title: Self-selection in the self-assembly of isomeric supramolecular squares from unsymmetrical bis(4-pyridyl)acetylene ligands.
abstract: A new approach wherein steric interactions between substituents of unsymmetrical bis(4-pyridyl)acetylene ligands dictate the self-selection of single isomers of [4 + 4] self-assembled squares is presented. Each [4 + 4] self-assembly is characterized by multinuclear (31)P and (1)H NMR spectroscopies and electrospray ionization mass spectrometry. NMR spectroscopic studies are used to provide a means of evaluating the efficiency of bulky substituents at proximal or remote positions relative to the Pt-N bonding motif to direct self-selection. Molecular modeling using the MMFF force field is utilized to determine the relative energy of different isomers of each assembly, and modeling results reasonably explain the trend in self-selectivity with varying pyridyl substitution.
authors.affiliation: Department of Chemistry, University of Utah, 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112, USA.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhao
authors.forename: Brian H
authors.initials: BH
authors.lastname: Northrop
authors.forename: Yao-Rong
authors.initials: YR
authors.lastname: Zheng
authors.forename: Hai-Bo
authors.initials: HB
authors.lastname: Yang
authors.forename: Hyo Jin
authors.initials: HJ
authors.lastname: Lee
authors.forename: Young Min
authors.initials: YM
authors.lastname: Lee
authors.forename: Joo Yeon
authors.initials: JY
authors.lastname: Park
authors.forename: Ki-Whan
authors.initials: KW
authors.lastname: Chi
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Stang
mesh_terms: D000114:Acetylene / Q000031:analogs & derivatives*; D002413:Cations, Divalent; D007536:Isomerism; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D009584:Nitrogen / Q000737:chemistry; D010165:Palladium / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry; D010984:Platinum / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013816:Thermodynamics
chemical_list: D002413:Cations, Divalent; D008024:Ligands; D011725:Pyridines; D010758:Phosphorus; D010984:Platinum; D010165:Palladium; D009584:Nitrogen; D000114:Acetylene