An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Solid-state structures of sym -dibenzo-16-crown-5 ( 1 ) and five derivatives with one or two substituents on the three-carbon bridge have been determined. The derivatives with three sp 3 -hybridized carbons include sym -(propyl)dibenzo-16-crown-5 ( 4 ), sym -(pentafluorophenoxy)-dibenzo-16-crown-5 ( 5 ), and sym -[di(methoxymethyl)]dibenzo-16-crown-5 ( 6 ). Structures of two derivatives with sp 2 -hybridization of the central carbon ( 7 and 8 ) were also determined. Twisting of the three-carbon bridge causes one of the terminal methylene groups to be oriented within the polyether cavity.

New di-ionizable p-tert-butylcalix[4]arene-1,2-crown-4 ligands with elongated side arms in cone, partial-cone, and 1,2-alternate conformations of the calixarene scaffold are prepared and characterized. The acidic groups on the side arms include carboxylic acid and N-(X)sulfonyl carboxamide with X variation of –Me, –Ph, –C6H4–4-NO2, and –CF3. Solvent extractions of alkaline earth metal cations, Hg2+, and Pb2+ from aqueous solutions into chloroform are employed to probe the effects of these structural modifications on the divalent metal ion complexation behavior of the new ligands.

TributeI first got to know Professor Bartsch as a typical premed student, who selected his class based upon reputation.Every lecture started with a sequential alphabetic molecule of the day.(He called it the "Sesame Street Approach").At a time when technology would have aided a presentation of organic chemistry, Professor Bartsch continued hand drawing lecture notes, and often supplemented live during class.Never had I known a professor so in tune with the writing pace of the class, maintaining a good pace, but always watching the number of pens still writing before switching to the next slide.I still remember the introduction to cycloaddition, with the concomitant analysis of HOMO-LUMO orbitals.It was my lack of understanding that drew me to his office for help.What proceeded over the next 45 minutes was the discovery of my gap in knowledge, then a supply of 5 pages of hand drawn notes.Needless to say, I aced this part of the next exam.Dr. Bartsch changed me to a chemistry major over the course of that semester.What started as undergraduate research in his lab "to look good on my medical school application" morphed into a love of experimental science.From that point in time, I knew that chemistry was my calling and joined his group for graduate work, not as a master's student, but as student in the Ph.D. program pushed by his guidance.I am not certain of what Professor Bartsch saw in me in those early days, but his high standards encouraged me to be the best I could, never wanting to disappoint.His standards of communication pushed me to adapt my methods: 1) to supply an executive summary for review, then 2) update my experimental chemistry to make the best use of his time.This learned, and practiced skill has been invaluable in my professional career.

A series of large-ring polybenzocrown ethers is prepared by cesium-assisted cyclizations.Reactions of diphenols/bisphenols, dimesylates of oligoethylene glycols and cesium carbonate in MeCN produce the large-ring polybenzocrown ethers in high yields.To gain further insight into the structures of these compounds, solid-state structures of three large-ring crown ethers are obtained by X-ray diffraction.

Macrocyclization of crown ethers and their methods of preparation were explored. We present a robust, scalable method for the preparation of these macrocycles. Additionally, the effect of changing the structures of the precursors was explored to determine whether the ‘cut’ of bisphenol and dimesylate influenced the course of the reaction as measured by the yield. Further, using catechol derivatives, the method was used for the preparation of monobenzocrown ethers. Interestingly, for the preparation of monobenzocrown ethers, [2+2] adducts were discovered to be significantly contaminating the products. Dimesylates were chosen as the leaving group due to their ease or preparation and the ability to use the unpurified products with no apparent impact on the macrocyclization.

A standard Sonogashira coupling protocol has been applied for the preparation of a C3-symmetric phenylacetylene (2) and the corresponding linear phenylacetylene (3) incorporating terminal biphenyl substituents. The study of the mesomorphic properties of the target compounds, as well as mixtures of both, reveals that only the calamitic biphenylylacetylene 3 forms smectic liquid crystals. Upon investigating the electronic situation of both biphenylylacetylenes by spectroscopic methods and computational calculations, it becomes evident that 2 can be considered the trimeric analogue of 3 which however does not form liquid crystalline phases.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Discotic 1,3,5-alkynylbenzenes, highly polarizable extended π-systems, have been synthesized to form columnar liquid crystals in the bulk phase. The LC material forms the active layer in an optoelectronic device, displaying modest photoconductivity upon irradiation around the absorption maximum of the target compounds.