Novel luminescent Ir(III) dyes for developing highly sensitive oxygen sensing films

New sensing films have been developed for the detection of molecular oxygen. These films are based on luminescent Ir(III) dyes incorporated either into polystyrene (with and without plasticizer) or metal oxide, nanostructured material. The preparation and characterization of each film have been investigated in detail. Due to their high sensitivity for low oxygen concentration, the parameters pO₂(S=1/2) and ΔI_1% have been also evaluated in order to establish the most sensitive membrane for controlling concentrations between 0 and 10% and low oxygen concentrations (lower than 1%), respectively. The results show that the use of nanostructured material increased the sensitivity of the film; the most sensitive membrane for controlling O₂ between 0 and 10% is based on N1001 immobilized in AP200/19 (k_sv = 2848 ± 101 bar⁻¹ and pO₂(S=1/2)=0.0006), and the complex N969 incorporated into AP200/19 seems to be the most suitable for applications in oxygen trace sensing (ΔI_1% = 93.13 ± 0.13%).     

Novel optical oxygen sensing material: metalloporphyrin dispersed in fluorinated poly(aryl ether ketone) films

A series of new fluorine-containing poly(aryl ether ketone)s (8F-PEKEK(Ar); Ar: 2-2-bis(4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane (6FBA), 2,2-bis(4-hydroxyphenyl)propane (BA), 2-(4-hydroxyphenyl)-2-(3-hydroxyphenyl)propane (3,4^′-BA) or 9,9^′-bis(4-hydroxyphenyl)fluorine (HF)) are synthesized and applied to the matrix of optical oxygen sensing using phosphorescence quenching of metalloporphyrins, platinum and palladium octaethylporphyrin, (PtOEP and PdOEP) by oxygen. The phosphorescence intensity of PtOEP and PdOEP in 8F-PEKEK(Ar) films decreased with increase of oxygen concentration. The ratio I₀/I₁₀₀ is used as a sensitivity of the sensing film, where I₀ and I₁₀₀ represent the detected phosphorescence intensities from a film exposed to 100% argon and 100% oxygen, respectively. For PtOEP in 8F-PEKEK(Ar) film, I₀/I₁₀₀ values are more than 20.0 and large Stern-Volmer constants more than 0.19%⁻¹ are obtained compared with PtOEP in polystyrene film. For PdOEP in 8F-PEKEK(Ar) film, on the other hand, the large I₀/I₁₀₀ values more than 143 are obtained. However, the Stern-Volmer plots of PdOEP in 8F-PEKEK(Ar) films exhibit considerable linearity at lower oxygen concentration range between 0% and 20%. These results indicate that PtOEP and PdOEP films are useful optical oxygen sensor at the oxygen concentration range between 0% and 100% and between 0% and 20%, respectively. The response times of PtOEP and PdOEP dispersed in 8F-PEKEK(Ar) films are 5.6 and 3.0 s on going from argon to oxygen and 110.1 and 160.0 s from oxygen to argon, respectively.     

Development of a durable fiber-optic oxygen sensor for harsh underground environments

This paper focuses on effects of protection with a silicone resin to develop a fiber-optic oxygen sensor with long-term stability and durability in harsh underground environments. Ruthenium (II) complexes were used as oxygen-sensing compounds. A uniform composite film composed of silicone resin and the Ru complex was prepared with spin coating technique. A comparison of dissolved-oxygen (DO) sensitivity between the composite film and a Ru complex film was made by exposing to hot water (80 °C). The result of the accelerated degradation test showed that sensitivity of the Ru complex film was stable; meanwhile that of the composite film increased with exposure time in a short period. In order to improve stability, the Ru complex film overcoated with silicone resin was prepared. Differences in sensitivity for saturated DO (8.5 ppm) between with and without the silicone resin overcoating on the Ru complex film were investigated by exposing to the hot water and simulated underground water. These results revealed that the sensitivities and response times of the overcoated films were stable and slow, respectively, compared to those of non-overcoated films. Then, optodes were evaluated for effects of the overcoating on sensing properties by exposing to 100 vol.% oxygen gas. The experiment showed that: (1) the response time was significantly influenced by the thickness of the overcoating; and (2) response speed of the overcoated optode was slow by a factor of about 35 compared to that of the non-overcoated. We concluded that the overcoating was effective in the application to mid- and long-term oxygen monitoring in the harsh environments.     

Synthesis and characterization of a new trans-2,2′-azoquinoxaline bridged bisphthalocyanine

A new trans-2,2′-azoquinoxaline bridged bisphthalocyanine was synthesized from the corresponding quinoxaline-2(1H)-one oxime, which can be obtained by the reaction of s-trans-chloroethanedial with 2-(3,4-diaminophenoxy)-9,16,23-tri(hexylthio)phthalocyanine zinc(II). 2-(3,4-Diaminophenoxy)-9,16,23-tri(hexylthio)phthalocyanine zinc(II) was synthesized by reduction of 2-(4-amino-3-nitrophenoxy)-9,16,23-tri(hexylthio)phthalocyanine zinc(II). Novel compounds were characterized by elemental analysis, UV/vis, IR and ¹H NMR spectroscopy. The conductivity and the humidity sensing properties of spin coated films of these compounds were investigated by measuring the complex impedance spectra at different humidities. Films of the final product show up to 10³ orders of magnitude higher conductivity than the starting and intermediate compounds. The results indicate that the presence of water vapour always leads to a drop in the real and imaginary part of the complex impedance. At room temperature, the capacitance of the films exhibits reversible increase with relative humidity, which makes these films attractive for humidity sensing applications.     

Fiber-optic fluorescence sensor for dissolved oxygen detection based on fluorinated xerogel immobilized with ruthenium (II) complex

A fiber-optic sensor based on fluorescence quenching was designed for dissolved oxygen (DO) detection. The fluorinated xerogel-based sensing film of the present sensor was prepared from 3, 3, 3-trifluoropropyltrimethoxysilane (TFP–TriMOS). Oxygen-sensitive fluorophores of tris (2, 2′- bipyridine) ruthenium (II) (Ru(bpy)₃²⁺) were immobilized in the sensing film and the emission fluorescence was quenched by dissolved oxygen. In the sensor fabrication, a two-fiber probe was employed to obtain the best fluorescence collection efficiency and the sensing film was attached to the probe end. Scanning electron microscope (SEM), UV–Vis absorption spectroscopy (UV–Vis) and fourier transform infrared spectroscopy (FTIR) measurements have been used to characterize the sensing film. The sensor sensitivity is quantified by I _deoxy/I _oxy, where I _deoxy and I _oxy represented the detected fluorescence intensities in fully deoxygenated and fully oxygenated environments, respectively. Compared with tetramethoxysilane (TMOS) and methyltriethoxysilane (MTMS)-derived sensing films, TFP–TriMOS-based sensor exhibited excellent performances in dissolved oxygen detection with short response time of 4 s, low limit of detection (LOD) of 0.04 ppm (R.S.D. = 2.5%), linear Stern–Volmer calibration plot from 0 to 40 ppm and long-term stability during the past 10 months. The reasons for the preferable performances of TFP–TriMOS-based sensing film were discussed.     

Acetone vapor sensing properties of screen printed WO3 thick films

This paper presents acetone vapor sensing properties of WO₃ thick films. In this work, the WO₃ thick films were prepared by standard screen-printing method. These films were characterized by X-ray diffraction (XRD) measurements, and scanning electron microscopy (SEM). The acetone vapor sensing properties of these thick films were investigated at different operating temperature and acetone vapor concentrations. The WO₃ thick films exhibit excellent acetone vapor sensing properties with the maximum sensitivity ∼456% at 300 °C in air atmosphere with fast response and recovery time.     

Preparation and optical properties of polyimide films linked with porphyrinato Pd (II) and Pt (II) complexes through a triazine ring and application toward oxygen sensors

5‐(3‐Aminophenyl)‐10,15,20‐tri(4‐methylphenyl) porphyrinato Pd (II) and Pt (II) complexes ( 2a ‐ Pd ) and ( 2a ‐ Pt ), respectively, were prepared from 5‐(3‐nitrophenyl)‐10,15,20‐tri(4‐methyl‐phenyl)porphyrin via two‐step reactions, and reacted with cyanuric chloride to produce corresponding porphyrin derivatives ( 3a ‐ Pd ) and ( 3a ‐ Pt ) with a dichlorotriazine ring. Aromatic polyimides were prepared using diamine ( 4 ); triazine dichlorides having porphyrin units ( 3a ‐ Pd ), ( 3a ‐ Pt ), ( 3c ‐ Pd ), and ( 3c ‐ Pt) ; fluoro‐functionality 6‐(p‐perfluorononenyl oxyanilino)triazine‐2,4‐dichloride ( 6 ); and tetracarboxylic dianhydride ( 5 ) in N‐methyl‐2‐pyrrolidone (NMP) at an elevated temperature up to 300 °C. The resulting viscous polymeric solution was cast on a glass plate, affording well‐proportioned reddish transparent films with number‐average molecular weights of 25,000–38,000. Glass transition temperatures of the polymers were ～230 °C; the films were stable up to 400 °C in air. The film emission spectra showed a broad peak ～670 nm, similar to those of porphyrins ( 2a ‐ Pd ) and ( 2a ‐ Pt ) dispersed in a polystyrene matrix. While the luminescence of these polymer films was quenched with oxygen, it rapidly recovered under a deoxygenated atmosphere. The polyimide film sensitivity to oxygen was higher under low oxygen concentrations than those of porphyrins ( 2a ‐ Pd ) and ( 2a ‐ Pt ) dispersed in polystyrene. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1086–1094     

Detection of chlorinated methanes by tin oxide gas sensors

Tin oxide thin films prepared by thermal oxidation of Sn films were used for the detection of chlorinated methanes (CH2Cl2, CHCl3 and CCl4). This resulted in better chemical selectivity, sensitivity, response speed and detection limit than seen with previous detectors. The temperature dependence of the sensing of 1% CCl4 gas was studied and the best sensing behavior was observed at 300 degrees C. The films showed different chemical selectivity in both speed and direction of sensing response to each gas and were stable for more than 3 weeks under operating conditions. The films showed rapid gas sensing (<40 s to reach 90% of full response) and low detection limits (< 4 ppm CCl4). The role of oxygen in the detection of chlorinated methanes and in resistance changes without chlorinated methanes was also studied. The changes at the surface of the film after gas sensing were examined using scanning electron microscopy with energy-dispersive X-ray spectrometry.     

Ultrathin films of functionalised single-walled carbon nanotubes: a potential bio-sensing platform

ABSTRACT

The Langmuir monolayer is a special class of lyotropic liquid crystalline system wherein phase transition essentially depends on surface density, temperature and ion-content in the aqueous medium. The variety of surface phases can be transferred onto devices by the Langmuir–Blodgett (LB) technique. The Langmuir monolayer of pristine single-walled carbon nanotubes (SWCNTs) exhibited gas and liquid-like phases. The LB film of SWCNTs shows target surface pressure dependent interesting morphologies. The methane gas sensing using parallel alignment of SWCNTs was found to be better than that of randomly oriented SWCNTs. The SWCNTs can be functionalised chemically to enhance the ease of film processability and affinity towards analytes. These are essential parameters for the development of a sensor. In this article, we present our work on Langmuir monolayer and LB films of octadecylamine functionalised SWCNTs (ODACNTs) and its sensing application towards bio-analytes, e.g. L-aspartic acid and bovine serum albumin. The sensing performance of LB film of ODACNTs was compared with that of spin-coated films of ODACNTs. The sensing performance of LB films of ODACNTs indicated a potential platform for bio-sensing application.     

Non‐covalent Immobilization of Iron‐triazole (Fe(Htrz)3) Molecular Mediator in Mesoporous Silica Films for the Electrochemical Detection of Hydrogen Peroxide

Mesoporous silica thin films encapsulating a molecular iron‐triazole complex, Fe(Htrz)₃ (Htrz=1,2,4,‐1H‐triazole), have been generated by electrochemically assisted self‐assembly (EASA) on indium‐tin oxide (ITO) electrode. The obtained modified electrodes are characterized by well‐defined voltammetric signals corresponding to the Fe^II/III centers of the Fe(Htrz)₃ species immobilized into the films, indicating fast electron transfer processes and stable operational stability. This is due to the presence of a high density of redox probes in the material (1.6×10^?4 mol g^?1 Fe(Htrz)₃ in the mesoporous silica film) enabling efficient charge transport by electron hopping. The mesoporous films are uniformly deposited over the whole electrode surface and they are characterized by a thickness of 110 nm and a wormlike mesostructure directed by the template role played by Fe(Htrz)₃ species in the EASA process. These species are durably immobilized in the material (they are not removed by solvent extraction). The composite mesoporous material (denoted Fe(Htrz)₃@SiO₂) is then used for the electrocatalytic detection of hydrogen peroxide, which can be performed by amperometry at an applied potential of ?0.4 V versus Ag/AgCl and by flow injection analysis. The organic‐inorganic hybrid film electrode displays good sensitivity for H₂O₂ sensing over a dynamic range from 5 to 300 μM, with a detection limit estimated at 2 μM.     

Os and Pd Modified Tin Oxide Films for Sensors by the Sol Gel Process

Pure, Pd and Os modified SnO₂ films were prepared by the sol gel process and used as active materials in gas sensing devices. The films have been prepared starting from tin tetrachloride in alcoholic solution hydrolysed with water. The modifier was added to the sol as inorganic salt. Pd acetate and Os chloride were the Pd and Os precursors respectively. A structural and morphological study was carried out by means of Atomic Force Microscope (AFM), Secondary Ion Mass Spectrometer (SIMS) and x-ray Diffraction (XRD). The electrical resistance variations as a function of various gaseous atmospheres and temperature were measured to evaluate the sensing properties of the films. CO, CH₄, CH₃OH and C₂H₅OH gases were used for the tests. Following results were obtained: Pd is present in the form of PdO nanoclusters in the polycrystalline SnO₂ matrix as evidenced by XRD spectra whereas Os is a cationic modifier uniformly dispersed as evidenced in SIMS studies. Optimum sensing temperature and the sensitivity variations, with respect to the undoped films, differ according to the gaseous species. It looks therefore promising to use inexpensive, sol-gel derived, array of films in smart gas sensing devices that are able to recognise gas species and concentration.     

Structurally integrated organic light emitting device-based sensors for gas phase and dissolved oxygen

A compact photoluminescence (PL)-based O2 sensor utilizing an organic light emitting device (OLED) as the light source is described. The sensor device is structurally integrated. That is, the sensing element and the light source, both typically thin films that are fabricated on separate glass substrates, are attached back-to-back. The sensing elements are based on the oxygen-sensitive dyes Pt- or Pd-octaethylporphyrin (PtOEP or PdOEP, respectively), which are embedded in a polystyrene (PS) matrix, or dissolved in solution. Their performance is compared to that of a sensing element based on tris(4,7-diphenyl-l,10-phenanthroline) Ru II (Ru(dpp)) embedded in a sol-gel film. A green OLED light source, based on tris(8-hydroxy quinoline Al (Alq3), was used to excite the porphyrin dyes; a blue OLED, based on 4,4'-bis(2,2'-diphenylviny1)-1,1'-biphenyl, was used to excite the Ru(dpp)-based sensing element. The O2 level was monitored in the gas phase and in water, ethanol, and toluene solutions by measuring changes in the PL lifetime tau of the O2-sensitive dyes. The sensor performance was evaluated in terms of the detection sensitivity, dynamic range, gas flow rate, and temperature effect, including the temperature dependence of tau in pure Ar and O2 atmospheres. The dependence of the sensitivity on the preparation procedure of the sensing film and on the PS and dye concentrations in the sensing element, whether a solid matrix or solution, were also evaluated. Typical values of the detection sensitivity in the gas phase, S(g) identical with tau(0% O2)/tau(100% O2), at 23 degrees C, were approximately 35 to approximately 50 for the [Alq3 OLED[/[PtOEP dye] pair; S(g) exceeded 200 for the Alq3/PdOEP sensor. For dissolved oxygen (DO) in water and ethanol, S(DO) (defined as the ratio of tau in de-oxygenated and oxygen-saturated solutions) was approximately 9.5 and approximately 11, respectively, using the PtOEP-based film sensor. The oxygen level in toluene was measured with PtOEP dissolved directly in the solution. That sensor exhibited a high sensitivity, but a limited dynamic range. Effects of aggregation of dye molecules, sensing film porosity, and the use of the OLED-based sensor arrays for O2 and multianalyte detection are also discussed.     

Oxygen and relative humidity monitoring with films tailored for enhanced photoluminescence

Approaches to generate porous or doped sensing films, which significantly enhance the photoluminescence (PL) of oxygen optical sensors, and thus improve the signal-to-noise (S/N) ratio, are presented. Tailored films, which enable monitoring the relative humidity (RH) as well, are also presented. Effective porous structures, in which the O₂-sensitive dye Pt octaethylporphyrin (PtOEP) or the Pd analog PdOEP was embedded, were realized by first generating blend films of polyethylene glycol (PEG) with polystyrene (PS) or with ethyl cellulose (EC), and then immersing the dried films in water to remove the water-soluble PEG. This approach creates pores (voids) in the sensing films. The dielectric contrast between the films’ constituents and the voids increases photon scattering, which in turn increases the optical path of the excitation light within the film, and hence light absorption by the dye, and its PL. Optimized sensing films with a PEG:PS ratio of 1:4 (PEG’s molecular weight M_w ∼8000) led to ∼4.4× enhancement in the PL (in comparison to PS films). Lower M_w ∼200 PEG with a PEG:EC ratio of 1:1 led to a PL enhancement of ∼4.7×. Film-dependent PL enhancements were observed at all oxygen concentrations. The strong PL enhancement enables (i) using lower dye (luminophore) concentrations, (ii) reducing power consumption and enhancing the sensor’s operational lifetime when using organic light emitting diodes (OLEDs) as excitation sources, (iii) improving performance when using compact photodetectors with no internal gain, and (iv) reliably extending the dynamic range.     

Luminescence and oxygen sensing properties of ORMOSILs covalently grafted with a novel ruthenium(II) complex

A series of VTES/TEOS composite xerogels covalently grafted with a novel complex Ru(phen)₂(Dppz-Si)Cl₂ were prepared, using the alkoxysilane-modified dipyrido[3,2-a:2′,3′-c]phenazine compound (denoted as Dppz-Si) as the second ligand of the Ru(phen)₂Cl₂ (phen = 1,10-phenanthroline) complex and a precursor of the sol–gel process. Bulk xerogels were obtained by co-hydrolyzing and co-condensation from a mixture of triethoxysilane (TEOS), Ru(phen)₂(Dppz-Si)Cl₂ and Vinyltriethoxysilane (VTES). The luminescence intensity of composite xerogels is enhanced by 18.2 times, and the sensitivity is improved from 1.1 to 3.1 by optimizing the molar ratio of VTES to TEOS. The composite xerogel containing 80% VTES in precursor was optimal, exhibiting the maximum luminescence intensity and sensitivity. These results indicate that the complex Ru(phen)₂(Dppz-Si)Cl₂ is sensitive to oxygen concentration, VTES is a kind of excellent organic modifier and can greatly improved photoluminescent (PL) and oxygen sensing performances.     

Reagentless pH-based biosensing using a fluorescently-labelled dextran co-entrapped with a hydrolytic enzyme in sol-gel derived nanocomposite films

We report on the development of reagentless fluorescence-based sensing films utilizing hydrolytic enzymes co-entrapped with polymers that are labelled with pH sensitive fluorophores. Aqueous solutions of a hydrophilic enzyme (urease) or a lipophilic enzyme (lipase) containing fluorescein or carboxy-seminaphtharhodafluor-1 (SNARF-1), either free or conjugated to a dextran polymer backbone, were mixed with hydrolyzed alkoxysilane solutions and cast onto planar surfaces to form thin, biologically active sol-gel derived films (ca. 500 nm thick). The films also contained various additives, such as methyltrimethoxysilane, dimethyldimethoxysilane, polyethylene glycol or polyvinyl alcohol, to optimize the activity of the entrapped enzymes. The photostability, leaching, pK_a and pH response of the entrapped probes were characterized, as was the performance of the entrapped enzymes, and an optimal set of processing conditions was obtained for each different sensing film. In general, the results indicated that SNARF-labelled dextran was the most useful pH sensitive dye owing to insensitivity to leaching and photobleaching. Furthermore, it was observed that the pK_a and pH response of this probe was insensitive to preparation conditions. The performance of the co-entrapped enzymes was highly dependent on the type and level of additive, but in all cases, it was possible to obtain active enzymes with good performance characteristics. Reagentless sensing films for urea and glyceryl tributyrate (GTB) are demonstrated based on the detection of enzyme-mediated pH changes from films coated onto planar substrates.     

Optimization of strontium- doping concentration in BaTiO3 nanostructures for room temperature NH3 and NO2 gas sensing

In this study, we comprehensively present the gas sensing performance of strontium (Sr)-doped barium titanate (BaTiO₃) nanostructures which are synthesized by a low-temperature hydrothermal route. The in-situ doping of strontium in BaTiO₃ nanostructures is achieved with different molar concentrations of Sr, and the sensing performance was evaluated by screen printing process of products to form their thick films. The thick films of as-prepared Sr-doped BaTiO₃ (BaSrTiO₃) were investigated for gas sensing performance for various gases at different operating temperatures where strong response was observed for both nitrogen dioxide (NO₂) and ammonia (NH₃) gases at room temperature. Furthermore, the sensing response at room temperature for NH₃ and NO₂ gases was also studied with respect to Sr doping concentrations in BaTiO₃ nanostructures.     

Organic vapor sensing properties and characterization of α-naphthylmethacrylate LB thin films

Determination of organic vapor sensing properties of α-Naphthylmethacrylate (α-NMA) monomer based Langmuir-Blodgett (LB) thin films was aimed in this study. LB thin film fabrication was performed on quartz glass and quartz crystal substrates in order to investigate the characterization and organic vapor properties of α-NMA materials by using UV-Visible, Atomic Force Microscopy (AFM) and Quartz Crystal Microbalance (QCM) techniques. π-A isotherm graph was taken and a suitable surface pressure value were primarily determined as 13?mN m^?1 for successful α-NMA LB thin film fabrication. Transfer ratio value was found to be ≥ 0.93 for quartz glass and quartz crystal substrates. The typical frequency shift per layer was obtained as 16.93?Hz/layer and the deposited mass onto a quartz crystal was calculated as 271.30?ng/layer (1.02?ng mm^?2). The sensing responses of α-NMA LB films against dichloromethane, chloroform, toluene and m-xylene were measured by QCM system. Dichloromethane created the maximum shift in the resonance frequency than other organic vapors used in this study. Results exhibited that α-NMA LB thin films were potential candidates for organic vapor sensing applications, especially high sensitive detection of dichloromethane at room temperature.     

Surface plasmon resonance sensor for lysozyme based on molecularly imprinted thin films

Molecularly imprinted polymers (MIPs) selective for lysozyme were prepared on SPR sensor chips by radical co-polymerization with acrylic acid and N,N′-methylenebisacrylamide. Gold-coated SPR sensor chips were modified with N,N′-bis(acryloyl)cystamine, on which MIP thin films were covalently conjugated. The presence of NaCl during the polymerization and the re-binding tests affected the selectivity and the optimization of NaCl concentration in the pre-polymerization mixture and the re-binding buffer could enhance the selectivity in the target protein sensing. When the lysozyme-imprinted polymer thin films were prepared in the presence of 40 mM NaCl, the selectivity factor (target protein bound/reference protein bound) of MIP in the re-binding buffer containing 20 mM NaCl was 9.8, meanwhile, that of MIP in the re-binding buffer without NaCl was 1.2. A combination of SPR sensing technology with protein-imprinted thin films is a promising tool for the construction of selective protein sensors.     

Development of Fluorescent Film Sensors Based on Electropolymerization for Iron(III) Ion Detection

Two electroactive materials, M1 and M2 , are synthesized and their fluorescent electropolymerized (EP) films are prepared and used to detect metal ions. From the tested metal ions, M1 and M2 are demonstrated to be sensitive and selective for Fe³⁺ ions. In particular, M2 exhibits higher sensitivity towards Fe³⁺ ions. The fluorescent detection ranges from 10^?5 M to 4×10^?4 M . The excellent performance of the EP fluorescent films is mainly due to the strong metal‐chelated properties of M2 and the intrinsic porous cross‐linked‐network microstructure of the EP films. This study, thus, provides a promising Fe³⁺ sensing candidate and a potential preparation method for fluorescent sensing films.     

Complexes in polymers III: Addition reactions of trans-Ir(PPh3)2(CO)Cl embedded in polystyrene with hydrogen,oxygen, sulfur dioxide,carbon monoxide and gaseous iodine and of (η-C5H5)Ru(η4-1,5-cyclooctadiene)Cl in polystyrene with carbon monoxide

The addition rections of trans-Ir(PPh₃)₂(CO)Cl embedded in films of polystyrene (PS) with hydrogen, oxygen, sulfur dioxide, carbon monoxide and gaseous iodine were monitored by infrared spectroscopy and found to be similar to those occurring in toluene. While the reaction with iodine was rapid at the surface of the film as determined by attenuated-total-reflectance infrared spectroscopy, the reaction was much slower in the body of the film, as shown by transmission infrared spectroscopy. No such difference was observed for oxygen. The complex CpRu(COD)Cl (Cp = η-C₅H₅, COD = 1,5-cyclooctadiene) in PS readily undergoes ligand substitution by carbon monoxide (CO and ¹³CO) to give CpRu(CO)₂Cl and CpRu(¹³CO)₂Cl embedded in PS, respectively.