Nghiên cứu tổng hợp vật liệu mới từ TCNQ và TCNQF4 tt tiếng anh

MINSTRY OF EDUCATION AND TRAINING THE UNIVERSITY OF DANANG RESEARCH ON THE SYNTHESIS OF NEW TCNQ AND TCNQF4 – BASED MATERIAL Major: Organic Chemistry Code: 60.44.01.14 Summary of Doctoral Thesis in Chemistry Danang - 2019 The work was completed in THE UNIVERSITY OF DANANG Supervisor: Assoc Prof Le Tu Hai Supervisor: Assoc Prof Lisa Martin Reviewers 1: Reviewers 2: Reviewers 2: The dissertation is protected before the Council meeting marked PhD thesis at the University of Danang in day month year 2019 Thesis can be found at - National library of Vietnam - Center for learning information resources and communications A DESSRTATION INTRODUCTION The significances of the research TCNQ-based materials (tetracyanoquinondimetan) have been studied since the 1960s Especially, a semiconductor compound was chemically synthesized from TCNQ with TTF Since then, there have been many researches on chemical synthesis and characterization of TCNQ-based materials The synthesis of TCNQ with nitrogen-containing organic compounds such as amine derivatives, amino acids has not been studied widely Especially, there have been not many publications on the chemistry and the synthesis of materials from TCNQFn derivatives The use of electrochemical method in synthesis and characterization of the materials has not been properly investigated Therefore, the thesis title: "Research on the synthesis of new TCNQ and TCNQF4 – based materials" has been chosen Subjects and tasks of the dissertation - Chemically synthesize new materials from TCNQ, TCNQF4 with amino acid compounds and transition metal cations - Use electrochemical method to study the conditions to synthesize TCNQF4 – based materials and provide suitable conditions for the electrochemical synthesis - Characterize the new materials with spectroscopic methods - Contribute to the research on the application of conductive organic polymers New findings of the dissertation - Novel materials of TCNQ with amino acid Proline, Leucine and their methyl derivatives has been successfully synthesized and chacracterze - Novel TCNQF42- - based materials with metal cations (Ag+, Cu+, Zn2+, Co2+, Mn2+) has been successfully synthesized and characterized - Electrochemical method has been used to study the synthesis the characterization of TCNQF4 – based materials an - The materials of TCNQ and amino acid derivatives have shown interesting conductive properties Chapter Overview Conductive Polymer Literature review on the conductive polymers and its applications TCNQ and TCNQF4 - In the world, there have been many researches on TCNQ-based materials At first, it was the result of the synthesis of semiconductor compounds from TCNQ and TTF, then the group of Prof Kim Dunbar and colleagues has also reported the chemical synthesis of TCNQbased materials with metal cations in different solvents The application of these products in the field of conductivity, optical transformation, sensors has been studied in depth Alan Bond and Lisa Martin research group has started to investigate the electrochemical synthesis as well as analyzing the reaction mechanism of these TCNQbased materials with metal cations - There have been less reports on the formation of TCNQ-based materials with organic cations, compared to with transition metal cations Also, the research on TCNQFn derivatives has only been started recently and there are not many significant results - The use of electrochemical methods to study the electrochemical properties and electrochemical synthesis of materials of TCNQ and TCNQF4 should be studied - The characterization of TCNQ, TCNQF4 and their anions in solid and solution states has been described Chapter 2: Content and research methods 2.1 Equipment, tools and chemicals 2.1.1 Chemicals 7,7,8,8-tetracyanoquinondimethane (TCNQ) 2,3,5,6-tetrafloro-7,7,8,8-tetracyanoquinondimethane (TCNQF4) L–Proline N,N-dimethyl-D-Proline methyl ester N,N,N-trimetyl Leucin metyl ester Tetrakis(acetonitrin) Silve(I) tetrafloborat Ag(CH3CN)4BF4 Tetrakis(acetonitrin) copper (I) hexafloborat [Cu(CH3CN)4]PF6 Zince perclorat hexahydrat Zn(ClO4)2·6H2O 2.1.2 Experimental equipment and tools Bioanalytical Systems (BAS) 100 W and Bioanalytical devices (BAS) Epsilon is a versatile system used to study the electrochemical properties of materials 2.2 Research Methods 2.2.1 Physical method 2.2.2 Chemical synthesis method 2.2.3 Electrochemical method 2.3 Research on synthesizing and characterizing properties of TCNQ with organic ions 2.3.1 TCNQ- Proline 2.3.2 TCNQ - N, N- dimetyl –proline este 2.3.3 Leucin(CH3)3 – TCNQ 2.4 Study on electrochemical properties and synthesis of TCNQF4 with metal cations 2.4.1 Electrochemical properties of TCNQF4 in the presence of Cu(CH3CN)4+ and Ag(CH3CN)4+ 2.4.2 Synthesis materials of TCNQF4 with Ag+, Cu+ in CH3CN 2.4.3 Synthesis M-TCNQF4 (M = Zn, Co, Mn) in mix solvent of CH3CN and DMF Chapter 3: Results and Discussion 3.1 Materials of TCNQ with amino acides 3.1.1 Material of Proline with TCNQ 3.1.1.1 Structure of product The Figure 3.3 Structure of ProTCNQ asymmetric unit of the product contains two crystallographically independent proline molecules and three halves of TCNQ species There are two groups of TCNQ are anionic radicals TCNQ-, the other TCNQ group is a neutral molecule of TCNQ0 alternating between TCNQ- 3.1.1.2 Spectral properties of the product Raman spectrum of TCNQ0 shows the vibrational bands of C≡N, ring C=C, exocyclic C=C and C-H bonds at 2227, 1601, 1454 and 1205 cm-1 respectively Raman spectrum of the crystal represents the vibrational band of C≡N stretch at 2194 cm-1 and of exo-ring C=C stretch at 1387 cm-1 These bands shift towards the lower energy showing the presence of TCNQ- Infrared and UV-Vis spectra also confirm the existence of two TCNQ- moieties and TCNQ0 moieties 3.1.1.3 Electrochemical properties of the product The steady state voltammogram of ProTCNQ dissolved in CH3CN is shown in Figure 3.7 The voltammogram illustrates that the magnitude of oxidation current doubles that of reduction one, implying the presence of two TCNQ.- and one TCNQ0 moieties in the solution 0.4 0.3 0.2 ProTCNQ i/[nA] 0.1 0.0 TCNQ -0.1 -0.2 -0.3 -0.4 0.0 0.1 0.3 0.2 0.4 0.5 0.6 + E/[V] vs Ag/Ag Figure 3.7 Steady state voltammogram of ProTCNQ and TCNQ in CH3CN 3.1.1.4 Conductivity of ProTCNQ The solid state conductivity of ProTCNQ is measured at 2.5mS.cm-1 at 295K That indicates it is within the semiconductor range (10-5 to 106 mS.cm-1) 3.1.2 Product of N,N-dimetyl- Proline methyl este with TCNQ 3.1.2.1 Crystall structure - ProCH3TCNQ (1:1) material Figure 3.10 Structure of Pro(CH3)3TCNQ (1:1) The product crystallizes in the monoclinic space group P21, with the asymmetric unit cell comprising of one Pro(CH3)3+ and an anionic TCNQ- (Figure 3.10) The structure of this crystal shows that it is a layer structure The charge of TCNQ moieties derived from the bond length in TCNQ is -1,07, indicating the presence of anionic mono TCNQ- - Material (ProCH3)2(TCNQ)3 Single crystals of ProCH3TCNQ (2:3) belong to the monoclinic space group P21/c with the asymmetric unit cells containing a Pro(CH3)3+ cation with two TCNQ moieties (Figure 3.11) The structure includes alternating layers of Pro(CH3)3+ and (TCNQ)32- From the results of analyzing the bond length of each TCNQ moieties, the charge (ρ) can be calculated as -0.30 for TCNQA and -0.94 for TCNQ-B Therefore TCNQ-A is considered almost as a TCNQ0 molecule, whereas TCNQ-B is close to the anion TCNQ- TCNQ-B TCNQ-A Figure 3.11 Structure of (ProCH3)2( TCNQ)3 2:3 3.1.2.2 Raman spectroscopy of ProCH3TCNQ (1:1 2:3) Raman spectra are shown in Figure 3.25 The four characteristic peaks of TCNQ, C=C-H, C-CN, C=C (round) and C≡N are at 1206, 1454, 1602 and 2227 cm-1, respectively Raman spectra of 1:1 ProCH3TCNQ and 2:3 (ProCH3)2(TCNQ)3 shows these vibrational bands with a shift to lower energy levels The shift of these pic confirm the existence of monoanion TCNQ- Figure 3.12 Raman spectra for (a) TCNQ0, (b) 1:1 ProCH3TCNQ and(c) 2:3 (ProCH3)2( TCNQ)3 In addition, in the Raman spectrum of (ProCH3)2(TCNQ)3, there are three peaks of the CN stretch at 2192, 2207, and 2225 cm-1 and peaks for C-CN stretch at 1296, 1350 and 1388 cm-1 This may be due to the special structure of (ProCH3)2(TCNQ)3, in which the three TCNQ moieties share the two negative charges, leading to the emergence of new vibrations 3.1.2.3 Electrochemical properties of the product Steady-state voltammogram of ProCH3TCNQ (1:1) (Figure 3.14) shows that it dissolves completely (nearly 100%) into monoanion TCNQ- TCNQ- can be oxidized to form TCNQ0, leading to a positive current or reduced to TCNQ2-, leading to a negative current, so the position of zero current is exactly between TCNQ0/and TCNQ-/2- processes 0.32 2.8 (ProCH3)TCNQ (1:1) 1.4 I/[nA] I/[nA] 0.16 0.00 (ProCH3)TCNQ (2:3) 0.0 -1.4 -0.16 -2.8 -0.32 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 -0.6 + -0.4 -0.2 0.0 0.2 0.4 0.6 + E/[V] vs Ag/Ag E/[V] vs Ag/Ag Figure 3.14 Curve line i-E of 1:1 ProCH3TCNQ (1:1 and 2:3) (0,2 mM) in CH3CN (0,1 M Bu4NBF6) , 10 µm Pt electrode diameter, 100 mV / s Steady-state voltammogram ProCH3TCNQ (2:3) shows the presence of TCNQ0 and TCNQ- Quantitative analysis of current magnitude related to the first process shows that the oxidative current derived from monoanion TCNQ- accounts for about 67% (about 2/3) of the total current, while the rest (1/3) is the reducing current generated from TCNQ The rate of oxidation/reduction currents shows that the ratio of this crystal is 2: 3.1.2.4 Conductivity of Pro(CH3)TCNQ 3.2 Products of [Ag(CH3CN)4]+, Cu(CH3CN)4+ với TCNQF4 3.2.1 Cyclicvoltammetry of TCNQF4, [Ag(CH3CN)4]+ and Cu(CH3CN)4+ in CH3CN (0.1 M Bu4NPF6) The voltammogram of 1.0 mM TCNQF4 in CH3CN (0.1 M Bu4NPF6) is shown in Figure 3.20 The peak values are shown in Table 3.7 (Em1 = (Ep1kh + Ep1ox)/2 and Em2 = (Ep2kh + Ep2ox)/2) It is clear fro the table that the value of Em does not depend on the material of the electrode -1/0 TCNQF4 -2/-1 TCNQF4 i (A) -1 -2 -3 0/-1 TCNQF4 -4 -1/-2 TCNQF4 TCNQF4 -5 -600 -300 300 600 + E (mV) vs Ag/Ag Figure 3.20 CV with GC mm) v =100 mV/s for 1.0 mM TCNQF4 in CH3CN (0.1 M Bu4NPF6) 120 i (A) 80 40 GC Au Pt ITO (chu ky 1) Ag 0/+ -40 Ag +/0 + Ag(CH3CN)4 -80 -600 -300 E / mV vs Ag/Ag 300 600 + Figure 3.21 CV of 2.0 mM Ag(CH3CN)4+ in CH3CN (0,1 M Bu4NPF6), v = 100 mV/s 11 Table 3.7 The obtained potential values (mV) for CV scan of TCNQF4 and Ag (CH3CN)4+ Compounds Ag(MeCN)4+ ( chu kỳ 1) TCNQF4 Ep(kh1) Ep(ox1) Em1 Ep(kh2) Ep(ox2) Em2 ∆E0 Epkh Epox Em Ep GC 277 345 311 -255 -185 -220 531 -331 68 -131.5 399 Au 277 343 310 -255 -185 -220 530 -99 79 -10 178 Pt 277 343 310 -256 -186 -221 531 -133 59 -37 192 ITO 201 406 303.5 -335 -157 -246 549.5 -447 34 -206.5 481 Cyclic voltammetry of solution containing 2.0 mM Ag(CH3CN)4+ in CH3CN (0.1 M Bu4NPF6) is shown in Figure 3.21 The reduction of Ag(CH3CN)4+ to Ag metal depends significantly on the electrode material It can be seen that cation Ag(CH3CN)4+ is easily reduced in order of Au