Title

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

Document Type

Article

Language

eng

Format of Original

14 p.

Publication Date

2014

Publisher

American Chemical Society

Source Publication

Inorganic Chemistry

Source ISSN

0020-1669

Abstract

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 14 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.

Comments

Inorganic Chemistry, Vol. 53, No. 22 (2014): 12108-12121. DOI.