Thallium complexes of tetraphenylporphyrin: Tl(tpp-N-O)(OAc) and cis-acetato-N-p-tert-butylbenzensulfonylimido-meso-tetraphenylporphyrinatothallium(III) Tl(N-p-NSO2C6H4tBu-tpp)(OAc)

The crystal structures of Tl(tpp-N-O)(OAc) (3) and acetato-N-p-tert-butylbenzensulfonylimido-meso-tetraphenylporphyrinatothallium(III) Tl(N-p-NSO2C6H4tBu-tpp)(OAc) (5) have been determined. The coordination sphere around Tl3+ is a distorted square-based pyramid in which the apical site is occupied by a bidentate chelating OAc− group for 3 and 5. The plane of three pyrrole nitrogen atoms (i.e., N(1), N(2) and N(3)), strongly bonded to Tl3+ in 3 and 5, is adopted as a reference plane, 3N. The porphyrin ring is severely distorted and the pyrrole ring N(4) bonding to the oxygen and NSO2C6H4tBu group makes a dihedral angle of 46.5° and 46.7° with the 3N plane for 3 and 5, respectively. In 3, Tl3+ and O(1) are located on the same side at 1.11 and 1.34 Å from its 3N plane, and in 5, Tl3+ and N(5) are also located on the same side at 1.15 and 1.30 Å from its 3N plane. The free energy of activation at the coalescence Tc for the intermolecular acetate exchange process of 3 and 5 in CD2Cl2 is found to be ΔG184‡=39.3 and ΔG208‡=44.1kJ/mol, respectively, through 1H NMR variable temperature measurements.An electronegative substituent, O(1), bonded to Tl in 3 causes a significant negative contribution up to 145 Hz for Δ3J(Tl–C, O) and 79 Hz for Δ2J(Tl–C, O) for OAc− in 3.

The crystal structures of Tl(tpp-N-O)(OAc) (3) was determined and the coordination sphere around Tl3+ in 3 is described as a distorted square-based pyramid in which the apical site is occupied by a bidentate chelating OAc− group.Figure optionsDownload as PowerPoint slide