Bogotá - Ciencias - Maestría en Ciencias - Química · 2025
N-Heterocyclic Carbenes as Coordinating Linkers for Platinum Nanoparticles and Spin-Crossover Fe(II) Coordination Polymers in Hybrid Nanomaterials with Potential Applications in Neuromorphic Learning
Inspirada en el funcionamiento de los sistemas nerviosos biológicos, la computación neuromórfica ofrece un enfoque prometedor para diseñar hardware más eficiente energéticamente y de alto rendimiento. En este contexto, los nanomateriales híbridos que integran nanopartículas metálicas con componentes moleculares capaces de imitar el comportamiento neuronal y sináptico se han convertido en candidatos atractivos. Esta tesis presenta la síntesis por autoensamblaje de materiales híbridos nanoestructurados compuestos por nanopartículas de platino ultrapequeñas (PtNPs, de 1,4 nm de tamaño, según se determinó mediante microscopía electrónica de transmisión) y polímeros de coordinación (PC) basados en Fe(II) que incorporan 4-amino-1,2,4-triazol (NH2-trz) o 4-amino-1,2,4-triazol y 1,3- dimetil-5- [(E)-(1,2,4-triazolimino)metil]-1H-imidazol-3-io tetrafluoroborato (compuesto 2) como ligandos. Los CP se caracterizaron mediante magnetometría de muestra vibrante (VSM), lo que confirmó su comportamiento de cruce de espín (SCO), y los materiales híbridos se examinaron minuciosamente mediante técnicas microscópicas, magnéticas y espectroscópicas. La conductividad eléctrica se analizó mediante microscopía de fuerza atómica conductiva (c-AFM). Cabe destacar que el orden de inclusión de los componentes influyó significativamente en la morfología y las propiedades electrónicas de los híbridos basados en NH2-trz, mientras que en los sistemas basados en el compuesto 2 solo se vieron afectadas las propiedades eléctricas. Estos resultados demuestran la naturaleza ajustable del comportamiento eléctrico en dichos híbridos, lo que ofrece información valiosa para el diseño de materiales multifuncionales para aplicaciones neuromórficas. (Texto tomado de la fuente)
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Contenido
- INTRODUCTIONp. 8
- Objectivesp. 15
- General objectivep. 15
- Specific objectivep. 15
- CHARACTERIZATION TECHNIQUESp. 15
- Magnetometry techniquesp. 15
- Vibrating sample magnetometry (VSM)p. 15
- Spectroscopic techniquesp. 16
- Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR)p. 16
- Raman spectroscopyp. 17
- Nuclear magnetic resonance (NMR)p. 17
- Spectrometric techniquesp. 19
- Mass Spectrometryp. 19
- Microscopic techniquesp. 19
- Transmission Electron Microscopy (TEM)p. 19
- Scanning Electron Microscopy (SEM)p. 20
- Conductive Atomic Force Microscopy (C-AFM)p. 21
- EXPERIMENTALp. 22
- General proceduresp. 22
- Synthesis of [Fe(NH2-trz)3](NO3)2 (CP1) 35p. 22
- Synthesis of [Fe(NH2-trz)3](OTs)2 (CP2) 77p. 23
- Ultrasmall Pt nanoparticles (PtNPs) synthesis 9p. 23
- Nanostructured hybrid material synthesis (HMs) 9p. 23
- Ligand synthesisp. 24
- 1,3-dimethyl-5-formyl-imidazolium tetrafluoroborate salt (Compound 1) 78p. 25
- (Compound 2)p. 25
- Synthesis of Fe(II) coordination polymer with compound 2 ligand (CP5)p. 25
- Synthesis of nanostructured hybrid material with compound 2 ligand (HMcs) 9p. 26
- RESULTSp. 26
- Spin crossover model compoundsp. 26
- Nanostructured hybrid materials (HMs)p. 33
- Ligandp. 39
- Nanostructured hybrid materials with compound 2 as ligandp. 46
- CONCLUSIONS AND PERSPECTIVESp. 50
- SUPPORTING INFORMATION (SI)p. 51
- REFERENCESp. 58
- Figure 1. Von Neumann´s architecture schemep. 8
- memory tasks and orange processing onesp. 9
- element (PE)p. 9
- Figure 4. Electronic distribution in the d orbitals of Fe(II) in a) high and b) low spin configurationsp. 11
- 1,2,4-triazole ligandp. 12
- Figure 6. Abrupt spin transition with hysteresis behaviourp. 13
- Figure 7. General scheme of a vibrating sample magnetometer (VSM)p. 16
- Figure 8. ATR-FTIR schemep. 17
- Figure 9. Schematic energy diagram of Rayleigh, Stokes, and anti-Stokes Raman scatteringp. 17
- Figure 10. General scheme of a transmission electron microscope (TEM)p. 20
- Figure 11. General scheme of a scanning electron microscope (SEM)p. 21
- Figure 12. General scheme of a conductive atomic force microscope c-AFMp. 22
- lattice relaxationp. 19
- Figure 14. General scheme of a mass spectrometerp. 19
- (blue) and [Fe(NH2-trz)3](OTs)2 (red)p. 27
- Fe(OTs)2●6H2O and NH2-trzp. 28
- (black), in can (CP3) (red), and with each component diluted 5 times in ACN (CP4)(green)p. 29
- (black), and with each component diluted 5 times in ACN (CP4) (green)p. 30
- (black), in can (CP3) (red), and with each component diluted 5 times in ACN (CP4)(green)p. 31
- (black), (CP3) in ACN (red), and (CP4) with each component diluted 5 times in ACN (green)p. 32
- determined from the TEM picturesp. 32
- synthesized in water (black), and with each component diluted 5 times in ACN (green)p. 33
- Figure 23. A) PtNPs synthesis scheme. B) Micrograph and size distribution of the PtNPsp. 34
- PtNPs + NH2-trz (green)p. 34
- material (HM1) (red)p. 35
- (HM1) (red)p. 36
- (green)p. 47
- (green)p. 47
- coordination polymer [Fe(NH2-trz)3](OTs)2 (CP2)p. 38
- material (HM4) mixing PtNPs + [Fe(NH2-trz)3](OTs)2 (yellow)p. 38
- Figure 32. Target ligandp. 39
- Figure 33. FTIR spectra of compound 1p. 40
- Figure 34. Proton NMR of the compound 1p. 41
- Figure 35. Correlations seen in a) COSY and b) HMBC experiments of compound 1p. 42
- Figure 36.1H (blue) and 13C (red) NMR signal asignation of compound 1p. 42
- Figure 37. FTIR spectra of compound 2p. 43
- Figure 38. Mass spectrum of compound 2p. 43
- Figure 39. 1NMR of compound 2p. 44
- Figure 40. Correlations seen in a) COSY b) 13C-1H, and c) 15N-1H HMBC experiments of compound 2p. 45
- Figure 41. 1H (blue) 13C (red), and 15N (green) NMR signal assignation of compound 2p. 46
- (blue) y PtNPs + compound 2 (green)p. 47
- +compound 2(1h) +Fe(OTs)2 (HMc3) (green), and PtNPs +[Fe(compound 2)3](OTs)2 (HMc4) (purple)p. 48
- +compound 2(1h) +Fe(OTs)2 (HMc3) (green), and PtNPs +[Fe(compound 2)3](OTs)2 (HMc4) (purple)p. 48
- (HMc4) (purple)p. 49
- coordination polymer prepared using compound 2 as ligandp. 50