463945-77-9Relevant academic research and scientific papers
Synthesis and NMR characterization of dinuclear Fe(II) organometallic complexes containing a non-equivalently bridging 5-aryl tetrazolate ligand
Palazzi, Antonio,Stagni, Stefano
, p. 2052 - 2061 (2007/10/03)
The synthetic routes to the formation of a wide range of dinuclear Fe(II) organometallic complexes of the general formula [Cp(CO)(L)Fe-N 4C-C6H4-CN-Fe(L)(CO)Cp][SO3CF 3], in which the 4-cyanophenyl-tetrazolate anion N 4C-C6H4-CN acts as bridging ligand, are described. 1H and 13C NMR characterization of the product complexes indicate the presence of a significant interannular conjugation effect involving the aromatic rings of the organic spacer, the extent of which can be chemically modified by addition of electrophiles such as CH3+ and H+. Furthermore, the reversibility of protonation reaction entails the opportunity of modulating the conjugative properties of the title compounds by a proton addition-elimination mechanism.
Interannular conjugation in new iron(II) 5-aryl tetrazolate complexes
Palazzi, Antonio,Stagni, Stefano,Bordoni, Silvia,Monari, Magda,Selva, Simona
, p. 3774 - 3781 (2008/10/08)
The synthesis of new Fe(II) 5-aryl tetrazolate complexes [CpFe(CO)(L)(N4C-C6H4-CN)] (4) [L = CO (4a); PPh3 (4b); P(OCH3)3 (4c); CN-2,6-Me2C6H3 (4d)] is described. The target compounds were obtained by addition of sodium azide to the parent 1,4-dicyanobenzene complexes [CpFe(CO)(L)(NC-C6H4-CN)][O3SCF3] (2a-d). X-ray molecular structure of 4c confirms the predictions based on NMR (1H, 13C) studies concerning the coplanarity between the tetrazole and phenyl rings, with consequent interannular conjugation effect. The multidentate nature of the tetrazole ring involves the presence of different sites that can undergo electrophilic attack; reaction of complexes 4a-c with methyl triflate afforded the methylated cationic complexes [CpFe(CO)(L)(CH3-N4C-C6H4-CN)][O 3SCF3], 5a-c, whose 1H and 13C NMR spectroscopy data suggested out-of-plane rotation of the phenyl ring and subsequent large reduction of interannular conjugation. Noteworthy, the same effect was obtained in a reversible way by addition of triflic acid to 4a, affording the protonated cationic complex [CpFe(CO)2(H-N4C-C6H4-CN)][O3 SCF3], 6a, which was easily converted into its neutral precursor by treatment with a base.
