A series of rare-earth metal diisopropylamide complexes has been obtained via salt metathesis employing LnCl3(THF)x and lithium (LDA) or sodium diisopropylamide (NDA) in n-hexane. Reactions with AM : Ln ratios ≥3 gave ate complexes (AM)Ln(NiPr2)4(THF)n (n = 1, 2; Ln = Sc, Y, La, Lu; AM = Li, Na) in good yields. For smaller rare-earth metal centres such as scandium and lutetium, a Li : Ln ratio = 2.5 accomplished ate-free tris(amido) complexes Ln(NiPr2)3(THF). The chloro-bridged dimeric derivatives [Ln(NiPr2)2(μ-Cl)(THF)]2 (Ln = Sc, Y, La, Lu) could be obtained in high yields for Li : Ln = 1.6-2. The product resulting from the Li : La = 1 : 1.6 reaction revealed a crystal structure containing two different molecules in the crystal lattice, [La(NiPr2)2(THF)(μ-Cl)]2·La(NiPr2)3(THF)2. Recrystallization of the chloro-bridged dimers led to the formation of the monomeric species Ln(NiPr2)2Cl(THF)2 (Ln = Sc, Lu) and La(NiPr2)3(THF)2. The reaction of YCl3 and LDA with Li : Y = 2 in the absence of THF gave a bimetallic ate complex LiY(NiPr2)4 with a chain-like structure. For scandium, the equimolar reactions with LDA or NDA yielded crystals of tetrametallic mono(amido) species, {[Sc(NiPr2)Cl2(THF)]2(LiCl)}2 and [Sc(NiPr2)Cl2(THF)]4, respectively. Depending on the Ln(iii) size, AM, and presence of a donor solvent, ate complexes (AM)Ln(NiPr2)4(THF)n show distinct dynamic behaviour as revealed by variable temperature NMR spectroscopy. The presence of weak LnCH(iPr) β-agostic interactions, as indicated by Ln-N-C angles <105°, is corroborated by DFT calculations and NBO analysis.
Both ultraviolet (UV) and infrared (IR) light have negative impact on the human health. With this background it is the main aim of the current research to realize a textile material which is able to protect against both UV light and IR light. For this research, regenerated cellulosic fibers from the Lyocell process are used and modified. Main analytical investigations are done by photo-spectroscopy in arrangement of diffuse transmission for the spectral range from 220 nm to 1400 nm. Additionally, microscopic investigations are done by scanning electron microscopy (SEM). For material development, Lyocell fibers functionalized with TiO2 particles are first processed into yarns and then into knitted fabrics. Compared to non-functionalized textiles, the transmission is reduced in the UV range due to the absorption behavior of TiO2. Subsequent dyeing with anthraquinone or reactive dyes enhanced the UV protective effect. To reduce the transmission in the near IR range (NIR), non-functionalized Lyocell knitted fabrics are functionalized with various IR absorbers in different concentrations. With increasing concentration, the transmission decreased. However, a grey coloration of the textile is observed simultaneously, with increased concentration. This must be considered in further processing steps. With these methods for functionalization, it is possible to produce textiles that offer increased protection against UV and IR radiation. These are promising materials for the production of clothing or work wear.
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