Chemical Cristallography

Coordinated by Alessia Bacchi

The pioneering and seminal work of the group of bright Italian crystallographers who worked in a number of strategic Italian Universities in the '60's gave birth to an Italian crystallographic Golden Age, and the urgence of "seeing the structure, understanding the chemistry" rapidly spred all over Italy. Today, along with the initial landmarks settled in Milan, Parma, Rome, Naples, Padua, Florence, Pavia, a large number of lively and creative laboratories has flourished in many other sites, playing crucial roles in the European landscape of Structural Chemistry.

In 2005 Florence will be the World scientific capital of Crystallography; the Florentine crystallographic community is centred around two laboratories, where the main research topics embrace structure-properties relationships of inorganic and organometallic compounds studied by experimental crystal structure analysis, systematic usage of structural databases, theoretical quantum-mechanical calculations[1], structure-activity relationships for small pharmacological organic molecules and macrocyclic metal complexes, coordination compounds of biological interest , and the interaction of small molecules (P4 , P4S3) with metal-ligand systems [2].

In Milan three laboratories operate in the field of structural chemistry, investigating: electrostatic properties by topological analysis of experimental electron density between 15K and 300K [3]; supramolecular architectures assembled by halogen bonding and organometallic complexes, weak H-bonds and metal-metal interactions by multipolar analysis of electron densities[4]; conventional X-ray single crystal diffractometry on organometallics and minerals, accurate LT structural determinations and topological analysis of experimental and theoretical charge densities, ab initio powder diffraction structural characterisation of materials, neutron diffraction, synthesis and characterisation of coordination polymers and supramolecular architectures (see figure), molecular modelling, crystal structure prediction, tomographic methods [5].

foto 5

New policatenation type in [Ni6(bpe)10(H2 O)16](SO4)6× xH2 O [bpe = bis(4-pyridyl)ethane] L. Carlucci, G. Ciani, D. M. Proserpio, S. Rizzato, Cryst.Eng.Comm., 2003, 5(34), 190-199

In Parma more than 20 researchers and technicians operate in the Laboratorio di Strutturistica [6], which has inherited the legacy of the Centro di Studio per la Strutturistica Diffrattometrica del C.N.R., founded in 1968. The scientific activity spans from structural and theorethical aspects of supramolecular chemistry and crystal engineering of organic/inorganic hybrid networks, to bioinorganic and bioorganic medicinal chemistry, from structure-reactivity relationships of organometallic compounds, to the characterization of superconducting and magnetic materials and to computational crystallography.

In Bologna, four groups operate in the laboratories of the Dipartimento di Chimica[7], where the research topics cover: hazard monitoring of asbestos, bone crystal growth, self-assembly of collagen fibers, drug delivery, hydroxyapatite based materials, chrysotile nanotubes, silica xero-gels, quantum wires, chemical-physical characterization of morphology and surfaces activity; design and development of new inorganic and composite materials with tailored functional properties (nano- and micro-crystalline inorganic phases, oriented growth of inorganic phases on nanostructured matrices, new biomaterials) ; group 8 metal carbonyl clusters and stereochemistry of low valent metal complexes; design of crystalline materials for applications in solid/solid and solid/gas solvent-free reactions, and polymorphism.

In Rome structure-activity studies on compounds of bio-pharmaceutical and industrial interest are a traditional interest of the IC-CNR Institute [8]. The research activities address: antiviral compounds; inhibitor-resistant b -lactamase to design new powerful inhibitors; design and synthesis of new peptide inhibitors of Zn-proteinases involved in inflammatory processes; polyamine catabolism in plants; inorganic compounds with possible antineoplastic activity; coordination and organometallic compounds of industrial interest. The reserachers at the Dipartimento di Chimica [9] are active since many years into the theoretical/experimental study and design of molecular adducts of nucleobases as a model for the DNA/RNA bases recognition.

The research activity at the University of Genova [10] started in the early fifties; since then, more than one thousand intermetallic compounds have been synthesized and structurally characterised; seventy new structure types have been discovered, and currently the crystal chemistry of intermetallic compounds, and structure-activity relationships for pharmaceutical organic compounds by XRD and QM methods are studied.

In Ferrara the group of structural physical chemistry[11] has contributed remarkably to the study of hydrogen bonded systems, and is currently involved in quantum-mechanical calculations of H-bonded systems, proton-transfer pathways, Bader's AIM topological analysis, molecular pharmacology , biothermodynamics, and molecular modelling.

In Turin crystal and molecular structures of coordination compounds and organometallic complexes are studied by X-ray and neutron diffraction since 1970s at the Laboratorio di Chimica Strutturale [12]. Study of experimental electron density and multipolar analysis from low temperature diffraction data of model molecules is addressed since late 1990s.

foto 6

Solid State Adducts between C60 and Decamethylferrocene (A. Arrais, E. Diana, R. Gobetto, M. Milanesio, D. Viterbo, P.L. Stanghellini, Eur. J. Inorg. Chem, 2003, 1186-1192)

In Padua at the Dipartimento di Scienze Farmaceutiche solid-state structural analyses of bioinorganic drugs, psychotropic agents belonging to the classes of cognition activators and nootropics, and theorethical analysis of coordination complexes and psychotropic agents are performed [13], while at the CNR Istituto di Chimica Biomolecolare crystallographic work is devoted to the conformational characterization of peptide antibiotics (peptaibols) and analogs thereof, synthetic peptides carrying non standard amino acid residues, and peptide foldamers [14].

In Messina the Interdepartmental Centre [15] shares human resources from many departments in the University. It is organised in three groups whose research topics cover physical and chemical crystallography, X-ray applications in cultural heritage materials, X-ray applications in materials science and engineering.

In Alessandria the group of structural physical chemistry [16] is involved in the study of biopharmacological compounds and of zeolites of catalytic interest. Weak interactions in molecular crystals and organic-inorganic interactions in relation to the biomineralization process are also being investigated.

At the University of Calabria [17] the current scientific fields of interest are the study of structure and magnetic behaviour of paramagnetic coordination compounds, and the interaction between metal ions and DNA components.

In Perugia [18] layered metal phosphates and phosphonates and synthetic hydrotalcites are designed for potential application in catalysis, proton conduction, ionic and molecular recognition and their structures are studied by powder diffraction.

1] ICCOM - CNR, Area Ricerca CNR di Firenze,

[2] Centro Interdipartimentale di Cristallografia Strutturale - Univ. Firenze,

[3] Dipartimento di Chimica Fisica ed Elettrochimica, Univ. Milano,

[4] ISTM-CNR, sede di Milano,

[5] Dip. di Chimica Strutturale e Stereochimica Inorganica, Univ. Milano,

[6] Dip. di Chimica G.I.A.F. - Univ. Parma,

[7] Dip. di Chimica 'G. Ciamician', Univ. Bologna,

[8] IC-CNR Sede di Bari, Sezione di Roma , Unità Staccata di Trieste,

[9] Dip. di Chimica - Univ. Roma La Sapienza,

[10] Dip. di Chimica e Chimica Industriale - Univ. Genova,

[11] Dip. di Chimica, Univ. Ferrara,

[12] Dip. di Chimica I.F.M., Univ. Torino,

[13] Dip. di Scienze Farmaceutiche - Univ. Padova,

[14] Ist. di Chimica Biomolecolare, CNR - Dip. di Chimica Organica - Univ. Padova,

[15] Centro Interdipartimentale per la Diffrattometria a Raggi-X, Univ. Messina,

[16] DISTA, Univ. Piemonte Orientale "A. Avogadro",

[17] Dip. di Chimica, Univ. Calabria,

[18] Dip. di Chimica, Univ. Perugia,