Premium
Spontaneous Symmetry Breaking in the Formation of a Dinuclear Gadolinium Semiquinonato Complex: Synthesis, High‐Field EPR Studies, and Magnetic Properties
Author(s) -
Dei Andrea,
Gatteschi Dante,
Massa Carlo A.,
Pardi Luca A.,
Poussereau Sandrine,
Sorace Lorenzo
Publication year - 2000
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20001215)6:24<4580::aid-chem4580>3.0.co;2-b
Subject(s) - electron paramagnetic resonance , triclinic crystal system , gadolinium , crystallography , chemistry , excited state , zero field splitting , ground state , molecule , paramagnetism , crystal structure , nuclear magnetic resonance , condensed matter physics , electron , atomic physics , spin polarization , physics , organic chemistry , quantum mechanics
The synthesis and characterisation of an asymmetric dinuclear gadolinium( III ) semiquinonato complex, namely [Gd 2 (HBPz 3 ) 2 (dtbsq) 4 ]⋅CHCl 3 ( 1 ; HBPz 3 =hydrotris(pyrazolyl)borate, dtbsq=3,5‐di‐ tert ‐butyl‐ o ‐semiquinone), is reported. The crystal structure of 1 was determined at room temperature. It crystallises in the triclinic system P 1¯, with a =16.735(5) Å, b =17.705(5) Å, c =19.553(5) Å, α=99.680(5)°, β=109.960(5)°, γ=107.350(5)°, Z =2 and R =9.96. The structure of 1 consists of a dinuclear asymmetric unit in which the two gadolinium( III ) ions have coordination numbers of eight and nine. Three of the dioxolene molecules act as asymmetric bridging ligands, while the fourth molecule behaves as a bidentate ligand towards a single metal ion. The magnetic properties of 1 were investigated by means of susceptibility measurements and high‐field electron paramagnetic resonance (HF‐EPR) spectroscopy. They revealed an S =0 ground spin state with excited states of higher spin very close in energy and a small negative zero‐field splitting with a transverse anisotropy term for a S =7 state.