Bond elongation in the anion radical of coordinated tetrazine ligands: A crystallographic, spectroscopic and computational study of a reduced {Re(CO)(3)Cl} complex

作者：Parimal Kumar; Vyas Shubham; Chen Chun Hsing; Hadad Christopher M; Flood Amar H^*

来源：Inorganica Chimica Acta, 2011, 374(1): 620-626.

DOI：10.1016/j.ica.2011.05.005

• Radical anion
• Rhenium complex
• Tetrazine

The binuclear complex [(mu-Me(2)BPTZ)(Re(CO)(3)Cl)(2)] (1), where Me(2)BPTZ = 3,6-(5-methyl-pyridyl)-1,2,4,5-tetrazine, can be reduced by addition of bis(eta(5)-pentamethylcyclopentadienyl) iron(II) (decamethylferrocene, Fc*), to obtain a stable radical anion form 1(.). A single-crystal X-ray diffraction study of the radical anion (1(.))(Fc*(+)) was conducted and compared with a computational model of the same compound in the neutral and reduced states. As such, this work presents the first structural analysis of a reduced diimine ligand that is coordinated to {Re(CO)(3)Cl} moieties. Bond-length changes within the tetrazine ring system were consistent with previously reported examples of tetrazine radicals and with calculated structures that show clear elongation of the azo-type N=N bond. Consistently atomic charge calculations indicate that the extra electron in the radical anion resides largely at the tetrazine core. A negligible change in the Re-Cl bond length is observed and computed.

• 出版日期2011-8-1