Correction: Supramolecular influence on cis-trans isomerization probed by ion mobility spectrometry.

Correction for 'Supramolecular influence on cis-trans isomerization probed by ion mobility spectrometry' by Izabella Czerwinska et al., Phys. Chem. Chem. Phys., 2016, 18, 32331-32336.

Supramolecular influence on cis-trans isomerization probed by ion mobility spectrometry.

We used tandem ion mobility spectrometry measurements to investigate how the photo-isomerization of a chromophore (a methylpyridinium derivative) is affected by the complexation with a crown ether. A dramatic blue-shift of the photo-isomerization spectrum was observed upon complexation, which could be well reproduced by ab initio calculations. Our results support that the observed changes in the photo-physical properties of the chromophore originate from the charge-solvation of its pyridinium moiety by the host cage.

Structural analysis of ruthenium-arene complexes using ion mobility mass spectrometry, collision-induced dissociation, and DFT.

Ion mobility mass spectrometry (IM-MS) and collision-induced dissociation (CID) techniques were used to investigate the influence of the phosphine ligand on the physicochemical properties of [RuCl2(p-cymene)(PCy3)] (), [RuCl2(p-cymene)(PPh3)] (), and [RuCl2(p-cymene)(PTA)] () in the gas phase (PTA is 1,3,5-triaza-7-phosphaadamantane). Electrospray ionization of complexes and led to the corresponding [RuCl(p-cymene)(PR3)](+) ions via the dissociation of a chlorido ligand, whereas RAPTA-C () afforded two molecular ions by in-source oxidation ([Ru(III)Cl2(p-cymene)(PTA)](+)) or protonation ([RuCl2(p-cymene)(PTA+H)](+)). Control experiments showed that the balance between these two ionization paths was strongly influenced by the nature of the solvent used for infusion. Collision cross sections (CCSs) of the four molecular ions accurately reflected the variations of steric bulk inferred from the Tolman steric parameters (θ) of the phosphine ligands. Moreover, DFT calculations combined with a model based on the kinetic theory of gases (the trajectory method of the IMoS software) afforded reliable CCS predictions. The almost two times higher dipole moment of [RuCl2(p-cymene)(PTA+H)](+) (µ = 13.75 D) compared to [Ru(III)Cl2(p-cymene)(PTA)](+) (µ = 7.18 D) was held responsible for increased ion-induced dipole interactions with a polarizable drift gas such as N2. Further experiments with He and CO2 confirmed that increasing the polarizability of the buffer gas improved the separation between the two molecular ions derived from complex . The fragmentation patterns of complexes were determined by CID. The sequence of collision voltages at which 50% of a precursor ion dissociates (V50) recorded for the molecular ions derived from compounds was in good agreement with simple electronic considerations based on the donor strength of the phosphine ligand. Thus, the CCS and V50 parameters used to determine the shape and stability of ionic species in the gas phase are complementary to the Tolman steric and electronic parameters (θ and TEP) commonly used by organometallic chemists in condensed phases.

Interactions of cyclic and non-cyclic naphthalene diimide derivatives with different nucleic acids.

Recently, strategy based on stabilization of G-quadruplex telomeric DNA by small organic molecule has been realized by naphthalene diimide derivatives (NDIs). At the same time NDIs bind to DNA duplex as threading intercalators. Here we present cyclic derivative of naphthalene diimide (ligand 1) as DNA-binding ligand with ability to recognition of different structures of telomeric G-quadruplexes and ability to bis-intercalate to double-stranded helixes. The results have been compared to non-cyclic derivative (ligand 2) and revealed that preferential binding of ligands to nucleic acids strongly depends on their topology and structural features of ligands.

Improving the affinity of naphthalene diimide ligand to telomeric DNA by incorporating Zn²âº ions into its dipicolylamine groups.

N,N'-bis[3-[3-(2,2'-dipicolyl)methylaminopropyl]-methylaminopropyl]naphthalene-1,4,5,8-tetracarboxylic acid diimide, 1, and its complex with zinc ions, 2, were investigated against telomeric sequences, [TAGGG(TTAGGG)(3)] and [AGGG(TTAGGG)(3)], which reveal different G-quadruplex structures depending on the conditions. Spectrophotometric, SPR, and CD techniques revealed that both ligands showed large binding constants to hybrid-type G-quadruplexes formed in the presence of K(+) ions. Moreover, 2 revealed higher affinity to investigated oligonucleotides suggesting that complex of naphthalene diimide derivative with Zn(2+), comparing to 1, provided additional electrostatic or coordination interactions between positively charged zinc ions and condensed negative charged phosphate anions from G4 DNA.

Photoisomerizable arylstilbazolium ligands recognize parallel and antiparallel structures of G-quadruplexes.

The photoisomerization and DNA interaction studies of three arylstilbazolium derivatives with various samples of nucleic acids (duplexes, triplexes and tetraplexes) are reported. The equilibrium dialysis study revealed high binding affinities of ligands to tetraplex structures. The quadruplex-binding affinity could be switched by light, e.g., the E,E and E,Z isomers of 1,4-bis(vinylquinolinium)benzene (1) interacted with parallel and antiparallel tetraplexes exhibiting different binding selectivity. The E,Z-1 showed higher binding preference for c-myc DNA (a propeller-type quadruplex), whereas the E,E-1 favorably interacted with telomeric DNA (a basket-type quadruplex). The presence of quadruplex DNA hampered photoisomerization of quadruplex-bound ligand.