Kalium

Ohne Zusammenfassung     

Structure Determination of the Products from the Acid-Catalyzed Condensation of Indole with Acetone

Four of the previously reported compounds obtained from the acid-catalyzed condensation of indole with acetone are now assigned the following structures: cis-4,4a,9,9a-tetrahydro-2-(1H-indol-3-yl)-4,4-dimethyl-3H-carbazole (2a), 1,1',4,4'-tetrahydro-1,1,1',1'-tetramethyl-3,3'(2H,2'H)-spirobi[cyclopent[b]indole] (4), 4,4a-dihydro-2-(3-1H-indolyl)-4,4-dimethyl-3H-carbazol-4a-ol (7), and 5-(2-aminophenyl)-1,3,4,5-tetrahydro-1,1,4,4-tetramethylcyclopent[kl]acridine (8). The structure of the novel rearrangement product 8 was solved by an X-ray crystal structure determination. The two previously reported autoxidation products of 4 are now assigned the following structures: 1,3',4,4'-tetrahydro-1,1,4',4'-tetramethyl-cis-dispiro[cyclopent[b]indole-3(2H),2'(5'H)-furan-5',3"-[3H]-indol]-2"(1"H)-one (5) and 1,4-dihydro-1,1,5',5'-tetramethylspiro[cyclopent[b]indole-3(2H),3'(4'H)-1-benzazocine]-2'(1'H),6'(5'H)-dione (6).     

Synthesis and Antibacterial Activity of Cefixime Metal Complexes

Cefixime (H₂cefixi) reacts with transition metal(II) ions to give [M(cefixi)(H₂O)₂] complexes (M = Mn, Co, Ni and Cd) and [Fe(cefixi)Cl(H₂O)], which were characterized by physicochemical and spectroscopic methods, and an octahedral geometry is suggested for their structure. The complexes are polymers with high temperature decomposition points and are insoluble in water and common organic solvents. The complexes have been screened for antibacterial activity against several bacteria, and the results are compared with the activity of cefixime.     

The Cohen–Macaulay property of separating invariants of finite groups

In the case of finite groups, a separating algebra is a subalgebra of the ring of invariants which separates the orbits. Although separating algebras are often better behaved than the ring of invariants, we show that many of the criteria which imply the ring of invariants is non-Cohen–Macaulay actually imply that no graded separating algebra is Cohen–Macaulay. For example, we show that, over a field of positive characteristic p, given sufficiently many copies of a faithful modular representation, no graded separating algebra is Cohen–Macaulay. Furthermore, we show that, for a p-group, the existence of a Cohen–Macaulay graded separating algebra implies the group is generated by bireections. Additionally, we give an example which shows that Cohen–Macaulay separating algebras can occur when the ring of invariants is not Cohen–Macaulay.     

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.     

STERIC AND ELECTRONIC DESTABILIZATION OF THE P—Se BOND IN TRIARYLPHOSPHINE SELENIDE SYSTEMS

Abstract

Electronic and steric effects in SeP(Ar), compounds are discussed with the assistance of ¹J(⁷⁷Se-³¹P) correlations with d(P—Se) values and the pKa of the arylphosphines.     

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?     

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.