1,3-Dialkyltriazenyl radicals: their electron spin resonance spectra. Electronic configuration, and addition to trialkyl phosphites

1982 ◽  
pp. 1549 ◽  
Author(s):  
John C. Brand ◽  
Brian P. Roberts
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Electronic Configuration ◽  
Spin Resonance ◽  
Trialkyl Phosphites

Electronic configuration and structure of paramagnetic iron dinitrosyl complexes

1992 ◽  
Vol 70 (7) ◽  
pp. 1917-1926 ◽  
Author(s):  
Traci R. Bryar ◽  
Donald R. Eaton
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Electronic Configuration ◽  
Donor Ligands ◽  
Planar Geometry ◽  
Tetrahedral Geometry ◽  
X Ray Crystallography ◽  
Spin Resonance ◽  
Frozen Solutions ◽  
Dinitrosyl Complexes

The electronic and geometric structures of paramagnetic iron dinitrosyl complexes have been investigated using electron spin resonance, infrared spectroscopy, and X-ray crystallography. It is concluded that these compounds are best described as 17 electron complexes with a d9 configuration rather than the d7 configuration assumed by most previous investigators. The anisotropy of the g values, determined from the electron spin resonance spectra of frozen solutions, varies considerably from complex to complex. The results are consistent with the supposition that all of the complexes have a distorted tetrahedral geometry, but the nature of the distortion changes as the ligands are varied. As a result of this variation there are changes in the nature of the spin-containing d orbital. Ligands containing hard, nonpolarizable donor atoms such as oxygen or fluorine produce a distortion towards a planar geometry, placing the odd electron in a predominantly [Formula: see text] orbital, while those containing softer donor atoms such as phosphorus or sulfur give complexes with a different type of distortion, leading to placement of the odd electron in a predominantly [Formula: see text] orbital. Nitrogen and halide donor ligands produce smaller distortions, leading to spin-containing molecular orbitals with contributions from a mixture of d orbitals. In accordance with this model, the crystal structure of [Fe(NO)2I2]− has been found to be only slightly distorted from regular tetrahedral coordination about the iron atom.

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