Molecular associations of 5-membered benzofused heterocyclic donors with organic acceptors

Benzofused heterocycles like 10H-[1]benzo thieno[3,2-b] indole and thieno[3,2-b]benzo[b]thiophene form molecular associations with ^* organic acceptors. The weak interactions involved are viewed in terms of UV-Vis and IR techniques. The results, mainly in the case of complexes of 10H-[1]benzo thieno[3,2-b] indole, are in some disagreement with the literature. The structure of the complex 10H-[1]benzo thieno[3,2-b] indole/tetracyanoethylene is also reported. The four condensed rings constitute a conjugate system with significant lengthenings of the aromatic ring bonds and a shortening of those of the five-membered rings. The fragment as a whole is almost planar, and forms a dihedral angle of 39.9(1)° with the planar tetracyanoethylene molecule.     

Incidence manifolds

It is shown that there are differentiable manifolds which can be characterized only by the geometric and topological structure of their linear subspaces. More precisely, such a characterization is possible for Grassmann and C. Segre's product manifolds. The starting point of this investigation was a paper by J. Misfeld, G. Tallini and the author [10], the ideas in which were further developed in [15,16,17].Dedicated to Professor Giuseppe Tallini on his 60^th birthday     

The structure of nitratotriphenylstannyltin(II): A compound with a tin(IV)tin(II) bond

A compound of formula [Sn^II(NO₃) [(C₆H₅)₃ Sn^IV], containing a tin(IV)tin(II) bond, has been prepared, and its crystal structure is determined.     

Sulfur-containing polymers. Synthesis and properties of novel poly(arylene thioether)s based on 2,2-bis(4-mercaptophenyl)propane

Novel poly(arylene thioether)s were synthesised using the one pot polymerisation method from the bis(N,N-dimethyl-S-carbamate) of 2,2-bis(4-mercaptophenyl)propane and activated difluoro aromatic compounds. Each of the polymers, obtained in good yields and with fairly high molecular weights, were characterised by IR, GPC and NMR analyses. In particular, the NMR characterisation was performed using ¹H NMR, ¹³C NMR, DEPT, 2D COSY and 2D HSQC experiments. To study the effect on the thermal properties of replacing the ethereal oxygen atoms with sulfur atoms, we have synthesised the counterparts, the poly(arylene ether)s, with similar molecular weights. We observed that the substitution of the ethereal oxygen atoms with sulfur atoms results in a slightly lower thermal stability for the poly(thioether ketone)s, both under nitrogen and in air, and does not modify the T_g values. For the poly(thioether sulfone), on the other hand, the thermal stability is equal to that of the poly(ether sulfone), while the T_g is 10 °C lower. Furthermore, each sample is completely amorphous, with the exception of one of the poly(thioether ketone)s (sample 1b), which shows the capacity to crystallise, even if with a very slow crystallisation kinetics.     

Column reversed-phase partition chromatography for the isolation of some radionuclides from biological materials

Revised-phase partition chromatography is a very useful tool for selective isolation of radionuclides from biological materials. Some new applications of this technique to the resolution of practical problems in radiation protection are reported. Natural thorium and enriched uranium can be determined separately and together in urine by means of a column of Microthene-710 supporting a solution of tri-n-octyl-phosphine oxide (TOPO) in cyclohexane; batchwise extraction processes with Microthene supporting TOPO are also successful. Strontium-90 is determined in urine by a batch extraction of yttrium-90 with a slurry of Microthene supporting the liquid cation exchanger di-(2-ethylhexyl)phosphoric acid. Only a wet mineralization of the urines is required and the analyses are simple, rapid and sufficiently accurate. A method for the isolation of iodine from foodstuffs with a Microthene-benzene column is also described.     

Activation of chlorobenzene as phenylating agent by means of a dinitrogen-molybdenum complex

Bis(dinitrogen)bis[1,2-bis(diphenylphosphino)ethane]molybdenum reacts with chlorobenzene to form molybdenum chloro complexes and phenylated organic products. Benzene, biphenyl, o-, m-, p-chlorobiphenyl, a dihydro derivative of o-chlorobiphenyl, triphenylphosphine and diphenylvinylphosphine were formed. The isomer distribution of the chlorobiphenyls is close to that obtained by decomposition of 0.02 M benzoyl peroxide in chlorobenzene under dinitrogen. The cleavage of the PhCl bond induced by the molybdenum-dinitrogen complex appears to give rise to the same homolytic reaction pattern. Phenylation of anisole and of triethyl phosphite has also been achieved with the same reagent.     

Synthesis of 2-[(E)-Hex-1′-enyl]tetrahydropyran Starting from 3-Nitro-4,5-dihydro-6H-pyran

The four steps preparation of 2-[(E)-hex-1′-enyl]tetrahydropyran starting from 3-nitro-4,5-dihydro-6H-pyran has been carried out in 40% overall yield.     

The adjoint representation inside the exterior algebra of a simple Lie algebra

For a simple complex Lie algebra g$\mathfrak{g}$ we study the space of invariants A=(?g^?⊗g^?)^g$A={(?{\mathfrak{g}}^{?}\otimes {\mathfrak{g}}^{?})}^{\mathfrak{g}}$, which describes the isotypic component of type g$\mathfrak{g}$ in ?g^?$?{\mathfrak{g}}^{?}$, as a module over the algebra of invariants (?g^?)^g${(?{\mathfrak{g}}^{?})}^{\mathfrak{g}}$. As main result we prove that A   is a free module, of rank twice the rank of g$\mathfrak{g}$, over the exterior algebra generated by all primitive invariants in (?g^?)^g${(?{\mathfrak{g}}^{?})}^{\mathfrak{g}}$, with the exception of the one of highest degree.