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
