[Ln[N(SiMe3)2]2(THF)2](Ln = Sm, Yb) reacts with 1 equiv. of carbon-bridged biphenols, 2,2'-methylene-bis(6-tert-butyl-4-methylphenol)(L1H2) or 2,2'-ethylidene-bis(4,6-di-tert-butylphenol)(L2H2), in toluene to give the novel aryloxide lanthanide(II) complexes [[LnL1(THF)n]2](Ln = Sm, n = 3 (1); Ln = Yb, n = 2 (2)) and [[LnL2(THF)3]2](Ln = Sm (5); Ln = Yb (6)) in quantitative yield, respectively. Addition of 2 equiv. of hexamethylphosphoric triamide (HMPA) to a tetrahydrofuran (THF) solution of 1, 2 and 5 affords the corresponding HMPA-coordinated complexes, [[LnL1(THF)m(HMPA)n]2(THF)y](Ln = Sm, n = 2, m = 0, y = 2 (3); Ln = Yb, m = 1, n = 1, y = 6 (4)) and [[SmL2(HMPA)2]2](7) in excellent yields. The single-crystal structural analyses of 3, 4 and 7 revealed that these aryloxide lanthanide(II) complexes are dimeric with two Ln-O bridges. The coordination geometry of each lanthanide metal can be best described as a distorted trigonal bipyramid. Complexes 1-3, 5 and 7 can catalyze the ring-opening polymerization of epsilon-caprolactone (epsilon-CL), and 1-3, along with 5 show moderate activity for the ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC) and the copolymerization of epsilon-CL and DTC to give random copolymers with high molecular weights and relatively narrow molecular weight distributions..
A simple and efficient preparation of α-amino phosphonates under relatively mild conditions by the one-pot reaction of aldehydes with amines and dialkyl phosphites using catalytic amounts of SmI 2 is described.
Self-powered
photodetectors (PDs) with inorganic lead halide perovskites
hold multiple traits of high sensitivity, fast response, independence
from external power supply, and excellent sustainability and stability,
thus holding a great promise for practical applications. However,
they generally contain high-temperature-processed electron-transporting
layers (ETLs) and high-cost, unstable hole-transporting layers (HTLs)
coupled with noble metal electrodes, which bring significant obstacles
of production cost and stability for their potential commercialization.
Herein, we demonstrate the building of high-performance HTL/ETL-free,
self-powered CsPbIBr2 PD with simplified architecture of
fluorine-doped tin oxide (FTO)/CsPbIBr2/carbon upon interfacial
modification by polyethyleneimine (PEI). The optimized PD yields a
dark current of 2.03 × 10–9 A, peak responsivity
(R) of 0.32 A/W, maximum specific detectivity (D*) of 3.74 × 1012 Jones, and response time
of 1.21 μs. These figures of merit are far beyond those of the
one prepared without PEI modification and even the PD containing TiO2 ETL. Hence, our work suggests a highly feasible route to
develop self-powered PDs with significantly simplified fabrication
and a reduced production cost.
In this study, we synthesized a series of pH-sensitive and salt-sensitive N-succinyl-chitosan hydrogels with N-succinyl-chitosan (NSCS) and the crosslinker glycidoxypropyltrimethoxysilane (GPTMS) via a one-step hydrothermal process. The structure and morphology analysis of the NSCS and glycidoxypropyltrimethoxysilane-N-succinyl chitosan hydrogel (GNCH) revealed the close relation between the swelling behavior of hydrogels and the content of crosslinker GPTMS. The high GPTMS content could weaken the swelling capacity of hydrogels and improve their mechanical properties. The hydrogels show high pH sensitivity and reversibility in the range of pH 1.0 to 9.0, and exhibit on-off switching behavior between acidic and alkaline environments. In addition, the hydrogels perform smart swelling behaviors in NaCl, CaCl2, and FeCl3 solutions. These hydrogels may have great potential in medical applications.
Treatment of the THF solution of (MeC5H4)2Sm(THF) with an equivalent of carbodiimine [RN=C=NR](R = Pr(i) or Cy; Cy = cyclohexyl) in the presence of an equivalent of hexamethylphosphoric triamide (HMPA) at room temperature gives, via a reduction-coupling reaction of carbodiimine, the corresponding bimetallic oxalamidino complex of samarium [eta4-C2(NR)4][(MeC5H4)2Sm(HMPA)]2.2THF.
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