The correct assignment of stereochemistry in di‐μ‐dichlorido‐bis{bis[2‐(5‐benzylsulfonyl)‐3‐fluoro‐2‐(pyridin‐2‐yl)phenyl‐κ2N,C1]iridium(III)} toluene monosolvate

The title complex, [Ir₂(C₁₈H₁₃FNO₂S)₄Cl₂]·C₇H₈, was crystallized from dichloromethane solution under a toluene atmosphere. It is a dimeric complex in which each of the two Ir^III centres is octahedrally coordinated by two bridging chloride ligands and by two chelating cyclometalated 2‐(4‐benzylsulfonyl‐2‐fluorophenyl)pyridine ligands. The crystal structure analysis unequivocally establishes the trans disposition of the two cyclometalated ligands bound to each Ir^III centre, contrary to our previous hypothesis of a cis disposition. The latter was based on the ¹H NMR spectra of a series of dimeric benzylsulfonyl‐functionalized dichloride‐bridged iridium complexes, including the compound described in the present work [Ragni et al. (2009). Chem. Eur. J. 15 , 136–148]. The toluene solvent molecules, embedded in cavities in the crystal structure, are highly disordered and could not be modelled successfully; their contribution was removed from the refinement using the SQUEEZE routine in the program PLATON [Spek (2009). Acta Cryst. D 65 , 148–155].     

Synthesis,characterization and properties of a soluble polymer with a poly(phenylenevinylene) structure

Soluble poly(2,5-dialkoxy-1,4-phenylenevinylene) has been prepared via Stille coupling reaction between 2,5-dialkoxy-1,4-diiodobenzene and E-1,2-bis(tributylstannyl)-ethene in the presence of palladium complexes. Characterization of this material by means of ¹H and ¹³C nuclear magnetic resonance (NMR), ultraviolet/visible (UV/VIS) and infrared (IR) spectra is described. Molecular weights, determined by means of gelpermeation chromatography (GPC) analysis and referred to standard polystyrene, were in the range number-average molecular weights M _n = 2061–2544 and weight-average molecular weights M _w = 3347–3878. X-ray diffraction (XRD) analysis of the polymer showed semicrystalline structure. T_g = 57°C, transition to a stable smectic mesophase at 115°C and clearing point at 210°C were revealed by differential scanning calorimetry analysis, optical microscopy observation and XRD of the annealed polymer.     

Synthesis and optical properties of a poly(2′,5′-dioctyloxy-4,4′,4″- terphenylenevinylene) with high content of (Z) vinylene units

Poly(2′,5′-dioctyloxy-4,4′,4″-terphenylenevinylene) with (E) configuration of the vinylene double bonds was prepared by Suzuki-Miyaura polymerization of (E)-4,4′-dibromostilbene and 2,5-dioctyloxy-1,4-benzenediboronic acid. Attempts to extend this simple procedure to the synthesis of the polymer with (Z) configuration, starting from (Z)-4,4′-dibromostilbene, were unsuccessful. However, the use of (Z)-4,4′-diiodostilbene and a careful choice of Pd catalyst and experimental conditions, lead to a material with a >95/<5 (Z)/(E) ratio of vinylene units. The investigation of optical properties of both the (E) and (Z) polymers evidenced that (Z) linkages act as defects which reduce the effective conjugation length in the polymer backbone.     

Iridium(III) Complexes with Sulfonyl and Fluorine Substituents: Synthesis,Stereochemistry and Effect of Functionalisation on their Photophysical Properties

The synthesis and photophysical and electrochemical characterisation of new heteroleptic iridium complexes with electron‐withdrawing sulfonyl groups and fluorine atoms bound to phenylpyridine ligands are reported. The emission energy of these materials strongly depends on the position of the sulfonyl groups and on the number of fluorine substituents. A 90 nm wide tuning range of photoluminescence from the blue‐green (λ_em=468 nm) of iridium(III)bis[2‐(4′‐benzylsulfonyl)phenylpyridinato‐N,C2′][3‐(pentafluorophenyl)‐pyridin‐2‐yl‐1,2,4‐triazolate] to the orange (λ_em=558 nm) of iridium(III)bis[2‐(3′‐benzylsulfonyl)phenylpyridinato‐N,C2′](2,4‐decanedionate) has been achieved. Emission quantum yields ranging from 47 to 71 % have also been found for degassed solutions of the complexes, and a surprisingly high value of 16 % was recorded for iridium(III)bis[2‐(5′‐benzylsulfonyl‐3′,6′‐difluoro)phenylpyridinato‐N,C2′](2,4‐decanedionate) in air‐equilibrated dichloromethane. A unusual stereochemistry of the benzylsulfonyl‐substituted dimer and heteroleptic complexes has been detected by ¹H NMR spectroscopy, and is characterised by the mutual cis disposition of the pyridyl nitrogen atoms of the phenylpyridine ligands, which differs from the most common trans arrangement reported in the literature.     

Synthesis and characterization of poly(2,3,5,6-tetrafluoro-1,4-phenylenevinylene)

Poly(2,3,5,6-tetrafluoro-1,4-phenylenevinylene) (PTFPV) was prepared for the first time by the Stille cross-coupling reaction and the resulting material was characterized through MALDI-TOF mass spectrometry, employing a novel sample preparation protocol suitable for insoluble compounds; preliminary optical and electrooptical measurements were performed.     

Thin film construction and characterization and gas-sensing performances of a tailored phenylene-thienylene copolymer

An alternating copolymer, poly(2,5-dioctyloxy-1,4-phenylene-alt-2,5-thienylene), has been synthesized and used in this research. The behavior of the floating film at the air-water interface has been investigated by measuring surface pressure versus area Langmuir isotherms and contemporaneously by reflection spectroscopy and Brewster angle microscopy. The floating films were transferred by the Langmuir-Sch?fer (horizontal lifting) method onto various substrates. It is apparent from these analyses that the effective conjugation length is larger than those in other electroactive polymers and that a strong coplanarity and interchain association takes place above all in the floating film on the water surface and in the transferred multilayers. Such films were used as the active layers in resistive chemical gas sensor devices, thus revealing excellent sensitivity toward NO(2), reversibility, and time stability of the response.     

Synthesis of poly(aryleneethynylene)s bearing glucose units as substituents

A series of poly(aryleneethynylene)s functionalized with acetylated glucopyranosyl units were synthesized by the Pd-catalyzed reaction of trimethylsilylethynyl derivatives with aromatic halides in the presence of silver oxide.