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Pd-catalyzed regioselective coupling of γ-C(sp³)-H bonds of oxalyl amide-protected amino acids with heteroaryl and aryl iodides is reported. A wide variety of iodides are tolerated, giving the corresponding products in moderate to good yields. Various oxalyl amide-protected amino acids were compatible in this C-H transformation, thus representing a practical method for constructing non-natural amino acid derivatives. [ABSTRACT FROM AUTHOR]

A method for palladium-catalyzed oxalyl amide-directed arylation of α-unsubstituted aliphatic amines with aryl iodides has been developed. A wide variety of aryl iodides are tolerated in this transformation, affording various γ-arylpropylamine derivatives. Heterocyclic iodides can also be competent reagents in this γ-C(sp³)-H bonds transformation. [ABSTRACT FROM AUTHOR]

Two new boroantimonates, namely, KSbB2O6 and BaSb2B4Ol2, have been successfully synthesized through high-temperature solid state reactions. Their structures feature two types of novel anionic 3D frameworks composed of ID chains of corner-sharing SbO6 octahedra that are interconnected by B2O5 groups. The ID chains of comer-sharing Sb06 octahedra in polar KSbB206 (space group Cc) are extended along the c-axis, whereas those in the centrosymmetric BaSb2B40!2 (space group C2/c) are propagated along the [101] direction. The K+ ions are located at the ID tunnels of the anionic frameworks along both b- and c-axis, whereas Ba2+ ions are located at the 1D tunnels of the anionic frameworks along both the a- and c-axis. KSbB2O6 is a polar material that displays weak SHG response, whereas BaSb2B4O12 is centrosymmetric and not SHG active. Studies on dieir optical properties, thermal stability, and band structure calculations based on DFT methods have been also performed. [ABSTRACT FROM AUTHOR]

Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is frequently present in indoor dust and can be detected in human milk. In order to evaluate the effects of TDCPP on vertebrate development, zebrafish embryos/larvae were used as an animal model to examine developmental phenotypes and explore possible mechanisms of toxicity by employing microarrays and iTRAQ labeling quantitative proteomics. The results demonstrated that treatment with TDCPP (3 μM) from 0.75 h postfertilization (hpf) inhibited cell rearrangement at 4 hpf, caused delay in epiboly at 5.7 and 8.5 hpf, and led to abnormal development (e.g., short tail, reduced body size) and lethality between 14 and 45 hpf, which might be related with altered expression of genes regulating embryogenesis. Furthermore, trunk curvature was observed as the main phenotype in 96 hpf zebrafish larvae exposed to 1 or 3 μM TDCPP, possibly by changing somite formation and expression of proteins related to fast muscle and cartilage development. Collectively, our results suggest that exposure to TDCPP causes developmental toxicity in vertebrates and warrant the need for studies to evaluate the potential health risks of TDCPP to developing human embryos/infants/children, due to its frequent presence in indoor dust and potential for human exposure. [ABSTRACT FROM AUTHOR]

Two new barium borogermanates with two types of novel structures, namely, Ba3[Ge2B7O16(OH)2](OH)(H2O) and Ba3Ge2B6O16, have been synthesized by hydrothermal or high-temperature solid-state reactions. They represent the first examples of alkaline-earth borogermanates. Ba3[Ge2B7O16(OH)2](OH)(H2O) crystallized in a polar space group Cc. Its structure features a novel three-dimensional anionic framework composed of [B7O16(OH)2]13- polyanions that are bridged by Ge atoms with one-dimensional (1D) 10-membered-ring (MR) tunnels along the b axis. The BaII cations, hydroxide ions, and water molecules are located at the above tunnels. Ba3Ge2B6O16 crystallizes in centrosymmetric space group P1¯. Its structure exhibits a thick layer composed of circular B6O16 units connected by GeO4 tetrahedra via corner sharing, forming 1D 4- and 6-MR tunnels along the c axis. Ba1 ions reside in the tunnels of the 6-MRs, whereas Ba2 ions are located at the interlayer space. Both compounds feature new types of topological structures. Second-harmonic-generation (SHG) measurements indicate that Ba3[Ge2B7O16(OH)2](OH)(H2O) displays a weak SHG response of about 0.3 times that of KH2PO4. Optical, thermal stability, and ferroelectric properties as well as theoretical calculations have also been performed. [ABSTRACT FROM AUTHOR]

Three novel rubidium borogermanates with three types of noncentrosymmetric structures, namely, RbGeB3O7, Rb2GeB4O9, and Rb4Ge3B6O17, have been synthesized by high-temperature solid-state reactions in platinum crucibles. The structure of RbGeB3O7 features a three-dimensional (3D) anionic framework composed of cyclic B3O7 groups corner-sharing GeO4 tetrahedra. The structure of Rb2GeB4O9 shows a 3D anionic framework based on B4O9 clusters connected by GeO4 tetrahedra via corner sharing. The structure of Rb4Ge3B6O17 is a novel 3D anionic framework composed of cyclic B3O8 groups, Ge2O7 dimers, and GeO4 tetrahedra that are interconnected via corner sharing. Second harmonic generation (SHG) measurements indicate that RbGeB3O7, Rb2GeB4O9, and Rb4Ge3B6O17 display moderate SHG responses that are approximately 1.3, 2.0, and 1.3 × KH2PO4 (KDP), respectively, which are slightly smaller than those from theoretical calculations (about 3.7, 2.8, and 2.4 × KDP, respectively). [ABSTRACT FROM AUTHOR]

Polymorphs of ZnHPO 3 ·2H 2 O with centrosymmetry ( Cmcm ) and noncentrosymmetry ( C 2) structures were prepared by modified solution evaporation and seed-crystal-induced secondary nucleation methods. In Cmcm -ZnHPO 3 ·2H 2 O, the zinc atoms are only octahedrally coordinated, while in C 2-ZnHPO 3 ·2H 2 O, they feature both tetrahedral and octahedral coordination. As a result, Cmcm -ZnHPO 3 ·2H 2 O features a 2D layered structure with lattice water molecules located in the interlayer space, while C 2-ZnHPO 3 ·2H 2 O features a 3D electroneutral framework of tfa topology connected by Zn(1)O 4 , Zn(2)O 6 , and HPO 3 units. The UV-visible diffuse reflectance spectra associated with Tauc's analyses give a direct bandgap of 4.24 and 4.33 eV for Cmcm -ZnHPO 3 ·2H 2 O and C 2-ZnHPO 3 ·2H 2 O, respectively. Moreover, C 2-ZnHPO 3 ·2H 2 O exhibits a weak second harmonic generation (SHG) response and a moderate birefringence for phase matching, indicating its potential as a nonlinear optical material. Detailed dipole moment calculation and analysis confirmed that the SHG response mainly derived from the HPO 3 pseudo-tetrahedra.

Cu2CdSnS4 and α/β-Cu2ZnSiS4 meet several criteria for promising nonlinear optical materials for use in the infrared (IR) region. Both are air-stable, crystallize in noncentrosymmetric space groups, and possess high thermal stabilities. Cu2CdSnS4 and α/β-Cu2ZnSiS4 display wide ranges of optical transparency, 1.4-25 and 0.7-25 μm, respectively, and have relatively large second-order nonlinearity as well as phase matchability for wide regions in the IR. The laser-damage threshold (LDT) for Cu2CdSnS4 is 0.2 GW/cm(2), whereas α/β-Cu2ZnSiS4 has a LDT of 2.0 GW/cm(2) for picosecond near-IR excitation. Both compounds also exhibit efficient third-order nonlinearity. Electronic structure calculations provide insight into the variation in properties.

Two new boroantimonates, namely, KSbB2O6 and BaSb2B4O12, have been successfully synthesized through high-temperature solid state reactions. Their structures feature two types of novel anionic 3D frameworks composed of 1D chains of corner-sharing SbO6 octahedra that are interconnected by B2O5 groups. The 1D chains of corner-sharing SbO6 octahedra in polar KSbB2O6 (space group Cc) are extended along the c-axis, whereas those in the centrosymmetric BaSb2B4O12 (space group C2/c) are propagated along the [101] direction. The K(+) ions are located at the 1D tunnels of the anionic frameworks along both b- and c-axis, whereas Ba(2+) ions are located at the 1D tunnels of the anionic frameworks along both the a- and c-axis. KSbB2O6 is a polar material that displays weak SHG response, whereas BaSb2B4O12 is centrosymmetric and not SHG active. Studies on their optical properties, thermal stability, and band structure calculations based on DFT methods have been also performed.

A new alkali-metal borogermanate with noncentrosymmetric structure, namely, Cs2GeB4O9, has been discovered, and a large crystal with dimensions of 20 × 16 × 8 mm(3) has been grown by a high-temperature top-seeded solution method using Cs2O-B2O3 as a flux. The compound crystallizes in the tetragonal space group I4 with a = b = 6.8063(2) Å, c = 9.9523(7) Å, V = 461.05(4) Å(3), and Z = 2. It features a three-dimensional anionic open framework based on GeO4 tetrahedra and B4O9 clusters that are interconnected via corner-sharing, forming one-dimensional channels of nine-/ten-membered rings along the a and b axes, which are occupied by Cs(+) cations. Cs2GeB4O9 exhibits a very high thermal stability with a melting point of 849 °C, and it possesses a short-wavelength absorption edge onset at 198 nm determined by UV-vis transmission spectroscopy measurements on a slab of polished crystal. Powder second-harmonic generation (SHG) measurement on sieved crystals reveals that Cs2GeB4O9 is a type I phase-matchable material with a strong SHG response of about 2.8 × KH2PO4. The preliminary investigation indicates that Cs2GeB4O9 is a new promising second-order nonlinear-optical crystalline material.

Two new acentric borogermanates, Ca(10)Ge(16)B(6)O(51) (Pba2) and Cd(12)Ge(17)B(8)O(58) (P4), have been successfully synthesized by high-temperature solid-state reactions of CaCO(3) (or CdCO(3)), GeO(2), and H(3)BO(3). Both structures display the same one-dimensional (1D) [Ge(4)O(12)](n) chains composed of GeO(4) tetrahedra and GeO(6) octahedra. In Ca(10)Ge(16)B(6)O(51), neighboring 1D [Ge(4)O(12)](n) chains are condensed into a two-dimensional (2D) [Ge(4)O(10.75)](n) layer via corner sharing, and such layers are further interconnected by "isolated" BO(4) tetrahedra and B(2)O(7) dimers into a three-dimensional (3D) framework, forming 1D tunnels of 5-, 6-, and 7-MRs along the c axis that are occupied by Ca(2+) cations. In Cd(12)Ge(17)B(8)O(58), neighboring 1D [Ge(4)O(12)](n) chains are interconnected into a [Ge(4)O(10.5)](n) open framework via corner sharing with large pores filled by big [Ge(B(2)O(7))(4)](28-) clusters, leading to formation of three types of 1D tunnels of 5-, 6-, and 7-membered rings (MRs) along the c axis which are occupied by the Cd(2+) cations. Both compounds are transparent in the range of 0.3-6.67 μm and exhibit very weak SHG responses.

Two new barium borogermanates with two types of novel structures, namely, Ba(3)[Ge(2)B(7)O(16)(OH)(2)](OH)(H(2)O) and Ba(3)Ge(2)B(6)O(16), have been synthesized by hydrothermal or high-temperature solid-state reactions. They represent the first examples of alkaline-earth borogermanates. Ba(3)[Ge(2)B(7)O(16)(OH)(2)](OH)(H(2)O) crystallized in a polar space group Cc. Its structure features a novel three-dimensional anionic framework composed of [B(7)O(16)(OH)(2)](13-) polyanions that are bridged by Ge atoms with one-dimensional (1D) 10-membered-ring (MR) tunnels along the b axis. The Ba(II) cations, hydroxide ions, and water molecules are located at the above tunnels. Ba(3)Ge(2)B(6)O(16) crystallizes in centrosymmetric space group P1. Its structure exhibits a thick layer composed of circular B(6)O(16) units connected by GeO(4) tetrahedra via corner sharing, forming 1D 4- and 6-MR tunnels along the c axis. Ba1 ions reside in the tunnels of the 6-MRs, whereas Ba2 ions are located at the interlayer space. Both compounds feature new types of topological structures. Second-harmonic-generation (SHG) measurements indicate that Ba(3)[Ge(2)B(7)O(16)(OH)(2)](OH)(H(2)O) displays a weak SHG response of about 0.3 times that of KH(2)PO(4). Optical, thermal stability, and ferroelectric properties as well as theoretical calculations have also been performed.

Three novel rubidium borogermanates with three types of noncentrosymmetric structures, namely, RbGeB(3)O(7), Rb(2)GeB(4)O(9), and Rb(4)Ge(3)B(6)O(17), have been synthesized by high-temperature solid-state reactions in platinum crucibles. The structure of RbGeB(3)O(7) features a three-dimensional (3D) anionic framework composed of cyclic B(3)O(7) groups corner-sharing GeO(4) tetrahedra. The structure of Rb(2)GeB(4)O(9) shows a 3D anionic framework based on B(4)O(9) clusters connected by GeO(4) tetrahedra via corner sharing. The structure of Rb(4)Ge(3)B(6)O(17) is a novel 3D anionic framework composed of cyclic B(3)O(8) groups, Ge(2)O(7) dimers, and GeO(4) tetrahedra that are interconnected via corner sharing. Second harmonic generation (SHG) measurements indicate that RbGeB(3)O(7), Rb(2)GeB(4)O(9), and Rb(4)Ge(3)B(6)O(17) display moderate SHG responses that are approximately 1.3, 2.0, and 1.3 × KH(2)PO(4) (KDP), respectively, which are slightly smaller than those from theoretical calculations (about 3.7, 2.8, and 2.4 × KDP, respectively)., (© 2011 American Chemical Society)