ASP studies on fluorine in biomedicine: two innovative applications

Author(s): Navarrini, Walter; (Canesi, Eleonora; Cantini, Marco; Resnati, Giuseppe; Metrangolo, Pierangelo; Ugger, Fulvio; Arcella, Vincenzo; Casati, Alessandro; Masella, Marco; Guala, Carlo; Ranzoni, Andrea; Sallemi, Livia; Sciacca, Beniamino; Scotti, Filippo.

Source: CHIMICA OGGI-CHEMISTRY TODAY

Volume: 25 Issue: 3 Pages: 48-50 Published: 2007

ABSTRACT:

Through the multiddiciplinary ASP project, some students of Politacnico di Milano and Politecnico di Torino had the possibility to deal with the peculiar properties of fluorinated compounds. In particular, we investigated the possible exploitation of these features for biomedical applications, focusing on two specific subjects: diagnostic tools and drug delivery. Perfluoroethers revealed to be suitable materials or these uses, because of a cohesive energy density and an enthalpy of vaporization lower than those of hydrogenated ethers.

Perfluoroalkylation of aromatic compounds with perfluorodiacyl peroxides

Author(s): Resnati, Giuseppe; Wlassics, Ivan; Sansotera, Maurizio; Metrangolo, Pierangelo; Navarrini, Walter.

Source: CHIMICA OGGI-CHEMISTRY TODAY

Volume: 25 Issue: 3 Supplement: 1 Pages: 23-25 Published: 2007.

ABSTRACT:

Perfluoroalkylation of aromatics obtained by perfluorodiacyl peroxide decomposition has been studied andrationalised. Products and by-products formed are in agreement with the proposed free radical/one electron transfer mechanism.

Metric engineering of supramolecular Borromean rings

Author(s): Liantonio, R; Metrangolo, P; Meyer, F; Pilati, T; Navarrini, W; Resnati, G.

Source: CHEMICAL COMMUNICATIONS

Issue: 17 Pages: 1819-1821

DOI: 10.1039/b516730b Published: 2006

ABSTRACT:

Two homologues of supramolecular Borromean rings were obtained based on the halogen-bonding-driven self-assembly of iodide ions with telechelic diiodoperfluoroalkanes.

http://pubs.rsc.org/en/journals/journalissues/cc#!recentarticles&all

Perfluorodiacyl peroxides: a class of free radical sources with a wide range of thermal decomposition temperatures

Author(s): Corvaja, Carlo; Famulari, Antonino; Franco, Lorenzo; Galimberti, Marco; Metrangolo, Pierangelo; Navarrini, Walter; Resnati, Giuseppe; Sansotera, Maurizio.

Source: CHIMICA OGGI-CHEMISTRY TODAY

Volume: 24 Issue: 3 Supplement: S Pages: 17-22 Published: 2006

ABSTRACT:

Perfluorodiacyl peroxides are an important class of perfluorinated peroxides. Thermal decompositions of selected temperature range perfluorinated peroxides have been analyzed in terms of stability of the radical products. In the temp of 0-90 C, all these peroxides undergo first-order decomposition in diluted solutions. EPR analyses provide important information in order to prove the structure of the oncoming perfluorinated radicals. Correlations between thermal stability and radical structures have been supposed.

New catalytic alkylation of in situ generated perfluoro-alkyloxy-anions and perfluoro-carbanions

Author(s): Galimberti, M; Fontana, G; Resnati, G; Navarrini, W.

Source: JOURNAL OF FLUORINE CHEMISTRY

Volume: 126 Issue: 11-12 Pages: 1578-1586

DOI: 10.1016/j.jfluchem.2005.09.005 Published: DEC 2005

ABSTRACT:

Alkyl fluoroformates RHOC(O)F are a new family of excellent alkylating agents. Perfluoroacyl fluorides, selected perfluoroketones and fluoroolefins can be alkylated to hydrofluoroethers R-F-O-R-H and hydrofluoroalkanes R-F-R-H, respectively. Potassium fluoride and cesium fluorides catalysts in glymes at 50-100 degrees C are the preferred experimental conditions.

http://www.sciencedirect.com/science/article/pii/S0022113905002551

alpha-Branched-perfluorodiacyl peroxides: preparation and characterization

Author(s): Galimberti, M; Barchiesi, E; Navarrini, W.

Source: JOURNAL OF FLUORINE CHEMISTRY

Volume: 126 Issue: 4 Pages: 587-593

DOI: 10.1016/j.jfluchem.2005.01.003 Published: APR 2005

ABSTRACT:

New perfluorodiacyl peroxides substituted at the a position have been synthesized and characterized. This class of peroxides shows good hydrolytic stability.

http://www.sciencedirect.com/science/article/pii/S0022113905000072#

New perfluorovinylethers through the bis(fluoroxy)difluoromethane (BDM) chemistry

Author(s): Navarrini, W; Corti, S.

Source: JOURNAL OF FLUORINE CHEMISTRY

Volume: 125 Issue: 2 Pages: 189-197

DOI: 10.1016/j.jfluchem.2003.07.011 Published: FEB 2 2004

ABSTRACT:

In the present work we give an overview of the CF2(OF)(2) radical reactivity and report the synthesis of new perfluorovinylethers. CF2=CF-OCF2OCF2CF3 and CF2=CF-OCF2OCF2CF2OCF3 are prepared in a semi-continuous methodology starting from CF2(OF)(2). These highly reactive vinylethers are characterized by the OCF2O group directly bonded to the insaturation. For this reason they are excellent candidates for the preparation of very low T-g perfluororubbers.

http://www.sciencedirect.com/science/article/pii/S0022113903002732

Perfluoro-4-methyl-1,3-dioxole: a new monomer for high-T-g amorphous fluoropolymers

Author(s): Russo, A; Navarrini, W.

Source: JOURNAL OF FLUORINE CHEMISTRY

Volume: 125 Issue: 1 Pages: 73-78

DOI: 10.1016/j.jfluchem.2003.10.009 Published: JAN 1 2004

ABSTRACT:

A 4-Chloro-5-trifluoromethyl-2,2,4-trifluoro-1,3-dioxolane (1) was synthesised by reaction of CF2(OF)(2) with CF3-CH=CFCl; the elimination of HCl from (1) in basic conditions led to the formation of dioxole perfluoro-4-methyl-1,3-dioxole (2). Both these synthetic steps gave the corresponding product in high yield. A new synthetic route for the preparation of CF3-CH=CFCl, starting from CF2ClBr and CH2=CF2, together with some examples of polymerisation products obtained by reaction of dioxole (2) with fluoroolefins are also reported.

http://www.sciencedirect.com/science/article/pii/S0022113903003099

Crown ethers as pre-organised exo-receptors in the divergent recognition of alpha,omega-diiodoperfluoroalkanes

Author(s): Navarrini, W; Metrangolo, P; Pilati, T; Resnati, G.

Source: NEW JOURNAL OF CHEMISTRY

Volume: 24 Issue: 10 Pages: 777-780

DOI: 10.1039/b002247k Published: 2000

ABSTRACT:

Both the nitrogen atoms of Kryptofix(R) 2.2. 1 act as electron-donors to the iodine atoms of alpha,omega-diiodoperfluoroalkanes 2a,b giving rise to infinite 1D chains 3a,b as white crystalline solids which are stable in air at room temperature. The structural features of these non-covalent co-polymers have been studied using various techniques (IR, H-1 NMR, F-19 NMR, X-ray diffraction) and it has been established that when Kryptofix 2.2. is halogen bonded to iodides 2, it adopts the same conformation as when in the pure form, namely the exo-exo topology. The co-existence of halogen-bonding and hydrogen-bonding in supramolecular architectures 3 suggests pre-organisation of the interacting partners as a new strategy in the rational design of divergent self-assembly processes.

http://pubs.rsc.org/en/Content/ArticleLanding/2000/NJ/b002247k#!divAbstract

Infrared and Raman analyses of the halogen-bonded non-covalent adducts formed by alpha,omega-diiodoperfluoroalkanes with DABCO and other electron donors

Author(s): Messina, MT; Metrangolo, P; Navarrini, W; Radice, S; Resnati, G; Zerbi, G.

Source: JOURNAL OF MOLECULAR STRUCTURE

Volume: 524 Pages: 87-94

DOI: 10.1016/S0022-2860(99)00445-7 Published: JUN 13 2000

ABSTRACT:

An attractive intermolecular interaction which has been called “halogen bonding” exists between the nitrogen, sulfur, or oxygen atoms present in HC motifs and the iodine atom of PFC residues. The “halogen bonding” is strong enough to overcome the low affinity existing between PFC and HC compounds, driving their self-assembly into supramolecular architectures. The non-covalent co-polymer formed by 1,2-diiodotetrafluoroethane with diazabicyclooctane has been prepared and characterised by FT-IR and -Raman spectroscopies. We propose the changes shown by the vibrational spectra of single PFC and HC components when involved in halogen bonded co-polymers as diagnostic probes of the interaction and as tools to rank the electron-donor ability of differently heteroatom substituted hydrocarbons.

http://www.sciencedirect.com/science/article/pii/S0022286099004457

COD ID: 7051307

From Repository: Crystallography Open Database.

Author(s): Navarrini, Walter; Metrangolo, Pierangelo; Pilati, Tullio; Resnati, Giuseppe

Source: Crystallography Open Database Source URL: http://www.crystallography.net/information_card.php?cif=7051307 Published Year: 2000

Organic hypofluorites and their new role in industrial fluorine chemistry

Author(s): Navarrini, W; Tortelli, V; Russo, A; Corti, S.

Source: JOURNAL OF FLUORINE CHEMISTRY

Volume: 95 Issue: 1-2 Pages: 27-39

DOI: 10.1016/S0022-1139(98)00296-6 Published: JUN 4 1999

ABSTRACT:

In this work a historical background of the synthesis and chemistry of fluorinated organic hypofluorites is given and some of the known applications of this class of compounds are reviewed. Recently, new industrial processes based on hypofluorite chemistry have been developed for the production of a variety of fluoromonomers. These processes are all based on the addition of hypofluorites having different structures to fluorinated olefins. Some mechanistic features of this key reaction are discussed, in terms of reactivity and stability of the intermediate primary radicals deriving from homolytic cleavage of the hypofluorite bond. Various aspects of these new processes are described and, in the light of these recent achievements, it is shown how hypofluorite chemistry has acquired great importance as a powerful and versatile methodology for the production of fluoromonomers of prominent industrial interest.

http://www.sciencedirect.com/science/article/pii/S0022113998002966

EPR AND ENDOR OF PERFLUOROALKYL RADICAL INTERMEDIATES IN THE REACTION BETWEEN PERFLUOROHYPOFLUORITES AND PERFLUOROALKENES

Author(s): CONTI, F; CORVAJA, C; CREMONESE, F; NAVARRINI, W; TORTELLI, V

Source: JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS

Volume: 91 Issue: 21 Pages: 3813-3820

DOI: 10.1039/ft9959103813 Published: NOV 7 1995

ABSTRACT:

EPR and ENDOR spectra of the reaction products of sterically hindered perfluoroalkenes with perfluoromethyl hypofluorite and with the perfluoroether hypofluorite X(CF2O)(n)(CF2CF2O)(m)CF2OF, where X is either OCF3 or a second hypofluorite group OCF2-OF, have been recorded. Tertiary and secondary free radicals are produced by the addition to the alkene double bond of a fluorine atom or of the partner radical formed by the homolysis of the hypofluorite O-F bond. Analysis of the spectra reveals that hyperfine splitting by F-19 nuclei in the gamma and delta positions, and even further from the radical centre, contribute spectra. The alpha- and beta-F-19 hyperfine splitting are discussed in relation to the radical structure and conformation. The beta-F-19 splittings are accounted for by the well known equation a(F)(beta) = B cos(2)(theta); different values of the constant B have to be used according to the number of beta-fluorine substituents bonded to the same alpha-carbon.

http://pubs.rsc.org/en/Content/ArticleLanding/1995/FT/ft9959103813#!divAbstract

RELATIVE RATE CONSTANTS FOR THE REACTIONS OF CF3OF WITH OLEFINS IN SOLUTION

Author(s):NAVARRINI, W; RUSSO, A; TORTELLI, V.

Source: JOURNAL OF ORGANIC CHEMISTRY

Volume: 60 Issue: 20 Pages: 6441-6443

DOI: 10.1021/jo00125a033 Published: OCT 6 1995

ABSTRACT:

The addition reactions of CF3OF to chloro fluoro olefins have been studied in solution at low temperature (-78, -105 degrees C), and their relative rate constants have been determined using the kinetic approach of competition reactions. The reactivity and regio- and stereoselectivity are consistent with a free radical chain-propagating reaction in which the alkenes are attacked by the CF3O. radical generated by homolitic cleavage of the O-F bond in the CF3OF molecule.

http://pubs.acs.org/doi/abs/10.1021/jo00125a033

THE REACTION OF CF3OOCF2OF WITH FLUOROOLEFINS

Author(s): RUSSO, A; MONTANARI, V; NAVARRINI, W; DESMARTEAU, DD.

Source: JOURNAL OF FLUORINE CHEMISTRY

Volume: 74 Issue: 1 Pages: 83-87

DOI: 10.1016/0022-1139(95)03243-7 Published: SEP 1995.

ABSTRACT

The reaction of fluoroxydifluoromethyl trifluoromethyl peroxide, CF3OOCF2OF (1), with fluoroolefins leads to the formation of novel fluorinated peroxides as major products. When 1 was added to 1,2-dichloro-1,2-difluoroethylene, CFCl=CFCl, under controlled conditions,the formation of 4,5-dichloro-2,2,4,5-tetrafluoro-1,3-dioxolane was also observed. A mechanism is proposed to rationalize these results.

http://www.sciencedirect.com/science/article/pii/0022113995032437