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The synthesis of three new heteroditopic receptors (5a-c) which are based on thiacalix[4]arenes in the 1,3-alternate conformation is reported herein. These new receptors each have two thiourea moieties linking phenyl groups, two of which are substituted with electron-withdrawing groups at their para-positions, and at the opposite side of the thiacalix[4]arene cavity, with two 2-pyridylmethyl groups. One example (5a) was also characterized by X-ray crystallography. A limited 1H-NMR and UV-vis anion complexation study was conducted. DFT computational determinations indicated that 5c, which has strongly electron-withdrawing NO2 groups, had the most effective recognition ability towards the selected anions. The binding of Ag+ at the 2-pyridyl moieties, and the binding of the anions at the two thiourea NH groups of the p-substituted phenylthioureido moieties, respectively, was also investigated. The appearance of a positive allosteric effect with receptor 5b was also found using 1H-NMR titration experiments.

This work presents a simple protocol that demonstrates the use of an inexpensive household carbon monoxide detector as a useful tool to detect the release of carbon monoxide gas from thermal cheletropic decarbonylation reactions. The carbon monoxide detection method described has been employed in a short series of reactions used in a university teaching laboratory setting, and full procedures for these are outlined. In each case, the procedure to isolate and identify the decarbonylation products has also been provided.

A laboratory activity is described for senior high school or first year undergraduate level students that illustrates key concepts linked to extractive metallurgy. This experiment demonstrates preferential binding of a methoxyphenolic oxime ligand to Cu[superscript 2+] in the presence of other transition metal ions in aqueous solution. The students are tasked to investigate the importance of the spatial relationship between the oxime and phenol group of two potential ligands by performing a series of short and simple tests. The objective is achieved by identifying which methoxyphenolic oxime ligand selectively and rapidly forms an isolable precipitate with Cu[superscript 2+] ions. Only one of the potential ligands exhibits a clear preference for binding to Cu[superscript 2+], and this can easily be identified visually (and confirmed by UV-visible spectroscopy if desired). The experiment has successfully been employed as part of an extracurricular laboratory course involving groups of 25-30 high school students.

Twelve new zinc(II) and cadmium(II) complexes with symmetric ligands, [MCl2((R2N)3PO)2] (M = Zn, R2N = pyrrolidinyl (1), piperidinyl (2); M = Cd, R2N = pyrrolidinyl (3), piperidinyl (4)), and differently substituted ligands of the general formula [MCl2(R2N)PO(R'2N)2] (M = Zn or Cd; R2N = Pyrr, Pip or Mor; R'2N = Pyrr, Pip or Mor (5–12) have been synthesized from reaction of zinc(II) or cadmium(II) chlorides with the ligands, giving yields of 43–76%. The complexes were characterized with multinuclear (1H, 13C and 31P) NMR, conductivity, IR spectroscopy, and X-ray analyses. Complexes 1, 3, 11, and 12 are comprised of two ligands coordinated to the metal center in a distorted monomeric tetrahedral arrangement. The P = O bond lengths of 1.490(3) (1), 1.497(4) (3), 1.480(4) (11), and 1.479(5) Å (12) are in the order observed for analogous phosphoramide complexes. The results are compared with those reported for related chalcogen counterparts. [ABSTRACT FROM AUTHOR]

Two bipolar host materials 3‐CBPy and 4‐mCBPy are reported. These hosts are structural analogs of the common host materials CBP and mCBP wherein the phenyl rings have been replaced with pyridines. The two materials possess deep highest occupied molecular orbital (HOMO) and shallow lowest unoccupied molecular orbital (LUMO) levels along with sufficiently high energy S1 and T1 states that make them suitable hosts for yellow emitters in electroluminescent devices. Yellow‐emitting thermally activated delayed fluorescence organic light‐emitting diodes are fabricated using 2,4,6‐tris (4‐(10H‐phenoxazin‐10‐yl)phenyl)‐1,3,5‐triazine (tri‐PXZ‐TRZ) as the dopant emitter with either 3‐CBPy or 4‐mCBPy employed as the host. Their device performance is compared to analogous devices using CBP and mCBP as host materials. The pyridine‐containing host devices show markedly improved external quantum efficiencies (EQE) and decreased roll‐off. The 7 wt% tri‐PXZ‐TRZ‐doped device exhibits very low turn‐on voltage (2.5 V for both 3‐CBPy and 4‐mCBPy) along with maximum external quantum efficiencies (EQEmax) reaching 15.6% (for 3‐CBPy) and 19.4% (for 4‐mCBPy). The device using 4‐mCBPy also exhibits very low efficiency roll‐off with an EQE of 16.0% at a luminance of 10 000 cd m−2. [ABSTRACT FROM AUTHOR]

Electrocatalytic generation of oxygen is of great significance for sustainable, clean, and efficient energy production. Multiple electron transfer in oxygen evolution reaction (OER) and its slow kinetics represent a serious hedge for efficient water splitting, requiring the design and development of advanced electrocatalysts with porous structures, high surface areas, abundant electroactive sites, and low overpotentials. These requisites are common for metal-organic frameworks (MOFs) and derived materials that are promising electrocatalysts for OER. The present work reports on the synthesis and full characterization of a heteroleptic 3D MOF, [Zn 2 (μ 4 -odba) 2 (μ-bpdh)] n · n DMF (Zn-MUM-1), assembled from 4,4'-oxydibenzoic acid and 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene (bpdh). Besides, a series of heterometallic MnZn-MUM-1 frameworks (abbreviated as Mn 0.5 Zn 0.5 -MUM-1, Mn 0.66 Zn 0.33 -MUM-1, and Mn 0.33 Zn 0.66 -MUM-1) was also prepared, characterized, and used for the fabrication of working electrodes based on Ni foam (NF), followed by their exploration in OER. These noble-metal-free and robust electrocatalysts are stable and do not require pyrolysis or calcination while exhibiting better electrocatalytic performance than the parent Zn-MUM-1/NF electrode. The experimental results show that the Mn 0.5 Zn 0.5 -MUM-1/NF electrocatalyst features the best OER activity with a low overpotential (253 mV at 10 mA cm -2 ) and Tafel slope (73 mV dec -1 ) as well as significant stability after 72 h or 6000 cycles. These excellent results are explained by a synergic effect of two different metals present in the Mn-Zn MOF as well as improved charge and ion transfer, conductivity, and stability characteristics. The present study thus widens the application of heterometallic MOFs as prospective and highly efficient electrocatalysts for OER.

Carbon dioxide (CO 2 ) fixation to generate chemicals and fuels is of high current importance, especially toward finding mild and efficient strategies for catalytic CO 2 transformation to value added products. Herein, we report a novel Lewis acid-base bifunctional amine-functionalized dysprosium(III) metal-organic framework [Dy 3 (data) 3 ·2DMF]·DMF (2,5-data: 2,5-diamino-terephthalate), NH 2 -TMU-73. This compound was fully characterized and its crystal structure reveals a 3D metal-organic framework (MOF) with micropores and free NH 2 groups capable of promoting the chemical fixation of CO 2 to cyclic carbonates. NH 2 -TMU-73 is built from the Dy(III) centers and data 2- blocks, which are arranged into an intricate underlying net with a rare type of xah topology. After activation, NH 2 -TMU-73 and its terephthalate-based analogue (TMU-73) were applied for CO 2 -to-epoxide coupling reactions to produce cyclic carbonates. Important features of this catalytic process concern high efficiency and activity in the absence of cocatalyst, use of solvent-free medium, atmospheric CO 2 pressure, and ambient temperature conditions. Also, NH 2 -TMU-73 features high structural stability and can be recycled and reused in subsequent catalytic tests. An important role of free amino groups and open metal sites in the MOF catalyst was highlighted when suggesting a possible reaction mechanism.