Abstract: A tetravalent metal diphosphonate-phosphite composition definable by the following general formula:M(O.sub.3 P--R--PO.sub.3).sub.1-x (HPO.sub.3).sub.2x (I)is described where:M is a tetravalent metal;x varies from 0.5 to 0.66;R is an organic radical of bivalent aromatic type, carrying side groups which increase its steric hindrance.The composition is in the form of a crystalline solid with a type .alpha. layered structure with the diphosphonic groups positioned to join said layers together by a covalent bond (pillared compounds). It has a B.E.T. surface area from 300 to 500 m.sup.2 /g depending on the nature of R in formula (I), and a porosity in the micropore radius range of less than 20 .ANG. (Angstrom), such micropores contributing to the extent of more than 95% of the total area for the most crystalline materials.

Abstract: The present invention discloses a compound comprising a diphosphonate/phosphite of a tetravalent metal:M[(O.sub.3 P--R--PO.sub.3).sub.1-(x+y) (HPO.sub.3).sub.2X (O.sub.3 P--R--PO.sub.3 H.sub.2).sub.2y ](where M, R, x and y have the meaning given in the description), in the form of a crystalline solid with an alpha-type lamellar structure with a distance between layers of 7.4 to 20.ANG. (depending on the dimensions of radical R), a BET surface area of 250 to 400m.sup.2 /g, and porosity within the mesopore range, with at least 50% of the pores measuring 20 to 30.ANG.. The compound, depending on the radical R used, may or may not have microporosity in the region between layers. Such a diphosphonate/phosphite of a tetravalent metal is obtained by reaction between diphosphonic acid, phosphorous acid and an oxyhalide of a tetravalent metal, in a solvent comprising dimethyl-sulphoxide/water containing hydrofluoric acid.

Abstract: A method is disclosed for preparing functionalized adenine derivatives, said method comprising the step of reacting a compound which contains an adenine nucleus which has been halogen substituted in the 8-position, with a compound having the general formula M.sup.+- S--(CH.sub.2).sub.n --COO.sup.- M.sup.+ wherein M.sup.+ is the ion of an alkali metal and n is an integer, the reaction being carried out in a polar aprotic solvent. Procedures for preparing macromolecularized adenine compounds are also indicated by reacting a functionalized adenine derivative with a polymer which has at least one primary or secondary aminic group in its structure. This is a division of application Ser. No. 705,012 filed July 14, 1976, U.S. Pat. No. 4,091,203.

Abstract: A method is disclosed for preparing functionalized adenine derivatives, said method comprising the step of reacting a compound which contains an adenine nucleus which has been halogen substituted in the 8-position, with a compound having the general formula N.sup.+- S--(CH.sub.2).sub.n --CO0.sup.- M.sup.+ wherein M.sup.+ is the ion of an alkali metal and n is an integer, the reaction being carried out in a polar aprotic solvent. Procedures for preparing macromolecularized adenine compounds are also indicated by reacting a functionalized adenine derivative with a polymer which has at least one primary or secondary aminic group in its structure.

Abstract: A method is disclosed for preparing functionalized adenine derivatives, said method comprising the step of reacting a compound which contains an adenine nucleus which has been halogen substituted in the 8-position, with a compound having the general formula M.sup.+- S--(CH.sub.2).sub.n --COO.sup.- M.sup.+ wherein M.sup.+ is the ion of an alkali metal and n is an integer, the reaction being carried out in a polar aprotic solvent. Procedures for preparing macromolecularized adenine compounds are also indicated by reacting a functionalized adenine derivative with a polymer which has at least one primary or secondary aminic group in its structure.