The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Reaction of metallocenes with thiocyanogen》. Authors are Dove, M. F. A.; Sowerby, D. B..The article about the compound:Bromoferrocenecas:1273-73-0,SMILESS:Br[C-]12[Fe+2]3456789([C-]%10C6=C7C8=C9%10)C1=C3C4=C25).Synthetic Route of C10BrFe. Through the article, more information about this compound (cas:1273-73-0) is conveyed.
An Et2O solution of (SCN)2 was added slowly to a solution of ferrocene to give a dark brown, unidentified powder, which was not a simple thiocyanate, although ferricinium ions were present. Using CH2 Cl2 as solvent a darkcolored crystalline product [(C5H5)2Fe]2Fe(NCS)4 precipitated Ir spectra showed strong bands at 3095, 1414, 1010, and 850 cm.-1 characteristic of the ferricinium ion and at 2055, 480, and 262 cm.-1 due to the iron thiocyanate group. The electronic spectrum in a KBr disk showed a strong maximum at 20.3 kK with a shoulder at 15.8 kK. An analogous reaction between cobaltocene and (SCN)2 in Et2 O at room temperature yielded as the main product yellow crystalline cobalticinium thiocyanate as shown by elemental anal., ir and electronic spectra, conductivity, and proton N.M.R.
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Reference:
Thiazolidine – Wikipedia,
Thiazolidine – ScienceDirect.com