Tellurium catecholate complexes were investigated to probe the redox chemistry of tellurium, whose oxidation state can span from −2 to +6. Treating TeO 2 with catechols resulted in tellurium coordination complexes in high yields within minutes to hours at room temperature or with extended heating, depending on the ligand substituents, giving Te(IV) complexes of the form Te(C) 2 , where C = 3,5-di-tert-butylcatecholate, ocatecholate, or tetrachlorocatecholate. The redox behavior of these complexes was investigated through addition of organic oxidants, giving nearly quantitative adducts of pyridine N-oxide or N-methylmorpholine Noxide with each tellurium complex, the latter set leading to ligand oxidation upon heating. Each compound was characterized crystallographically and computationally, providing data consistent with a mostly electrostatic interaction and very little covalent character between the N-oxide and Te complex. The Te N-oxide bond orders are consistently lower than those with the catechol derivatives, as characterized with the Mayer, Gopinathan−Jug (G-J), and first Nalewajski−Mrozek (N-M1) bond indices. The tellurium lone pair is energetically buried by 1.93−2.81 eV, correlating with the observation that the ligands are more reactive than the tellurium center toward oxidation. This combined experimental and theoretical study finds structure−property relationships between ligand design and reactivity that will aid in future efforts for the recovery of tellurium.

Reaction of the zirconium-benzyne complex [CpZr(PMe)(CH)] with sodium phosphaethynolate, Na[OCP], affords a zircono-phosphaalkene complex. Notably, unlike reactions of other transition metal complexes with Na[OCP] that yield the products of simple salt metathesis, this transformation represents novel Na[OCP] insertion chemistry and formation of an unusual solid state coordination polymer. The polymer is disrupted upon addition of MeSiCl to afford a silyl-capped dimer that retains the zirconophosphaalkene functionality. Protonation of either form of zirconophosphaalkenes results in the formation of benzoylphosphine, PhC([double bond, length as m-dash]O)PH.

Fluorescent molecules and materials that exhibit emission changes in response to analytes are of great interest across multiple disciplines. Herein, we investigate the response of NHcontaining fluorophores carbazole and 2-phenylbenzimidazole (Ph-BIM) with two representative isolable singlet carbenes. Specifically, N-heterocyclic carbene 1,3-bis(2,6-diisopropylphenyl)imidazol-2ylidene (IPr) and cyclic (alkyl)(amino)carbene (2,6-diisopropylphenyl)-4,4-diethyl-2,2-dimethyl-pyrrolidin-5-ylidene ( Et CAAC) were discovered to afford three different types of reaction products with carbazole and Ph-BIM. Depending on the reaction pair, hydrogen bonding (1), NH-insertion (2,3), or proton transfer (4) products can be isolated, each displaying variable photophysical responses. These products have been structurally authenticated by single crystal X-ray diffraction and NMR spectrometric methods. Studies of the solution state behavior of 1−4 reveals that these adducts are labile and can reversibly dissociate to free carbenes and fluorophores to varying extents. These equilibria produce concentration dependent solution state behavior as identified and quantified via UV−visible absorption, emission, 1 H DOSY, and NMR spectroscopic measurements.

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We report the synthesis and characterization of the first series of tellurium and selenium complexes featuring an η 5cyclopentadienyl ligand. Reaction of Ph 3 TeX (X = Cl, S 2 CNEt 2 ) with MCp R (M = Li, K; R = H, Me 4 , Me 5 ) results in high yields of [Cp][TePh 3 ] (1), [Cp Me4 ][TePh 3 ] (2), and [Cp*][TePh 3 ] (3), respectively. Similarly, reaction of Ph 3 SeCl with LiCp and KCp* furnishes [Cp][SePh 3 ] (4) and [Cp*][SePh 3 ] ( 5). Each was characterized by X-ray crystallography, revealing similar η 5coordination with little distortion from an idealized half-sandwich geometry, presumably from the remaining lone pair on tellurium and selenium. The Te−centroid distances are relatively long (1: 2.770(3), 2: 2.746(1), and 3: 2.733(1) Å), suggesting a mostly ionic interaction. Se−centroid distances (4: 2.748(3), 5: 2.707(2), 2.730(2) Å) were found to be surprisingly similar despite its smaller atomic radius. Compounds 2, 3, and 5 display rapid decomposition at room temperature, extruding a phenylated cyclopentadiene and the respective diphenylchalcogenide. The nature of bonding within these complexes was investigated through DFT methods and found to be primarily ionic in nature.

Hydrogen reacts with a mixture of cobalt bromide and phenylmagnesium bromide to yield a novel cobalt hydride species. EXAFS analysis reveals a binuclear cobalt hydride complex comprising three absorbers, principally a Co-Co centre, and also two types of supporting hydride ligands. Further, DFT, XANES, (1)H NMR spectra and elemental analyses also support the title formulation.

The separation of tellurium from cadmium telluride is examined using a unique combination of mild, anhydrous chlorination and complexation of the subsequent tellurium tetrachloride with 3,5-di-tert-butylcatecholate ligands (dtbc). The resulting tellurium complex, Te(dtbc) 2 , is isolated in moderate yield and features a 10 3 to 10 4 reduction in cadmium content, as provided by XRF and ICP-MS analysis. Similar results were obtained from zinc telluride. A significant separation between Te, Se, and S was observed after treating a complex mixture of metal chalcogenides with this protocol. These three tunable steps can be applied for future applications of CdTe photovoltaic waste.