Direct asymmetric reductive amination utilizing secondary amines as an efficient tool for one-step construction of tertiary chiral amines.

In this study, Sm 3+ -doped double-perovskite Mg 2 InSbO 6 phosphors were synthesized via high-temperature solid-state reaction. Mg 2 InSbO 6 belongs to the doubleperovskite family with a space group of R3 (No.148). The photoluminescence (PL) spectrum illustrates that Mg 2 InSbO 6 :0.05Sm 3+ phosphor can emit intense orange-red emission light at 607 nm due to the 4 G 5/2 → 6 H 7/2 transition. The optimum concentration of Mg 2 InSbO 6 :xSm 3+ is confirmed to 0.05 mol. The asymmetric ratio ( 4 G 5/2 → 6 H 9/2 / 4 G 5/2 → 6 H 5/2 ) of Mg 2 InSbO 6 :0.05Sm 3+ phosphor is 2.73. The quenching temperature exceeds 500 K, illustrating that Mg 2 InSbO 6 :Sm 3+ sample has excellent heat resistance. The high color purity and correlated color temperature (CCT) of Mg 2 InSbO 6 :Sm 3+ phosphors are obtained. Furthermore, a white light-emitting diode (w-LED) is successfully fabricated, possessing CCT of 6769 K and high color rendering index (R a ) of 89. Therefore, the orange-red-emitting Mg 2 InSbO 6 :Sm 3+ phosphors exhibit great potential to apply in solid-state lighting fields. K E Y W O R D S LED, luminescence, Mg 2 InSbO 6 :Sm 3+ , phosphor | 5967 LIU et aL. | INTRODUCTIONw-LEDs show a high potential application in displays and lighting. In addition, w-LEDs are replacing conventional solid-state lighting sources (fluorescent, incandescent, and metal-halide lamps), which are based on admirable merits, like high efficiency, energy conservation, long lifetimes, and eco-friendliness. [1][2][3][4] Currently, the method to fabricate commercial w-LEDs is a combination of yellow phosphor Y 3 Al 5 O 12 :Ce 3+ (YAG) and a blue LED chip. However, these products show high CCT and poor R a , owing to the lack of red composition. 5,6 These inevitable disadvantages greatly limit their application and popularization. An alternative way is developed using trichromatic (green, blue, and red) phosphors coated on the near-ultraviolet (n-UV) chips, which have recently received increasing attention. 7 Nitride is regarded as an excellent red phosphor like SrLiAl 3 N 4 :Ce 3+ , Sr 2 [BeAl 3 N 5 ]:Eu 2+ , and CaAlSiN 3 :Eu 2+ . 8-10 However, the synthesis condition (high temperature and high pressure) is strict. 11,12 Hence, exploring new orange-red-emitting or redemitting phosphors with good luminescence properties is extremely urgent. 13 Sm 3+ with 4f 5 electronic configuration is an important activator ion among the lanthanoid ions. [14][15][16] Sm 3+ usually exhibits orange-red or red emission in the visible region while excited by n-UV or blue light, which attributes to the 4 G 5/2 → 6 H 7/2 or 4 G 5/2 → 6 H 9/2 transitions, respectively. 17,18

Direct reductive amination (DRA) is one of the most efficient methods for amine synthesis.Herein we report a practical homogeneous DRA procedure utilizing iridium catalysis. Applying simple, readily available and inexpensive PPh3 and alike ligands at as low as 0.003 mol%, aldehydes and ketones reductively coupled with primary and secondary amines to efficiently form structurally and functionally diverse amine products, including a set of drugs and their late-stage manipulation. The reaction conditions were exceptionally mild and additive-free, and they tolerated oxygen, moisture, polar protic groups and multiple other functional groups. For targeted products, this methodology is versatile and could offer multiple synthetic routes in regard to the selection of starting materials. The 10 gram-scale synthesis further demonstrated the potential and promise of this procedure in practical amine synthesis.

Direct reductive amination (DRA) is one of the most efficient methods for amine synthesis. Herein we report a practical homogeneous DRA procedure utilizing iridium catalysis. Applying simple, readily available and inexpensive PPh3 and alike ligands at as low as 0.003 mol%, aldehydes and ketones reductively coupled with primary and secondary amines to efficiently form structurally and functionally diverse amine products, including a set of drugs and their late-stage manipulation. The reaction conditions were exceptionally mild and additive-free, and they tolerated oxygen, moisture, polar protic groups and multiple other functional groups. For targeted products, this methodology is versatile and could offer multiple synthetic routes in regard to the selection of starting materials. The 10 gram-scale synthesis further demonstrated the potential and promise of this procedure in practical amine synthesis.