Towards Molecular Construction Platforms: Synthesis of a Metallotricyclic Spirane Based on Bis(2,2′:6′,2“‐Terpyridine)RuII Connectivity

The design and construction of the first multicomponent stepwise assembly of a <tpy‐Ru^II‐tpy>‐based (tpy=terpyridine), three‐dimensional, propeller‐shaped trismacrocycle, 8 , are reported. Key steps in the synthesis involve the preparation of a hexaterpyridinyl triptycene and its reaction with dimeric, 60°‐directional, bisterpyridine‐Ru^II building blocks. Characterization includes ESI‐ and ESI‐TWIM‐MS and TEM, along with 1D and 2D ¹H NMR spectroscopy.     

Synthesis and single-crystal X-ray characterization of 4,4"-functionalized 4'-(4-bromophenyl)-2,2':6',2"-terpyridines

To expand the utility of bis(terpyridine) metal connectivity, the selective symmetrical and unsymmetrical 4,4"-functionalization (-CN, -Me, -CO2Me) of 4'-(4-bromophenyl)-2,2':6',2"-terpyridines was achieved using the Kr?hnke synthesis. The final substituted 2,2':6',2"-terpyridines along with their corresponding intermediates, 4a-c, were recrystallized and characterized by 1H NMR and 13C NMR as well as X-ray crystallography; COSY correlations were also conducted to permit definitive proton assignment.     

Unbordered partial words

An unbordered word is a string over a finite alphabet such that none of its proper prefixes is one of its suffixes. In this paper, we extend the results on unbordered words to unbordered partial words. Partial words are strings that may have a number of “do not know” symbols. We extend a result of Ehrenfeucht and Silberger which states that if a word u can be written as a concatenation of nonempty prefixes of a word v, then u can be written as a unique concatenation of nonempty unbordered prefixes of v. We study the properties of the longest unbordered prefix of a partial word, investigate the relationship between the minimal weak period of a partial word and the maximal length of its unbordered factors, and also investigate some of the properties of an unbordered partial word and how they relate to its critical factorizations (if any).     

Metallo- and metalloido-micellane™derivatives: Incorporation of metals and nonmetals within unimolecular superstructures

Cascade polymeric architecture possessing internal functionalities was employed for the preparation of metallo- and nonmetallo-Micellane^TM derivatives. Specifically, tetra- and dodeca-o-carborane superclusters, were obtained via treatment of the corresponding 1^st and 2^nd generation tetra- and dodeca-alkyne, hydrocarbon cascade (Micellane^TM) derivatives with decaborane. Reaction of the same polyalkyne dendritic precursors with Co₂(CO)₈ afforded the benzyl protected, Cobaltomicellanes^TM possessing 12 and 24 internal metal centers, respectively. Control of amide-based, carboxylic acid terminated macromolecular hydrodynamic radius via changes in solution pH was demonstrated. Heterocascade syntheses employing amide and metalligand monomer connectivity were accomplished. The relation of interior cascade reactivity to macromolecular “void volume” was examined.