pH-responsive aldehyde-bearing cyclometalated iridium(Ⅲ) complex for tracking intracellular pH fluctuations under external stimulation

Intracellular p H undertakes critical functions in various biological and pathological processes. It is important to monitor intracellular p H fluctuations for understanding physiological and pathological processes.Here, one aldehyde-bearing cyclometalated iridium(Ⅲ) complex([(4-pba)_(2)Ir(dcphen)]PF_(6), 4-pba = 4-(2-pyridyl) benzaldehyde, dcphen = 4,7-dichloro-1,10-phenanthroline, probe 1) was synthesized and used to track intracellular p H fluctuations. Probe 1 displayed p H-dependent luminescence property in p H range of 1.81–6.81 with an evaluated p Kavalue of 4.30 in BR buffer-DMSO(v:v = 99:1). An intramolecular hydrogen bonds assisted p H-responsive mechanism was proposed for the p H-responsive behavior of probe1. Probe 1 was successfully applied for imaging and tracking p H fluctuations in He La cells under external stimulation with fast response time, good photostability as well as low cytotoxicity and high cell permeability. This work demonstrates that aldehyde-bearing cyclometalated iridium(Ⅲ) complex can be used as alternative p H-responsive probe for real-time tracking intracellular p H fluctuations, which provides a strategy for the design of p H-responsive probe in versatile applications.

Cyclometalated platinum(Ⅱ) complexes with sterically bulky camphor-derived groups as β-diketonate ancillary ligand:a new route to efficiently reducing π-π interactions and Pt-Pt interactions

A new series of mono-cyclometalated square planar platinum(Ⅱ) complexes have been synthesized and the single-crystal X-ray structures of complex 1 and 2 have been determined.The complexes have the general formula ppyPt(O^O),where ppy is 2-phenylpyridyl,and O^O is β-diketonate ancillary ligands with the acyl substituent group in position 3 of(D)-(+)-camphor.Although,like the many Pt(Ⅱ) complexes with square-planar geometry,these complexes have plane stacking modes in crystal structure,the sterically bulky camphor-derived groups compel extensive slipping of the molecular stacking planes,resulting in the negligible overlapping of the aromatic ring fragments between molecules and the considerable Pt-Pt distance.The resolved spectra and a little shifted emission in solid state of complexes show that there is significant reduction of π-π interactions and Pt-Pt interactions,and suggest these complexes may be good candidates for doped phosphorescent organic light emitting diodes(PhOLEDs) and even for nondoped PhOLEDs.

Tuning the Excited-state Properties of Cyclometalated Platinum(II) Complexes of 6-Phenyl-2,2′-bipyridine by Ancillary Acetylide Ligand

A series of luminescent cyclometalated platinum(II) complexes, (C^N^N)Pt(C≡CR) [HC^N^N=4 (4 tolyl) 6 phenyl 2,2′ bipyridine; R=4 chlorophenyl (1), phenyl (2) and 4 tolyl (3)], were synthesized, and their spectroscopic properties have been examined. These complexes are brightly emissive both in fluid solution and in the solid state, attributed to triplet metal to ligand charge transfer ( 3MLCT) state. The excited state energy can be tuned by ancillary acetylide ligands. The emission lifetimes in dichloro^methane solution at room temperature were up to 1 64 μs and the emission quantum yields were in the range of 0 03-0 15.

Cyclometalated Ruthenium Complexes of 1,2,3-Triazole-containing Ligands： Synthesis, Structural Studies, and Electronic Properties

Six bis-tridentate and two tris-bidentate cyclometalated ruthenium complexes with a 1,2,3-triazole-containing ligand have been prepared and characterized. Single-crystal X-ray analyses of complexes [（MeOptpy）Ru（Budtab）]-（PF6） and [（Mebip）Ru（Budtab）]（PF6） are presented, where MeOptpy is 4′-p-methoxyphenyl-2,2′：6′,2＂-terpyridine, Budtab is the 2-deprotonated form of 1,3-di（N-n-butyl-l,2,3-triazol-4-yl）benzene, and Mebip is bis（N-methyl-ben-zimidazolyl）pyridine. The electronic properties of these complexes are probed by spectroscopic and electrochemical analyses. Time-dependent density functional theory calculations have been performed to assist the assignment of the absorption spectra.

Advances on supramolecular assembly of cyclometalated platinum(Ⅱ) complexes

Organoplatinum（Ⅱ） compounds have received enormous attention over the past decades due to their square-planar geometry as well as intriguing photo-physical properties.Self-assembly has emerged as an excellent approach to create well-ordered supramolecular architectures with tunable properties,which underpin the role of solvent-directed approach for the design of functional materials.In this minireview,the recent advances on supramolecular self-assembly of cyclometalated platinum（Ⅱ） complexes have been discussed.During the self-assembly process,non-covalent Pt-Pt and π-π interactions play crucial roles in controlling the structures and functions of the resulting assemblies.

Study on Cyclometalated Palladium-azo Complexes as Colorimetric Probes for Hazardous Gas in Water

A synthesized cyclometalated palladium-azo complex was explored as a multifunctional probe for visual detection of SO2, H2S and NH3 in water. In acidic aqueous environment, the sensing solution underwent a sharp color change from poor violet to deep blue when titrated with Na2SO3 standard solution. But the color changed from poor violet to bright yellow when titrated with Na2S standard solution. In basic environment, the sensing solution rapidly changed to magenta when titrated by NH4Cl-NH3 standard buffer solution at high concentration. However, the color of sensing solution changed to blue when titrated by NH4Cl-NH3 standard buffer solution at low concentration although the pH was kept constant during the titration. Different species of these hazardous gases at environmentally relevant concentration levels were differentiated by independent optical signal outputs, and the interference from other inorganic ions commonly existing in water was very small.

Synthesis and polarized photoluminescence of novel phosphorescent cyclometalated platinum dimer

A novel phosphorescent cyclometalated platinum dimer with bis-[2-（p-dodecyloxyphenyl） pyridyll-hexane-1,6-diol as ligand and 1,3-（1-n-hexyl,3-n-heptadecyl）diketone as ancillary ligand was synthesized.The chemical structure and liquid crystal property of the dimer were characterized by ~1H NMR,ESl-MS,polarizing optical microscopy（POM） and differential scanning calorimetry （DSC）.The aligned film of title compound on the rubbed polyimide film is intensely emissive at room temperature with emission maximum at 516nm.The luminescence dichroic ratio（（？） ） at 516 nm is 3.1.

Unprecedented 1D Mixed-metal Polynuclear Cyclometalated Platinum Complexes： Synthesis, Structural Characterization and Spectroscopic Properties

The complexes [Pt2L2（μ-dppm）]（ClO4）2 （1） and {[Pt2L2（μ-dppm）Li（CH3CN）2]（ClO4）3}n （2）, where HL is 6-[4-（diethoxyphosphorylmethyl）phenyl]-2,2′-bipyridinyl and dppm is bis（diphenylphosphino）methane, have been synthesized and characterized. In complex 1 the platinum（Ⅱ） center adopts a distorted square planar coordination geometry. The polymer 2 exhibits a ＂stairstep＂ configuration with one-dimensional Pt（Ⅱ）N^N^CPO- Li（Ⅰ）-OPC^N^ NPt（Ⅱ） mixed-metal units which are linked through dppm. Both complexes have metal-metal interaction with Pt- Pt distances of 3.325（2） and 3.1432（9） A, respectively, and display strong metal-metal-to-ligand charge-transfer （MMLCT） triplet state emission. The density-functional-theory calculation was used to interpret the absorption spectra of the complexes.

Applications of Cyclometalation Five-Membered Ring Products and Intermediates as Catalytic Agents

The five-membered ring products and intermediates of cyclometalation reactions are very easily synthesized via donation from a hetero atom to a metal atom, which leads to the very high functionality of the product. This functionality is caused by the donation of the hetero atom and various types of metal atoms, halogen atom and other ligands such as alkanes, alkenes, alkynes, Cp, Cp*, aryl groups and heterocyclic compounds. These products have three types of catalytic applications: cyclometalation five-membered ring products as catalysts, cyclometalation five-membered ring intermediates as catalyst agents and cyclometalation five-membered ring intermediates with unconventional substrates and as catalyst actions. Because of the high functionality of these products, the applications of them have been increasing not only as the metathesis in the first and second generations of Hoveyda-Grubbs catalysts but also as in chiral reactions, cross-coupling reactions and polymerization reactions. The above cyclometalation products have been utilized for the production in many industrial fields such as pharmaceuticals, OLEDs, carbon dioxide utilizations, dye-sensitizer solar cells and sensors. We expect that these products would be used for the development of further new industrial products.

Structural, Electronic and Optical Properties of Multifunctional Iridium（III） and Platinum（II） Metallophosphors for Organic Light-Emitting Diodes

An elaborated theoretical investigation on the optical and electronic properties of three fluorene-based plati- num（II） and iridium（III） cyclometalated complexes Pt-a, Ir-a and lr-b is reported. The geometric and electronic structures of the complexes in the ground state are studied with density functional theory and Hartree Fock ap- proaches, while the lowest triplet excited states are optimized by singles configuration interaction （CIS） methods. At the time-dependent density functional theory （TD-DFT） level, molecular absorption and emission properties were calculated on the basis of optimized ground- and excited-state geometries, respectively. The computational results show that the appearance of triphenylamino （TPA） moiety at the 9-position of fluorene ring favors the hole-creation and leads to red-shifts of absorption and emission spectra. Moreover, Pt-a and Ir-b are nice hole-transporting materials whereas Ir-a has good charge-transfer balance, which render them useful for the realiza- tion of efficient OLEDs （Organic Light-Emitting Diodes）.

Development of Dual Phosphorescent Materials Based on Multiple Stimuli-Responsive Ir(Ⅲ)Acyclic Carbene Complexes

A new series of Ir(Ⅲ)carbene complexes with luminescent mechanochromism derived from trans-cis isomerization has been developed.Through the introduction of π-conjugating groups into the acyclic carbene ligand,the mechanochromic trans-and cisconfigurations can be readily interconverted,leading to dual emissive properties in the solid state.Moreover,the solid-or film-forming solvent system can control the dual emission and mechanoresponsive properties in the solid state.The potential uses of a single emissive complex to develop multicolor emissive and multiple stimuli-responsive films have been studied.