Molecular Structures of Ge(tpp)(OAc)2 and In(tpp)(OAc) and Their Implications:  Correlations between the 13C NMR Chemical Shift of the Acetato Ligand and Different Types of Carboxylate Coordination in M(por)(OAc)n {por = tpp (5,10,15,20-Tetraphenylporphyrinate), tmpp (5,10,15,20-Tetrakis(4-methoxyphenyl)porphyrinate), tpyp (5,10,15,20-Tetrakis(4-pyridyl)porphyrinate); M = Ga, In, Tl, Ge, Sn; n = 1, 2}

In this work, we determine the crystal structure of bis(acetato)(meso-tetraphenylporphyrinato)germanium(III), Ge(tpp)(OAc)2. Experimental results indicate that the germanium atom has an octahedral coordination geometry. The geometry around the germanium center of the Ge(tpp)(OAc)2 molecule has Ge−O(1) = 1.874(5) Å and an average Ge−N = 1.999 Å. The acetate groups are unidentately coordinated to the germanium(IV) atom. In the title compound, (acetato)(meso-tetraphenylporphyrinato)indium(III), In(tpp)(OAc), the coordination sphere of the In3+ ion is an approximately square-based pyramid in which the apical site is occupied by an asymmetric (chelating) bidentate OAc- group. The average In−N bond distance is 2.173(3) Å, and the In atom is displaced 0.762 Å from the porphyrin plane. The In−O(1) and In−O(2) distances are 2.322(4) and 2.215(4) Å, respectively. To develop the correlations between the 13C chemical shifts of the acetato ligand and types of carboxylate coordination, this work also thoroughly examines the 13C NMR data of the methyl and carbonyl carbons on 13 acetato porphyrinato metal complexes M(por)(OAc)n with n = 1, 2, por = tpp, tmpp (5,10,15,20-tetrakis(4-methoxyphenyl)porphyrinate), tpyp (5,10,15,20-tetrakis(4-pyridyl)porphyrinate), and M = Ga, In, Tl, Ge, Sn. According to these results, the 13C methyl and carbonyl chemical shifts of the acetato group at 24 °C are separately located at 20.5 ± 0.2 and 168.2 ± 1.7 ppm for the acetate, which is unidentately coordinated to the metal (i.e., the unidentate case) and at 18.0 ± 0.7 and 175.2 ± 1.6 ppm for the chelating bidentate case.