Browsing by Author "Chiang, Ming-Hsi"

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Highly hydrophobic metal-organic framework for self-protecting gate dielectrics
(2020-06-28)
Inamdar, Arif I.
;
Pathak, Abhishek
;
Usman, Muhammad
;
Chiou, Kuan-Ru
;
Tsai, Pei-Hsien
A hydrophobic metal-organic framework (MOF) showing high-kappa behaviour was synthesized by the reaction of copper ions with 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (HFDPA). The unique, highly hydrophobic nature of the material protects it from re-adsorbing water, even in a high humidity environment. The dielectric constant of the MOF showed an unprecedented increasing trend, reaching up to kappa approximate to 99 at 300 K and 1 kHz after the complete removal of guest and coordinated water molecules. The unusual dielectric behaviour of the compound along with its water resistant properties is the first report of such behaviour and it paves the way for the development of moisture-stable microelectronic devices.
Iron(III) Bound by Hydrosulfide Anion Ligands: NO-Promoted Stabilization of the [Fe-III-SH] Motif
(2014-07-02)
Tsou, Chih-Chin
;
Chiu, Wei-Chun
;
Ke, Chun-Hung
;
Tsai, Jia-Chun
;
Wang, Yun-Ming
Spontaneous transformation of the thermally stable [HS](-)bound {Fe(NO)(2)}(9) dinitrosyl iron complex (DNIC) [(HS)(2)Fe(NO)(2)](-) (1) into [(NO)(2)Fe(mu-S)](2)(2-) (Roussin's red salt (RRS)) along with release of H2S, probed by NBD-SCN (NBD = nitrobenzofurazan), was observed when DNIC 1 was dissolved in water at ambient temperature. The reversible transformation of RRS into DNIC 1 (RRS -> DNIC 1) in the presence of H2S was demonstrated. In contrast, the thermally unstable hydrosulfide-containing mononitrosyl iron complex (MNIC) [(HS)(3)Fe-III(NO)](-) (3) and [Fe-III(SH)(4)](-) (5) in THF/DMF spontaneously dimerized into the first structurally characterized Fe-III-hydrosulfide complexes [(NO)(SH)Fe(mu-S)](2)(2-) (4) with two {Fe(NO)}(7) motifs antiferromagnetically coupled and [(SH)(2)Fe(mu-S)](2)(2-) (6) resulting from two Fe-III (S = 5/2) centers antiferromagnetically coupled to yield an S = 0 ground state with thermal occupancy of higher spin states, respectively. That is, the greater the number of NO ligands bound to [2Fe2S], the larger the antiferromagnetic coupling constant. On the basis of DFT computation and the experimental (and calculated) reduction potential (E-1/2) of complexes 1, 3, and 5, the NO-coordinate ligand(s) of complexes 1 and 3 serves as the stronger electron-donating ligand, compared to thiolate, to reduce the effective nuclear charge (Z(eff)) of the iron center and prevent DNIC 1 from dimerization in an organic solvent (MeCN).
Iron(III) Bound by Hydrosulfide Anion Ligands: NO-Promoted Stabilization of the [Fe-III-SH] Motif
(2014-07-02)
Tsou, Chih-Chin
;
Chiu, Wei-Chun
;
Ke, Chun-Hung
;
Tsai, Jia-Chun
;
Wang, Yun-Ming
Spontaneous transformation of the thermally stable [HS](-)bound {Fe(NO)(2)}(9) dinitrosyl iron complex (DNIC) [(HS)(2)Fe(NO)(2)](-) (1) into [(NO)(2)Fe(mu-S)](2)(2-) (Roussin\'s red salt (RRS)) along with release of H2S, probed by NBD-SCN (NBD = nitrobenzofurazan), was observed when DNIC 1 was dissolved in water at ambient temperature. The reversible transformation of RRS into DNIC 1 (RRS -> DNIC 1) in the presence of H2S was demonstrated. In contrast, the thermally unstable hydrosulfide-containing mononitrosyl iron complex (MNIC) [(HS)(3)Fe-III(NO)](-) (3) and [Fe-III(SH)(4)](-) (5) in THF/DMF spontaneously dimerized into the first structurally characterized Fe-III-hydrosulfide complexes [(NO)(SH)Fe(mu-S)](2)(2-) (4) with two {Fe(NO)}(7) motifs antiferromagnetically coupled and [(SH)(2)Fe(mu-S)](2)(2-) (6) resulting from two Fe-III (S = 5/2) centers antiferromagnetically coupled to yield an S = 0 ground state with thermal occupancy of higher spin states, respectively. That is, the greater the number of NO ligands bound to [2Fe2S], the larger the antiferromagnetic coupling constant. On the basis of DFT computation and the experimental (and calculated) reduction potential (E-1/2) of complexes 1, 3, and 5, the NO-coordinate ligand(s) of complexes 1 and 3 serves as the stronger electron-donating ligand, compared to thiolate, to reduce the effective nuclear charge (Z(eff)) of the iron center and prevent DNIC 1 from dimerization in an organic solvent (MeCN).