The Front Cover shows the various “flavours” of α-functionalized phosphine chalcogenides that can be generated from the hydrophosphorylation of C=O/N bonds. Even with multiple potential operative mechanisms such as a concerted [2+2] hydrophosphorylation, or a stepwise P(V)−P(III) tautomerization and subsequent nucleophilic attack, the resultant α-functionalized phosphine chalcogenide remains the same. Additionally, the separation and organization of each α-functionalized phosphine chalcogenide displays that each is distinctly unique and is treated as such throughout the course of the Review. More information can be found in the Review by J.-W. Lamberink-Ilupeju, P. J. Ragogna, and J. M. Blacquiere.

A series of triamidoamine complexes of uranium and thorium with N-SiPh₂Bu^t substituents are described, including chlorides, azides, cyclometallates.

Abstract

We report the synthesis and characterisation of thorium(IV), uranium(III), and uranium(IV) complexes supported by a sterically demanding triamidoamine ligand with N-diphenyl-tert-butyl-silyl substituents. Treatment of ThCl₄(THF)_3.5 or UCl₄ with [Li₃(Tren^DPBS)] (Tren^DPBS={N(CH₂CH₂NSiPh₂Bu^t)₃}³⁻) afforded [An(Tren^DPBS)Cl] (An=Th, 1Th; U, 1U). Complexes 1An react with benzyl potassium to afford the cyclometallates (Tren^DPBS _cyclomet) [An{N(CH₂CH₂NSiPh₂Bu^t)₂(CH₂CH₂NSiPhBu^tC₆H₄)}] (An=Th, 2Th; U, 2U). Treatment of 1An with sodium azide affords [An(Tren^DPBS)N₃] (An=Th, 3Th; U, 3U). Reaction of 3Th with potassium graphite affords 2Th. In contrast, 3Th reacts with cesium graphite to afford the doubly-cyclometallated (Tren^DPBS _d-cyclomet) ate complex [Th{N(CH₂CH₂NSiPh₂Bu^t)(CH₂CH₂NSiPhBu^tC₆H₄)}₂Cs(THF)₃] (4). In contrast to 3Th, reaction of 3U with potassium graphite produces the uranium(III) complex [U(Tren^DPBS)] (5), and 5 can also be prepared by reaction of potassium graphite with 1U. The loss of azide instead of conversion to nitrides contrasts to prior work when the silyl group is iso-propyl silyl, underscoring how ligand substituents profoundly drive the reaction chemistry. Several complexes exhibit T-shaped meta-C−H⋅⋅⋅phenyl and staggered parallel π–π-stacking interactions, demonstrating subtle weak interactions that drive ancillary ligand geometries. Compounds 1An–3An, 4, and 5 have been variously characterised by single crystal X-ray diffraction, multi-nuclear NMR spectroscopy, infrared spectroscopy, UV/Vis/NIR spectroscopy, and elemental analyses.

NIR luminescent materials are widely available for biological applications, and the NIR emitting of Ho³⁺ ions has received widespread attention in the second biological window. The NIR emitting of Ho³⁺ ion sensitized by Mn⁴⁺ has achieved in Ca₁₄Zn₆Ga_9.88O₃₅ : Mn⁴⁺,Ho³⁺ upon UV-vis light excited, and the energy transfer from Mn⁴⁺ to Ho³⁺ ions is mainly dominated by dipole-dipole interaction. The sample displays NIR emitting spectra ranging from 1100 to 1300 nm with two emission centers including Mn⁵⁺ and Ho³⁺ emission, respectively, which holds promising potential for applications in the second biological window.

Abstract

NIR luminescent materials are widely available for biological applications, and the NIR emitting of Ho³⁺ ions has received widespread attention in the second biological window. In this work, Ca₁₄Zn₆Ga₁₀O₃₅ : Mn⁴⁺,Ho³⁺ luminescent materials were synthesized using a high temperature solid state method. Optical properties and energy transfer mechanisms have studied in detail. Upon UV-vis light excitation, the Mn single doped Ca₁₄Zn₆Ga₁₀O₃₅ phosphors exhibit deep red and NIR emission centered at 712 and 1151 nm assigned to Mn⁴⁺ and Mn⁵⁺, respectively. Another stronger NIR emitting peaked at 1195 nm occurs when the Ho³⁺ ion is co-doped into Ca₁₄Zn₆Ga₁₀O₃₅ : Mn⁴⁺. The energy transfer from Mn⁴⁺ to Ho³⁺ ion is performed through a resonant type by a dipole-dipole interaction mechanism. In addition, the thermal stability of Ca₁₄Zn₆Ga₁₀O₃₅ : Mn⁴⁺,Ho³⁺ phosphor has been investigated, and the NIR emission of Ho³⁺ ion maintains more than half the strength at 423 K. The findings indicate that the as-prepared Ca₁₄Zn₆Ga₁₀O₃₅ : Mn⁴⁺,Ho³⁺ luminescent materials hold promise for potential applications in the second biological window.