (L4) with CuX yields the series {Cu2(μ4-X)(μ2-X)}(μ2-L4) n (CP13–CP15). With 2-phenyl-1,3-dithiane (L5), the outcome of the reaction with CuI depends on the reaction conditions. Reaction with CuI in MeCN provides a 1D ribbon {Cu(μ2-I)2Cu}(MeCN)2(μ2-L5)2 n (CP16), whereas treatment of CuI with L5 in hot EtCN yields 2D-polymeric{Cu3(μ3-I)(μ2-I)2(μ2-L5)2} n (CP17). A reversible phase transition from triclinic P1̅ to monoclinic P21/m is observed when recording the structure of CP16 at five different temperatures in the 100–300 K range. Ligand L6 containing a ferrocenyl function at the 2-position was also probed as organometallic dithioether ligand. Reaction of L6 with 1 equiv of CuI produces the 0D dinuclear complex {Cu(μ2-I)2Cu}(η1-L6)2(MeCN)2 (D1), whereas treatment with 2 equiv of CuI affords the novel 1D CP {Cu(μ3-I)2Cu}(μ-L6) n (CP18), in which both S atoms of one L6 molecule span two copper centers of the infinite (CuI) n ribbon. Some selected results of thermal analyses and luminescence measurements are also presented.
This paper focuses on the syntheses, structures, and luminescence properties of 1D, 2D, and 3D coordination polymers built upon the tetranuclear Cu4X4 clusters and mono‐ and dithioether assembling ...ligands. A review of the relevant literature is presented along with our own results stressing on the salient features of the interactions between the CuI salt as the starting material and the thioethers. Among the features, the solvato‐ (lost or gain of a monothioether or solvent molecule) and luminescence thermochromism (temperature dependence of the emission) of the solids, and the enhanced versatility of the CuI salt to form clusters of different nuclearity (Cu2I2, Cu4I4, Cu6I6) and structures (closed cubane, partially open “flower‐basket‐like” cubane, and open cubane) upon the reaction conditions and ligands, are described. The steady state and time‐resolved solid‐state emission and excitation spectra (at 298 and 77 K) as well as the emission lifetimes are examined. Simple and apparently “innocent” modification may have a drastic effect on the polymer network and cluster structures, but this paper finds no obvious trend for the moment except for the ligand rigidity. The rhombic Cu2I2 and closed‐cubane Cu4I4 clusters are the most encountered motifs whereas the open‐flower‐basket Cu4I4 cubane and the hexagonal Cu6I6 clusters are scarce.
This paper focuses on the syntheses, structures, and luminescence properties of 1D, 2D, and 3D coordination polymers built upon the tetranuclear Cu4X4 clusters and mono‐ and dithioether assembling ligands. A review of the relevant literature is presented along with our own results stressing on the salient features of the interactions between the CuI salt as the starting material and the thioethers.
A series of spiropyrrolidin-2,3′-oxindoles has been synthesized by exo -selective 1,3-dipolar cycloaddition reaction of a stabilized azomethine ylide, generated in situ by thermal 1,5-prototropy, ...across various ( E )-3-arylidene-1-phenyl-pyrrolidine-2,5-diones. The stereochemistry of these N-heterocycles has been confirmed using an X-ray diffraction study. To rationalize the observed regio- and stereoselectivity, DFT calculations at the B3LYP/6-31G(d,p) level were employed. It was found that this reaction preferentially affords the kinetic product. The compounds have been screened for their in vitro antibacterial, antifungal, antimalarial and antitubercular activities. Several compounds exhibited good activities comparable to those of established standard drugs.
A novel series of 14 spiropyrrolidines bearing thiochroman-4-one/chroman-4-one, and oxindole/acenaphthylene-1,2-dione moieties were synthesized and characterized by spectroscopic techniques, as well ...as by three X-ray diffraction studies, corroborating the stereochemistry. Quantum chemical calculations studies, using the DFT approach, were performed to rationalize the stereochemical outcome. These
-heterocycles were evaluated for their antibacterial and antifungal activities against some pathogenic organisms. Several compounds displayed moderate to excellent activity towards the screened microbe strains in the study compared to Amoxicillin (AMX), Ampicillin (AMP), and Amphotericin B. Furthermore, a structural activity relationship (SAR) was established considering the synthesized compounds. Pharmacokinetic studies reveal that these derivatives exhibit an acceptable predictive ADMET profile (Absorption, Distribution, Metabolism, Excretion and Toxicity) and good drug-likeness.
The 1D coordination polymer (CP) (Me2S)3{Cu2(μ-I)2} n (1) is formed when CuI reacts with SMe2 in n-heptane, whereas in acetonitrile (MeCN), the reaction forms exclusively the 2D CP (Me2S)3{Cu4(μ-I)4} ...n (2) containing “flower-basket” Cu4I4 units. The reaction product of CuI with MeSEt is also solvent-dependent, where the 1D polymer (MeSEt)2{Cu4(μ3-I)2(μ2-I)2}(MeCN)2 n (3) containing “stepped-cubane” Cu4I4 units is isolated in MeCN. In contrast, the reaction in n-heptane affords the 1D CP (MeSEt)3{Cu4(μ3-I)4} n (4) containing “closed-cubane” Cu4I4 clusters. The reaction of MeSPr with CuI provides the structurally related 1D CP (MeSPr)3{Cu4(μ3-I)4} n (5), for which the X-ray structure has been determined at 115, 155, 195, 235, and 275 K, addressing the evolution of the metric parameters. Similarly to 4 and the previously reported CP (Et2S)3{Cu4(μ3-I)4} n (Inorg. Chem. 2010, 49, 5834), the 1D chain is built upon closed cubanes Cu4(μ3-I)4 as secondary building units (SBUs) interconnected via μ-MeSPr ligands. The 0D tetranuclear clusters (L)4{Cu4(μ3-I)4} L = EtSPr (6), Pr2S (7) respectively result from the reaction of CuI with EtSPr and n-Pr2S. With i-Pr2S, the octanuclear cluster (i-Pr2S)6{Cu8(μ3-I)3}(μ4-I)2} (8) is formed. An X-ray study has also been performed at five different temperatures for the 2D polymer (Cu3Br3)(MeSEt)3 n (9) formed from the reaction between CuBr and MeSEt in heptane. The unprecedented framework of 9 consists of layers with alternating Cu(μ2-Br)2Cu rhomboids, which are connected through two μ-MeSEt ligands to tetranuclear open-cubane Cu4Br4 SBUs. MeSPr forms with CuBr in heptane the 1D CP (Cu3Br3)(MeSPr)3 n (10), which is converted to a 2D metal–organic framework (Cu5Br5)(μ2-MeSPr)3 n (11) incorporating pentanuclear (Cu5(μ4-Br)(μ2-Br) SBUs when recrystallized in MeCN. The thermal stability and photophysical properties of these materials are also reported.
For the first time, POSS‐based coordination polymers (CPs) have been structurally characterized. These CPs were obtained in high yield via self‐assembly reactions of thioether‐functionalized ...polysilsesquioxanes with CuI salts under mild conditions. Single crystal analyses revealed the formation of 3D networks incorporating different secondary building units (SBUs) as connection nodes. The nature of the ‐SAr functionality allows a fine‐tuning of the cluster nuclearity, that is, butterfly‐shaped Cu2X2 or closed cubane‐type Cu4I4 cores. As such, the resulting hybrid materials exhibit a combination of high thermal stability arising from the inorganic POSS core along with interesting luminescent properties conferred by the cubane cluster core. Furthermore, the occurrence of channels has been shown crystallographically in the case of the Cu4I4 cluster containing CP.
POSS‐based coordination polymers (CPs) have been obtained via self‐assembly reactions of thioether‐functionalized polysilsesquioxanes with CuI salts. Single crystal analyses revealed the formation of 3D networks incorporating different secondary building units (SBUs) as connection nodes. The resulting hybrid materials exhibit a combination of high thermal stability along with interesting luminescent properties
Despite the effectiveness of COVID-19 vaccines, there is still an urgent need for discovering new anti-viral drugs to address the awful spread and transmission of the rapidly modifiable virus. In ...this study, the ability of a small library of enantiomerically pure spirooxindolopyrrolidine-grafted piperidones to inhibit the main protease of SARS-CoV-2 (Mpro) is evaluated. These spiroheterocycles were synthesized by 1,3-dipolar cycloaddition of various stabilized azomethine ylides with chiral dipolarophiles derived from N-(S)-(-)-methylbenzyl-4-piperidone. The absolute configuration of contiguous carbons was confirmed by a single crystal X-ray diffraction analysis. The binding of these compounds to SARS-CoV-2 Mpro was investigated using molecular docking and molecular dynamics simulation. Three compounds 4a, 4b and 4e exhibited stable binding modes interacting with the key subsites of the substrate-binding pocket of SARS-CoV-2 Mpro. The synthesized compounds represent potential leads for the development of novel inhibitors of SARS-CoV-2 main protease protein for COVID-19 treatment.
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