Rafizah Rahamathullah
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Preferred name
Rafizah Rahamathullah
Official Name
Rafizah, Rahamathullah
Alternative Name
Rahamathulla, Rafizah
Rahamathullah, R.
Main Affiliation
Scopus Author ID
55764144700
Researcher ID
DMZ-6313-2022

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  • Publication
    Exploring ethynyl-based chalcones as green semiconductor materials for optical limiting interests
    ( 2024)
    Wan M. Khairul
    ;
    Fatimah Hashim
    ;
    Rafizah Rahamathullah
    ;
    Mas Mohammed
    ;
    Siti Aisyah Razali
    ;
    Syed Ahmad Tajudin Tuan Johari
    ;
    Suha Azizan
  • Publication
    Computational and experimental investigation of antibacterial properties of Some Fluorinated Thioureas
    (Taylor & Francis, 2023)
    Anisatul Aqidah Tagiling
    ;
    Wan Mohd Khairul
    ;
    Rafizah Rahamathullah
    ;
    Vigneswari Sevakumaran
    ;
    Mas Mohammed
    ;
    Syaharil Saidin
    Herein, fluorinated thioureas with various substituents (F1-F3) were synthesized and characterized spectroscopically and analytically to investigate their properties as antibacterial agents. Prior to experimental studies, Density Functional Theory (DFT) modeling was performed at B3LYP/6-31G (d,p) to complement and offer comparative overview with the experimental findings. With regards to all theoretical analyses, the Frontier Molecular Orbital (FMO) demonstrated a desirable low HOMO-LUMO gap for all three designated derivatives, particularly F1 (1.60 eV), which is consistent with its GCRDs values, namely its high electronegativity and low hardness values that corresponds to low LUMO energy, suggesting higher bacterial activity. Agar diffusion assay was used for the preliminary screening of in-vitro antibacterial activity against pathogenic Gram-positive and Gram-negative bacteria. All three derivates successfully inhibit at least two bacterial strains (B. cereus, S. aureus), but none were able to penetrate into E. coli. The highest inhibition rate was exhibited by F3 at 33.33 ± 0.71% against S. aureus, whilst F1 only managed to gain 29.63 ± 0.00% of inhibition rate for the same bacterium. Meanwhile, the lowest penetration rate was recorded at 1.53 ± 0.35% by F2 against B. cereus.
  • Publication
    The experimental and DFT approaches on electronic, thermal and conductivity properties of non-linear optical bearing fused aromatic chalcones towards prospective OLEDs
    (Elsevier, 2025-01)
    Wan M. Khairul
    ;
    Anisatul Aqidah Tagiling
    ;
    Ain Qarina Muzaman
    ;
    Rafizah Rahamathullah
    ;
    Mas Mohammed
    ;
    Syaharil Saidin
    ;
    Suhana Arshad
    ;
    Ibrahim Abdul Razak
    ;
    Fazira Ilyana Abdul Razak
    ;
    Suhaila Sapari
    New derivatives of push-pull chalcone was successfully synthesized to demonstrate as NLO active on the impact of organic light emitting diode (OLED) materials. A total of three fused-aromatic chalcones (AA, AB, AC) with different substituents have been characterized through TGA, Z-scan analysis, 1H & 13C NMR, IR and UV–Vis. All the targeted compounds are nonlinear refraction (NLR) active with the range of χ(3) (∼ × 10–6 esu). AC reveals the highest value of first order hyperpolarizability (βtot) at 528.08 × 10–30 esu upon the substitution of strong electron acceptor. Theoretical investigation was performed by employing the theory of B3LYP/6–31 G (d,p) level via density functional theory (DFT) to optimize the geometries, molecular electrostatic potential (MEP) and frontier molecular orbitals (FMO). The predicted electronic properties of the molecule are supported by the experimental results, confirming the theoretical conclusions. The examination of its potential as emissive layer in OLED application was constructed on ITO substrate for electroluminescence behaviour evaluation under various direct current (DC) voltages supply. The preliminary outcomes reveal that these simple chalcone derivatives are capable of being utilised in any optoelectronic application.
  • Publication
    Deciphering ethynyl single crystal for NLO applications: Synergistic studies on the structural, Hirshfeld surface, photophysical and DFT assessment
    ( 2024)
    Wan M. Khairul
    ;
    Mas Mohammed
    ;
    Rafizah Rahamathullah
    ;
    Muhamad Fikri Zaini
    ;
    Suhana Arshad
    ;
    Abdul Razak Ibrahim
    ;
    Fazira Ilyana Abdul Razak
    ;
    Suhaila Sapari
      29  4