This study investigates the novel spin behavior of vanadyl tetrakis(thiadiazole) porphyrazine (VOTTDPz) molecules adsorbed on Au(111). By replacing the inert phthalocyanine ligand with a reactive thiadiazole moiety, the molecule-molecule interaction is enhanced. Scanning tunneling spectroscopy (STS) reveals Kondo resonance features, showing site-dependent variations in shape and intensity, indicating complex spin-spin interactions. Two distinct molecular arrangements (phases I and II) are observed, with phase II exhibiting alternating VO-up and VO-down molecules leading to ferromagnetic (FM) and antiferromagnetic (AFM) couplings, influencing the Kondo resonance.
