A. Aza-crown ether functionalized silicon quantum dots as metal ion sensors

The B3LYP/LanL2DZ method was employed to calculate the binding energy between metal ions and aza-crown ether (C12H23O5N, C14H27O6N, and C14H28O5N2). The magnitudes of binding energies are found to correlate with the capability of aza-crown ether functionalized silicon quantum dots used as metal ion (K+, Na+, Mg2+,Ca2+, Sr2+, Ba2+, Mn2+) sensors.

B. Functionalized MoS2 quantum dots as metal ion sensors

B3LYP with LanL2DZ and QZVP were used to study the capability of three functionalized (-COOH, -NH2, and -SH) MoS2 quantum dots to detect Co2+, Cd2+and Pb2+ ion. The binding energy between the ions and MoS2 clusters was investigated to
assess the sensing mechanism.

C. Theoretical study of Bn clusters in ionic liquids

The interactions between Boron clusters (Bn, n=6) and ionic liquid were investigated using the B3LYP/cc-pVTZ level of calculations. The likely structures and their IR and Raman spectra are obtained.

A. Aza-crown ether functionalized silicon quantum dots as metal ion sensors

The B3LYP/LanL2DZ method was employed to calculate the binding energy between metal ions and aza-crown ether (C12H23O5N, C14H27O6N, and C14H28O5N2). The magnitudes of binding energies are found to correlate with the capability of aza-crown ether functionalized silicon quantum dots used as metal ion (K+, Na+, Mg2+,Ca2+, Sr2+, Ba2+, Mn2+) sensors.

B. Functionalized MoS2 quantum dots as metal ion sensors

B3LYP with LanL2DZ and QZVP were used to study the capability of three functionalized (-COOH, -NH2, and -SH) MoS2 quantum dots to detect Co2+, Cd2+and Pb2+ ion. The binding energy between the ions and MoS2 clusters was investigated to
assess the sensing mechanism.

C. Theoretical study of Bn clusters in ionic liquids

The interactions between Boron clusters (Bn, n=6) and ionic liquid were investigated using the B3LYP/cc-pVTZ level of calculations. The likely structures and their IR and Raman spectra are obtained.

Table of Contents
Abstract
Table of Contents I

A. Aza-crown ether functionalized silicon quantum dots as metal ion sensors
1.Introduction 1
2.Theoretical Method 2
3.Result and Discussion 2
4.Conclusion 5
5.Reference 6
Table 1. Binding energy of crown ether and metal ions (C12H23O5N+Mg2+,C14H27O6N+Mn2+, C14H28O5N2+Ca2+) with B3LYP/ LanL2DZ 8
Table 2. Binding energy of crown ether and metal ions with B3LYP/cc-pVTZ 9
Figure 1. Bar chart plot of the fluorescence intensity of SiQDs/CE sensors with metal ions 10
Figure 2. Fluorescence response of (a) SiQDs/aza15C5, (b) SiQDs/aza18C6, and (c) SiQDs/diaza18C6 sensors with diverse metal ions. Concentration of each metal ion for (a) SiQDs/aza15C5 and (c) SiQDs/diaza18C6 system is 5 × 10–5 M; for (b) SiQDs/aza18C6 system is 5 × 10–6 M 10
Figure 3. Binding energy of C12H23O5N+Mg2+, C14H27O6N+Mn2+, C14H28O5N2+Ca2+ calculated by using the B3LYP method 11
Figure 4. Binding geometries presentation
12
Figure 5. Binding energies for C14H28O5N2 in the presence of diverse metal ions, calculated by using the B3LYP/LanL2DZ method 13
Figure 6. Bonding order of C14H28O5N2 with diverse metal ions 13
B. Functionalized MoS2 quantum dots as metal ion sensors
1. Introduction 15
2. Theoretical Method 15
3. Result and Discussion 16
4. Conclusion 22
5. Reference 23

Table 1.Binding energy of B3LYP/LanL2DZ for functionalized MoS2 with metal ions. Boltznmann average in kcal/mol 25
Table 2. Binding energy of B3LYP/QZVP for functionalized MoS2 with metal ions. Boltznmann average in kcal/mol 25
Table 3. Binding energy of B3LYP/LanL2DZ for functionalized MoS2 with metal ions 26
Table 4. Binding energy of B3LYP/QZVP for functionalized MoS2 with metal ions 29
Figure 1. Fluorescence spectra and intensity responses of (a, b) MoS2/COOH, (c, d) MoS2/NH2 and (e, f) MoS2/SH QDs with varying concentrations of Co2+, Cd2+ and Pb2+ ions, respectively. 32
Figure 2. Selectivity plot of (a) MoS2/COOH, (b) MoS2/NH2 and (c) MoS2/SH QDs in the presence of diverse metal ions
32
Figure 3.The B3LYP/LanL2DZ optimized geometry of MoS2+Functional Groups+Metals with binding bond lengths, point groups, charge distribution, and relative energy for each conformer 33
Figure 4. The B3LYP/QZVP optimized geometry of MoS2+Functional Groups+Metals with binding bond lengths, point groups, charge distribution, and relative energy for each conformer 45
C. Theoretical study of Bn clusters in ionic liquids
1. Introduction 57
2. Theoretical Method 58
3. Result 58
4. Reference 66
Table 1. Energy of harmonic and anharmonic frequency for ionic lquids 67
Table 2. Vibration mode description/Frequency/Anharmonic frequency/The ratio
verification of frequency to anharmonic frequency/IR/Raman spectrum 68
Table 3. XYZ coordination of molecules 100
Table 4. Energy of ionic liquid MAT-DCA with B6 cluster and the intensity of IR spectrum 108
Figure 1. The B3LYP/cc-pVTZ optimized geometry of each ionic liquid single particle and B6 cluster 109

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