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We recently reported on how the surface energy and work function of AlOx/Al substrates can be tuned by self-assembled monolayers of fluorinated and nonfluorinated benzylphosphonic acid derivatives in view of organic electronic applications. In this contribution, we present a thorough investigation of these monolayers by photoemission (XPS) and infrared (PM-IRRAS) spectroscopies, to provide a quantitative understanding of their structural properties (packing density and orientation) and chemical composition. A detailed analysis of XPS chemical shifts makes an assignment of the carbon species present in the SAMs feasible, from the low-binding-energy aromatic carbon (∼284.5 eV) to the highly electronegative fluorine-substituted carbon (∼287.5 eV), whereby an upper limit for the fraction of nonspecific hydrocarbons (

The performance of organic electronic devices can be significantly improved by modifying metal electrodes with organic monolayers, which alter the physical and chemical nature of the interface between conductor and semiconductor. In this paper we examine a series of twelve phosphonic acid compounds deposited on the native oxide layer of aluminum (AlOx/Al), an electrode material with widespread applications in organic electronics. This series includes dodecylphosphonic acid as a reference and eleven benzylphosphonic acids, seven of which are fluorinated, including five newly synthesized derivatives. The monolayers are experimentally characterized by contact angle goniometry and by X-ray photoemission spectroscopy (XPS), and work function data obtained by low-intensity XPS are correlated with molecular dipoles obtained from DFT calculations. We find that monolayers are formed with molecular areas ranging from 17.7 to 42.9 Å2/molecule, and, by the choice of appropriate terminal groups, the surface energy can be tuned from 23.5 mJ/m2 to 70.5 mJ/m2. Depending on the number and position of fluorine substituents on the aromatic rings, a variation in the work function of AlOx/Al substrates over a range of 0.91 eV is achieved, and a renormalization procedure based on molecular density results in a surprising agreement of the changes in surface potential with interface dipoles as expected from Helmholtz’ equation. The ability to adjust energetics and adhesion at organic semiconductor/AlOx interfaces should have immediate applications in devices such as OLEDs, OTFTs, organic solar cells, and printed organic circuits.

The alignment of the electrode Fermi level with the valence or conduction bands of organic semiconductors is a key parameter controlling the efficiency of organic light-emitting diodes, solar cells, and printed circuits. Here, we introduce a class of organic molecules that form highly robust dipole layers, capable of shifting the work function of noble metals (Au and Ag) down to 3.1 eV, that is, ∼1 eV lower than previously reported self-assembled monolayers. The physics behind the considerable interface dipole is elucidated by means of photoemission spectroscopy and density functional theory calculations, and a polymer diode exclusively based on the surface modification of a single electrode in a symmetric, two-terminal Au/poly(3-hexylthiophene)/Au junction is presented. The diode exhibits the remarkable rectification ratio of ∼2·10(3), showing high reproducibility, durability (3 years), and excellent electrical stability. With this evidence, noble metal electrodes with work function values comparable to that of standard cathode materials used in optoelectronic applications are demonstrated.

Oligomers of aniline and their derivatives have electrical and chemical properties that parallel those of polyaniline, while having the advantage of being available as homogeneous, chemically pure materials. Despite this advantage, little experimental data is available on the electrical transport properties of thin films of oligoanilines compared to polyaniline. Here, we investigate three types of ultrathin films (

n-Alkyl self-assembled monolayers can be directly attached to gold through C–Au bonds by the deposition of organomercury salts on gold substrates, as shown here using n-butylmercury and n-octadecylmercury tosylate derivatives. The Hg atoms, which are codeposited during this process, are removed by thermal annealing at 95 °C, resulting in alkyl monolayers having a significantly enhanced thermal stability compared with alkanethiol monolayers, however, a lower degree of conformational order. The monolayer properties are elucidated by X-ray photoemission and IR spectroscopy, STM, ellipsometry, and contact-angle goniometry.

Oligoanilines are interesting candidates for organic electronics, as their conductivity can be varied by several orders of magnitude upon protonic doping. Here we demonstrate that tetraaniline self-assembled monolayers exhibit an unprecedented conductance on/off ratio of ∼710 (at +1 V) upon doping of the layers from the emeraldine base to the emeraldine salt form. Furthermore, a pronounced asymmetry in the current–voltage characteristics indicates dynamic doping of the tetraaniline layer by protons generated through field-enhanced dissociation of water molecules, a phenomenon known as the second Wien effect. These results point toward oligoanilines as promising substitutes for polyaniline layers in next-generation thin film devices.

Electron transfer across proteins plays an important role in many biological processes, including those relevant for the conversion of solar photons to chemical energy. Previous studies demonstrated the generation of photocurrents upon light irradiation in a number of photoactive proteins, such as photosystem I or bacteriorhodopsin. Here, it is shown that Sn-cytochrome c layers act as reversible and efficient photoelectrochemical switches upon integration into large-area solid-state junctions. Photocurrents are observed both in the Soret band (λ = 405 nm) and in the Q band (λ = 535 nm), with current on/off ratios reaching values of up to 25. The underlying modulation in charge-transfer rate is attributed to a hole-transport channel created by the photoexcitation of the Sn-porphyrin.

The oriented assembly of molecules on metals is a requirement for rectification in planar metal-molecule-metal junctions. Here, we demonstrate how the difference in adsorption kinetics between dithiocarbamate and thioacetate anchor groups can be utilized to form oriented assemblies of asymmetric molecules that are bound to Au through the dithiocarbamate moiety. The free thioactate group is then used as a ligand to bind Au nanoparticles and to form the desired metal-molecule-metal junction. Besides allowing an asymmetric coupling to the electrodes, the molecules exhibit an asymmetric molecular backbone where the length of the alkyl chains separating the electrodes from a central, para-substituted phenyl ring differs by two methylene units. Throughout the junction fabrication, the layers were characterized by photoelectron spectroscopy, infrared spectroscopy, and scanning tunneling microscopy. Large area junctions using a conducting polymer interlayer between a mercury-drop electrode and the self-assembled monolayer prove the relationship between electrical data and molecular structure.

ObjectivesSubstance abuse, a multidimensional disorder, is frequently complicated by additional psychosocial needs that, left unresolved, may adversely affect clients' treatment retention and outcome. This article presents and discusses findings of a study designed to identify associations b

This contribution reports the synthesis of water-soluble silica-coated CdTe nanocrystals that possess an ideally designed ligand shell with respect to colloidal properties and surface coupling reactions. We describe conjugation strategies for the modification of the fluorescent biocompatible nanocrystals with biomolecules that provide a molecular recognition potential like the biotin/avidin couple and DNA.

Tris(hydroxymethyl)phosphine-capped gold nanoparticles (ca. 1−2 nm diameter) bind densely to DNA, although both species are negatively charged. The particles are also active catalysts for electroless plating of gold. Electroless plating after adsorption to calf thymus DNA immobilized on silicon provides nanowires as narrow as ca. 30−40 nm and electrical conductivities ca. one-thousandth that of bulk gold. Here we summarize our physical characterization of the particles and their DNA conjugates and initial electrical measurements after plating.

The photosensitization of colloidal particles of antimony-doped SnO2 by electrostatically adsorbed Ru(bpy)32+ (bpy = 2,2‘-bipyridine) produced Ru(bpy)33+ and a conduction band electron (ecb-) with ...

Uncharged, water-soluble nitroxyl free radicals are shown by laser flash photolysis to be effective reductants of the Ru(bpy)33+ (bpy = 2,2‘-bipyridine) that is produced via photosensitization at the surfaces of colloidal semiconductor particles composed of antimony-doped tin dioxide. The bimolecular rate constant for the reduction of Ru(bpy)33+ by the 3-carbamoyl-PROXYL radical in the colloidal suspension, (4.9 ± 0.2) × 108 M-1 s-1, is about one-third of the rate constant for the corresponding reaction in homogeneous aqueous solution, (1.4 ± 0.1) × 109 M-1 s-1. The high quantum efficiency for production of Ru(bpy)33+, 0.93 ± 0.01, together with the fact that the oxidized nitroxyl radicals are widely used as oxidants in organic syntheses, makes such systems of interest for effecting photocatalytic oxidation reactions.

In the 1970s and 1980s, several techniques for assessing the needs for substance user treatment were developed. Generally these techniques relied upon the data developed from large-scale data-gathering systems, originally designed to assess the capacity of the substance user treatment system nationwide. The need assessment techniques generally require making estimates of the prevalence of substance use disorders in the population and then applying them to the national utilitization experience. As first attempts often do, these approaches tended to simplify complex problems and tended to rely too heavily on the only available data. The result was that they tended to reify current practice rather than to define best practice. In the 1990s, new challenges face those attempting to assess needs for substance user services. As a result of the last decade's emphasis on cost containment, new concepts have challenged traditional views of needs assessment. This paper will discuss those new concepts and their impact on the needs assessment endeavor. In particular, the impact of the concept of medical necessity will be examined.

Tris (2,2'-bipyridyl)ruthenium(II)chloride hexahydrate (Ru[bpy]3(2+)) free in solution and adsorbed onto antimony-doped SnO2 colloidal particles was used as a photosensitizer for a comparison of the O2(1 delta g) and electron-transfer-mediated photooxidation of tryptophan (TRP), respectively. Quenching of excited Ru(bpy)3(2+) by O2(3 sigma g-) in an aerated aqueous solution leads only to the formation of O2(1 delta g) (phi delta = 0.18) and this compound was used as a type II photosensitizer. Excitation of Ru(bpy)3(2+) adsorbed onto Sb/SnO2 results in a fast injection of an electron into the conduction band of the semiconductor and accordingly to the formation of Ru(bpy)3(2+) and was used for the sensitization of the electron-transfer-mediated photooxidation. The Ru(bpy)3(3+) is reduced by TRP with a bimolecular rate constant kQ = 5.9 x 10(8) M-1 s-1, while O2(1 delta g) is quenched by TRP with kt = 7.1 x 10(7) M-1 s-1 (chemical + physical quenching). Relative rate constants for the photooxidation of TRP (kc) via both pathways were determined using fluorescence emission spectroscopy. With Np, the rate of photons absorbed, being constant for both pathways we obtained kc = (372/Np) M-1 s-1 for the O2(1 delta g) pathway and kc > or = (25,013/Np) M-1 s-1 for the electron-transfer pathway, respectively. Thus the photooxidation of Trp is more than two orders of magnitude more efficient when it is initiated by electron transfer than when initiated by O2(1 delta g).

The adsorption of Ru(bpy)32+ (bpy = 2,2‘-bipyridine) onto negatively charged antimony-doped SnO2 colloidal particles (ca. 4-nm diameter) was monitored by time-resolved luminescence. Electron injection from photoexcited Ru(bpy)32+ into the conduction band of the semiconductor particle results in luminescence quenching predominantly within the laser pulse when the complex is bound to the particle, whereas the luminescence of the unbound complex decays with a lifetime of several hundred nanoseconds. The relative concentrations of the bound and free species are thus readily obtained by determining the relative contributions of the quenched and unquenched components in the luminescence decay curve. Binding of Ru(bpy)32+ to the particles conforms to the Frumkin adsorption isotherm and suggests that the adsorbed Ru(bpy)32+ molecules self-associate with a free energy of interaction equal to −1.9 ± 0.7 kcal mol-1. The average maximal capacity of each particle for adsorbed Ru(bpy)32+ determined by the binding data,...

Aqueous colloidal silica suspensions modified by incorporation of tris(2,2`-bipyridyl)ruthenium(II) and zinc(II)tetrakis(N-methyl-4-pyridyl)porphyrin into the particle matrix were prepared. The photophysical properties of the complexes in this environment were investigated using laser flash photolysis and steady-state luminescence techniques. The excited states exhibit nonexponential kinetics and their lifetimes are increased compared to homogeneous aqueous solutions. The metal-to-ligand charge transfer state of the Ru(II) complex is not affected by the presence of dissolved oxygen, whereas a fraction of the triplet states of the porphyrin is quenched by O{sub 2}. Didodecyldimethylammonium ion was used to build surfactant bilayers supported on the silica surface. The possibility of using this system for transmembrane electron transfer is discussed. 42 refs., 4 figs.

The complex [(H 2 Nphen)Ru(bpy) 2 ] 2+ (H 2 Nphen=5-amino-1,10-phenanthroline; bpy≡2,2'-bipyridine) was covalently attached to the surfaces of colloidal SnO 2 particles (ca. 4-nm diameter) by using cyanuric chloride and (3-aminopropyl)triethoxysilane as coupling agents. Electron injection from the MLCT excited state of the complex, * RuL 3 2+ , into the conduction band of SnO 2 and recombination of RuL 3 3+ with the conduction band electron, e cb - (SnO 2 ), were investigated by nanosecond laser flash photolysis (532-nm excitation) and steady-state luminescence techniques

The quenching by O[sub 2] of the MLCT excited states of 10 Ru(II)-diimine complexes (RuL[sup 2+]) of the form Ru(bpy)[sub 3[minus]m[minus]z] (bpm)[sub m](bpz)[sub z][sup 2+] (bpy = 2,2'-bipyridine, bpm = 2,2'-bipyrimidine, bpz = 2,2'-bipyrazine, m and z = 0, 1, 2, 3 and m + z [

The palladium complex of 1,6,10,15,19,24,28,33-octabutoxynaphthalocyanine, PdNc(OBu) 8 , is shown to undergo reversible addition of O 2 in benzene solution at ambient temperature (22±1 o C) during steady-state photolysis with an Ar ion laser. On the basis of 1 H-NMR and electronic absorption spectral evidence, the photoadduct is postulated to be an endoperoxide which has molecular oxygen added to one of the benzene rings at the sites a to the point of fusion with the tetrapyrrole ring, i.e., the positions bearing butoxy substituents. The formation of this product probably involves O 2 ( 1 Δ g )

The synthesis and photoproperties of six new metal 1,4,8,11,15,18,22,25-octabutoxyphthalocyanines and photoproperties of the known, analogous Zn and metal-free phthalocyanines are described. The new compounds are AlPc(OBu){sub 8}OSiEt{sub 3}, GaPc(OBu){sub 8}OSiEt{sub 3}, GePc(OBu){sub 8}(OSiEt{sub 3}){sub 2}, SnPc(OBu){sub 8}(OSiEt{sub 3}){sub 2}, RuPc(OBu){sub 8}(py){sub 2}, and PdPc(OBu){sub 8} (where Pc(OBu){sub 8} represents the octabutoxyphthalocyanine ligand). Benzene-d{sub 6} solutions of all eight of the compounds give NMR spectra showing large ring-current effects. Benzene solutions of the compounds give visible spectra with absorption maxima in the 688-779-nm range having extinction coefficients between 1.0 {times} 10{sup 5} and 2.2 {times} 10{sup 5} M{sup {minus}1} cm{sup {minus}1}. The triplet-state properties of the phthalocyanines in benzene solutions have been measured by laser flash photolysis. The triplet states have absorption maxima in the 550-640-nm range, quantum yields in the 0.1-0.9 range, and lifetimes when the solutions are deaerated in the 0.5-150-{mu}s range. The rate constants for energy transfer from the triplet states of the compounds to O{sub 2} are between 1.3 {times} 10{sup 8} and 2.8 {times} 10{sup 9} M{sup {minus}1} s{sup {minus}1}.

The synthesis and characterization of 30 Al, Ga, Si, and Sn naphthalocyanines relevant to the search for improved photodynamic therapy agents are reported. The compounds that have been studied are AlNcCl, AlNcOH, AlNcOSi-(n-C 6 H 13 ) 3 ...

The synthesis and characterization of 30 Al, Ga, Si, and Sn naphthalocyanines relevant to the search for improved photodynamic therapy agents are reported. The compounds that have been studied are AlNcCl, AlNcOH, AlNcOSi-(n-C 6 H 13 ) 3 ...

The localized photoexcitation of a Ru(II) polypyridine complex covalently attached by a flexible link to pyrene results in a rapid intramolecular transfer of triplet energy with a forward rate constant of (1.3 {+-} 0.3) x 10{sup 8} s{sup -1} in deaerated methanol solution. On account of the energetic proximity of the states, reverse transfer occurs with a rate constant lower by a factor of 18{+-} 3. This equilibiration is rapid compared with the relaxation processes that are deactivating the system, which have a common lifetime of 11.2 {+-}4 {mu}s. These results may be the first direct observation of an equilibrium being reached in an intramolecular triplet energy transfer reaction. 17 refs., 4 fig.

— The excited state behavior of an anionic ruthenium(II) complex, RuL34-(L=bathophen-anthroline disulfonate), that is electrostatically bound to positively charged alumina-coated silica particles is investigated. The apparent association constant for the binding of RuL34-to the particles is 1.2 × 104M-1. Surface photochemical processes result in decreased emission yields and multiexponential excited state decay. Excited state quenching by ground-state molecules is evident at high surface coverages. The non-exponential decay kinetics observed at low surface coverages can be attributed either to clustering of the RuL34-molecules or photoionization promoted by Lewis acid sites on the particle surface.

A set of anti-melanoma immunoconjugates were prepared which contained chlorin e6: antibody molar ratios of 18.9:1, 11.2:1, 6.8:1, and 1.7:1. All immunoconjugates retained antigen binding activity regardless of the chromophore:antibody substitution ratio that was attained. In contrast, the ground-state absorption spectra of the immunoconjugates showed features which appeared to be dependent on the chromophore: antibody molar ratio. In addition, the quantum yield of singlet oxygen generated by the conjugated chromophores was observed to be significantly less than that observed with the unbound dye. Time-resolved absorbance spectroscopy of the chromophore excited triplet state indicated that the loss of singlet oxygen quantum yield resulted from diminished chromophore triplet yield. Analysis of data obtained from in vitro photolysis of target melanoma cells, in combination with that obtained from the immunochemical and photochemical studies, indicates that the observed immunoconjugate phototoxicity can be reasonably quantitatively represented by (1) the ability of the immunoconjugate to bind SK-MEL-2 cell surface antigen, (2) the amount of chromophore localized at the target cells by immunoconjugate binding, (3) the delivered dose of light at 634 nm, and (4) the singlet oxygen quantum yield of the antibody-bound photosensitizer. Though these data argue strongly for photolysis by the cumulative dosage of singlet oxygen at the cell membrane, nonetheless, the concurrent photoinduced release of other cytotoxic agents should not be ruled out.

Laser flash photolysis experiments are described which demonstrate triplet energy transfer from tris (2,2′-bipyridine)ruthenium(II) to acridine, acridine-9-carboxylate and phenazine, and electron transfer from para-substituted phenols to methyl viologen mediated by the triplet state of acridine-9-carboxylate. The latter reaction occurs via reductive quenching of the triplet state. Rate constants and efficiencies of these reactions are reported.

The structure and electrical properties of self-assembled monolayers of cyclic aromatic and aliphatic dithioacetamides (1,4-bis(mercaptoacetamido)benzene and 1,4-bis(mercaptoacetamido)cyclohexane) and of mixed dithioacetamide/alkanethiol monolayers are characterized by X-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM) and contact angle goniometry. Both dithioacetamides are found to pack densely on Au(111), however the monolayers are poorly ordered as a result of hydrogen bond formation between the amide groups. The coassembly and the insertion method are compared for the formation of mixed dithioacetamide/alkanethiol monolayers. By coassembly, islands of dithioacetamides in a dodecanethiol matrix can only be obtained at a low dithioacetamide/dodecanethiol concentration ratio in solution (1/10) and by thermal annealing of the resulting monolayers. Small and well defined dithioacetamide domains are realized by insertion of dithioacetamides into defect sites of closely packed octanethiol monolayers. These domains are used to determine the molecular conductance by means of STM height profiles and molecular lengths resulting from density functional theory (DFT) calculations. The difference in the tunneling decay constant beta measured for aromatic dithioacetamides (beta = 0.74-0.76/A) and for aliphatic dithioacetamides (beta = 0.84-0.91/A) highlights the influence of the conjugation within the cyclic core on molecular conductance.

Coprecipitation of urea-melt modified carbon nanotubes and calcium carbonate from an aqueous solution by two methods yielded microcrystalline composite particles. Powders obtained by colloidal crystallization from a supersaturated solution that were isolated and dried soon after precipitation were a mixture of raspberry-shaped and rhombohedral particles. These were shown by infrared and X-ray diffraction analyses to be mainly calcite. Particles that were kept wet for 1 day or longer before being isolated were typically entirely rhombohedral with edge lengths in the range of 5-30 microm. Scanning electron microscopy investigations revealed that the nanotubes were adsorbed on the particle surface and also incorporated into the interior matrix. Removal of the calcium carbonate component by treating the particles with acid yielded nanotube shells whose size and shape reflected those of the original particles.

The synthesis and photoproperties of six new metal 1,4,8,11,15,18,22,25-octabutoxyphthalocyanines and photoproperties of the known, analogous Zn and metal-free phthalocyanines are described. The new compounds are AlPc(OBu){sub 8}OSiEt{sub 3}, GaPc(OBu){sub 8}OSiEt{sub 3}, GePc(OBu){sub 8}(OSiEt{sub 3}){sub 2}, SnPc(OBu){sub 8}(OSiEt{sub 3}){sub 2}, RuPc(OBu){sub 8}(py){sub 2}, and PdPc(OBu){sub 8} (where Pc(OBu){sub 8} represents the octabutoxyphthalocyanine ligand). Benzene-d{sub 6} solutions of all eight of the compounds give NMR spectra showing large ring-current effects. Benzene solutions of the compounds give visible spectra with absorption maxima in the 688-779-nm range having extinction coefficients between 1.0 {times} 10{sup 5} and 2.2 {times} 10{sup 5} M{sup {minus}1} cm{sup {minus}1}. The triplet-state properties of the phthalocyanines in benzene solutions have been measured by laser flash photolysis. The triplet states have absorption maxima in the 550-640-nm range, quantum yields in the 0.1-0.9 range, and lifetimes when the solutions are deaerated in the 0.5-150-{mu}s range. The rate constants for energy transfer from the triplet states of the compounds to O{sub 2} are between 1.3 {times} 10{sup 8} and 2.8 {times} 10{sup 9} M{sup {minus}1} s{sup {minus}1}.

This contribution discusses the influence of the metal binding group on the charge transport and optical properties of percolated networks of nanoparticles interlinked with bis‐dithiocarbamate or dithiol derivatives. DFT calculations show that the bis‐dithiocarbamate derivatives form valence states that are delocalized on the metal and the molecule. This is a characteristic, which is classically not known from the thiol‐gold interface. Conclusive experimental and theoretical evidence for the excellent electronic behavior of dithiocarbamate groups is provided.

In this work we present a simple and effective process to overcome the water insolubility of mildly oxidized Single Walled Carbon Nanotubes (SWCNTs). As this insolubility mainly arises from strong van‐der Waals and π‐π stacking interactions of the nanotubes, we applied a urea‐melt process to break up the bundles and simultaneously convert the carboxylic functional groups into primary amides. After intense washing and precipitation steps the urea functionalized nanotubes (U‐SWCNTs) show a remarkably increased solubility in water and some alcohols which, makes them accessible for further functionalization and applications in these solvents.

The optical and electrical properties of 11-20 nm thick films composed of approximately 4 nm gold nanoparticles (Au-NPs) interlinked by six organic dithiol or bis-dithiocarbamate derivatives were compared to investigate how these properties depend on the core of the linker molecule (benzene or cyclohexane) and its metal-binding substituents (thiol or dithiocarbamate). Films prepared with the thiol-terminated linker molecules, (1,4-bis(mercaptomethyl)benzene, 1,4-bis(mercaptomethyl)cyclohexane, 1,4-bis(mercaptoacetamido)benzene, and 1,4-bis(mercaptoacetamido)cyclohexane), exhibit thermally activated charge transport. The activation energies lie between 59 and 71 meV. These films show distinct plasmon absorption bands with maxima between 554 and 589 nm. In contrast, the film prepared with 1,4-cyclohexane-bis(dithiocarbamate) has a significantly red-shifted plasmon band ( approximately 626 nm) and a pronounced absorbance in the near infrared. The activation energy for charge transport is only 14 meV. These differences are explained in terms of the formation of a resonant state at the interface due to overlap of the molecular orbital and metal wave function, leading to an apparent increase in NP diameter. The film prepared with 1,4-phenylene-bis(dithiocarbamate) exhibits metallic properties, indicating the full extension of the electron wave function between interlinked NPs. In all cases, the replacement of the benzene ring with a cyclohexane ring in the center of the linker molecule leads to a 1 order of magnitude decrease in conductivity. A linear relationship is obtained when the logarithm of conductivity is plotted as a function of the number of nonconjugated bonds in the linker molecules. This suggests that nonresonant tunneling along the nonconjugated parts of the molecule governs the electron tunneling decay constant (beta(N)(-)(CON)), while the contribution from the conjugated parts of the molecule is weak (corresponding to resonant tunneling). The obtained value for beta(N)(-)(CON) is approximately 1.0 (per non-conjugated bond) and independent of the nanoparticle-binding group. Hence, the molecules can be viewed as consisting of serial connections of electrically insulating (nonconjugated) and conductive (conjugated) parts.

The concept of medical necessity is a provision of commercial insurance contracts and federal government Medicaid requirements that limits the payment to only those services that are essential for treating a person's sickness, injury, or condition. The concept of medical necessity is one tool used by third-party payers to contain their financial risk in a seemingly nonarbitrary manner. Also, the definitions of medical necessity used by commercial insurers or by the federal government reflect their product's or program's philosophies. Expanding commercial insurance or Medicaid psychiatric coverage would require changing those philosophies. As long as society is faced with a greater demand for health-related service than resources to meet them, such systems of rationing will be used. Even with full parity for psychiatric benefits, mechanisms will be used by payers to limit or control demand, thereby controlling financial risk. The short-term challenge for psychiatric advocates is to secure the most acceptable definitions of medical necessity from third-party payers. The long-term challenge for MH/SA advocates and for all health care advocates, is to develop a system that pays for the greatest number of quality services for the greatest number of people in need, in an affordable manner, regardless of diagnosis.

Methods for the preparation of three siloxysilicon naphthalocyanines, a siloxygermanium tetraphenoxynaphthalocyanine, a siloxysilicon tetra-t-butyl-naphthalocyanine, a cofacial double-ring siloxysilicon naphthalocyanine, and a cofacial triple-ring siloxysilicon naphthalocyanine that are relevant to the search for second generation PDT sensitizers are outlined. Ultraviolet-visible spectra, NMR spectra, and other properties of these compounds are given and discussed. In addition, an attempt to make an aluminum tetradibenzobarreleno-naphthalocyanine is described.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Methods for the preparation of the naphthalocyanines SiNc(OSi(n-C6H13)3)2, SiNc(OSi(i-C4H9)2n-C18H37)2, GeNc(OSi(n-C6H13)3)2, SnNc(OSi(n-C6H13)3)2, AlNcOSi(n-C6H13)3 ' and GaNcOSi(n-C6H13)3 the halonaphthalocyanine isomer mixtures SiMc(Cl)4(OSi(n-C6H13)3)2 and SiNc(Br)4(OSi(n-C6H13)3)2; and the butoxyphthalocyanines GePc(0-n-C4H9)g(OSi(C2H5)3)2 , SnPc(O-n-C4H9)8(OSi(C2H5)3)2, Al(O-n- C4H9)8OSi(C2H5)3 , Ga(O-n-C4H9)8OSi(C2H5)3 , PdPc(O-n-C4H9)8, and Ru(O-n- C4H9)8(C6H5N)2 are outlined. Ultraviolet-visible spectra and other properties of these compounds are described, and their potential as sensitizers is touched upon.© (1990) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Several demand-based models for forecasting alcoholism/drug abuse bed needs have been developed over the past few years. Demand models have inherent problems for predicting future needs because of the unknown relationship between the demand group and the nondemand group. Nonetheless, these models hold promise for the alcoholism/drug abuse service system because of some of the unique characteristics of that system. Three models for forecasting alcoholism bed need and one for forecasting drug abuse bed need are discussed; the strengths and weaknesses of each are presented. Projections for the same geographic area are compared. Criteria for selecting one model over another are also recommended.