Black phosphorus is a two-dimensional material of great interest, in part because of its high carrier mobility and thickness dependent direct bandgap. However, its instability under ambient conditions limits material deposition options for device fabrication. Here we show a black phosphorus ink that can be reliably inkjet printed, enabling scalable development of optoelectronic and photonic devices. Our binder-free ink suppresses coffee ring formation through induced recirculating Marangoni flow, and supports excellent consistency (< 2% variation) and spatial uniformity (< 3.4% variation), without substrate pre-treatment. Due to rapid ink drying (< 10 s at < 60 °C), printing causes minimal oxidation. Following encapsulation, the printed black phosphorus is stable against long-term (> 30 days) oxidation. We demonstrate printed black phosphorus as a passive switch for ultrafast lasers, stable against intense irradiation, and as a visible to near-infrared photodetector with high responsivities. Our work highlights the promise of this material as a functional ink platform for printed devices.

We fabricate ultrasmall phosphorene quantum dots (PQDs) with an average size of 2.6 ± 0.9 nm using a liquid exfoliation method involving ultrasound probe sonication followed by bath sonication. By coupling the as-prepared PQDs with microfiber evanescent light field, the PQD-based saturable absorber (SA) device exhibits ultrafast nonlinear saturable absorption property, with an optical modulation depth of 8.1% at the telecommunication band. With the integration of the all-fiber PQD-based SA, a continuous-wave passively mode-locked erbium-doped (Er-doped) laser cavity delivers stable, self-starting pulses with a pulse duration of 0.88 ps and at the cavity repetition rate of 5.47 MHz. Our results contribute to the growing body of work studying the nonlinear optical properties of ultrasmall PQDs that present new opportunities of this two-dimensional (2D) nanomaterial for future ultrafast photonic technologies.

Four amidate-functionalized N-heterocyclic carbene (NHC) rare-earth metal amido complexes [(κ 2 -N,O-κ 1 -L) 2 REN(SiMe 3 ) 2 ] (L = 1-(C 6 H 5 CONCH 2 CH 2 )-3-(CH 3 ) 3 C 6 H 2 (N(CH) 2 NC)) [RE = Er (1), Y (2), Dy (3), Gd (4)] were synthesized by one-pot reactions of 2 equiv of (1-(C 6 H 5 CONHCH 2 CH 2 )-3-(CH 3 ) 3 C 6 H 2 -(N(CH) 2 NCH))Br (H 2 LBr) with 5 equiv of KN(SiMe 3 ) 3 followed by treatment with 1 equiv of RECl 3 in tetrahydrofuran at −40 °C. These complexes were fully characterized, and their catalytic activities toward hydroboration of unactivated imines and nitriles were investigated, and it was found that these complexes displayed excellent activities as well as remarkable functional group compatibility for imine and nitrile substrates such as halo-, alkyl-, hydroxyl-, N,N-dimethylamino-, and nitro-substituents. Among those, the chemoselectivity for this reaction among the common unsaturated functional groups was achieved in the order CO ≫ CN > CN > CO 2 Et > CC in the current catalytic system, which may facilitate their further application in synthetic chemistry.

It is demonstrated that the cyclopentadienyl-free simple lanthanide amides [(Me(3)Si)(2)N](3)Ln(mu-Cl)Li(THF)(3)(Ln = La, Sm, Eu, Y, Yb) and Ln[N(SiMe(3))(2)]3 (Ln = Y, Yb) are highly efficient catalysts for the guanylation of both aromatic and secondary amines with a high activity under mild conditions. It is found that these catalysts are compatible with a wide range of solvents and substrates.

A series of neutral rare earth metal amides with different metal-nitrogen bonds were synthesized and characterized. The selective catalytic activity and reactivity of the complexes incorporating different metal-nitrogen (Ln-N, Ln = rare earth metal) bonds were studied. Treatment of (Me 6), Sm ( 7)) incorporating different Ln-N bonds in good yields. Reaction of 6 or 7 with grease (Me 2 SiO) 3 in toluene produced the selective insertion products [C 6 H 5 N(Me 2 Si)N(C 6 H 5 )(Me 2 SiO)LnN(SiMe 3 ) 2 ] 2 (Ln = Yb (8), Sm ( 9)). The structures of complexes 1, 2, 4, 5, 8, and 9 were additionally determined by single-crystal X-ray analyses. Investigation of catalytic activity of the complexes indicated that the complexes displayed a high selectivity on cyclotrimerization or cyclodimerization toward isocyanates depending on the nature of the isocyanates. These catalysts have the advantages of a high reactivity and good selectivity toward isocyanates, easy preparation, low catalyst loading, and high conversion, as well as mild reaction conditions.

No abstract

Two series of new lanthanide amido complexes supported by bis(indolyl) ligands with amino-coordinate-lithium as a bridge were synthesized and characterized. The interactions of [(Me(3)Si)(2)N](3)Ln(III)(μ-Cl)Li(THF)(3) with 2 equiv of 3-(CyNHCH(2))C(8)H(5)NH in toluene produced the amino-coordinate-lithium bridged bis(indolyl) lanthanide amides [μ-{[η(1):η(1):η(1):η(1)-3-(CyNHCH(2))Ind](2)Li}Ln[N(SiMe(3))(2)](2)] (Cy = cyclohexyl, Ind = Indolyl, Ln = Sm (1), Eu (2), Dy (3), Yb (4)) in good yields. Treatment of [μ-{[η(1):η(1):η(1):η(1)-3-(CyNHCH(2))Ind](2)Li}Ln[N(SiMe(3))(2)](2)] with THF gave new lanthanide amido complexes [μ-{[η(1):η(1)-3-(CyNHCH(2))Ind](2)Li(THF)}Ln[N(SiMe(3))(2)](2)] (Ln = Eu (5), Dy (6), Yb (7)), which can be transferred to amido complexes 2, 3, and 4 by reflux the corresponding complexes in toluene. Thus, two series of rare-earth-metal amides could be reciprocally transformed easily by merely changing the solvent in the reactions. All new complexes 1-7 are fully characterized including X-ray structural determination. The catalytic activities of these new lanthanide amido complexes for hydrophosphonylation of both aromatic and aliphatic aldehydes and various substituted aldimines were explored. The results indicated that these complexes displayed a high catalytic activity for the C-P bond formation with employment of low catalyst loadings (0.1 mol % for aldehydes and 1 mol % for aldimines) under mild conditions. Thus, it provides a convenient way to prepare both α-hydroxy and α-amino phosphonates.

Reactions of [(Me 3 Si) 2 N] 3 RE(μ-Cl)Li(THF) 3 with aminomethylene-substituted pyridine 2- Pr(2c), Nd(2d), Sm(2e), Dy(2f), Er(2g), and Lu (2h)). However, reaction of [(Me 3 Si) 2 N] 3 Y(μ-Cl)Li(THF) 3 with pyridin-2-ylmethyl-substituted amines such as 2-(RNHCH 2 )C 5 H 4 N (R = t Bu (3a) and 2,6-i Pr 2 Ph (3b)) or benzyl-substituted amine O(CH 2 CH 2 ) 2 NCH 2 CH 2 NHCH 2 C 6 H 5 (5) afforded the corresponding yttrium complexes containing monoanionic ligands [2-(RNCH 2 )C 5 H 4 N] 2 YN(SiMe 3 ) 2 (R = t Bu (4a) and 2,6-i Pr 2 Ph (4b 6). Dianionic α-iminopyridine rare-earth metal amido complexes showed high catalytic activities for the dehydrogenation coupling reaction of hydrosilanes and amines providing a variety of silylamines in high yields.