Dinuclear silver(I) complexes of N,N′-dibenzyl-4,13-diaza-18-crown-6-ether and dibenzo-24-crown-8-ether

Silver(I) 3-Aminomethylpyridine Complexes, Part 1: Effect of Ligand Ratio, π-Stacking, and Temperature with a Noninteracting Anion

“…The π-cloud of the pyridyl rings approach to within 3.03 Å (Ag−ring atom distances range from 3.031(9) to 4.176(9) Å) from the silvers, constructing a pseudo-double-metal sandwich arrangement. This is comparable to other known compounds with aromatic Ag−π interactions. − The stacking of the rings onto the sides of the metal centers effectively flattens out the ligands surrounding Ag1 into a near perfectly planar environment with respect to both the donor−metal geometry and the planes of the two coordinated pyridyl rings themselves. The rings vary from being coplanar by an angle of 7.3(4)°.…”

Reaction Chemistry of Silver(I) Trifluoromethanesulfonate Complexes of Nitrogen-Confused C-Scorpionates

“…Noteworthy is the fact that while the Ag−N bond of tosylpyrazolyl is nearly 0.1 Å longer than those of the other pyrazolyls (Table 1), the average Ag−N pz distance of 2.37 Å is firmly in the 2.3−2.4 Å range for other four-coordinate silver pyrazolyl complexes 42 43 [Ag(4-MeO-2,6pz* 2 -triazine)]OTf (2.292 Å), 44 and Ag[HC(pz 3tBu ) 3 ]}OTf (2.264 Å) 22a and is between the distances found in {Ag 2 (μ 2 -4,13-dibenzyl-4,13-diaza-18-crown-6)}(OTf) 2 [2.252(3) and 2.215(3) Å]. 45 The bond angles about silver in 1a give a τ δ parameter 46 of 0.61 near the border of a distorted sawhorse coordination geometry (τ δ = 0.63−0.45) and a distorted tetrahedral geometry (τ δ = ∼0.9−0.63).…”

“…The three pyrazolyls are also disparately twisted, as quantified by either the Ag–N–C–C meth torsion angle of the “confused” pyrazolyl (4°, here) or the Ag–N–N–C methine torsion angles of the “normal” pyrazolyls (6 and 18° for rings containing N11 and N21, respectively). The Ag–O distance [Ag–O3 2.224(2) Å] is among the shortest known for silver triflate complexes; it is shorter than relatives such as {Ag­[C 6 H 5 CH 2 OCH 2 Cpz 3 ]}­OTf (2.343 Å), [Ag­(4-MeO-2,6-pz* 2 -triazine)]­OTf (2.292 Å), and Ag­[HC­(pz 3tBu ) 3 ]}­OTf (2.264 Å) and is between the distances found in {Ag 2 (μ 2 -4,13-dibenzyl-4,13-diaza-18-crown-6)}­(OTf) 2 [2.252(3) and 2.215(3) Å] . The bond angles about silver in 1a give a τ δ parameter of 0.61 near the border of a distorted sawhorse coordination geometry (τ δ = 0.63–0.45) and a distorted tetrahedral geometry (τ δ = ∼0.9–0.63).…”

“…Instead, the coordination sphere about each silver center is completed by interaction with an oxygen atom of a triflate anion, Ag found for other complexes of silver triflate. (47) Figure 3. Views of the structure of 2a with hydrogen atoms removed for clarity: (left) asymmetric unit with atom labeling; (right) dimeric unit.…”

“…(51) That is, for complexes 1a, 1b, 3a, and 3b with pz* groups, the resonance for the acidic methine, that for H4 of the "confused" pyrazolyl ring, and that for one set of methyl pz* hydrogen atoms (closest to the methine) are unexpectedly shifted upfield from those in the spectrum of the free ligand. Given the different groups on the confused pyrazolyls and the propensity for triflate to be located near the methine positions of silver poly(pyrazolyl)methane complexes in the solid state, (47) it is likely that these hydrogen atoms are shielded by proximity to a nearby triflate ion. It is noted that the 1 H NMR spectrum of a concentrated mixture of NBu4OTf and each charge-neutral ligand is a simple sum of the individual spectra of the pure components.…”