To Bond or Not to Bond: Metal–Metal Interaction in Heterobimetallic Rare-Earth Metal–Silver Complexes

The reaction of 2,4- t Bu2-6-(PPh2)­PhOH (HOArP) with silver­(I) triflate in a 3:1 molar ratio gave the mononuclear coinage metal complex (HOArP-κP)3AgIOTf (1). Treatment of HOArP with LnIII[N­(SiMe3)2]3 (Ln = La, Sm, Y, Yb) in a 3:1 molar ratio yielded the mononuclear rare-earth metal complexes LnIII(OArP-κ2 O,P)3 (2-Ln). The heterobimetallic rare-earth metal–silver complexes LnIII(OTf)­(μ-OArP-1κ1 O,2κ1 P)3AgI (3-Ln) were prepared from monometallic precursors by reactions of equimolar amounts of 1 with LnIII[N­(SiMe3)2]3 or 2-Ln with silver­(I) triflate, respectively. The compounds were characterized by NMR, ultraviolet–visible (UV–vis), and infrared (IR) spectroscopy, single-crystal X-ray diffraction, elemental analysis, and the effective magnetic moments of the paramagnetic complexes were determined via the Evans NMR method. Computational studies were conducted on 3-La and 3-Y.