On-surface structural and electronic properties of spontaneously formed Tb₂Pc₃ single molecule magnets

Abstract

The single molecule magnet (SMM) bis(phthalocyaninato)terbium(iii) (TbPc2) has received significant and increasing attention as an exemplar system for realizing molecule-based spin electronics. Attaining higher nuclearity via multi-decker TbPc systems has remained an outstanding challenge, as known examples of Tb2Pc3 systems are only those containing Pc rings with substituents (e.g. alkyl, alkoxyl). Here we report on the spontaneous formation of Tb2Pc3 species from TbPc2 precursors via sublimation in ultrahigh vacuum (UHV) onto an Ag(111) surface. The presence of Tb2Pc3 molecules on the surface are inspected using scanning probe microscopy with submolecular resolution supported by density functional theory (DFT) calculations and additional chemical analysis. We observe the selective presence of a Kondo resonance (30 K) in the Tb2Pc3 species, that we attribute to differences in the orientation of the internal molecular ligands. Formation of triple-decker complexes offers new possibilities to study and control magnetic interactions not accessible with standard TbPc2 molecules.

Magnetic properties of on-surface synthesized single-ion molecular magnets

“…11,31,32 The brighter features, imaged with an apparent height of 330 pm with respect to the underlying TbPc 2 molecules, are attributed to second layer TbPc 2 , 11,33,34 although formation of Tb 2 Pc 3 cannot be excluded. 35,36 Combining the information obtained from XPS and STM with that from XAS, XMCD, and XLD measurements, we conclude that the metalation reaction leads to the formation of TbPc 2 at RT.…”

Supramolecular structures of terbium(iii) porphyrin double-decker complexes on a single-walled carbon nanotube surface

“…51,52 Tb III -porphyrin double-decker complexes have an important feature: they are present in three forms, i.e., protonated, anionic, and radical forms (Schemes 1 and S1 †), and the electronic and magnetic properties of these forms can be switched as reversible interconversion between these forms is possible. 48,51 Although the supramolecular structures of lanthanidetetraazolic-based double-decker complexes on at nanocarbon surfaces, i.e., HOPG, have been extensively studied, 45,46,[53][54][55][56][57][58] the self-assembly of arrays on the curved carbon surfaces of SWNTs has not been reported yet, and it remains difficult to predict and understand the structures. However, some attempts have been made to reveal the chemistry needed to bridge the carbon nanotubes and double-decker domains.…”

In‐Situ Growth of Gadolinium Phthalocyaninato Sandwich Complexes on the Ag(111) Surface

“…On one hand, rare‐earth metal atoms promote octa‐coordinated sandwich‐type complexes that have been recently under the spotlight due to the large magnetic moment and anisotropy of the lanthanide elements, which results in the expression of single molecular magnetism, thus with great potential for organic field‐effect transistors, molecular magnets, chemical sensors and liquid crystals, and single‐molecule qubits. Steered by these functionalities, surface science studies have addressed the sublimation, self‐assembly, electronic and magnetic properties of such compounds when deposited on surfaces . On the other hand, surface‐confined multi‐decker species have revealed their capability to be used as axial molecular rotors, while simultaneously introducing columnar growth on surfaces, though limited to triple‐deckers …”