The physiological roles of CO in neurotransmission, vasorelaxation and cytoprotective activities have raised interest in the design and syntheses of CO-releasing materials (CORMs) that could be employed to modulate such biological pathways. Three iron-based CORMs namely, [(PaPy3)Fe(CO)](ClO4) (1), [(SBPy3)Fe(CO)](BF4)2 (2) and [(Tpmen)Fe(CO)](ClO4)2 (3), derived from designed polypyridyl ligands have been synthesized and characterized by spectroscopy and X-ray crystallography. In these three Fe(II) carbonyls, the CO is trans to a carboxamido-N (in 1), an imine-N (in 2) and a tertiary amine-N (in 3) respectively. This structural feature has been correlated to the strength of the Fe-CO bond. The CO-releasing properties of all three carbonyls have been studied in various solvents under different experimental conditions. Rapid release of CO is observed with 2 and 3 upon dissolution in both aqueous and nonaqueous media in the presence and absence of dioxygen. With 1, CO release is observed only under aerobic conditions and the final product is an oxo-bridged diiron species while with 2 and 3, the solvent bound [(L)Fe(CO)]2+ (where L = SBPy3 or Tpmen) results upon loss of CO under both aerobic and anaerobic conditions. The apparent rates of CO loss by these CORMs are comparable to other CORMs such as [Ru(glycine)(CO)3Cl] reported recently. Facile delivery of CO to reduced myoglobin has been observed with both 2 and 3. In tissue bath experiments, 2 and 3 exhibit rapid vasorelaxation of mouse aorta muscle rings. Although the relaxation effect is not inhibited by the soluble guanylate cyclase inhibitor ODQ, significant inhibition is observed with the BKCa channel blocker iberiotoxin.

Can. J. Chem. 68, 530 (1990). The proton and I3C NMR of azulene and dialkylaminohydroxyphenyl squaraines have been investigated. The four-membered ring carbon resonances occur in the 180-190 ppm range and are attributed to the cyclobutenediylium character of this structure. Some charge delocalization from the central ring to the pendent aromatic substituents was also observed, indicative of a substituent effect of the squaraine moiety on aminoaromatic systems equivalent to that of a formyl or acetyl group. Hydroxy squaraines 10 and 11 show the presence of two isomeric squaraine species in the proton NMR in deuterochloroform. Saturation transfer experiments confirm that these species are readily interconverted, and cisltrans isomerism (9a 9b) is consistent with these observations. The free energy difference between the two isomers at 318 K is calculated to be 3.0 and 3.2 kJ/mol for hydroxysquaraines 10 and 11 respectively.Key words: squaraines, saturation transfer, NMR. On a examink les spectres RMN du proton et du I3c de l'azulkne et des dialkylaminohydroxyphCnyl squara'ines. Les resonances des carbones du cycle 5 quatre chainons sont observkes dans la plage allant de 180 a 190 ppm et elles sont attribukes au caractere cyclobutenediylium de cette structure. On a aussi observe une certaine dClocalisation de la charge du noyau central vers les substituants attaches au noyau aromatique; ces observations suggerent qu'il existe un effet de substituant de la portion squaraine sur les systkmes aminoaromatiques equivalent a celui d'un groupement formyle ou acyle. Dans les spectres RMN du proton des hydroxy squarai'nes 10 et 11 en solution dans le deutkrochloroforme, on observe la prksence de deux especes isomkres. Des expkriences de transfert de saturation confirment que ces especes se transforment facilement l'une dans I'autre; une isomkrie cislrrans (90 S 9b) est en accord avec ces observations. On a calcule que, a 318 K, les diffkrences d'knergie libre entre les deux isomeres sont de 3,O et de 3,2kJ/mol respectivement pour les hydroxysquarai'nes 10 et 11.

Abstract:The reported structure of aceanthrene green, a pigment prepared by potassium hydroxide fusion of 1.9-anthracenedicarboxylic imide, was found to be incorrect. The structure of the pigment is reassigned to 7,8,15,16-dibenzo[a j]perylenetetracarboxylic diimide on the basis of COSY, NOESY, and inversion-recovery 'H NMR experiments. N-Alkyl-or N-phenyl-l,9-anthracenedicarboxylic imides, aceanthryleno[l,2-blquinoxaline, and a benzimidazole derivative of 1,9-anthracenedicarboxylic anhydride were found to give the same dibenzo[a jlperylene structure when reacted in potassium hydroxide. The electronic spectra of these derivatives is reported and it is shown that, as predicted by Pariser-Parr-Pople calculations, they absorb in the near-infrared. Finally, a mechanistic outline for the fusion is proposed on the basis of AM1 and frontier molecular orbital calculations.Key words: photoconductor, near-infrared, aceanthrene green, alkalifusion, polycyclic aromatic hydrocarbon.RCsumC : On a trouvC que la structure proposCe anterieurement pour l'ackanthrbne vert, un pigment prCparC par fusion de l'imide de l'acide anthracbne-l,9-dicarboxylique avec de l'hydroxyde de potassium, est incorrecte. En se basant sur des expkriences COSY, NOESY et d'inversion-rCcupCration en RMN du 'H on lui a rCattribuC la structure du diimide de l'acide dibenzo[a jlpCrylbne-7,8,15,16-tCtracarboxylique. On a trouvC que par rCaction, par fusion avec de l'hydroxyde de potassium, les N-alkyl-ou N-phCnylimides de l'acide anthrackne-1,9-di-carboxylique, l'acCanthrylCno[l,2-b]quinoxaline et un dCrivC benzimidazole de l'anhydride de l'acide anthracbne-l,9-dicarboxylique conduisent tous B la m&me structure dibenzo[a jlpCrylkne. On rapporte les spectres Clectroniques de ces dCrivCs et il est montrC, tel que prCdit par des calculs de type Pariser-Parr-Pople, qu'ils absorbent dans le proche infrarouge. Enfin, en se basant sur des calculs d'orbitales molCculaires AM1 et frontibres, on propose un aperp du mCcanisme pour la fusion.Mots cles : photoconducteur, proche infrarouge, acCanthrbne vert, fusion alcaline, hydrocarbure polycyclique aromatique.[Traduit par la rCdaction]

The purpose of this paper is to describe and assess one of the first comprehensive residential green-builder programs in the U.S. It compares trends of items used in residential construction during the past five years and reports why participating builders chose to incorporate specific items and their level of commitment to the program. This description provides a baseline of strategies to investigate the effect of this program in developing sustainable communities. The builder study population was derived from a database of registered “green” residences built during 1998-2002 in greater Austin, Texas (2,335 homes and 73 listed builders). Almost half the builders constructed just one “green” home, whereas two builders built almost 75% of the green homes during the 5-year study period. Less than 1% of the homes received a perfect 5-star rating, whereas 87% were rated 1 or 2 stars. The frequency of implementing the 122 green features were compared over time and analyzed for correlation with cost and their associated star-value. Cost was the primary factor determining item use frequency. Participating builders generally concurred that the program was successful and beneficial to homeowners but that the additional work required for participation provided little financial reward for builders. While much can be done with low-cost interventions to reduce the negative environmental impacts of residential construction, builder participation may be enhanced by promotion of some of the higher cost features. In addition, public education about the long-term benefits of green homes is needed to increase homeowner participation, and encourage builders to incorporate more environmentally friendly features in the homes they construct.

The usefulness of the Pariser-Pam-Pople molecular orbital method for the identification of nearinfrared absorbing pigment candidates for photogenerator applications is outlined. Several pigments based on the well-known class of photogenerators N,N'-dialkyl-3,4,9,1O-perylenetetracarboxylic diimides were investigated and pigments of the dibenzoperylene, bisanthene, and zethrene classes were identified as the most promising candidates of the series. On the basis of the predictions, 7,8,15,16-dibenzo[n, jlperylenetetracarboxylic diimide was prepared and the validity of the calculations was verified.Key words: photoconductor, near-infrared, Pariser-Pam-Pople calculations, polycyclic aromatic hydrocarbon, aceanthrene green.RCsumC : On prCsente des donntes montrant I'utilitt de la mCthode des orbitales molCculaires Pariser-ParrPople pour l'identification de pigments pouvant etre des candidats pour une absorption dans le proche infrarouge pour des applications comme photogenerateurs. On a CtudiC plusieurs pigments derives de la classe bien connue de photogknerateurs des diimides de l'acide N,N'-dialkylpCryl&ne-3,4,9,IO-tCtracarboxylique et on a identifit des pigments des classes du dibenzoptrylkne, du bisanthbne et du ztthrkne comme les candidats les plus prometteurs de la sCrie. Sur la base de ces prtdictions, on a prtpart le diimide de l'acide dibenzo- lntroduct ion # Diimide (1) and bis(benzimidazo1e) (2) derivatives of 3,4,9,10-perylenetetracarboxylic dianhydride (Scheme 1) are well-known pigments and have been used in a wide variety of applications (1-5). These compounds have proven to be photogenerating materials with high photosensitivity in the visible, low dark decay, and excellent cyclic stability (6-9). Because of the increased interest in near-infrared photosensitive materials for laser printing applications, it would be highly desirable to design photogenerators with these properties and which would be photosensitive at the gallium aluminium arsenide (GaAlAs) diode laser wavelength around 780 nm. The preparation of polycyclic aromatic imides and benzimidazole derivatives is expected to be difficult because of the insolubil- ity of these pigments and also because the available synthesis methodology for polycyclic aromatics is very substrate specific. In view of these constraints, it is essential to have a calculational method that would predict the spectral response of a pigment prior to embarking on a lengthy synthesis process.Pariser-Parr-Pople (PPP) calculations have been shown to be a useful method for the colour prediction of organic dye Can.