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The correlations between stimulated Brillouin scattering (SBS) characteristics of perfluoro-compound (PFC) and perfluoropolyether (PFPE) and their chemical structure are analyzed in detail and a series of new PFC and PFPE are reported. In the Nd:YAG laser system, the absorption coefficient, optical breakdown threshold (OBT), SBS threshold, and Brillouin frequency shift of new media such as FC-87, FC-43, HT-55, and DET are measured. Parameters such as gain coefficient, Brillouin linewidth, and phonon lifetime are calculated. The results demonstrate their good SBS properties: the absorption coefficients are below [10.sup.-3][cm.sup.-1] and OBTs are above 100 GW/[cm.sup.2]. These media also exhibit a series of unique physicochemical properties, i.e., high heat-resistance, high oxidation stability, good chemical inertness, and insulation properties. The discovery of new media not only diversifies SBS medium, but also improves the performance of the SBS system, thereby laying a good foundation for the application of a SBS phase conjugation mirror in a high-power laser system. OCIS codes: 190.0190, 290.5830, 190.2640.

Many criteria are used to focus the design and search for the variations on minor groove binding motifs. The findings of the study support the concept that diamidines with varied structure and functional groups are able to escape the classical constraints on minor groove complexes.

Several 1,3,5-tricarbonyl derivatives were prepared by reaction of 1,3-bisS9ilyl enol ethers) with acid chlorides under mild conditions. 1,3-bis(silyl enol ethers) were derived form methyl acetoacetate and the use of 1,3-diketone-derived 1,3-bis(silyl enol ethers) resulted in functionalzation of the central carbon atom of the bis (silyl enol ethers).

The binding energies are calculated for hydrogen-bonded complexes of six cyclic ethers having four to six C and O ring atoms, with five hydrogen-bond donor molecules mimicking amino acid side chains, with and without counterpoise correction throughout the structure optimizations. This study is the first step toward the development of an affordable computational level for estimating the binding energies of natural product, fused ring ether systems to the human estrogen receptor.

Studies related to some of the possibilities of side chain and skeletal variation and the diversity that could be achieved by the combination of two types of bifunctional building blocks like steroidal dicarboxylic acids and the biaryl ether diisocyanide are presented. The findings reveal that skeletal diversity is based on the variation of highly bifunctional building blocks, which allow the parallel formation of macrocyclic cavities that are highly diverse in shape and size and thus perspectively in function.

Water-ice has been characterized as a stationary phase for liquid chromatography. Solutes having two or more polar groups are retained on this stationary phase with THF/hexane as the mobile phase, suggesting that multipoint interactions are required for measurable solute retention. Chromatographic separation of phenols or crown ethers on water-ice is possible. The ice surface is expected to provide two different adsorption sites coming from the OH and O dangling bonds. Although the solute partition into the quasiliquid layer is also considered, the dependence of the retention times on the THF concentration implies that the interaction of solutes with the water-ice surface rather than the partition into the quasiliquid layer is responsible for solute retention. A retention model suggests that the number of adsorption sites for a crown ether depends on its ring size, whereas two sites are involved for the retention of phenols having two hydroxyl groups. Although hydroxyl groups can act as both a hydrogen bond donor and an acceptor, the interaction with the ice OH sites, which are exposed to the surroundings in comparison with the ice O sites, is more important. However, when an acyclic polyether is added to the mobile phase, its adsorption onto the water ice surface allows the creation of the O sites that phenols can approach without steric hindrance. In the presence of the polyethers adsorbed on the ice surface, the retention of phenols is enhanced, whereas crown ethers become less retained due to the competitive adsorption of the polyethers.

A comparative geometric study base on the density functional theory (DFT) was conducted to study the effect of doping and interface formation on poly-phenylene vinylene (Ppv) ether copolymer in powder as well as film states. The analysis presented the energy position of the lowest occupied molecular orbital with respect to the electrode Fermi level in addition to the energetic diagram near the interface.

A computational approach to the deliberate design of improved host architectures that involves the use of computer-aided design software by application to cation hosts containing multiple aliphatic ether oxygen binding sites is presented. De nova molecule building software, HostDesigner, is interfaced with molecular mechanics software, providing a tool for generating and screening millions of potential bidentate building block structures.

All conformers of several single-chain alcohols, thiols, ethers, and sulfides are investigated. The two-dimensional approximation scheme is an effective tool for adequately describing the relative energies of all possible conformers at a minimal computational cost.

Simple model compounds 1-methoxy-2-ethenol and 1-methoxypropane to mimic the effect of binding to sugars on the vertical excitation energies of purine and pyrimidine base is presented to substitute the ribose and deoxyribose molecules of RNA and DNA nucleosides. It is found that binding the ethers causes qualitative and quantitative changes in the low-lying excited states.

The syntheses and structure of unsaturated selenacrown ethers are reported with the formation and inclusion behavior of the silver complexes. The cyclic voltammograms indicated that the large unsaturated selenacrown ethers are oxidized more easily than the small ones.

A structural and photophysical study of lanthanide complexes with the di-deprotonated form of the bibracchial lariat ether N,N'-bis(2-salicylaladiminobenzyl)-4, 10-diaza-12-crown-4 (L(sup 3)) (Ln-Ho (III)-Lu(III)) is reported. The findings reveal that both sidearms of L(super 3) are on the same side of the crown moiety, resulting in a syn conformation.

A novel ruthenium-catalyzed tandem ring-closing metathesis (RCM) double-bond isomerization reaction is described. The utility of this method for the efficient syntheses of five-, six-, and seven-membered cyclic enol ethers is demonstrated.

The efficient total syntheses of gambierol and 16-epi-gambierol is executed in a study on the basis of a convergent strategy. The study demonstrates the power of the methodology, involving the imtramolecular allylation of alpha-chloroacetoxy ether and subsequent ring-closing metathesis, as a practical tool for constructing polycyclic ether frameworks.

The gauche/trans conformational equilibria of 2,2'-bi-1,3'-dioxanyl (1), 2,2'-dimethyl-2,2'-bi-1,3'-dioxanyl (2), 2,2'-bi-1,3'dithianyl (3), and 2,2'-dimethyl-2,2'-bi1,3'-dithianyl (4) dissolved in carbon tetrachloride and benzene are investigated through dipole moment determination. The differences seen in conformational preference of 2,2'-bi-1,3'dithianyl in CCl4 and benzene is explained in terms of the solvation effect of benzene.

The opening of tartrate acetals with dialkylboron bromide is studied. The mechanism for the induction of diastereoselectivity that is derived from the opening is downstream for the ring fission.

Formal steric enthalpy (FSE) is the difference between the energy of a target molecule and the sum of the energies of its constituent structural groups as defines by standard molecules. The calculation of FSE is group isodermic, and thus provides extensive cancellation of deficiencies of basis set/electron correlation methods.

With the increase of areal density of magnetic recording, several new perfluoropolyether (PFPE) lubricants, including A20H, DDPA-S, and Ztetraol multidentate, have been recently reported to enhance the performance and reliability of hard disk drive with ultra-low head-media spacing. At the molecular level, the static conformation and detailed dynamic structure of these PFPE films are still not well-determined. In this paper, molecular dynamics simulations with bead-spring models were employed to investigate the conformation and dynamics of new types of PFPE films. The detailed static structures were revealed by functional end bead density profiles and visualization. The distribution of anisotropic radius of gyration was examined to investigate the conformations of PFPE monolayers. And the self-diffusion coefficient quantifying the mobility of films was compared for these PFPE monolayers. It was found that the molecular structure played a critical role in the conformation and dynamics of PFPE thin films. Index Terms--Conformation, diffusion coefficient, head-disk interface, molecular dynamics, perfluoropolyether.

A new orthogonal-bonding approach for assembling functional molecules which involves the simultaneous introduction of a bis(chelating) dianion to coordinate to two equatorial sites of two fac-[(CO).sub.3]Re cores and a ditopic nitrogen-donor ligand to the remaining orthogonal axial site leading to generation of a new class of metallacylces, is described. It is seen that the highly luminescent metallacyles contain crown-ether-like recognition sites, which are capable of selectively recognizing metal ions and planar aromatic molecules.

The formation of cyclic allyl ethers with a smaller ring size of pentadienyl ether with a larger ring size compete with each other in the formation of medium-sized ether by diene-ene ring-closing methathesis. In the competition between six- and eight-membered and seven- and nine-membered ring formation, the smaller rings are formed exclusively, whereas in the competition between the five and seven-membered rings, both products are formed in comparable amounts.

The reaction of bromo-2,4,6-triphenylbenzene with calcium in varying stoichiometric ratios was used to mechanically study the formation of the stable inverse Ca(I) sandwich complex [[(thf).sub.3]Ca([mu]-[C.sub.6][H.sub.3]-1,3,5-[Ph.sub.3])Ca[(thf).sub.3]]. The modified substitution pattern of arylcalcium halides showed that phenyl substituents at the para position induce lability, leading to an enhanced tendency to cleave ethers.

Several studies are conducted to explain the various different catalytic asymmetric Claisen rearrangements of the unactivated allyl vinyl ethers.

A series of [beta]-peptides containing diether and hydrocarbon bridges is described and compared on the basis of cell uptake and localization, affinities for hDM2, and 14-helix structure. The results have shown the relative merits of the cationic-patch and hydrophobic-bridge strategies for improving [beta]-peptide uptake and have identified a correlation between uptake efficiency and hDM2 affinity.

The preparation and evaluation of a simpler analog of the natural product migrastatin (migrastatin ether (ME)) is described. In vivo and in vito studies have shown that ME has displayed a concentration-dependent inhibitory effect on migration of breast cancer cells.

A series of oligo(ethylene oxide) (oligoEO) substituted 2-ureido-pyrimidinones (UPy) are prepared, which have differed in the number of ethylene oxide units and the length of the aliphatic spacer connecting the oligoEO side chain with the UPy group. The relation between dimerization strength, length of aliphatic spacer, and the number of EO units in the oligoEO chain has shown that the reduction in hydrogen bond strength is caused by competitive intramolecular hydrogen bonding of the ether atoms of the oligoEO chain to the hydrogen bond donors of the UPy unit.

Oxidative cleavage of benzylic ethers and related Ar[CH.sub.2]OR substrates by 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate in wet C[H.sub.3]CN at room temperature to give the corresponding aromatic aldehyde and alcohol in high yield is described. The slow reaction of substrates bearing electron-withdrawing substituents provides evidence for the oxidation which likely involves a formal hydride abstraction from the benzylic carbon.

The [beta]-alkoxide elimination reactions of propargylic ether with Negishi reagent which leads to allenes and/or alkynes after hydrolysis are reported. The coupling reactions of the allenic/propargylic zirconium intermediates with aryl iodides in the presence of Pd[(P[Ph.sub.3]).sub.4]/CuCl as a simple pathway for the synthesis of multisubstituted allenes are reported.

A combination of cluster spectroscopy and density functional theory is used for studying host-guest complexes in the gas phase and mass-selected [M.sup.+](18-crown-6 ether)[([H.sub.2]O).sub.1-4] complexes for the alkali metal ion series are detected by using infrared predissociation spectroscopy in the OH stretching region. The results for [Cs.sup.+](18-crown-6-ether)[([H.sub.2]O).sub.4] have shown that [H.sub.2]O'[H.sub.2]O hydrogen bonding is a dominant interaction present at this size.

The reactions of indoles with ethers were performed to obtain a variety of symmetric and unsymmetric 1,1-bis-indolylmethane derivatives. The reaction process involved iron-catalyzed C- H bond oxidation and C- O bond cleavage.

The synthesis of [n,5]-spiroketals (n = 5, 6) via use of exocyclic enol ethers as starting materials is reported. Addition of catalytic amounts of the Lewis acid [Yb(OTf).sub.3] is observed to facilitate the ring enlargement and increase the yield of the corresponding spiroketal in many synthesis examples.

The various mechanisms involved in the silylene-mediated ring contraction method of the homoallylic ethers for the formation of various allylic silanes are discussed. The various stereochemical properties of the ring contraction reaction are also explained.

The concept of structural symmetry was applied to perform synthesis of plakortethers F and G. The COSY, 1D NOE, and chemical transformation studies confirmed the identical structures of the prepared compounds.

Ether cleavage is carried out on arene bearing a diazonium salt. The deprotection has taken place with boron tribromide under very mild conditions without affecting the diazonium group.

A wide range of diaryl ethers and alkyl aryl ethers are prepared through intermolecular C (aryl)-O bond formation from the corresponding aryl iodides/aryl bromides and phenols/alcohols through Ullmann-type coupling reaction in the presence of a catalytic amount of ([plusmn])-diol L3-CuI complex under very mild reaction conditions. The catalytic system is not only capable of coupling hindered substrate but has also tolerated a broad range of a series of functional groups.

Thermolysis of the fullerene hexaadduct [C.sub.60][(OO[super t]Bu).sub.6] has resulted in cleavage of two O-O bonds and elimination of two tert-butoxy groups to form two isomeric products with the formula [C.sub.60][(O).sub.2][(OO[super t]Bu).sub.4]. The addition of hydroxylamine to other isomer has opened both the epoxy and the ether moieties to provide a cage-opened keto-ketoxime derivative.

The photoisomerization of terminal (E)-[alpha]-methylstilbene units of dialkylammonium salts in the presence of the crown ether dibenzo[24]crown-8 (DB24C8) was used to synthesize two [2]rotaxanes, each having a (Z)-[alpha]-methylstilbene unit as one of its stoppers. The obtained rotaxanes are found to be stable at room temperature, but dissociate slowly to their two components at elevated temperatures.

A novel microwave-assisted, chemoselective and efficient method is described for the cleavage of silyl ethers catalyzed by Selectfluor. The chemoselective deprotection of phenolic TBS ethers, and not the TIPS- or TBDPS-protected phenolic ethers, and the deprotection of silyl esters are achieved and the transetherification and etherification of benzylic hydroxyl groups in alcoholic solvents is observed.

The para-siletanylbenzyl (PSB) ether is electronically similar to the benzyl ether and its cleavage is accomplished under mild conditions involving alkaline hydrogen peroxide that are unique among cleavage protocols for arylmethyl ether protecting groups. A new reagent is described for installing PSB ethers under neutral mix and heat conditions.

An efficient and chemoselective deprotection protocol is described for the aryl silyl ethers by using LiOAc as a bifunctional Lewis acid-Lewis base catalyst. Acetates, epoxides and aliphatic silyl ethers are preserved, whereas aryl TBS and TBDPS ethers are differentiated.

An alternate reaction mechanism for the boron tribromide mediated deprotection of aryl propargyl ethers based on the isolation of a key boron-containing byproduct is presented. The findings for reaction mechanism revealed that HB[Br.sub.2] is an effective cleaving reagent for propargyl ethers bearing terminal alkyne moieties.