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Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
Leaded SMT packages are used for transistors, diodes, and integrated circuits. Transistors are commonly in a variety of SOT packages, including SOT-23 (also used for diodes), SOT-89, SOT-223, and TO-252 (Motorola D-PAK) packages. Packages such as the SOT-89, SOT-223, and TO-252 are used for highpower devices since they include relatively large solder tabs to improve heat transfer to the board. The SOT-23 package has been modified by several manufacturers to increase the lead count to a total of five or six, and to use them for IC packaging, such as op amps. Overall body size remains the same (Figure 125.2).
A guanylurea ligand and its Cu(II), Ni(II) and Zn(II) complexes: antibacterial activities and DNA binding properties
Published in Inorganic and Nano-Metal Chemistry, 2020
Ozge Gungor, Seda Nur Kertmen Kurtar, Feridun Koçer, Muhammet Kose
A single absorption band was observed in the ligand, whereas two absorption bands were observed in the complexes. The complexes [Cu(L)2]·(ClO4)2 and [Ni(L)2]·(ClO4)2 and [Zn(L)Cl2] exhibit absorption bands in the UV region at 252, 263 and 270 nm, respectively. By the addition of increasing amounts of FSds-DNA to the complex solutions, a sharp hyperchromic effect in the absorption bands with a moderate red shift of 5, 3 and 10 nm, respectively is observed. Hyperchromic effect reflects the corresponding changes of DNA in its conformation and structure after the complex–DNA interaction has occurred. The binding constants of the complexes were calculated as 4.7 × 104, 6.2 × 104 and 2.3 × 105, respectively. Binding constants of ligands and complexes are given in Table 3.
Nitrogen centered inverse coordination complexes. A survey of molecular topologies
Published in Journal of Coordination Chemistry, 2018
Structures based upon “head-on/head-on” connectivity are known for titanium [199–217], zirconium [215, 218–220], hafnium [221], vanadium [222–225], niobium [225–228], tantalum [225, 229–231], chromium [232, 233], molybdenum [212, 234–252], tungsten [212, 253–261], manganese [215, 262, 263], technetium [264], rhenium [265], iron [80, 215, 263, 266–283], ruthenium [284–295], osmium [296, 297], cobalt [298, 299], rhodium [300–302], iridium [303–308], and nickel [309–315]. A small sample of examples (46-53) selected from a large number of known structures are shown in Scheme 18 to illustrate the variety of bonding modes. The bonding in [(µ2-N2){M(η5-C5H5)2}2] inverse coordination complexes was theoretically analyzed with the aid of DFT method [316].