Isomer Dependence in the Assembly and Lability of Silver(I) Trifluoromethanesulfonate Complexes of the Heteroditopic Ligands, 2‑, 3‑, and 4‑[Di(1H‑pyrazolyl)methyl]phenyl(di‑p‑tolyl)phosphine

Three isomers of a new heteroditopic ligand that contains a di­(1H-pyrazolyl)­methyl (−CHpz₂) moiety connected to a di­(p-tolyl)­phosphine group via a para-, meta-, or ortho-phenylene spacer (pL, mL, and oL, respectively) have been synthesized by using a palladium(0)-catalyzed coupling reaction between HP­(p-tolyl)₂ and the appropriate isomer of (IC₆H₄)­CHpz₂. The 1:1 complexes of silver­(I) trifluoromethanesulfonate, Ag­(OTf), were prepared to examine the nature of ligand coordination and the type of supramolecular isomer (monomeric, cyclic oligomeric, or polymeric) that would be obtained. The single crystal X-ray diffraction studies showed that [Ag­(pL)]­(OTf), 1, and [Ag­(mL)]­(OTf), 2, possessed cyclic dimeric dications, whereas [Ag­(oL)]­(OTf), 3, was a coordination polymer. The polymeric chain in 3 could be disrupted by reaction with triphenylphosphine, and the resulting complex, [Ag­(oL)­(PPh₃)]­(OTf), 4, possessed a monometallic cation where the ligand was bound to silver in a chelating κ²P,N- coordination mode. The solution structures of 1–4 were probed via a combination of IR, variable-temperature multinuclear (¹H, ¹³C, ³¹P) NMR spectroscopy, as well as by electron spray ionization (ESI)­(+) mass spectrometry. A related complex [Ag­(m-IC₆H₄CHpz₂)₂]­(OTf), 5, was also prepared, and its solid-state and solution spectroscopic properties were studied for comparison purposes. These studies suggest that the cyclic structures of 1 and 2 are likely preserved but are dynamic in solution at room temperature. Moreover, both 3 and 4 have dynamic solution structures where 3 is likely extensively dissociated in CH₃CN or acetone rather than being polymeric as in the solid state.