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A series of soluble and thermally stable group 10 platinum(II) polyyne polymers of the type [−C≡C−Pt(PBu3)2−C≡C−Ar−Ox−Ar−]n (where Ox = 1,3,4-oxadiazole; Ar = p-C6H4 or 2,7-dihexyl-9,9-fluorene) and [−C≡C−Pt(PBu3)2−C≡C−Ar−Ox−Ar−Ox−Ar−]n (where Ar = 2,7-dihexyl-9,9-fluorene) along with their corresponding dinuclear model compounds [Ph−Pt(PEt3)2−C≡C−Ar−]2−Ox− (where Ar = p-C6H4 or 2,7-dihexyl-9,9-fluorene) and [Ph−Pt(PEt3)2−C≡C−Ar−Ox−]2−Ar− (where Ar = 2,7-dihexyl-9,9-fluorene) were prepared and characterized. The regiochemical structure of the polymers has been ascertained by single-crystal X-ray analysis on the model compound [Ph−Pt(PEt3)2−C≡C−p−C6H4−]2−Ox−. The photophysical properties (absorption, excitation, emission, and nanosecond transient absorption spectra) of these metalated compounds in 2MeTHF at 298 and 77 K are reported. These findings are correlated by density functional theory (DFT) calculations. Geometry optimizations predict totally planar molecules for these metalated complexes and polyme...

Energy remains one of the world's great challenges. Growing concerns about limited fossil fuel resources and the accumulation of CO(2) in the atmosphere from burning those fuels have stimulated tremendous academic and industrial interest. Researchers are focusing both on developing inexpensive renewable energy resources and on improving the technologies for energy conversion. Solar energy has the capacity to meet increasing global energy needs. Harvesting energy directly from sunlight using photovoltaic technology significantly reduces atmospheric emissions, avoiding the detrimental effects of these gases on the environment. Currently inorganic semiconductors dominate the solar cell production market, but these materials require high technology production and expensive materials, making electricity produced in this manner too costly to compete with conventional sources of electricity. Researchers have successfully fabricated efficient organic-based polymer solar cells (PSCs) as a lower cost alternative. Recently, metalated conjugated polymers have shown exceptional promise as donor materials in bulk-heterojunction solar cells and are emerging as viable alternatives to the all-organic congeners currently in use. Among these metalated conjugated polymers, soluble platinum(II)-containing poly(arylene ethynylene)s of variable bandgaps (∼1.4-3.0 eV) represent attractive candidates for a cost-effective, lightweight solar-energy conversion platform. This Account highlights and discusses the recent advances of this research frontier in organometallic photovoltaics. The emerging use of low-bandgap soluble platinum-acetylide polymers in PSCs offers a new and versatile strategy to capture sunlight for efficient solar power generation. Properties of these polyplatinynes--including their chemical structures, absorption coefficients, bandgaps, charge mobilities, accessibility of triplet excitons, molecular weights, and blend film morphologies--critically influence the device performance. Our group has developed a novel strategy that allows for tuning of the optical absorption and charge transport properties as well as the PSC efficiency of these metallopolyynes. The absorbance of these materials can also be tuned to traverse the near-visible and near-infrared spectral regions. Because of the diversity of transition metals available and chemical versatility of the central spacer unit, we anticipate that this class of materials could soon lead to exciting applications in next-generation PSCs and other electronic or photonic devices. Further research in this emerging field could spur new developments in the production of renewable energy.

The synthesis, characterization and photophysics of a solution-processable metallopolyyne of platinum (P1) functionalized with the dioctyloxyphenyl-substituted thienopyrazine–thiophene hybrid spacer and its model molecular complex (M1) are described. Such metallopolymer P1 possesses a very low bandgap of 1.50 eV which extends towards the near-infrared (NIR) range of the solar spectrum, and represents one of the lowest optical bandgaps reported for metallopolyynes. With the capability of spanning a wider solar-radiation range, P1 can be used to fabricate efficient solar cells with power conversion efficiencies (PCEs) of up to 0.46% under air mass (AM1.5) simulated solar illumination. The electronic effect of the central heterocyclic ring sandwiched between the two thiophene units on the optical properties of these metallopolyynes has been investigated. The present study provides a good approach towards achieving conjugated polymeric materials with a broad solar absorption and demonstrates the potential of low-bandgap metallopolyynes for simultaneous visible and NIR light power generation.

The use of diethynylsilane, diethynyldisilane and diethynyldisiloxane in the synthesis of some linked metal carbonyl clusters is demonstrated. New dimeric η2-diyne complexes of cobalt [{Co2(CO)6}2(η2-diyne)], ruthenium [{(μ-H)Ru3(CO)9}2(μ3-η2,η2-diyne)] and osmium [{(μ-CO)Os3(CO)9}2(μ3-η2-diyne)] {diyne=HC≡CSi(CH3)2C≡CH, HC≡CSi(CH3)2–Si(CH3)2C≡CH, HC≡CSi(CH3)2–O–Si(CH3)2C≡CH or HC≡CSi(Ph)2C≡CH} have been prepared in good yields from the reaction of [Co2(CO)8], [Ru3(CO)12] and [Os3(CO)10(NCMe)2] with half an equivalent of the appropriate diyne ligand, respectively. All the twelve compounds have been characterized by IR and 1H NMR spectroscopies and mass spectrometry. The molecular structures of eight of them have been determined by X-ray crystallography. Structurally, each of the tetracobalt species displays two Co2C2 cores adopting the pseudo-tetrahedral geometry with the alkyne bond lying essentially perpendicular to the Co–Co vector. For the group 8 ruthenium and osmium analogues, the hexanuclear carbonyl clusters consist of two trinuclear metal cores with the μ3-η2,η2 bonding mode for the acetylene groups in the former case and μ3-(η2-||) bonding mode in the latter one. Density functional theory was employed to study the electronic structures of these molecules in terms of the nature of the silyl or disilyl unit and its substituents.

A homologous set of 9,9-dialkyl-4,5-diazafluorene compounds were prepared by alkylation of 4,5-diazafluorene with the appropriate alkyl bromide and under basic conditions. The structures of these simple organic compounds were confirmed by spectroscopic techniques (FTIR, NMR, and FABMS). Their biological effects toward a panel of human carcinoma cells, including Hep3B hepatocellular carcinoma, MDAMB-231 breast carcinoma, and SKHep-1 hepatoma cells, were investigated; a structure-activity correlation was established with respect to the length of the alkyl chain and the fluorene ring structure. The relationship between the mean potency [log(1/IC(50))] and alkyl chain length was systematically studied. The results show that compounds with butyl, hexyl, and octyl chains exhibit good growth inhibitory effects toward these three human carcinoma cell lines, and the 9,9-dihexyl-4,5-diazafluorene further exhibits antitumor activity in athymic nude mice Hep3B xenograft models. For the structurally related dialkylfluorenes that lack the diaza functionality, in vitro cytotoxicity was not observed at clinically relevant concentrations.

Phosphorus-bridged strained [1]ferrocenophanes [Fe{(eta-C(5)H(4))(2)P(CH(2)CMe(3))}] (2) and [Fe{(eta-C(5)H(4))(2)P(CH(2)SiMe(3))}] (3) with neopentyl and (trimethylsilyl)methyl substituents on phosphorus, respectively, have been synthesized and characterized. Photocontrolled living anionic ring-opening polymerization (ROP) of the known phosphorus-bridged [1]ferrocenophane [Fe{(eta-C(5)H(4))(2)P(CMe(3))}] (1) and the new monomers 2 and 3, initiated by Na[C(5)H(5)] in THF at 5 degrees C, yielded well-defined polyferrocenylphosphines (PFPs), [Fe{(eta-C(5)H(4))(2)PR}](n) (R=CMe(3) (4), CH(2)CMe(3) (5), and CH(2)SiMe(3) (6)), with controlled molecular weights (up to ca. 60 x 10(3) Da) and narrow molecular weight distributions. The PFPs 4-6 were characterized by multinuclear NMR spectroscopy, DSC, and by GPC analysis of the corresponding poly(ferrocenylphosphine sulfides) obtained by sulfurization of the phosphorus(III) centers. The living nature of the photocontrolled anionic ROP allowed the synthesis of well-defined all-organometallic PFP-b-PFS(F) (7a and 7b) (PFS(F)=polyferrocenylmethyl(3,3,3,-trifluoropropyl)silane) diblock copolymers through sequential monomer addition. TEM studies of the thin films of the diblock copolymer 7b showed microphase separation to form cylindrical PFS(F) domains in a PFP matrix.

By wisely utilizing combinations of exciton-managed orange-phosphorescence/sky blue-fluorescence, we report on high-efficiency white organic light-emitting diodes (WOLEDs) with high color-stability together with reduced efficiency roll-off. Two WOLEDs with the peak current efficiencies of 34.5 and 42.5 cd A−1 which slightly shift to 34.2 and 40.0 cd A−1 at 1000 cd m−2 are demonstrated. Systematic investigations focused on the effects of hole-injection buffer layer, thickness of emitting-layer (EML) and the stepwise-doping profile of orange phosphorescent EML on the device performance have been performed. It is evidently shown that careful management of the triplet/singlet excitons and charge-carriers is key to realizing such high performance of the devices. The results will beyond doubt be helpful to the design of both material and device structure for high-performance WOLEDs and next-generation solid-state lighting sources.

The synthesis, thermal and emission properties of an electrophosphorescent platinum(II) metallopolyyne polymer consisting of 9-butylcarbazole-2,7-diyl spacer P1 are described. The optical and electronic properties of P1 are compared to their molecular diplatinum(II) and digold(I) model complexes. The photophysical properties of P1 are somehow analogous to its 2,7-fluorene-linked congener but differs significantly from that for the 3,6-carbazole derivative. Its optical band gap is notably reduced as compared to that for the 3,6-carbazole analog. Multi-layer polymer light-emitting diodes (PLEDs) were fabricated with P1 as the emitting layer which gave a strong green-yellow electrophosphorescence. The best PLED can reach the maximum current efficiency of 4.7 cd . A(-1) at 5 wt.-% doping level, corresponding to an external quantum efficiency of 1.5%. This represents the first literature example of efficient PLEDs exhibiting pure triplet emission under electrical excitation for metallopolyynes without the concomitant singlet emission.

A series of soluble and thermally stable group 10 platinum(II) polyyne polymers of the type [−C≡C−Pt(PBu3)2−C≡C−X−]n along with their corresponding dinuclear model compounds [Ph−Pt(PEt3)2−C≡C]2−X− and [Ph3P−Au−C≡C]2−X− where X = F, Cz′, Cz, Cz−F, (Cz)2, (Cz)3 and Cz−F−Cz; F = 2,7-fluorene, Cz′ = 2,7-carbazole, Cz = 3,6-carbazole, were prepared and characterized. The electronic spectra (absorption, excitation, emission and ns transient absorption spectra) and the photophysical properties of these metalated compounds in 2MeTHF at 298 and 77 K are reported. These findings are correlated to the computational data obtained by density functional theory (DFT). Evidence for intramolecular singlet electron and triplet energy transfers from the Cz chromophore to the F moiety is provided and discussed in detail for those with organic spacers consisting of the carbazole−fluorene hybrids. The rate for electron transfer is very rapid (ket > 4 × 1011 s−1 at 298 K) whereas that for triplet−triplet energy transfer is much...

A series of cyclometalating platinum(II) complexes with substituted 9-arylcarbazolyl chromophores have been synthesized and characterized. These complexes are thermally stable and most of them have been characterized by X-ray crystallography. The phosphorescence emissions of the complexes are dominated by (MLCT)-M-3 excited states. The excited state properties of these complexes can be modulated by varying the electronic characteristics of the cyclometalating ligands via substituent effects, thus allowing the emission to be tuned from bright green to yellow, orange and red light. The correlation between the functional properties of these metallophosphors and the results of density functional theory calculations was made. Because of the propensity of the electron-rich carbazolyl group to facilitate hole injection/transport, the presence of such moiety can increase the highest occupied molecular orbital levels and improve the charge balance in the resulting complexes relative to the parent platinum(II) phosphor with 2-phenylpyridine ligand.

Transition-metal-based phosphorescent materials have recently received considerable academic and industrial attention for fabricating electrophosphorescent organic light-emitting diodes (PHOLEDs), owing to their potential to harness the energies of both the singlet and triplet excitons after charge recombination. Materials suitable for application in PHOLEDs have been actively researched in the past decade and chemical principles have played a crucial role in the evolution of efficient devices for commercialization. More current attention has been paid to the structure–property relationships of phosphorescent small-molecule heavy metal chelate complexes and polymers featuring multiple functional moieties. These organometallic electrophosphors typically possess various hole-transporting, electron-transporting and phosphorescent chromophores with tunable charge-transporting and triplet light-emitting properties. Rational design of multi-component small-molecular metallophosphors, metallodendrimers and metallopolymers aiming at color tuning and multiple functions forms the major focus of this review. In this way, different functional groups can perform specific roles such as photoexcitation, charge transportation and phosphorescence so that highly efficient and simple electrophosphorescent device structures can be developed. The electronic, optical, structural, photo- and electroluminescence properties of these multi-component compounds will be surveyed and discussed. This prominent class of organometallic compounds constitutes an attractive new class of electrophosphors that are thermally and morphologically stable, structurally diverse, and potentially important in optoelectronic applications.

A new series of luminescent group 10–12 metal alkynyl complexes and polyyne polymer containing a central tris(p-ethynylphenyl)amine bridging chromophore were prepared. The regiochemical structures of these triangular-shaped trinuclear compounds and polymer were studied by various spectroscopic and photophysical analyses. Upon photoexcitation, each of them emits an intense purple-blue fluorescence emission in the near UV region in dilute fluid solutions at room temperature. Harvesting of organic triplet emissions observed in the low-energy region harnessed through the strong heavy-atom effects of group 10–12 transition metals was examined and the results were compared among these three neighboring late transition metal elements. The influence of group 15 nitrogen-based heteroatom on the intersystem crossing rate and the spatial extent of the lowest singlet and triplet excitons was fully elucidated and a comparison was made to the nearest group 14 and 16 neighbors in the same row of the Periodic Table.

A series of solution-processable and strongly visible-light absorbing polyplatinynes containing oligothienyl–fluorene ring hybrids were synthesized and characterized. These rigid-rod organometallic materials are soluble in polar organic solvents and show intense absorptions in the visible spectral region, rendering them excellent candidates for bulk heterojunction polymer solar cells. The photovoltaic behavior depends significantly on the number of thienyl rings along the polymer chain, and some of these polymer solar cells show high power conversion efficiencies (PCEs) of up to 2.9% and a peak external quantum efficiency to 83% under AM1.5 simulated solar illumination. The effect of oligothienyl chain length on improving the polymer solar cell efficiency and on their optical and charge transport properties is elucidated in detail. At the same blend ratio of 1:5, the light-harvesting capability and PCE increase markedly with increasing number of thienyl rings. The power dependencies of the solar cell parameters (including the short-circuit current density, open-circuit voltage, fill-factor, and PCE) were also examined. The present work opens up an attractive avenue to developing conjugated metallopolymers with broad and strong solar energy absorptions and tunable solar cell efficiency and supports the potential of metalated conjugated polymers for efficient power generation.

The synthesis of polymers of the type (-Cz-C[triple chemical bond]C-PtL(2)-C[triple chemical bond]C-Cz-X-)(n) along with the corresponding model compounds (Ph-PtL'(2)-C[triple chemical bond]C-Cz)(2)-X-, where Cz=3,3'-carbazole, X=nothing, Cz, or F (2,2'-fluorene), L=PBu(3), and L'=PEt(3) are reported. The electronic spectra (absorption, excitation, emission, and ns-transient spectra) and the photophysics of these species in 2-methyltetrahyrofuran (2MeTHF) at 298 and 77 K are presented. Evidence for singlet electron and triplet energy transfer from the Cz chromophore to the F moiety are provided and discussed in detail. The rate for electron transfer is very fast (>4 x 10(11) s(-1)), whereas that for triplet-triplet energy transfer is much slower (approximately 10(3) s(-1)). This work represents a very rare example of studies that address electronic communication in the backbone of a conjugated organometallic polymer.

With the target to design and develop new functionalized green triplet light emitters that possess distinctive electronic properties for robust and highly efficient phosphorescent organic light-emitting diodes (PHOLEDs), a series of bluish-green to yellow-green phosphorescent tris-cyclometalated homoleptic iridium(III) complexes [Ir(ppy-X)(3)] (X=SiPh(3), GePh(3), NPh(2), POPh(2), OPh, SPh, SO(2)Ph, Hppy=2-phenylpyridine) have been synthesized and fully characterized by spectroscopic, redox, and photophysical methods. By chemically manipulating the lowest triplet-state character of Ir(ppy)(3) with some functional main-group 14-16 moieties on the phenyl ring of ppy, a new family of metallophosphors with high-emission quantum yields, short triplet-state lifetimes, and good hole-injection/hole-transporting or electron-injection/electron-transporting properties can be obtained. Remarkably, all of these Ir(III) complexes show outstanding electrophosphorescent performance in multilayer doped devices that surpass that of the state-of-the-art green-emitting dopant Ir(ppy)(3). The devices described herein can reach the maximum external quantum efficiency (eta(ext)) of 12.3 %, luminance efficiency (eta(L)) of 50.8 cd A(-1), power efficiency (eta(p)) of 36.9 Lm W(-1) for [Ir(ppy-SiPh(3))(3)], 13.9 %, 60.8 cd A(-1), 49.1 Lm W(-1) for [Ir(ppy-NPh(2))(3)], and 10.1 %, 37.6 cd A(-1), 26.1 Lm W(-1) for [Ir(ppy-SO(2)Ph)(3)]. These results provide a completely new and effective strategy for carrier injection into the electrophosphor to afford high-performance PHOLEDs suitable for various display applications.

A new and synthetically versatile strategy has been developed for the phosphorescence color tuning of cyclometalated iridium phosphors by simple tailoring of the phenyl ring of ppy (Hppy=2-phenylpyridine) with various main-group moieties in [Ir(ppy-X)(2)(acac)] (X=B(Mes)(2), SiPh3, GePh3, NPh2, POPh2, OPh, SPh, SO2Ph). This can be achieved by shifting the charge-transfer character from the pyridyl groups in some traditional iridium ppy-type complexes to the electron-withdrawing main-group moieties and these assignments were supported by theoretical calculations.

The synthesis, structures, photophysics, electrochemistry and electrophosphorescent properties of new red phosphorescent cyclometalated iridium(III) isoquinoline complexes, bearing 9-arylcarbazolyl chromophores, are reported. The functional properties of these red phosphors correlate well with the results of density functional theory calculations. The highest occupied molecular orbital levels of these complexes are raised by the integration of a carbazole unit to the iridium isoquinoline core so that the hole-transporting ability is improved in the resulting complexes relative to those with I-phenylisoquinoline ligands. All of the complexes are highly thermally stable and emit an intense red light at room temperature with relatively short lifetimes that are beneficial for highly efficient organic light-emitting diodes (OLEDs).

This chapter focuses on the recent developments in luminescent metallopolymers. Synthetic routes to these polymers are briefly described and their applications in polymer white light-emitting diodes are discussed.

Two complexes dichloro(9,9-dihexyl-4,5-diazafluorene)platinum(II) (Pt-DHF) and dichloro(9,9-dihexyl-4,5-diazafluorene)palladium(II) (Pd-DHF) were synthesized and their in vivo antitumour activity was investigated using an athymic nude mice model xenografted with human Hep3B carcinoma cells. Pt-DHF- and Pd-DHF-treated groups showed significant tumour growth inhibition (with about 9-fold and 3-fold tumour growth retardation) when compared with the vehicle control group. The liver toxicology effects on the animals of the two compounds were investigated. Pt-DHF and Pd-DHF-treated groups had a lower alanine transaminase and aspartate transaminase values than those of the vehicle treated group as the animals from the vehicle control group had very heavy hepatoma burden. We assume that both complexes could be further investigated as effective antitumour agents and it is worthwhile to study their underlying working mechanism.

The synthesis and photophysical studies of several multifunctional phosphorescent iridium(III) cyclometalated complexes consisting of the hole-transporting carbazole and fluorene-based 2-phenylpyridine moieties are reported. All of them are isolated as thermally and morphological stable amorphous solids. Extension of the pi-conjugation through incorporation of electron- pushing carbazole units to the fluorene fragment leads to bathochromic shifts in the emission profile, increases the highest oc- cupied molecular orbital levels and improves the charge balance in the resulting complexes because of the propensity of the carbazole unit to facilitate hole transport. These iridium-based triplet emitters give a strong orange phosphorescence light at room temperature with relatively short lifetimes in the solution phase. The photo- and electroluminescence properties of these phosphorescent carbazolylfluorene-functionalized metalated complexes have been studied in terms of the coordinating position of carbazole to the fluorene unit. Organic light-emitting diodes (OLEDs) using these complexes as the solution-processed emissive layers have been fabricated which show very high efficiencies even without the need for the typical hole-transporting layer.I These orange-emitting devices can produce a maximum current efficiency of similar to 30 cd A(-1) corresponding to an external quantum efficiency of similar to 10 % ph/el (photons per electron) and a power efficiency of similar to 14 Im W-1.

Three new unsymmetrical phenothiazine-based platinum(II) bis(acetylide) complexes PT1-PT3 with different electron-donating arylacetylide ligands were synthesized and characterized. Their photophysical, electrochemical, and photovoltaic properties have been fully investigated and the density functional theory (DFT) calculations have been carried out. Under AM 1.5 irradiation (100 mW cm(-2)), the PT1-based dye-sensitized solar cell (DSSC) device exhibited an attractive power conversion efficiency (η) up to 5.78 %, with a short-circuit photocurrent density (J(sc)) of 10.98 mA cm(-2), an open-circuit photovoltage (V(oc)) of 0.738 V, and a fill factor (ff) of 0.713. These findings provide strong evidence that platinum-acetylide complexes have great potential as promising photosensitizers in DSSC applications.

A new family of luminescent platinum(II) acetylide complexes and polymers were formed by the copper(I) catalyzed reaction of cis-[PtCl2(PR3)2] (R=C6H5–p-CH3) with appropriate acetylide ligands. The reaction of metal precursors with 2.5 equivalents of monoterminal acetylide ligands provided metal complexes trans-[Pt(p-tolyl3P)2(C≡C-R)2] (R=C6H4-p-NO2 (1) C6H4 -p-CH3 (2)), and equimolar amounts of diterminal ligand and metal chloride precursor, under reflux, afforded the metal poly-yne polymers [-Pt(p-tolyl3P)2C≡C–R–C≡C–]n, (R=biphenyl and 2,5-dioctyloxybenzene). Characterization of the newly developed polymer and metal complexes was accomplished by FT-IR, multinuclear NMR (1H, 31P, 13C) and mass spectrometry, as well as elemental analysis. The molecular structure of the metal complex trans-[Pt(p-tolyl3P)2(C≡CC6H4–p-NO2)2] (1) was confirmed by single crystal X-ray crystallography. The electronic absorption and photoluminescence spectra of the metal complexes and polymers have been used to probe their photophysical properties. The studies reveal that the presence of heavy metal atom and substituent groups on the phenyl ring of the ligands can enhance the efficiency of intersystem crossing from the S1 singlet excited state to the T1 triplet excited state and thus give intense phosphorescence.

Rigid-rod transition metal acetylide polymers or polymetallaynes belong to a class of metallopolymers, which are technologically and scientifically important owing to their unique structures and optoelectronic properties. Fine-tuning of the desired physical and functional properties can be achieved by appropriate structural variations of the polymetallaynes involving the exploitation of different metal groups, auxiliary co-ligands around the metal coordination spheres or bridging spacers. This article reviews recent progress over the past decade in the developments of transition metal-based polymetallaynes and their related molecular model oligomers. These model compounds are considered as useful building blocks for the high-molecular-weight polymers and valuable insights concerning their molecular and electronic properties can be obtained through the detailed studies of these oligomers. The driving force for such research work derives from the possibility of coupling the chemical, electronic, optical and redox properties of transition metal complexes to those of the organic chromophores, thus affording novel metal-containing macromolecules with new material properties. Synthetic routes for the preparation of the metallopolymers as well as their photophysical and structural aspects are summarized. Various up-and-coming applications of such family of compounds as molecular electronic, photonic and chemical sensing devices are also critically discussed in this review.

A new class of luminescent and thermally stable mononuclear group 10 platinum(II) and palladium(II) acetylides trans -[Pt(PR 3 ) 2 (L) 2 ] (R = Bu, Et) and trans -[Pd(PBu 3 ) 2 (L) 2 ] ( LH = 3-( N -carbazolyl)-1-propyne) have been successfully synthesized and characterized. The structural properties of these discrete metal complexes have been studied by X-ray crystallography. We report their optical absorption and photoluminescence spectra and interpret the results in terms of the nature of the metal center and the type of phosphines used. Our investigations indicate that they display heavy metal-enhanced phosphorescence bands at 77 K and we find that the platinum complexes afford more intense triplet emission than that for the palladium congener, consistent with the stronger heavy-atom effect of the third row element than the second row neighbor of the same group.

The first example of phosphorescent I(-) ion sensors based on borylated Pt(II) ppy-type phosphors (Hppy = 2-phenylpyridine) was reported, which shows good selectivity and sensitivity.

With the rapid growth of population and urbanization, the energy demand is increasing annually. Due to the major problems concerning the rapid depleting nature of the extraction of fossil resources, energy conservation and transition to renewable energy supplies have been a hot topic worldwide. Organic light-emitting diodes and solar cells represent two important techniques to allow the efficient utilization of energy resources in energy-saving devices and exploration of using renewable energy in energy-producing devices. In this chapter, the importance of using organometallic and organic molecules in both areas of research is discussed.

In modern research on organic light-emitting diodes (OLEDs), cyclometalated iridium(III) complexes represent one of the most studied class of compounds. The high emission efficiency caused by the strong spin-orbit coupling in the presence of heavy metals leads to the mixing of singlet and triplet manifolds so that both the singlet and triplet excitons can be harvested. For OLEDs to be useful in displays application, true red, green, and blue emissions of sufficient luminous efficiencies and proper chromaticity are required. In recent years, the development of materials for phosphorescent red OLEDs has indeed gone through several important evolutional stages. However, the luminescent quantum yields of red-emitting iridium(III) phosphors tend to be intrinsically low which are governed by the energy gap law for triplet states in which the luminescence quantum yields tend to decrease with an increase in the emission wavelength. Many red organic dyes currently in use do not show a good compromise between device efficiency and color purity. In general, a dilemma facing red OLEDs was realized in which efficient and bright dopants are not red enough, and red-enough dopants are not efficient and bright. In this review article, we highlight the recent progress and current challenges of efficient OLEDs based on cyclometalated iridium(III) dyes which exhibit saturated red and near-infrared electroluminescence. Optimization of the phosphorescent red OLED efficiency/color purity trade-off and extension of the work to other organometallic phosphors are also presented and discussed.

Organic light-emitting devices (OLEDs) are on the lips of most electronic manufacturers currently. With good progress made in terms of production cost, efficiency and color output, OLEDs have found more applications recently as compared to those some years ago. Because of the possibility of obtaining long-lasting, durable and energy-efficient OLEDs, researchers devote much time and effort towards the improvement of OLED technology and development of advanced OLED products. Blue light-emitting materials, especially blue phosphorescent materials, are indispensable for full-color displays and white OLED lighting. Compared with green and red light-emitting materials and devices, the blue-emitting counterparts show a relatively inferior performance in terms of color purity, luminescence efficiency and device durability. In this perspective article, we highlight the recent progress and current challenges of blue-emitting metallophosphors based on small molecules and their applications in phosphorescent OLEDs.

A new two-dimensional small molecule (DCA3T(VT)BDT) with an acceptor–donor–acceptor framework showed a high power conversion efficiency of 4% with a high fill factor of up to 0.63 in solution-processed organic solar cells.

While lighting applications account for about 19% of the electricity consumption of the world,1 the need to reduce energy consumption associated with the low efficiency of conventional lighting systems (e.g. the incandescent bulbs) has prompted researchers to pay considerable research attention to d...

A polyferroplatinyne polymer can be patterned on the surface of Si wafer in ordered nanoline or nanodot shapes with PDMS molds through nanoimprint lithography (NIL), and subsequent thermal treatment gives rise to the nanopatterned arrays of L1(0) -FePt nanoparticles with the same periodicities. The method offers excellent potential to be utilized in the simple and rapid fabrication of bit patterned media for magnetic data recording.

Organic photovoltaic (OPV) devices have attracted much interest in recent decades because they have a great potential for low cost solar cells. Among different kinds of organic solar cells, conjugated polymer/fullerene bulk heterojunction (BHJ) solar cells have exhibited improvements in the power conversion efficiency (PCE) in recent years. The performance of BHJ solar cells is highly dependent on different fabrication processes. To address this issue, we focus on the dependence of different photovoltaic parameters on the fabrication methods. BHJ solar cells fabricated using platinum metallopolyyne (P1) with a low band gap of 1.85 eV as an electron donor and phenyl-C61-butyric acid methyl ester (PCBM) as an electron acceptor have been studied. The fabrication parameters, such as ratios of P1 to PCBM, solvents used, thickness of the active layers and top contact materials, have been systematically investigated. Blend ratio and solvent used had most significant influence on photovoltaic performance with several times higher efficiency of the best condition compared to the worst condition. They affected all photovoltaic parameters [open circuit voltage (Voc), short circuit current density (Jsc) and the fill factor (FF)]. Top contact materials affected the Voc and the FF, while thickness of the active layer mainly affected the Jsc and FF. The influence of different fabrication conditions on photovoltaic performance has been discussed.

A list of diethynylfluorenes and their gold(I) derivatives have been studied for their antitumor activity as a function of their structure–activity relationships. End-capping the fluoren-9-one unit with gold(I) moieties could significantly strengthen the cytotoxic activity in vitro on three human cancer cell lines with induction of reactive oxygen species generation on Hep3B hepatocellular carcinoma cells and exhibit attractive antitumor activity from in vivo nude mice Hep3B xenograft model with limited adverse effects on vital organs including liver and kidney.

The synthesis, isomeric studies, and photophysical characterization of a series of multifunctional cyclometalated iridium(III) complexes containing a fluoro- or methyl-substituted 2-[3-(N-phenylcarbazolyl)]pyridine molecular framework are presented. All of the complexes are thermally stable solids and highly efficient electrophosphors. The optical, electrochemical, photo-, and electrophosphorescence traits of these iridium phosphors have been studied in terms of the electronic nature and coordinating site of the aryl or pyridyl ring substituents. The correlation between the functional properties of these phosphors and the results of density functional theory calculations was made. Arising from the propensity of the electron-rich carbazolyl group to facilitate hole injection/transport, the presence of such a moiety can increase the highest-occupied molecular orbital levels and improve the charge balance in the resulting complexes relative to the parent phosphor with 2-phenylpyridine ligands. Remarkably, the excited-state properties can be manipulated through ligand and substituent effects that allow the tuning of phosphorescence energies from bluish green to deep red. Electrophosphorescent organic light-emitting diodes (OLEDs) with outstanding device performance can be fabricated based on these materials, which show a maximum current efficiency of approximately 43.4 cd A(-1), corresponding to an external quantum efficiency of approximately 12.9 % ph/el (photons per electron) and a power efficiency of approximately 33.4 Lm W(-1) for the best device. The present work provides a new avenue for the rational design of multifunctional iridium-carbazolyl electrophosphors, by synthetically tailoring the carbazolyl pyridine ring that can reveal a superior device performance coupled with good color-tuning versatility, suitable for multicolor-display technology.

Cysteine (Cys) plays important roles in many physiological processes of eukaryotic cells and its detection in cells is of fundamental significance. However, glutathione (GSH), homocysteine, N-acetyl-L-cysteine and other thiols greatly hamper the detection of Cys. In particular, GSH strongly interferes with the detection of cellular Cys (30–200 μM) due to its high intracellular concentration (1–10 mM). In this work, an off–on fluorescent probe (HOTA) for the detection of Cys is presented. This probe possesses both excellent sensitivity and satisfactory selectivity for cellular Cys detection: with the addition of 200 μM Cys, the fluorescence intensity of the probe (10 μM) enhanced 117-fold and the detection limit was calculated to be 13.47 μM, which is lower than the cellular Cys concentration; the probe also selectively detected 30–200 μM cysteine over 1–10 mM glutathione. Consequently, cell imaging experiments were performed with probe HOTA. Furthermore, the results of the thiol-blocking and GSH synthesis inhibiting experiments confirmed that the intracellular emission mainly originates from the interaction between Cys and HOTA.