Nanostructures through self‐assembly: Suitably designed planar cyclic peptides like 1 form cylindrical dimers in nonpolar organic solvents. These ensembles are good models for the fundamental description of parallel and antiparallel β‐sheet structures as well as for the design of novel peptide nanostructures. The analysis of the structural and thermodynamic aspects of the dimerization process showed that the hydrogen bonds between the peptide backbones are crucial factors for the stability of the ensembles and selective formation of β‐sheet arrangements. Furthermore 1 crystallizes to form a novel, porous, solid‐state object with an amphiphilic tubular superlattice, which may have potential utility in the molecular inclusion of hydrophilic and hydrophobic substrates.

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Low‐temperature (<0°C) applications of Li‐ion batteries have prompted the search for improved, high‐conductivity electrolytes. Because the performance of the carbonaceous anode is highly sensitive to changes in electrolyte composition, we focused our efforts on this electrode. Electrolytes containing LiAsF6,LiPF6,normalLiNfalse(SO2CF3)2 [lithium bis(trifluoromethanesulfonyl)imide], or LiIm, and normalLiCfalse(SO2CF3)3 [lithium tris(trifluoromethanesulfonyl)methide], or LiMe, in methyl formate (MF)‐ethylene carbonate (EC) solvent mixtures were tested in lithium‐graphite half‐cells. The graphite electrodes could be cycled at ambient temperature with high reversible capacity. The best supporting electrolyte was found to be LiAsF6 , and the presence of a high concentration of ethylene carbonate and up to 300 ppm H2O in the solution considerably increased the reversible capacity upon cycling. The conductivity values of a binary solvent mixture of methyl formate and ethylene carbonate containing LiAsF6 or LiMe were measured between −40°C and room temperature. Graphite electrodes cycled at −2°C in these electrolytes obtained reasonable reversible capacity, approaching 50%.

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Experimental procedures for the preparation of two classes of derivatives of the cinchona alkaloids dihydroquinine and dihydroquinidine are described. Ligands (DHQ)2-PHAL, la, and (DHQDh: PHAL, 2a, are conveniently synthesized in good yield by the reaction of the corresponding alkaloid with 1,4-dichlorophthalazine in the presence of K2CO3 and KOH in refluxing toluene. Derivatives

The total synthesis of (-)-Tax01 has been achieved. Functional group manipulation of diol 2 provided the ABC ring system with the correct C9-keto, C10-acetyloxy functionality. Careful optimization allowed the oxidation of the C5-C6 alkene in 4 at C5 via a hydroboration reaction. Functional group manipulation of this product, 29, provided, through two routes, the oxetane D ring as 36. Following the method developed by degradative studies provided the natural enantiomer of Taxol (1).

The synthesis, single-crystal X-ray structures, and magnetochemical properties are reported for two new hexanuclear ferric complexes, [Fe6(M3-0)2(M2-OH)2(M2-02CCH3)io(C7HnN20)2]4CH2Cl2 (9-4CH2Cl2) and [Fee0*3-0)2(C6H6N0)8C14](C104)24MeCN (KMMeCN). The ligand C7HnN20-is the anion of 2-(7V-methylimidazol-2yl)-2-hydroxypropane and C6H6NO™ is the anion of 2-pyrididylcarbinol. The reaction of [Fe3G(OAc)6(py)3] C104 in acetonitrile with 2-(iV-methylimidazol-2-yl)-2-hydroxypropane gives a brown oil which can be crystallized via vapor diffusion of CH2C12 with hexanes to give complex 94CH2Cl2• The reaction of FeCl3-6H20 and 2-pyridylcarbinol in acetonitrile gives, upon addition of NaC104, complex KMMeCN. Complex 9 has six high-spin Fem ions and can be viewed as two trinuclear /i3-oxo-bridged subunits bridged by two M2-hydroxo and M2-acetato ligands. Complex 10 can also be viewed as two asymmetric triangular ß3-µ3-subunits bridged together by alkoxo groups. However, in complex 9 there is a planar array of six Fem ions, whereas in complex 10 the six high-spin Fem ions are arranged in a chair conformation. Variable temperature DC magnetic susceptibility data measured at 10.0 kG are presented for both complexes. For complex 9-3/2CH2Cl2 Meff/molecule was found to be 9.10 mb at 300.0 K, and as the temperature is decreased, this value increases to a maximum of 10.55 mb at 30.0 K, whereupon there is a decrease to 9.77 mb at 5.00 K. Complex 10-MeCN in a 10.0 kG field gives MCff/molecule = 8.82 mb at 320.0 K. In contrast to 9, the Mefr/ molecule for complex 10-MeCN decreases with decreasing temperature to 6.08 mb at 5.01 K. Least-squares Fitting of the reduced magnetization (M/ µb) versus H/T data for paraffin-embedded complex 9-3/2CH2Cl2 in the range of 5.00-50.0 kG external field and 2.0-30.0 K clearly shows that complex 9 has a well isolated Sj = 5 ground state. Reduced magnetization versus H/T data are also presented for a parafilm-embedded sample of complex 10-MeCN in external fields of 0.50-50 kG at temperatures of 2-30 K. Fitting the high-Field data suggests the presence of a ST = 3 ground state. However, the fit of the low-field data is not good for just an isolated St = 3 ground state. Theoretical calculations were carried out for two of the known Fem6 complexes. The energies of all of the 4332 different spin states of a Fenl6 complex were calculated, taking into account the pairwise magnetic exchange interactions within µ3-bridged Fem3 triangular subunits (parameters J\, /2, and /3) and the interaction (J4) between iron ions in two Fe30 triangular subunits. The 20-320 K data measured at 10.0 kG for complex 5 (isostructural to 9) could be Fit well with a theoretical calculation where J¡ = -5.6(5) cm-1, /2 = /3 = -38(1) cm-1, and J4 = -7.5(1) cm-1. In agreement with experimental data, a well-isolated St = 5 ground state is predicted. The theoretical fit of 20-320 K data for complex 10-MeCN in a 10.0 kG Field gives fitting parameters of J¡ = 72 = -18(1) cm-1, /j = -52(2) cm-1, and J4 = -3(2) cm-1.Even though all pairwise exc...

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