scholarly journals 1,3,5-[(tBu2MeSi)2Si]3C6H3: Isolable Si-centered Triradical with a High-spin Quartet Ground State

2015 ◽  
Vol 44 (1) ◽  
pp. 56-57 ◽  
Author(s):  
Takeshi Nozawa ◽  
Masaaki Ichinohe ◽  
Akira Sekiguchi
Keyword(s):  
1998 ◽  
Vol 53 (9) ◽  
pp. 755-765
Author(s):  
Christian Kollma ◽  
Sighart F. Fischer ◽  
Michael C. Böhm

AbstractThe origin of the displacement of the Fe atom in deoxymyoglobin with respect to the porphyrin plane in the high-spin state is examined by a qualitative molecular orbital (MO) analysis on the extended Hückel level. We find that attachment of a fifth ligand (imidazole in our model complex) to Fe(II)porphyrin favors the out-of-plane shift due to a strengthening of the bonding interaction between Fe and the nitrogen of the imidazole ligand. This results in a high-spin (5 = 2) ground state with Fe shifted out-of-plane for the five-coordinate complex instead of an intermediate spin ground state (5 = 1) with Fe lying in the plane for four-coordinate Fe(II)porphyrin. The relative energies of the different spin states as a function of the distance between Fe and the porphyrin plane are evaluated using an ROHF (restricted open shell Hartree-Fock) version of an INDO (intermediate neglect of differential overlap) method. We observe a level crossing between high-spin and intermediate spin states whereas the low-spin (5 = 0) state remains always higher in energy.


2019 ◽  
Vol 5 (5) ◽  
pp. eaav2336 ◽  
Author(s):  
A. E. London ◽  
H. Chen ◽  
M. A. Sabuj ◽  
J. Tropp ◽  
M. Saghayezhian ◽  
...  

Interest in high-spin organic materials is driven by opportunities to enable far-reaching fundamental science and develop technologies that integrate light element spin, magnetic, and quantum functionalities. Although extensively studied, the intrinsic instability of these materials complicates synthesis and precludes an understanding of how fundamental properties associated with the nature of the chemical bond and electron pairing in organic materials systems manifest in practical applications. Here, we demonstrate a conjugated polymer semiconductor, based on alternating cyclopentadithiophene and thiadiazoloquinoxaline units, that is a ground-state triplet in its neutral form. Electron paramagnetic resonance and magnetic susceptibility measurements are consistent with a high-to-low spin energy gap of 9.30 × 10−3 kcal mol−1. The strongly correlated electronic structure, very narrow bandgap, intramolecular ferromagnetic coupling, high electrical conductivity, solution processability, and robust stability open access to a broad variety of technologically relevant applications once thought of as beyond the current scope of organic semiconductors.


2020 ◽  
Author(s):  
Jie Su ◽  
Wei Fan ◽  
Pingo Mutombo ◽  
Xinnan Peng ◽  
Shaotang Song ◽  
...  

The ability to engineer geometrically well-defined antidots in large triangulene homologues allows for creating an entire family of triangulene quantum ring (TQR) structures with tunable high-spin ground state and magnetic ordering, crucial for next-generation molecular spintronic devices. Herein, we report the synthesis of an open-shell [7]triangulene quantum ring ([7]TQR) molecule on Au(111) through the surface-assisted cyclodehydrogenation of a rationally-designed kekulene derivative. Bond-resolved scanning tunneling microscopy (BR-STM) unambiguously imaged the molecular backbone of a single [7]TQR with a triangular zigzag edge topology, which can be viewed as [7]triangulene decorated with a coronene-like antidot in the molecular centre. Additionally, dI/dV mapping reveals that both inner and outer zigzag edges contribute to the edge-localized and spin-polarized electronic states of [7]TQR. Both experimental results and spin-polarized density functional theory calculations indicate that [7]TQR retains its open-shell septuple ground-state (� = 3) on Au(111). This work demonstrates a new route for the design of high-spin graphene quantum rings as the key components for future quantum devices.


2007 ◽  
Vol 129 (5) ◽  
pp. 1014-1015 ◽  
Author(s):  
Wen-Guo Wang ◽  
Ai-Ju Zhou ◽  
Wei-Xiong Zhang ◽  
Ming-Liang Tong ◽  
Xiao-Ming Chen ◽  
...  

Polyhedron ◽  
1996 ◽  
Vol 15 (5-6) ◽  
pp. 1041-1044 ◽  
Author(s):  
Zhang Shi-Wei ◽  
Wei Yong-Ge ◽  
Liu Qun ◽  
Shao Mei-Cheng ◽  
Zhou Wen-Sheng

2006 ◽  
Vol 118 (25) ◽  
pp. 4240-4243 ◽  
Author(s):  
Theocharis C. Stamatatos ◽  
Khalil A. Abboud ◽  
Wolfgang Wernsdorfer ◽  
George Christou

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