On-Surface Synthesis of One-Dimensional Coordination Polymers with Tailored Magnetic Anisotropy.
Benjamin MalladaPiotr BłońskiRostislav LangerPavel JelínekMichal OtyepkaBruno de la TorrePublished in: ACS applied materials & interfaces (2021)
One-dimensional (1D) metalloporphyrin polymers can exhibit magnetism, depending on the central metal ion and the surrounding ligand field. The possibility of tailoring the magnetic signal in such nanostructures is highly desirable for potential spintronic devices. We present low-temperature (4.2 K) scanning tunneling microscopy and spectroscopy (LT-STM/STS) in combination with high-resolution atomic force microscopy (AFM) and a density functional theory (DFT) study of a two-step synthetic protocol to grow a robust Fe-porphyrin-based 1D polymer on-surface and to tune its magnetic properties. A thermally assisted Ullmann-like coupling reaction of Fe(III)diphenyl-bromine-porphyrin (2BrFeDPP-Cl) on Au(111) in ultra-high vacuum results in long (up to 50 nm) 1D metal-organic wires with regularly distributed magnetic and (electronically) independent porphyrins units, as confirmed by STM images. Thermally controlled C-H bond activation leads to conformational changes in the porphyrin units, which results in molecular planarization steered by 2D surface confinement, as confirmed by high-resolution AFM images. Spin-flip STS images in combination with DFT self-consistent spin-orbit coupling calculations of porphyrin units with different structural conformations reveal that the magnetic anisotropy of the triplet ground state of the central Fe ion units drops down substantially upon intramolecular rearrangements. These results point out to new opportunities for realizing and studying well-defined 1D organic magnets on surfaces and demonstrate the feasibility of tailoring their magnetic properties.
Keyphrases
- density functional theory
- high resolution
- molecular dynamics
- atomic force microscopy
- single molecule
- high speed
- molecularly imprinted
- photodynamic therapy
- metal organic framework
- electron transfer
- deep learning
- energy transfer
- molecular dynamics simulations
- room temperature
- convolutional neural network
- optical coherence tomography
- randomized controlled trial
- sensitive detection
- gene expression
- genome wide
- solid phase extraction
- neural network
- quantum dots
- cystic fibrosis
- water soluble