Tetra-Armed Cyclen Bearing Two Benzo-15-Crown‑5 Ethers in the Side Arms IkedaMari MatsumotoMikako KuwaharaShunsuke HabataYoichi 2014 A tetra-armed cyclen bearing two benzo-15-crown-5 ethers in the side arms (<b>1</b>) is reported. When 1 equiv of Ag<sup>+</sup> is added to <b>1</b>, the aromatic side arms cover the Ag<sup>+</sup> incorporated in the cyclen. Upon the addition of more than 1 equiv of Ag<sup>+</sup> to <b>1</b>, the cyclen moiety binds Ag<sup>+</sup> first, before the crown ether in the side arms subsequently binds Ag<sup>+</sup>. The log <i>K</i><sub>11</sub>, log <i>K</i><sub>12</sub>, and log <i>K</i><sub>13</sub> values for the 1:1, 1:2, and 1:3 (= <b>1</b>/Ag<sup>+</sup>) complexes were estimated to be 9.4, 5.8, and 4.0, respectively. We found that the tetra-armed cyclen possessing crown ethers in the side arms behaves like an argentivorous molecule even though the crown ether arms bind metal cations.