Synthesis of ferrocene derivatives and application studies for biosensor materials

Soon after discovery of ferrocene in the early 1950s, it has attracted the attention of scientist worldwide in preparation of bridged ferrocenes or ferrocenophanes with bivalve-like structure (Moline et al., 2001)

PREPARATION OF LAYERED MATERIAL Zn/Al-LAYERED DOUBLE HYDROXIDE-FERULATE NANOCOMPOSITES

A new layered material-drug nanocomposite namely, Zn/Al-layered double hydroxide-ferulate (Zn/Al-LDH-FA) has been synthesized using the ion exchange method. PXRD pattern and elemental analysis showed that Zn/Al-LDH-FA nanocomposite yielded high crystalline and pure phase material with a basal spacing of 17.4 Å and anion loading of 35.9 % respectively. The FTIR spectra reveal the presence of FA in the interlayer of Zn/Al-LDH, while the thermal analysis shows that the Zn/Al-LDH has enhanced the thermal stability of FA in the interlayer compared to its pure form. Anionic FA intercalated into the interlayer of Zn/Al-LDH as vertical monolayer with the carboxylate groups pointing towards the Zn/Al-LDHs layers. The intercalation of FA into the interlayer of Zn/Al-LDH is also supported by morphology analysis, FESEM.Keywords: Synthesis, Intercalation, Layered Double Hydroxide, Ferulic AcidABSTRAKSebuah bahan-obat berlapis nanokomposit baru yaitu, Zn/Al-berlapis ganda hidroksida-ferulate (Zn/Al-LDH-FA) telah disintesis dengan menggunakan metode pertukaran ion. Pola PXRD dan analisis unsur menunjukkan bahwa Zn/Al-LDH-FA nanokomposit menghasilkan kristalinitas tinggi dan material fase murni dengan jarak basal dari 17,4 Å dan pemuatan anion 35,9%. Spektrum FTIR mengungkapkan adanya FA di lapisan Zn/Al-LDH, sedangkan analisis termal menunjukkan bahwa Zn/Al-LDH telah meningkatkan stabilitas termal FA di antar lapisan dibandingkan dengan bentuk murninya. Anionik FA diselingi ke dalam interlayer Zn/Al-LDH sebagai monolayer vertikal dengan gugus karboksilat menunjuk ke arah lapisan Zn/Al-LDHs. Interkalasi dari FA ke dalam interlayer Zn/Al-LDH juga didukung oleh analisis morfologi, FESEM.Kata kunci: Sintesis, interkalasi, hidroksida berlapis ganda, asam feruli

Preparation of zinc layered hydroxide–chloroacetate nanohybrid using direct reaction method

The intercalation of chloroacetic acid (CAA) into the interlayer gallery of zinc layered hydroxide has been achieved via a facile direct reaction method. The nanohybrid synthesised, zinc layered hydroxide-chloroacetate was characterised using Powder X-ray diffraction patterns (PXRD), which demonstrated the progressive evolution of the nanohybrid structure, as the CAA molarity were increased from 0.05 to 0.3 M. Sharp and symmetrical peaks of 0.3 M CAA were observed in the PXRD pattern. The emergence of intercalation peak, with basal spacing of 14.3 Å signifying the success intercalation of chloroacetate anions into the interlayer space of the host. The intercalation was also validated by FTIR spectroscopy and CHNS elemental analyser. The increased thermal stability of zinc layered hydroxide-chloroacetate nanohybrid was confirmed by thermogravimetric analysis

Synthesis, crystal structure, spectroscopic characterisation, and photophysical properties of iridium(iii) complex with pyridine-formimidamide ancillary

Two-dimensional MoS2 has been speculated to be the best material to replace graphene due to its peculiar structural-electronic properties. The MoS2 with size smaller than its exciton Bohr radius (ca. 1.61 nm) would favor multi exciton generation upon absorption of photon with sufficient energy, Ephoton ≫ Egap (1.89 eV); which would increase the efficiency of an excitonic solar cell greater than 60%. Despite promising properties of the MoS2, however an excitonic solar cell with high efficiency is yet to be exhibited. In this work, the MoS2 thin films were fabricated using vacuum thermal evaporation technique and characterized. Four objectives have been outlined i.e., to study the effect of heating rate (steady, and rapid) on the (i) morphology, (ii) size, (iii) optoelectronic and (iv) crystal properties of the fabricated thin films. The MoS2 precursor was heated at the rate 2.027 A/s (steady), and 18.75 A/s (rapid), 1.5 × 10−3 Torr, 1.48 A, and 4.58 V. The deposited films later were characterized using Field Emission Scanning Electron Microscope with Energy Dispersive X-ray attachment, photoluminescence spectrometer, UV–vis-NIR spectrometer, and X-ray Diffractometer. The fabricated thin films exhibited nanosphere morphology with different size distributions i.e., wide (steady heating), and narrow (rapid heating). Two hypotheses were made based on the optoelectronic properties i.e., the basic building block of the MoS2 thin film fabricated under steady heating is (i) experiencing stronger quantum confinement effect, and (ii) dominated by nanocrystals which are smaller than that of the rapid heating. Similar energy loss could be expected in both MoS2 thin films i.e., ca. 0.15 to 0.17 eV, indicating the existence of shallow trap states. The MoS2 thin films were dominated by (0 0 2), (0 0 4), and (1 0 6) crystal planes. Therefore, the vacuum thermal evaporation technique would offer materials with unique size, crystal arrangement, and optoelectronic properties upon change of heating rate

Synthesis and Application of Zinc Layered Hydroxide: A Short Review

Zinc Layered hydroxide (ZLH) is a layered material easily synthesized with a structure identical to brucite-like material. Due to the exchangeable anions in the interlayer compensating for the positive charge of a brucite-type layer, ZLH provides a wide application in many fields. This review focuses on the properties and method of synthesis of ZLH by giving an overview of intercalated guest anion in the interlayer of ZLH. The further discussion involved the application of intercalated guest anion in zinc layered hydroxide layer and its properties as a sensitizer, controlled release biomedical, and agriculture to provide the scientific community for research and development by giving current findings. This brief review also presents the success of anion intercalation for controlled release along with the kinetic model involved, which increases the bioavailability and effectiveness of the nanocomposite on its target. It shows the development of research on ZLH nanocomposites toward the sustainability of human life and the environment. This study implies that it is a source of knowledge for researchers about zinc-layered hydroxide materials involving synthesis methods and their application to produce more beneficial nanomaterials

Sensitisation of Eu(III)- and Tb(III)- based luminescence by Ir(III) units in Ir/lanthanide dyads: evidence for parallel energy-transfer and electron-transfer based mechanisms

A series of blue-luminescent Ir(III) complexes with a pendant binding site for lanthanide(III) ions has been synthesized and used to prepare Ir(III)/Ln(III) dyads (Ln = Eu, Tb, Gd). Photophysical studies were used to establish mechanisms of Ir→Ln (Ln = Tb, Eu) energy-transfer. In the Ir/Gd dyads, where direct Ir→Gd energy-transfer is not possible, significant quenching of Ir-based luminescence nonetheless occurred; this can be ascribed to photoinduced electron-transfer from the photo-excited Ir unit (*Ir, 3MLCT/3LC excited state) to the pendant pyrazolyl-pyridine site which becomes a good electron-acceptor when coordinated to an electropositive Gd(III) centre. This electron transfer quenches the Ir-based luminescence, leading to formation of a charge-separated {Ir4+}•—(pyrazolyl-pyridine)•− state, which is short-lived possibly due to fast back electron-transfer (<20 ns). In the Ir/Tb and Ir/Eu dyads this electron-transfer pathway is again operative and leads to sensitisation of Eu-based and Tb-based emission using the energy liberated from the back electron-transfer process. In addition direct Dexter-type Ir→Ln (Ln = Tb, Eu) energytransfer occurs on a similar timescale, meaning that there are two parallel mechanisms by which excitation energy can be transferred from *Ir to the Eu/Tb centre. Time-resolved luminescence measurements on the sensitised Eu-based emission showed both fast and slow rise-time components, associated with the PET-based and Dexter-based energy-transfer mechanisms respectively. In the Ir/Tb dyads, the Ir→Tb energy-transfer is only just thermodynamically favourable, leading to rapid Tb→Ir thermally-activated back energy-transfer and non-radiative deactivation to an extent that depends on the precise energy gap between the *Ir and Tb-based 5D4 states. Thus, the sensitised Tb(III)-based emission is weak and unusually short-lived due to back energy transfer, but nonetheless represents rare examples of Tb(III) sensitisation by a energy donor that could be excited using visible light as opposed to the usually required UV excitation

Preparation of zinc layered hydroxide–chloroacetate nanohybrid using direct reaction method

The intercalation of chloroacetic acid (CAA) into the interlayer gallery of zinc layered hydroxide has been achieved via a facile direct reaction method. The nanohybrid synthesised, zinc layered hydroxide-chloroacetate was characterised using Powder X-ray diffraction patterns (PXRD), which demonstrated the progressive evolution of the nanohybrid structure, as the CAA molarity were increased from 0.05 to 0.3 M. Sharp and symmetrical peaks of 0.3 M CAA were observed in the PXRD pattern. The emergence of intercalation peak, with basal spacing of 14.3 Å signifying the success intercalation of chloroacetate anions into the interlayer space of the host. The intercalation was also validated by FTIR spectroscopy and CHNS elemental analyser. The increased thermal stability of zinc layered hydroxide-chloroacetate nanohybrid was confirmed by thermogravimetric analysis

Synthesis and characterization of mesoporous zinc layered hydroxide-isoprocarb nanocomposite

The ion exchange method was used to intercalate a poor water-soluble insecticide, isoprocarb into zinc layered hydroxide (ZLH). PXRD analysis indicated the successful intercalation with good crystallinity for the resulting nanocomposite, with a basal spacing of 33.1 Å. FTIR analyses showing the resemblance of an absorption peak of the nanocomposite with the host and the guest anion. The thermal analysis confirmed that the nanocomposite had better thermal stability compared to the pristine isoprocarb. The nanocomposite also characterized by elemental and surface morphology analysis. The surface analyses of the host and nanocomposite showed mesoporous-type material characteristics. On the whole, the intercalation process decreased the pore size of the nanocomposite compared to the pristine host, layered zinc layered hydroxide-sodium dodecyl sulphate (ZLH-SDS). The obtained material is believed has a great potential as an environmentally friendly insecticide. Keywords: Intercalation, Characterization, Zinc layered hydroxide, Isoprocarb, Mesoporou