Colour tuneability of heteroleptic iridium complexes through second-sphere coordination.

Novel H-bond-rich iridium(iii) complexes with different systems of cyclometalating ligands bearing the general formula [Ir(C^N)(N^N)] were synthesised, characterised and their photophysical properties determined. The incorporated guanidine moieties allow us to introduce a hydrogen-bonding array for the formation of self-assembled iridium-bound hydrogen-bonded systems. Through a series of experimental and computational studies we demonstrated the host-guest chemistry of these systems.

Elucidation of Charge Contribution in Iridium-Chelated Hydrogen-Bonding Systems.

We present two iridium complexes and that contain cationic ligands to extend the knowledge of charge-assisted hydrogen bonding (CAHB), which counts among the strongest non-covalent bonding interactions. Upon protonation, both complexes were converted into new hydrogen-bonding arrays with various selectivity for respective H-bonding partners. This study compares the association strengths of four hydrogen-bonding co-systems, emphasizing the roles of CAHB in supramolecular systems.

A pH-Switchable Triple Hydrogen-Bonding Motif.

A stimuli responsive linear hydrogen bonding motif, capable of protonation and deprotonation, has been investigated. The interactions of the responsive hydrogen bonding motif with complementary partners were examined through a series of H NMR experiments, revealing that the recognition preference of the responsive hydrogen bonding motif in a mixture can be switched between two states.

Thiourea and Guanidine Compounds and Their Iridium Complexes in Drug-Resistant Cancer Cell Lines: Structure-Activity Relationships and Direct Luminescent Imaging.

Thiourea and guanidine units are found in nature, medicine, and materials. Their continued exploration in applications as diverse as cancer therapy, sensors, and electronics means that their toxicity is an important consideration. Iridium complexes present new opportunities for drug development and imaging in terms of structure and photoactivity.

Structures, Phase Behavior, and Fluorescent Properties of 3-Phenyl-1-(pyridin-2-yl)-1-pyrazol-5-amine and Its ZnCl Complex.

The synthesis of the asymmetric ligand 3-phenyl-1-(pyridin-2-yl)-1-pyrazol-5-amine () and its single-crystal X-ray structure are reported. displays crystallographic symmetry (orthorhombic, ) higher than its molecular symmetry (point group ) and also displays supercooling, with a difference in the melting and solidification points of over 100 °C. Upon complexation with ZnCl, engages in both primary cation and secondary anion coordination via hydrogen bonding, and the complex exhibits a room-to-low-temperature single crystal-to-crystal phase transition.

Influencing the Optoelectronic Properties of a Heteroleptic Iridium Complex by Second-Sphere H-Bonding Interactions.

The use of a new second-sphere coordination methodology for emission color tuning of iridium complexes is presented. We demonstrate that a complementary H-bonding guest molecule binding through contiguous triple H-bonding interactions can induce a shift in the emission of the iridium complex from green to blue without the need to alter the ligand structure around the metal center, while simultaneously increasing the photoluminescence quantum yield in solution. The association constant for this host-guest interaction was determined to be K = 4.

ABCB1 as predominant resistance mechanism in cells with acquired SNS-032 resistance.

The CDK inhibitor SNS-032 had previously exerted promising anti-neuroblastoma activity via CDK7 and 9 inhibition. ABCB1 expression was identified as major determinant of SNS-032 resistance. Here, we investigated the role of ABCB1 in acquired SNS-032 resistance.