Dual phosphorescent emissions from conformers of iridium complex rotors.

The chiral iridium rotors Ir(ppy)(pyX)Cl (X = CC-SiR, R = alkyl) remarkably contain two distinct rotational conformers in the ground (S) and excited (T) states that can be detected by NMR and emission measurements respectively at variable temperatures. The observed phosphorescent emissions, vibronic (involving L = ppy) and broad (L = pyX), arise from different triplet ligand to metal charge transfers from the two rotational conformers at distinct MLCT excited states. Both conformers exist in these Ir(ppy)(pyX)Cl rotors due to the electron-withdrawing, conjugated substituent X.

Light Activated Release of Nitrile Ligands from -Ru(L)(PPh)(nitrile) Complexes.

A series of -RuL(PPh)(nitrile) and {RuL(PPh)}.-μ-(nitrile)-based complexes [where L = 2,2'-(3,4-diphenyl-pyrrole-2,5-diyl)dipyridine (dpp), di(pyridin-2-yl)isoindoline-1,3-diimine (bpi), or 4-(4-methoxyphenyl)-6-phenyl-2,2'-bipyridine (Pbpy); and nitrile = 1,4-dibenzontirile, 4-ethynylbenzonitrile, or dicyanamide] were synthesized and characterized, and their electrochemical and photochemical behaviors were investigated. Those complexes that contained a significant nitrile contribution to their MLLCT show a release of their nitrile ligand (when L = dpp or Pbpy and the nitrile ligand = 4-dibenzontirile, or 4-ethynylbenzonitrile) with dissociation constants up to 8.

Scrolling in Supramolecular Gels: A Designer's Guide.

Gelation by small molecules is a topic of enormous importance in catalysis, nanomaterials, drug delivery, and pharmaceutical crystallization. The mechanism by which gelators self-organize into a fibrous gel network is poorly understood. Herein, we describe the crystal structures and gelation properties of a library of bis(urea) compounds and show, via molecular dynamics simulations, how gelator aggregation progresses from a continuous pattern of supramolecular motifs to a homogeneous fiber network.

Connectivity-Dependent Conductance of 2,2'-Bipyridine-Based Metal Complexes.

The present work provides an insight into the effect of connectivity isomerization of metal-2,2'-bipyridine complexes. For that purpose, two new 2,2'-bipyridine (bpy) ligand systems, 4,4'-bis(4-(methylthio)phenyl)-2,2'-bipyridine (L) and 5,5'-bis(3,3-dimethyl-2,3-dihydrobenzothiophen-5-yl)-2,2'-bipyridine (L) were synthesized and coordinated to rhenium and manganese to obtain the corresponding complexes MnL(CO)Br, ReL(CO)Br, MnL(CO)Br, MoL(CO) and ReL(CO)Br. The experimental and theoretical results revealed that coordination to the para system, i.

Single-Molecule Conductance Behavior of Molecular Bundles.

Controlling the orientation of complex molecules in molecular junctions is crucial to their development into functional devices. To date, this has been achieved through the use of multipodal compounds (i.e.