Supported phosphine-Rh systems, prepared in situ from silica-supported bridgehead monophosphines and [Rh(OH)(cod)](2), have enabled ortho-selective C-H borylation for a range of arenes containing nitrogen-based directing groups. The regioselectivity was excellent with various N-directing groups, including saturated and unsaturated N-heterocycles, tert-aminoalkyl groups, and imine-type C-N double bonds. The reaction showed significant tolerance toward steric repulsion around the reacting C-H bond. This Rh catalysis complements the Ir-catalyzed ortho-borylation, which is effective for arenes with oxygen-based directing groups.

Direct C(sp(3))-H borylation of amides, ureas, and 2-aminopyridine derivatives at the position α to the N atom, which gives the corresponding α-aminoalkylboronates, has been achieved with a heterogeneous catalyst system consisting of [Rh(OMe)(cod)]2 and a silica-supported triarylphosphine ligand (Silica-TRIP) that features an immobilized triptycene-type cage structure with a bridgehead P atom. The reaction occurs not only at terminal C-H bonds but also at internal secondary C-H bonds under mild reaction conditions (25-100 °C, 0.1-0.5 mol % Rh).

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The film properties of a variety of poly(ester imide)s (PEsIs) were evaluated for development of a novel high temperature base film in flexible printed circuit (FPC) boards. In this work, three types of PEsI systems were systematically prepared from the following combinations of monomers: (1) ester-containing tetracarboxylic dianhydrides: hydroquinone bis(trimellitate anhydride) (TAHQ), methyl-substituted TAHQ (M-TAHQ), and methoxy-substituted TAHQ (MeO-TAHQ) with common diamines such as p-phenylenediamine (PDA), (2) common tetracarboxylic dianhydrides such as pyromellitic dianhydride (PMDA) with ester-containing diamines: 4-aminophenyl-4 0 -aminophenylbenzoate (APAB) and methyl-substituted APAB (ATAB), and (3) the TAHQ series with the APAB series. The effects of the substituents on the PEsI film properties and polymerizability were also discussed in this work. The ester-containing monomers used in this work (TAHQ series and the APAB series) were all highly reactive and led to PEsAAs possessing high inherent viscosities ranging 1.09-9.33 dL/g. The incorporation of methyl and methoxy substituents into rigid TAHQ-based PEsI systems caused no significant decrease in T g but allowed molecular motions above the T g s. In some cases, these substituents, in particular, the methoxy group contributed to a significant decrease in water absorption without sacrificing other target properties. For practical FPC application, a flexible diamine was copolymerized into the highly esterified rigid PEsI systems derived from the TAHQ series with the APAB series. One of the PEsI copolymers obtained achieved excellent combined properties: a low CTE (17.8 ppm/K) completely consistent with that of copper foil as a conductive layer, considerably low water absorption (0.47 wt %), a high T g exceeding 360 C, and improved toughness (elongation at break > 40%). Polyimides (PIs) have been widely utilized in a variety of micro-and optoelectronic applications such as flexible printed circuit boards (FPC), chip on film (COF) assembling system, tape automated bonding tapes (TAB), buffer-coating films and interlayer dielectrics for LSI chips, high temperature adhesives, light wave guides for their combined excellent properties, i.e., high glass transition temperatures (T g ), high resistance to chemicals and radiation, relatively low dielectric constants, and good mechanical properties.1-10 The advantages of PI materials are considerably high purity (extremely low contents of metal contaminations and residual monomers and solvents) in the resins, simple fabrication processes, and the ease of structural modifications through copolymerization using various commercially available monomers.FPC, TAB, and COF are fabricated from PI film/Cu foil laminates (flexible copper clad laminates, FCCL or CCL). Adhesive-free FCCL has an advantage in the view point of dimensional stability against heat cycles compared to that using thermally less stable conventional adhesives. This type of FCCL is usually produced by the casting method (thermal imidization after s...

The electrical properties of p-Si/n-GaAs heterojunctions fabricated by using surface-activated bonding (SAB) were investigated by measuring their current-voltage (I-V) and capacitance-voltage (C-V) characteristics. The I-V characteristics showed rectifying properties. Their flat-band voltage obtained from C-V measurements was around 1.6 V. Observation by using field-emission-scanning electron microscopy and energy dispersive X-ray spectroscopy revealed neither structural deficits nor oxide layers at the interfaces. These results suggest that the SAB-based Si/ GaAs heterojunctions are applicable for fabricating novel devices.

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Electrical properties of n-Si/n-Si, p-Si/n-Si, and p À-Si/n þ-Si junctions fabricated by using surface-activated-bonding are investigated. The transmission electron microscopy/energy dispersive X-ray spectroscopy of the n-Si/n-Si interfaces reveals no evidence of oxide layers at the interfaces. From the current-voltage (I-V) and the capacitance-voltage (C-V) characteristics of the p-Si/n-Si and p À-Si/n þ-Si junctions, it is found that the interface states, likely to have formed due to the surface activation process using Ar plasma, have a more marked impact on the electrical properties of the p-Si/n-Si junctions. An analysis of the temperature dependence of the I-V characteristics indicates that the properties of carrier transport across the bonding interfaces for reverse-bias voltages in the p-Si/n-Si and p À-Si/n þ-Si junctions can be explained using the trap-assisted-tunneling and Frenkel-Poole models, respectively. V

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