The synthesis and behavior in water of a set of various cis(Cl,Cl)-[R-tpyRuCl2(NO)](PF6) and trans(Cl,Cl)-[R-tpyRuCl2(NO)](PF6) (R = fluorenyl, phenyl, thiophenyl; tpy = 2,2′:6′,2′′-terpyridine) complexes are presented.
Boron and tin complexes have been a versatile and very interesting scaffold for the design of nonlinear optical (NLO) chromophores. In this paper we present a wide range of reports since the 1990s to date, which include second-order (e.g., second harmonic generation) and third-order (e.g., two-photon absorption) NLO properties. After a short introduction on the origin of the NLO response in molecules, the different features associated with the introduction of these inorganic motifs in the organic-based NLO materials are discussed: Their effect on the accepting/donating capabilities of the substituents, on the efficiency of the π-conjugated linkage, and on the topology of the chromophores which can be tuned from the first generation of “push-pull” chromophores to more sophisticated two- or three-dimensional architectures.
One monometallic and three bimetallic ruthenium nitrosyl (RuNO) complexes are presented and fully characterized in reference to a parent monometallic complex of formula [FTRu(bpy)(NO)] 3 + , where FT is a fluorenyl-substituted terpyridine ligand, and bpy the 2,2'-bipyridine. These new complexes are built with the new ligands FFT, TFT, TFFT, and TF-CC-TF (where an alkyne C�C group is inserted between two fluorenes). The crystal structures of the bis-RuNO 2 and bis-RuNO complexes built from the TFT ligand are presented. The evolution of the spectroscopic features (intensities and energies) along the series, at one-photon absorption (OPA) correlates well with the TD-DFT computations. A spectacular effect is observed at two-photon absorption (TPA) with a large enhancement of the molecular cross-section (σ TPA ), in the bimetallic species. In the best case, σ TPA is equal to 1523 � 98 GM at 700 nm, in the therapeutic window of transparency of biological tissues. All compounds are capable of releasing NO * under irradiation, which leads to promising applications in TPA-based drug delivery.
Since the discovery of the numerous physiological roles exhibited by nitric oxide (NO), ruthenium nitrosyl (RuNO) complexes have been regarded as one of most promising NO donors, stable, well tolerated...
Two, acyclic (1) and cyclic (2), steroidal
molecular rotors containing 1,4-diethynyl-2,3-difluoro-phenylene units
as rotators were investigated by means of single crystal X-ray diffraction,
high resolution solid state NMR spectroscopy, and computer methods.
The aim of this study was to understand and search for a correlation
between the size of difluoro-phenylene units and free space in the
crystal lattice required for molecular reorientation as well as the
topology and time scale of dynamic processes. As a primary tool for
analysis of molecular motions in the solid state, 1H–13C PISEMA, a technique which allows following the dynamics
in the range of 10–3–10–6 s, was employed. The PISEMA data defining the 1H–13C dipolar couplings, whose values are sensitive to local
motion, were confronted with 13C CSA parameters. Our studies
revealed that replacing hydrogen by fluorine in acyclic rotors has
significant consequences for dynamic processes. In the case of hydrogen-substituted
species, free rotation around the 1–4 axis of the benzene ring
was proven. For fluorine derivatives 1, only small amplitude
wobbling of aromatic residues was observed. The only large amplitude
reorientation, a so-called π-jump around the 1–4 axis,
was observed during the phase transition related with solvent migration
from the crystal lattice. For cyclic rotors (2) two crystallographic
forms 2A (triclinic, P1 space group)
and 2B (monoclinic, P21 space
group) are established. The form 2B containing a heptane
molecule in the crystal lattice undergoes a thermal transition with
large amplitude motion of building units of the steroidal frame. The
high dynamics of the fluorinated rotator for 2A is proven.
As et of BODIPY-carboranyl dyads synthesizedb ya Sonogashira cross-coupling reaction, where different C-substituted ortho-a nd meta-carboranyl fragments have been linked to aB ODIPY fluorophore is described. Chemical, photophysical and physicochemical analyses are presented, in-cludingN MR and singleX RD experiments, optical absorption/emission studies and partition coefficient(log P)m easurements. These studies, supported by DFT computations (M06-2X/6-31G**), provide an explanation to the largely divergentc ell income that thesef luorescent carboranyl-based fluorophores display,f or which as tructural or physicochemi-cal explanation remainse lusive. By studying the cell uptake efficiency and subcellular localization for our set of dyads on living HeLa cells, we trackedt he origins of these differences to significant variations in their static dipolem oments and partitionc oefficients,w hich tune their ability to interactw ith lipophilic microenvironments in cells. Remarkably, m-carboranyl-BODIPY derivativesw ith ah igherl ipophilicity are much betteri nternalisedb yc ells than their homologous with ocarborane, suggestingt hat m-isomers are potentially better theranostic agents for in vitro bioimaging and boron carriers for boron neutron capture therapy.
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