Synthesis of phenanthro[2,3-h]isoquinoline and phenanthro[3,2-h]isoquinoline

The suspected environmental contaminants phenanthro[2,3-h]isoquinoline 12 and phenanthro[3,2-h]isoquinoline 11 were synthesized in four steps from a common intermediate 1,4-phenanthroquinone 3 , using a Diels-Alder reaction.     

Synthesis and characterization of titanium (IV) Schiff base complexes,part III1. Octahedral titanium (IV) complexes of some dibasic terdentate Schiff base ligands

Summary Complexes of the X₂Ti(SB) type, where X is OMe, OEt and OPr-i and SB is the dianion of salicylaldehyde-2-hydroxyanil (H₂SAP), acetylacetone-2-hydroxyanil (H₂AAP) and acetylacetone-2-mercaptoanil (H₂ASP), have been prepared and characterized by means of conductivity, molecular weight, i.r., n.m.r and mass spectral measurements. The ONO and ONS donor ligands are terdentate and the titanium(IV) atom attains six-coordinationvia dimerization of the complexes. The tendency of (i-PrO)₂Ti(AAP), where AAP is the dianion of acetylacetone-2-hydroxyanil, to become monomeric and to disproportionate to Ti(AAP)₂ and Ti(OPr-i)₄ was also investigated. Spectral data are also presented for the octahedral complexes of the Ti(SB)₂ type, where SB is the dianion of H₂SAP, H₂AAP, H₂ASP or of the related ONO donor ligands salicylaldehyde-2-hydroxyethylimine (H₂SAE), salicylaldehyde-3-hydroxypropylimine (H₂SPA), and diisopropylethanolamine (H₂DIP).Presented in part at the 166th ACS National Meeting, Chicago, Illinois, Aug. 26–31, 1973; No. INORG. 50.     

Solubility enhancement and QSPR correlations for polycyclic aromatic hydrocarbons complexation with α, β, and γ cyclodextrins

Through batch equilibrium experiments, hydroxypropyl substituted α, β, and γ cyclodextrin (CDs) were shown to greatly increase the apparent solubility of eight common polycyclic aromatic hydrocarbons (PAHs) in aqueous solutions. Equations based on the volume fraction of solution composed of water and CDs have been developed to determine guest phase distribution. Based on these equations, the results of this and similar studies for CD showed that a log–log relationship exists between the fraction of CD occupied with a guest organic compound and the aqueous solubility of those guests (rsq 0.980). Analysis of potential quantitative structure property relationship (QSPR) found strong correlations between structural properties of the guests (e.g. aqueous solubility, octanol/water partitioning coefficient, molar volume, molecular surface area, and polarizability) and water/CD partitioning coefficients, phase distribution of the PAH between water and CD phases, and the fraction of CD molecules occupied with a guest PAH. Noteworthy among these, is the inverse relationship between the log of the fraction of CD molecules occupied under saturated conditions and the ratio of the molar volume of the PAH to the volume of the CD cavities (rsq for α, β, and γ: 0.887–0.892). Comparisons of the three CDs shows that while the size of the guest compound reduces its propensity to enter into the CD cavity, the effect of the guest size is lessened as the width of the CD ring increases. Development of these QSPR correlations provides a means to predict and evaluate guest/CD interactions for homologous series of compounds.     

Focal sets of hypersurfaces

Let M ? R ⁿ⁺¹ be a compact connected smooth hypersurface, and let W ? R ⁿ⁺¹ be the area bounded by M. We study the question: Does W contain a principal centre of curvature for some point of M?     

Restoration and conservation of ancient artifacts: A new area of application of plasma chemistry

The application of low-pressure hydrogen plasma for the restoration and conservation of iron artifacts has been developed. This method of treatment at temperatures below 400°C is relatively fast and efficiently removes chlorides which, otherwise, would cause a fast postcorrosion of the excavated object. Furthermore, the application of this method to freshly excavated objects enables the restorer to easily uncover the original surface.     

Reaction products of 2-aminobenzenethiol with some β-diketones

2-Aminobenzenethiol undergoes condensation reactions with several β-diketones (CH₃, CF₃ and C₆H₅ substituents) to form benzothiazolines. Conversion to benzothiazines and benzothiazoles occurs in some instances, as documented by the isolation and spectroscopic characterization of the products.     

Molybdenum-95 nuclear magnetic resonance studies. Monosubstituted molybdenum carbonyls

Summary The⁹⁵Mo n.m.r. spectra for a series of molybdenum(0) complexes [Mo(CO)₅L] (L=N,P,As, or Sb donor ligands) have been observed; resonances occur in the –1433 to –1864 ppm range for the twenty-six complexes with the⁹⁵Mo shielding order being: N1J(⁹⁵Mo–³¹P) coupling constants areca. 135 Hz and 220 Hz for phosphines and phosphites, respectively. Factors that influence the trends in coupling constants and chemical shifts are discussed.     

Structure of zinc tetraphenylporphyrin dimethyl formamide-methylene chloride

C₄₈H₃₇N₅ZnOCl₂,M _r+836.13, triclinic, $P\bar 1$ ,a+11.2231(15),b+12.5155(18),c+14.6013(19)Å, α=99.001(7), β=94.600(8), γ=103.221(7)^o,V+1957.6(5)ų,Z+2, D_x+1.419 gcm^?3, MoKα (λ=0.7107Å), µ_cale,F(000)=1670,T+173±1K, final discrepancy factor 2.8% for 5274 unique reflections above 2.5σ(I) in the range 3<2θ<48^o. The metal is coordinated to the four nitrogen atoms of the porphyrin ring and the oxygen of the dimethyl formamide moiety. The geometry of this porphyrin is nonplanar with respect to the overall structure, although the pyrrole rings are nearly coplanar with the zine metal pulled out of the plane in the familiar domed-shaped geometry.