Coordination-driven face-directed self-assembly of trigonal prisms. Face-based conformational chirality.

The coordination-driven self-assembly of four different trigonal prisms from 3 equiv of one of four different tetrapyridyl star connectors and 6 equiv of a platinum linker dication in nitromethane is presented. This face-directed approach affords high yields without template assistance. The prisms have been characterized by multinuclear and DOSY NMR and dual ESI-FT-ICR mass spectrometry.

Pyridine ligand rotation in self-assembled trigonal prisms. Evidence for intracage solvent vapor bubbles.

The rate of interconversion of the two inequivalent edges of the pyridine rings in the trigonal prism 3c, self-assembled from 3 equiv of the star connector, tetrakis[4-(4-pyridylethynyl)phenyl]cyclobutadienecyclopentadienylcobalt, and 6 equiv of a platinum linker, cis-(Me3P)2Pt(2+) 2 TfO(-), was determined by DNMR in nitromethane. It exhibits a highly unusual bilinear Eyring plot. In the low temperature regime, the activation enthalpy DeltaH(double dagger) is approximately 12 kcal/mol and an activation entropy DeltaS(double dagger) ranges from approximately -15 to approximately 0 cal/mol x K as a function of the nature and concentration of the anions present.

Toward self-assembled surface-mounted prismatic altitudinal rotors. A test case: trigonal and tetragonal prisms.

[structure: see text] A self-assembly path toward prismatic molecular rotors based on transversely reactive terminally metalated molecular rods and pyridine-terminated star connectors has been extended. The concept has been tested on the assembly of trigonal and tetragonal prisms from the biphenyl rod, [Ph2P(CH2)3PPh2]Pt+ -C6H4-C6H4-Pt+ [Ph2P(CH2)3PPh2], and the star-shaped connectors, 1,3,5-tris(4-ethynylpyridyl)benzene and [tetrakis(4-pyridyl)cyclobutadiene]cyclopentadienylcobalt, respectively. The prisms have been fully characterized by NMR and MS, including diffusion-ordered NMR and collision-induced dissociation, and their chiral structures optimized by molecular mechanics are discussed.

Toward self-assembled surface-mounted prismatic altitudinal rotors. A test case: molecular rectangle.

[structure: see text] A self-assembly path toward prismatic molecular rotors based on transversely reactive terminally metalated molecular rods and pyridine-terminated star connectors is outlined. The concept is tested on the assembly of the biphenyl rod [Ph(2)P(CH(2))(3)PPh(2)Pt(+)-C(6)H(4)-C(6)H(4)-Pt(+)[Ph(2)P(CH(2))(3)PPh(2)] and 4,4'-bipyridyl into a molecular rectangle, fully characterized by NMR and MS, including diffusion-ordered NMR and collision-induced dissociation MS.

Computational studies of aliphatic amine basicity.

Computational studies have been used to examine the structural and energetic effects of adding small numbers of water molecules to ammonia, methylamine, dimethylamine, and trimethylamine, and their respective ammoniums ions using the effective fragment potential method. Distinct structural effects with only a few fragment water molecules are revealed. The complexity of structures increases with the number of water fragments with the water fragments forming complex networks.