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Synthesis, characterization and redo...

Shotonwa, Ibukun.

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Synthesis, characterization and redox behaviour of 1,2,4-dithiazolium salts and their radicals.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Synthesis, characterization and redox behaviour of 1,2,4-dithiazolium salts and their radicals./
作者:	Shotonwa, Ibukun.
面頁冊數:	213 p.
附註:	Source: Masters Abstracts International, Volume: 54-03.
Contained By:	Masters Abstracts International54-03(E).
標題:	Organic chemistry. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=1583854
ISBN:	9781321557992

Synthesis, characterization and redox behaviour of 1,2,4-dithiazolium salts and their radicals.
Shotonwa, Ibukun.

Synthesis, characterization and redox behaviour of 1,2,4-dithiazolium salts and their radicals. - 213 p.

Source: Masters Abstracts International, Volume: 54-03.

Thesis (M.Sc.)--University of Lethbridge (Canada), 2015.

This item must not be sold to any third party vendors.

This thesis describes the synthesis, characterization and redox behaviour of three potential candidates for molecular conductors with the aim of determining whether or not a stable neutral species is accessible. The target compounds are 3,5-diphenyl-1,2,4-dithiazolium perchlorate salt 3+, 3-diethylamino-5-phenyl-1,2,4-dithiazolium perchlorate salts 1+ and 3,3,5,5-tetramethyl-1,2,4-dithiazolium hexafluorophosphate salt 14+. Crystals of 3+ are monoclinic, space group P21/c, a = 8.9194 (11) A, b = 10.8047 (14) A, c = 15.422 (2) A, beta = 102.91 (2) º, V = 1448.67 (3) A3, Z = 4 and R = 6.79 %. Crystals of 1+ are monoclinic, space group P21/n, a = 7.4531 (9) A, b = 12.0752 (15) A, c = 17.09 (2) A, beta = 102.5 (10) º, V = 1501.6 (3) A3, Z = 4 and R = 2.9 %. Crystals of 14+ are monoclinic, space group P21/c, a = 9.344 (3) A, b = 19.100 (7) A, c = 7.383 (3) A, beta = 101.815 (5) º, V = 1289.74 (8) A3, Z = 4 and R = 12.1 %. They all possess flat central NC2S2 rings with almost coplanar aryl and alkylamino substituents. The redox-active properties of these compounds were investigated via cyclic voltammetry and rotating disk electrode (RDE) voltammetry in CH 2Cl2 and CH3CN solutions containing 0.4 and 0.1 M [nBu4N][PF6] on platinum and glassy carbon electrodes. Cyclic voltammetry revealed the three compounds to show uniform behaviour with chemically and electrochemically irreversible 0/+1 reduction processes with strong offset reoxidation waves that show dependence on scan rates, solvents and substituent size. Diffusion coefficients were estimated by RDE voltammetry in CH3CN/0.1 M [nBu 4N][PF6]: 3, 8.48(2) x 10-6 cm 2/s; 1, 4.51(4) x 10-5 cm2/s; 14, 4.30(2) x 10-5 cm2/s. The electronic structures of cationic, neutral, anionic and dianionic species of 3, 1, and 14 are herein discussed in the light of density functional theory (DFT) calculations. Digital simulations of experimental CVs detected an E1E2C mechanism (open anion model) that displayed slow electron transfer rates for both the reductive and offset oxidation processes coupled with the determination of rate constants for the follow up first order homogenous chemical step. An alternate mechanism is the E1C2E2C 2' (dimer model) wherein the neutral radicals act as "spectator" molecules in the electrochemical-chemical cycle without having any effect on the equilibrium. Both mechanisms had very common parameters (E0, k s, kf and Keq) extracted from them in addition to giving clues for the non-detection of neutral radicals via SEEPR experiments. On the basis of energy requirements, the open anion model is favoured while on the basis of extent of fits between theoretical and experimental CVs, the dimer model is better favoured.

ISBN: 9781321557992Subjects--Topical Terms:

523952
Organic chemistry.

Synthesis, characterization and redox behaviour of 1,2,4-dithiazolium salts and their radicals.
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100 1 $a Shotonwa, Ibukun. $3 3181193
245 1 0 $a Synthesis, characterization and redox behaviour of 1,2,4-dithiazolium salts and their radicals.
300 $a 213 p.
500 $a Source: Masters Abstracts International, Volume: 54-03.
500 $a Adviser: Rene T. Boere.
502 $a Thesis (M.Sc.)--University of Lethbridge (Canada), 2015.
506 $a This item must not be sold to any third party vendors.
520 $a This thesis describes the synthesis, characterization and redox behaviour of three potential candidates for molecular conductors with the aim of determining whether or not a stable neutral species is accessible. The target compounds are 3,5-diphenyl-1,2,4-dithiazolium perchlorate salt 3+, 3-diethylamino-5-phenyl-1,2,4-dithiazolium perchlorate salts 1+ and 3,3,5,5-tetramethyl-1,2,4-dithiazolium hexafluorophosphate salt 14+. Crystals of 3+ are monoclinic, space group P21/c, a = 8.9194 (11) A, b = 10.8047 (14) A, c = 15.422 (2) A, beta = 102.91 (2) º, V = 1448.67 (3) A3, Z = 4 and R = 6.79 %. Crystals of 1+ are monoclinic, space group P21/n, a = 7.4531 (9) A, b = 12.0752 (15) A, c = 17.09 (2) A, beta = 102.5 (10) º, V = 1501.6 (3) A3, Z = 4 and R = 2.9 %. Crystals of 14+ are monoclinic, space group P21/c, a = 9.344 (3) A, b = 19.100 (7) A, c = 7.383 (3) A, beta = 101.815 (5) º, V = 1289.74 (8) A3, Z = 4 and R = 12.1 %. They all possess flat central NC2S2 rings with almost coplanar aryl and alkylamino substituents. The redox-active properties of these compounds were investigated via cyclic voltammetry and rotating disk electrode (RDE) voltammetry in CH 2Cl2 and CH3CN solutions containing 0.4 and 0.1 M [nBu4N][PF6] on platinum and glassy carbon electrodes. Cyclic voltammetry revealed the three compounds to show uniform behaviour with chemically and electrochemically irreversible 0/+1 reduction processes with strong offset reoxidation waves that show dependence on scan rates, solvents and substituent size. Diffusion coefficients were estimated by RDE voltammetry in CH3CN/0.1 M [nBu 4N][PF6]: 3, 8.48(2) x 10-6 cm 2/s; 1, 4.51(4) x 10-5 cm2/s; 14, 4.30(2) x 10-5 cm2/s. The electronic structures of cationic, neutral, anionic and dianionic species of 3, 1, and 14 are herein discussed in the light of density functional theory (DFT) calculations. Digital simulations of experimental CVs detected an E1E2C mechanism (open anion model) that displayed slow electron transfer rates for both the reductive and offset oxidation processes coupled with the determination of rate constants for the follow up first order homogenous chemical step. An alternate mechanism is the E1C2E2C 2' (dimer model) wherein the neutral radicals act as "spectator" molecules in the electrochemical-chemical cycle without having any effect on the equilibrium. Both mechanisms had very common parameters (E0, k s, kf and Keq) extracted from them in addition to giving clues for the non-detection of neutral radicals via SEEPR experiments. On the basis of energy requirements, the open anion model is favoured while on the basis of extent of fits between theoretical and experimental CVs, the dimer model is better favoured.
590 $a School code: 1112.
650 4 $a Organic chemistry. $3 523952
650 4 $a Physical chemistry. $3 1981412
650 4 $a Molecular chemistry. $3 1071612
690 $a 0490
690 $a 0494
690 $a 0431
710 2 $a University of Lethbridge (Canada). $b Chemistry & Biochemistry. $3 3181194
773 0 $t Masters Abstracts International $g 54-03(E).
790 $a 1112
791 $a M.Sc.
792 $a 2015
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=1583854