Syntheses and Crystal Structures of Bis‐Citrato, Bis‐Citramalato and Bis‐Malato Germanate(IV) Complexes

Abstract

Bis‐citrato 1a‐d, bis‐citramalato 2 and bis‐malato 3 germanate(IV) complexes were synthesized from germanium dioxide and citric acid, citramalic acid and malic acid respectively and were identified with IR, NMR and elementary analysis. Crystal 1a is triclinic, space group P1 with a = 7.919(2), b = 7.968(3), c = 9.605(3) Å, α = 94.25(3), β = 108.03(2), γ= 113.05(3)°, Z = 1, and the final residue, R(F), is 0.033 for 2583 reflections. Crystal 2 is monoclinic, space group C2 with a = 10.226(4), b = 12.802(4), c = 6.141(1) Å, β = 100.75(2)°, Z = 2, and the final residue, R(F), is 0.034 for 934 reflections. Both 1a and 2 have slightly distorted octahedral structures with citrate or citramalate ions as a tridentate ligand that forms five‐, six‐ and seven‐membered rings with the central metal. There is a two‐fold axis through the central atom of compound 2 instead of the inversion center of 1a. Same structures for these six complexes are indicated because the spectral patterns of the other four compounds, 1b‐d and 3, are similar to those of compounds 1a and 2.