Conjugated, trans‐Spanning Ligands as Models for Multivalent p‐Phenyleneethynylenes

Abstract

A conjugated, pyridine-containing, phenylethynyl ligand that forms complexes with Ag I and Pd II has been developed. NMR titration studies with Pd II reveal a stoichiometric binding of the ligand to the metal atom, while similar studies with Ag I reveal a binding that is dynamic on the NMR timescale. Analysis of the NMR spectroscopic data by Job's plot analysis and non-linear curve fitting of a titration curve reveals a 1:1

Halogen-Bonded Supramolecular Parallelograms: From Self-Complementary Iodoalkyne Halogen-Bonded Dimers to 1:1 and 2:2 Iodoalkyne Halogen-Bonded Cocrystals

“…The halogen bond has an I−N separation of 2.773( 16) Å, 79% of the sum of the van der Waals radii, 28 with a C−I•••N angle of 175.70(6)°. The halogen-bonded dimer is essentially planar, with a slight twist along the axis of the alkyne and an interplanar angle of 13.56 (10)°between the two aromatic rings. The iodoalkyne moiety is slightly bent with the iodine atom 0.570 (4) Å above the plane of the benzene ring.…”

“…We initially focused on the formation of simple planar macrocyclic coordination complexes from suitable conjugated bipyridyls. The planar triangular coordination complexes formed with the trans -coordinating ligand 1,2- bis (2-pyridylethynyl) benzene served as initial inspiration. , We expanded the use of metal coordination to lock in coplanar macrocycle conformations with multiaryl systems forming rhomboidal ( A in Figure ), isosceles trapezoidal ( B in Figure ), and hexagonal π-conjugated coordination complexes …”

Molecular Turnstiles Featuring Bicyclic Rotators: Solution and Solid‐State Investigation of Steric and Electronic Concerns

“…As with 1‐Ag , [2b] tight interlayer packing in the crystals of arylethynyl complexes 2‐Ag and 3‐Ag likely prevent significant rotation of the arene rotator in the solid‐state. Recognizing this limitation, we set out to explore the viability of rotation in solution.…”

“…Schmittel and coworkers have exploited similar designs in the construction of nanoswitches [3] . Studies focused on the environment around the central arene have illustrated that rotation is influenced by the size of this group, as benzene or dimethoxybenzene ( C , R=−CH 3 ) centerpieces display notably different behavior than those with triptycyl groups ( D ) or benzenes with longer alkyl substituents ( C , R=−(CH 2 ) n CH 3 ) [2b–d] . In the current study, we set out to explore how the movement of a 2,1,3‐benzothiadiazole rotator ( B ) might impact its electronic and crystal‐packing behavior.…”

The Influence of Secondary Interactions on the [N−I−N]+ Halogen Bond

“…Ligand 9 was prepared following a published procedure, [19] while ligands 10 and 11 were achieved through modification of this route (Scheme 1 ). Hence, 1‐bromo‐2‐iodo‐4‐ tert ‐butyl‐benzene was converted to 7 through Sonogashira coupling with 3‐ ethynylpyridine.…”