Cai, Yue-Peng Su, Cheng-Yong Chen, Chun-Long Li, Yue-Ming Kang, Bei-Sheng S. C. Chan, Albert Kaim, Wolfgang Formation of Racemate and Mesocate Complexes from an Achiral Tripodal Ligand Containing Three Benzimidazole Groups Two complexes of the achiral tripodal ligand tris(1-benzimidazolylethyl)amine (nteb), viz., [Mn(nteb)<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>](ClO<sub>4</sub>)<sub>2</sub>·CH<sub>3</sub>OH, <b>1</b>, and [Ag<sub>2</sub>(nteb)<sub>2</sub>](CF<sub>3</sub>CO<sub>2</sub>)<sub>2</sub>·2H<sub>2</sub>O, <b>2</b>, have been synthesized and characterized by IR, <sup>1</sup>H NMR, and EPR spectroscopy (<b>1</b>), electrospray mass spectrometry, thermogravimetric analysis, and X-ray crystallography. Compound <b>1</b> contains chiral complex cations due to the same handedness of two nteb ligands (δδ or λλ) but crystallizes as a racemate, while <b>2</b> contains a dinuclear mesocate because of the opposite handedness (δλ) of two nteb ligands. Crystal data for <b>1</b>:  space group <i>P</i>1̄ with<i> a</i> = 9.471(4) Å, <i>b</i> = 16.884(7) Å, <i>c</i> = 19.906(8) Å, α = 77.930(7)°, β = 88.063(7)°, γ = 89.706(7)°, <i>V</i> = 3111(2) Å<sup>3</sup>, and <i>Z</i> = 2. Crystal data for <b>2</b>:  space group <i>P</i>1̄ with<i> a</i> = 9.3390(12) Å, <i>b</i> = 10.2168(13) Å, <i>c</i> = 16.382(2) Å, α = 75.721(3)°, β = 87.857(3)°, γ = 71.738(3)°, <i>V</i> = 1437.2(3) Å<sup>3</sup>, and <i>Z</i> = 1. In <b>1</b>, water serves as an auxiliary ligand, connected to one imidazole N atom of each nteb ligand through a H-bridge; the cationic complexes are associated intermolecularly via π···π interactions. In contrast to <b>1</b>, the coordination to the Ag<sup>+</sup> ions in <b>2</b> occurs in a heterochiral manner and produces a dinuclear mesocate. EPR;ligand;nteb;OH;imidazole N atom;1 H NMR;H 2 O;CH;CO;handednes;dinuclear mesocate;2. Crystal data;complex;IR;CF;Achiral Tripodal Ligand Containing;Ag 2002-11-28
    https://acs.figshare.com/articles/dataset/Formation_of_Racemate_and_Mesocate_Complexes_from_an_Achiral_Tripodal_Ligand_Containing_Three_Benzimidazole_Groups/3610041
10.1021/ic025934y.s001