The coordination-restricted ortho -site C–H bond activation and dehydrogenative homocoupling of 4,4′-(1,3-phenylene)dipyridine (1,3-BPyB) and 4,4′-(1,4-phenylene)dipyridine (1,4-BPyB) on different metal surfaces were studied by a combination of scanning tunneling microscopy, noncontact atomic force microscopy, and density functional theory calculations. The coupling products on Cu(111) exhibited certain configurations subject to the spatial restriction of robust two-fold Cu–N coordination bonds. Compared to the V-shaped 1,3-BPyB, the straight backbone of 1,4-BPyB helped to further reduce the variety of reactive products. By utilizing the three-fold coordination of Fe atoms with 1,4-BPyB molecules on Au(111), a large-scale network containing single products was constructed. Our results offer a promising protocol for controllable on-surface synthesis with the aid of robust coordination interactions.

Leakage current reduction is crucial for operating transformerlss PV systems. In this letter, a new three-phase topology and modulation strategy is proposed. It is derived from the single-phase ZVR (zero-voltage state rectifier) topology, but the operation mechanism is quite different. Therefore, a new modulation strategy based on the Boolean logic function is proposed to achieve the constant common mode voltage, so as to eliminate the leakage current. Finally, the experimental tests are carried out to verify the feasibility and effectiveness of the proposed solution.

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