Ruddlesden-Popper (RP) two-dimensional (2D) halide perovskite (HP), with attractive structural and optoelectronic properties, has shown great potential in optoelectrical devices. However, the relatively wide bandgap (E_g) and stability, which cause inferior efficiency, prevent its feasibility from further applications. To tackle these issues, for the first time, a novel fluorine-containing piperidinium spacer, (3-HCF₂CF₂CH₂OCH₂-PPH⁺), abbreviated as (4FH-PPH⁺), has been designed for the stable and efficient n = 1 2D HPs. Its fluorophobicity can significantly enhance the noncovalent interactions between cations and [PbI₆]^4- octahedra. The observed E_g of the fluorinated (4FH-PPH)₂PbI₄ perovskite is found to be 2.22 eV, which is the lowest value among all fluorinated perovskites reported so far. Interestingly, this fluorinated film-based 2D perovskite photodetector (PD) exhibits the outstanding responsivity of 502 mA W^-1, photodetectivity of 5.73 × 10¹⁰ cm Hz^1/2 W^-1, and impressive response/recovery time of 42/46 ms under 450 nm at 20 V. To the best of our knowledge, it is found for the first time that the 2D HP, with the fluorinated short-chained segment included into the organic spacer, shows remarkable stability for up to 49 days. These results strongly demonstrate the potential of the 2D fluorinated short-chained (4FH-PPH)₂PbI₄ HP with a low E_g as a promising candidate for next-generation optoelectronic devices.

The reaction of [PdCl₂(CH₃CN)₂] and bis-4,4′-(R_fCH₂OCH₂)-2,2′-bpy (1a–d), where R_f = n-C₁₁F₂₃ (a), n-C₁₀F₂₁ (b), n-C₉F₁₉ (c) and n-C₈F₁₇ (d), respectively, in the presence of dichloromethane (CH₂Cl₂) resulted in the synthesis of Pd complex, [PdCl₂[4,4′-bis-(R_fCH₂OCH₂)-2,2′-bpy] (2a–d). The Pd-catalyzed Stille arylations of vinyl tributyltin with aryl halides were selected to demonstrate the feasibility of recycling usage with 2a as the catalyst using NMP (N-methyl-2-pyrrolidone) as the solvent at 120–150 °C. Additionally, recycling and electronic effect studies of 2a–c were also carried out for Suzuki-Miyaura reaction of phenylboronic acid derivatives, 4-X-C₆H₄-B(OH)₂, (X = H or Ph) with aryl halide, 4-Y-C₆H₄-Z, (Y = CN, H or OCH₃; Z = I or Br) in dimethylformamide (DMF) at 135–150 °C. At the end of each cycle, the product mixtures were cooled to lower temperature (e.g., −10 °C), and then catalysts were recovered by decantation with Pd leaching less than 1%. The products were quantified by gas chromatography/mass spectrometry (GC/MS) analysis or by the isolated yield. The complex 2a-catalyzed Stille reaction of aryl iodides with vinyl tributyltin have good recycling results for a total of 8 times, with a high yield within short period of time (1–3 h). Similarly, 2a–c-catalyzed Suzuki-Miyaura reactions also have good recycling results. The electronic effect studies from substituents in both Stille and Suzuki-Miyaura coupling reactions showed that electron withdrawing groups speed up the reaction rate. To our knowledge, this is the first example of recoverable fluorous long-chained Pd-catalyzed Stille reactions under the thermomorphic mode.

Three fluorinated Zn complexes were synthesized and characterized. Their single crystals were grown and studied via X-ray and neutron diffraction methods. These fluorinated metal complexes tend to form two special noncovalent interactions: an intramolecular tetrel bond (TB) and an intramolecular blueshifting hydrogen bond (HB). In 4FH-ZnCl₂ [2,6-(HCF₂CF₂CH₂OCH₂)₂-py-ZnCl₂], an intramolecular TB induces significant elongation of a C-H bond in a methylene group, H1A-C1-H1B, to 1.108(2) Å, whereas the intramolecular C1-H1A···F2 blueshifting HB shortens the C1-H1A bond to 1.092(1) Å. Thus, C1-H1B is longer than C1-H1A by 16(2) mÅ such that either one of the C1-H1 stretches becomes a methine-like stretch with a peak appearing at 3020 or 2688 cm^-1. A peak corresponding to a lengthened sp³ C1-H1B bond is greatly redshifted and appears at 2688 cm^-1. When this 2688 cm^-1 peak is compared with its other methylene C-H peak (3020 cm^-1), their C-H vibrational stretches then differ by 332 cm^-1, which is likely the largest ever sp³ C-H bond stretching difference reported between two methylene C-H bonds. Additionally, two C-D bonds of deuterated 4FH-ZnCl₂, which has an intramolecular C···F TB that induces very different lengths of the two C-D bonds in a D-C-D group, become a local mode, as proven by Hooke's law. Thus, Badge's rule has been extended by using both neutron and spectroscopic studies.