Foto del docente

Silvia Bordoni

Associate Professor

Department of Industrial Chemistry "Toso Montanari"

Academic discipline: CHIM/03 General and Inorganic Chemistry

Research

Keywords: coordination Ru-nucleotidic bases amphiphilic and water soluble complexes chelate O,O and N,O Ru complexes experimental and DFT studies Ru-THA and R(9)hydroxy stearic acid coordination modes

2013-up to now. Studies on coordination shapes of  dihydride Ru complexes towards nucleotidic bases as THA (Timine acetic acid) to shed light on the way of acting to design novel anticancer drugs.

2009-2012 Diminishing of fossil fuel reserves, hazardous chemicals and wasteful processes have led to the emergence of 'green' technologies . An innovative  thermal-insulating material, derived from renewable resources and potentially able to offer an eco-friendly alternative to the conventional light-weighed synthetic products is currently studied, in collaboration with the ICIE, Bologna a Tecnology Transfer Architecture Lab for Construction.The designed material is suppose d to be a foamed low-cost organic-inorganic composite of lignosulfonate (LS), as the main waste product of cellulose-production, dispersed into an inert silicate gel matrix with the addition of a non-food corn starch-oil microemulsion (SOM), acting as thickener and gluing agent. The  resulting foamed organo-inorganic composite can be utilized as bore- brick filler or as sandwich panels between wood skins.

The introduction of hydroxyl groups into ligands is able to transfer high hydrophilic features to the related metal systems. The atom-economy synthetic procedure adopted which consists in the one-step Cyclopentene-oxide ring opening, quantitatitatively affords stereoselective formation of the multi-hydroxyl rac-1,2,4- C5H2[CH(CH2)3CHOH]3 CpOOO ligand.  Rh complexation of CpOOO gives rise to a novel class of water-soluble complexes (L,L)RhCpOOO  (LL=NBD 1, COD 2, CH2CH2 3, CO 4) characterized by their spectroscopic features (ESI-MS, IR, 2D NMR, n.O.e.). The X-ray diffraction studies of rac-1 reveal the occurrence of one couple of enantiomeric pairs in the crystal structure, whilst the crystal packing shows an interesting self-organization in chains of dimeric units of 1a, promoted by strong intermolecular hydroxyl H-bonding. This effect is exploited by VT NMR experiments in different solvents (CDCl3, py, DMSO). Unpredictably, in spite of the absence of chiral tag, 1 exhibits solvent-dependent chiroptical properties (ECD, aD25), which are correlated to UV transitions and DFT calculations in the vacuum and in the presence of several molecules of DMSO, which is responsible of the chiral amplification . The intra/inter molecular H-binding is crucial in driving the equilibrium between the distinct conformers of 1, by generating preferential orientations for the hydroxyl groups that cause a small discrepancy between the two forms.

 The use of silylated ligands such as [RC5H4(CH2)2OSiMe3 R=H, SiMe3] constitutes an efficient method to generate p-coordination and/or metal-alkoxy complexes. Upon the favoured release of Me3SiCl, [1] the silyl-mediated synthesis is an efficient strategy to afford nucleophilic additions under milder condition. The silyl-fluorenide [SiMe3Flu-, Flu=C13H8] with propylene oxide causes prompt O-silyl migration to give [Flu(CH2CH(Me)OSiMe3]- to obtain:

A)  p-Rh-coordination. 

B) monohapto h 1-Flu(CH2CHMeOSiMe 3)TiCl3(THF)2, which does not form h 5-Flu(CH2CHMeOSiMe 3)TiCl3  even under photolytic or thermal treatment.

C)  siloxy-silyl Fluorene derivative which can be viewed as a synthone of the corresponding dianion

With the aim of exploring the chemistry of Cp-alkoxide Ti complexes to thep-extended ligands, we report the reaction of TiCpCl3 with Flu ring bearing alcohol- or siloxy-moieties [C13H9(CH2CH(Me)OR)] [R=H FluOH a; R=SiMe3 FluOSi b]. Both b and c afford new alkoxy-Ti species FluOTiCpCl2 , via  releasing of [HPy]Cl



Chemistry of new anphiphilic cyclopentadienyl Rhodium complexes.         The atom- and chiral-economy diasteroselective synthesis of new polydentate 1-3 alcoholic CpO,O,O [C5H5-nRn; n=1,2,3 R = CH(CH2)3CHOH] performed either by one pot or multistep sequence, yields to selected (1,2,4) substitution positions and chirality sequence. The atropisomerism of the wing-span cycloalkyl substituents drives the Rh coordination to one prevalent form showing air stability and water solubility and M planar chirality. The racemic complexes (1S,2R,4S/R) h5-{C5H2[CH(CH2)3CHOH] 3Rh(LL) (LL=CO, COD, CH2CH2, NBD), have been isolated in high yield (80%) and the structure of the NBD derivative was determined by X-ray studies [Bordoni S. et al. Organomet. 2008, 27, 5, 945-954]. In spite of its racemic form in solid, it exhibits unexpected chiroptical properties in DMSO solution (UV, ORD, ECD), All the mono- and bis-functionalized intermediates have been isolated and characterized by Rh(L,L)-coordination. DFT calculations suggested the assignments and correlation of UV transitions in agreement to the observed Cotton effect. Asymmetric induction in hydrogenation catalysis and further extension to Ir coordination reaction has been studied.              Synthesis and coordination of new alcohol-substituted fluorenyl ligands.The nucleophylic addition of lithium fluorenyl to racemic propylene oxide diasteroselectively forms bifunctionalized fluorenes (80%) with enhancement of the racemic forms (R,R or S,S). The first epoxide opening reaction forms the intermediate species alcoholate, which causes O-migration from gem-carbon atom to give fluorenyl-alcohol. The latter species, keeping chirality memory [Zhao H. Synthesis 2005, 1, 1-16; J. Gawroński Chirality 2004, 16, 405-413] of the first side arm conformation, adds preferentially a second homo-chiral pendant. The spectroscopic features (performed by 1H NMR and IR) in solution will be compared with the three X-ray chiral structures of C13H9(CH2CHMeO)TiCpCl2 showing different supramolecular 3D macrocycles networks due to different intermolecular H-bonds generated by OH groups. The bis-alcohol forms quantitatively the desired chelate alkoxy Ti complexes such as C13H8(CH2CHMeO)2TiCpCl. The bis-alcohol-species forms quantitatively the desired chelate alkoxy Ti complexes such as C13H8(CH2CHMeO)2TiCpCl. Coordination of Cr(CO)3(NCMe)3 gives rise to the expected h6-benzo-coordinated complexes. The presence of traces of O2 promote the oxidation of the alcoholic pendants to ketone functionalities. From 2008 till now we are investigating on a novel ecocompatible formulate for  expanded insulating materials based on lignosulfonate and maize oil-starch composite incapsulated in a inert matrix of silicate. Currently the research is focused on coordinative studies on Ru hydride substrates of Thymine (TH) and its derivatives (THA) to investigate distinct coordination modes which rules the potential antitumoral activity

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