4 research outputs found
Novel Imino Thioether Complexes of Platinum(II): Synthesis, Structural Investigation, and Biological Activity
The reactions of the nitrile complexes <i>cis</i>- and <i>trans</i>-[PtCl<sub>2</sub>(NCR)<sub>2</sub>] (R = Me, Et, CH<sub>2</sub>Ph, Ph) with an excess of ethanethiol,
EtSH, in the presence of a catalytic amount of <i>n</i>-BuLi
in tetrahydrofuran (THF), afforded in good yield the bis-imino thioether
derivatives <i>cis</i>-[PtCl<sub>2</sub>{<i>E</i>-N(H)C(SEt)R}<sub>2</sub>] (R = Me (<b>1</b>), Et (<b>2</b>), CH<sub>2</sub>Ph (<b>3</b>), Ph (<b>4</b>))
and <i>trans</i>-[PtCl<sub>2</sub>{<i>E</i>-N(H)C(SEt)R}<sub>2</sub>] (R = Me (<b>5</b>), Et (<b>6</b>), CH<sub>2</sub>Ph (<b>7</b>), Ph (<b>8</b>)). The imino thioether ligands
assumed the <i>E</i> configuration corresponding to a <i>cis</i> addition of the thiol to the nitrile triple bond. The
spectroscopic properties of these complexes have been reported along
with the molecular structures of <b>1</b>, <b>2</b>, and <b>7</b> as established by X-ray crystallography which indicated
that these compounds exhibit square-planar coordination geometry around
the platinum center. Four N–H···Cl intermolecular
contacts (N–H···Cl ca. 2.5–2.7 Å)
between each chlorine atom and the N–H proton of the imino
thioether ligand gave rise to “dimers” Pt<sub>2</sub>Cl<sub>4</sub>L<sub>4</sub> (L = imino thioether) formed by two PtCl<sub>2</sub>L<sub>2</sub> units. The cytotoxic properties of these new
platinum(II) complexes were evaluated against various human cancer
cell lines. Among all derivatives, <i>trans</i>-[PtCl<sub>2</sub>{<i>E</i>-N(H)C(SEt)CH<sub>2</sub>Ph}<sub>2</sub>] showed the greatest in vitro cytotoxic activity being able
to decrease cancer cell viability roughly 3-fold more effectively
than cisplatin
Interplay between Structural and Dielectric Features of New Low k Hybrid Organic–Organometallic Supramolecular Ribbons
The synthesis and characterization of low k one-dimensional (1D) hybrid organic–organometallic supramolecular ribbons <b>3a</b>,<b>b</b>, through halogen-bond driven co-crystallization of <i>trans</i>-[Pt(PCy<sub>3</sub>)<sub>2</sub>(CC-4-py)<sub>2</sub>] (<b>1</b>) with 1,4-diiodotetrafluorobenzene (<b>2a</b>) and <i>trans</i>-1,2-bis-(2,3,5,6-tetrafluoro-4-iodophenyl)-ethylene (<b>2b</b>), are reported. The co-crystals <b>3a</b>,<b>b</b> have been obtained by isothermal evaporation of a chloroform solution containing the corresponding starting materials at room temperature. X-ray structure determinations show that noncovalent interactions other than halogen bonds help in the construction of the crystal packing; these interactions are stronger in <b>3b</b>, thus reducing the chain mobility with respect to <b>3a</b>. Accordingly, the broadband dielectric spectroscopic determinations, carried out from 10<sup>–2</sup> to 10<sup>7</sup> Hz and at a temperature ranging from 25 to 155 °C, showed that both <b>3a</b> and <b>3b</b> materials exhibit a real component of dielectric permittivity (ε′) significantly lower than SiO<sub>2</sub>. In particular in the case of <b>3b</b>, the rigidity of the 1D chain explains the observed ε″ and tan δ values. A permittivity value that is significantly lower than that of the silica reference, tan δ values lower than 0.02 in the entire investigated temperature range, and less than 0.004 at <i>T</i> < 100 °C make <b>3b</b> a very promising low k hybrid organic–organometallic material for application as dielectric films in next generation microelectronics
Platinum(II) Complexes with Novel Diisocyanide Ligands: Catalysts in Alkyne Hydroarylation
A series of novel diisocyanide ligands
(<i>o</i>-CNC<sub>6</sub>H<sub>4</sub>O)<sub>2</sub>Y (diNC-1:
Y = P(O)Ph; diNC-2:
Y = <i>o</i>-C(O)C<sub>6</sub>H<sub>4</sub>C(O); diNC-3:
Y = <i>m</i>-C(O)C<sub>6</sub>H<sub>4</sub>C(O); diNC-4:
Y = C(O)C<sub>2</sub>H<sub>4</sub>C(O); diNC-5: Y = <i>trans</i>-C(O)C<sub>2</sub>H<sub>2</sub>C(O)) was successfully synthesized
by reaction of lithium 2-isocyanophenate (generated in situ from benzoxazole
and <i>n</i>-BuLi) and a diacylic or phosphonic dichloride.
The corresponding platinum(II) complexes of general formula [PtX<sub>2</sub>(diNC)]<sub>1,2</sub> (X = Cl, Me; diNC = diisocyanide ligand)
were isolated by simple substitution of 1,5-cyclooctadiene in the
starting [PtX<sub>2</sub>(COD)] complexes. The structure of the complexes,
mononuclear or dinuclear, was confirmed by single-crystal X-ray analysis.
A dinuclear complex of formula {(μ-diNC)[<i>cis</i>-PtCl<sub>2</sub>(PPh<sub>3</sub>)]<sub>2</sub>} could also be obtained
with the diisocyanide ligand having a rigid fumaryl bridge and consequently
the isocyanide moieties pointing in opposite directions. All the complexes
were employed as catalysts in the hydroarylation of alkynes, showing
generally good activity and selectivity toward the <i>trans</i>-hydroarylation product. With <i>N</i>-methylindole as
aromatic substrate the major product was instead a heterocycle:alkyne
2:1 adduct
Platinum(II) Complexes with Novel Diisocyanide Ligands: Catalysts in Alkyne Hydroarylation
A series of novel diisocyanide ligands
(<i>o</i>-CNC<sub>6</sub>H<sub>4</sub>O)<sub>2</sub>Y (diNC-1:
Y = P(O)Ph; diNC-2:
Y = <i>o</i>-C(O)C<sub>6</sub>H<sub>4</sub>C(O); diNC-3:
Y = <i>m</i>-C(O)C<sub>6</sub>H<sub>4</sub>C(O); diNC-4:
Y = C(O)C<sub>2</sub>H<sub>4</sub>C(O); diNC-5: Y = <i>trans</i>-C(O)C<sub>2</sub>H<sub>2</sub>C(O)) was successfully synthesized
by reaction of lithium 2-isocyanophenate (generated in situ from benzoxazole
and <i>n</i>-BuLi) and a diacylic or phosphonic dichloride.
The corresponding platinum(II) complexes of general formula [PtX<sub>2</sub>(diNC)]<sub>1,2</sub> (X = Cl, Me; diNC = diisocyanide ligand)
were isolated by simple substitution of 1,5-cyclooctadiene in the
starting [PtX<sub>2</sub>(COD)] complexes. The structure of the complexes,
mononuclear or dinuclear, was confirmed by single-crystal X-ray analysis.
A dinuclear complex of formula {(μ-diNC)[<i>cis</i>-PtCl<sub>2</sub>(PPh<sub>3</sub>)]<sub>2</sub>} could also be obtained
with the diisocyanide ligand having a rigid fumaryl bridge and consequently
the isocyanide moieties pointing in opposite directions. All the complexes
were employed as catalysts in the hydroarylation of alkynes, showing
generally good activity and selectivity toward the <i>trans</i>-hydroarylation product. With <i>N</i>-methylindole as
aromatic substrate the major product was instead a heterocycle:alkyne
2:1 adduct