Pierre D. Harvey

Recent Progress on the Photonic Properties of Conjugated Organometallic Polymers Built Upon the trans-Bis(para-ethynylbenzene)bis(phosphine)platinum(II) Chromophore and Related Derivatives

This review article surveys the electronic and photophysical properties of conjugated organometallic polymers built upon the title compound and its related derivatives focussing primarily on systems investigated in our laboratories. The general structure of the polymers is (trans-bis(para-ethynylbenzene)bis(phosphine)platinum(II)-G)(n) where G is a conjugated group such as thiophene, fluorene, carbazole, substituted silole, quinone derivative, and metalloporphyrin residue, or a non-conjugated main-group moiety. Systems based on substituted phenylene units and other related fused rings are also discussed. The phosphine ligands are generally triethyl- or tri-n-butylphosphine groups. These trans-platinum(II) polymers and the corresponding model compounds are compared to the corresponding ortho-derivatives in the quinone series, and the newly prepared paracyclophane-containing polymers. For the porphyrin series, a comparison of fully conjugated oligomers exhibiting the general structure (trans-bis(para-ethynyl(zinc(porphyrin)))bis(phosphine)platinum(II))(n) (i.e., the C(6) H(4) group is absent from the main chain) will be made. This contribution also includes a description of the properties of the mononuclear chromophore itself, properties that define those of the polymers. Potential applications with regard to electronic and optical devices will be highlighted. These soluble and stable materials feature both the processing advantages of polymers and the functionality provided by the presence of metal centers. These multifunctional organometallic polyyne polymers exhibit convenient structural variability as well as optical and electronic properties, which renders them important for use in different research domains as chemical sensors and sensor protectors, as converters for light/electricity signals, and as patternable precursors to magnetic metal alloy nanoparticles.

A reaction-based chromogenic and fluorescent chemodosimeter for fluoride anions

An innovative trihexylsilylacetylene-containing BODIPY dye was designed and proved to be a highly selective, sensitive, and fast chromogenic and fluorescent chemodosimeter for fluorides.

Photoproperties of the polymeric {[M(dmb)2]Y]}n materials: photoinduced intrachain energy and intermolecular electron transfers, and design of photovoltaic cells

Abstract This paper describes the structural and electronic spectroscopic properties of polymeric materials of the type {[M(dmb) 2 ]Y]} n (M = Cu, Ag; dmb = 1,8-diisocyano- p -menthane; Y = BF 4 − , NO 3 − , PF 6 − , ClO 4 − ). The replacement of Y by TCNQ (tetracyanoquinodimethane anion) leads to electrically insulating materials, which upon doping with neutral TCNQ become conducting. For M = Cu, the materials are also photoconducting where a photoinduced electron transfer from the excited CuL 4 center to the neutral TCNQ is demonstrated. Finally, photovoltaic cells have been designed.

Multinuclear Cytotoxic Metallodrugs: Physicochemical Characterization and Biological Properties of Novel Heteronuclear Gold-Titanium Complexes

An unprecedented series of titanocene-gold bi- and trimetallic complexes of the general formula [[(η(5)-C(5)H(5))(μ-η(5):κ(1)-C(5)H(4)(CH(2))(n)PPh(2))TiCl(2)](m)AuCl(x)](q+) (n = 0, 2, or 4; m = 1, x = 1, q = 0 or m = 2, x = 0, q = 1) have been prepared and characterized spectroscopically. The luminescence spectroscopy and photophysics of one of the compounds, [[(η(5)-C(5)H(5))(μ-η(5):κ(1)-C(5)H(4)PPh(2))TiCl(2)](2)Au]PF(6), have been investigated in 2MeTHF solution and in the solid state at 77 and 298 K. Evidence for interfragment interactions based on the comparison of electronic band positions and emission lifetimes, namely, triplet energy transfer (ET) from the Au- to the Ti-containing chromophores, is provided. The cytotoxicity of the complexes was evaluated on A2780 ovarian cancer cells and on their cisplatin-resistant cell line A2780cisR; the compounds showed activity in the low micromolar range that was markedly more active than the corresponding titanocene-phosphine precursors [(η(5)-C(5)H(5))(η(5)-C(5)H(4)(CH(2))(n)PPh(2))TiCl(2)], cisplatin, and, for some of them, the gold analogue [(PPh(3))AuCl]. In an attempt to draw preliminary structure-activity relationships, cell uptake measurements and interaction studies with plasmid DNA and the model protein ubiquitin (Ub) have been undertaken on some of the compounds.

Slow and Fast Singlet Energy Transfers in BODIPY-gallium(III)corrole Dyads Linked by Flexible Chains

Red (no styryl), green (monostyryl), and blue (distyryl) BODIPY-gallium(III) (BODIPY = boron-dipyrromethene) corrole dyads have been prepared in high yields using click chemistry, and their photophysical properties are reported. An original and efficient control of the direction of the singlet energy transfers is reported, going either from BODIPY to the gallium-corrole units or from gallium-corroles to BODIPY, depending upon the nature of the substitution on BODIPY. In one case (green), both directions are possible. The mechanism for the energy transfers is interpreted by means of through-space Förster resonance energy transfer (FRET).

Reactivity of CuI and CuBr toward Et2S: a reinvestigation on the self-assembly of luminescent copper(I) coordination polymers.

CuI reacts with SEt(2) in hexane to afford the known strongly luminescent 1D coordination polymer [(Et(2)S)(3){Cu(4)(mu(3)-I)(4)}](n) (1). Its X-ray structure has been redetermined at 115, 235, and 275 K in order to address the behavior of the cluster-centered emission and is built upon Cu(4)(mu(3)-I)(4) cubane-like clusters as secondary building units (SBUs), which are interconnected via bridging SEt(2) ligands. However, we could not reproduce the preparation of a coordination polymer with composition [(Et(2)S)(3){Cu(4)(mu(3)-Br)(4)}](n) as reported in Inorg. Chem. 1975, 14, 1667. In contrast, the autoassembly reaction of SEt(2) with CuBr results in the formation of a novel 1D coordination polymer of composition [(Cu(3)Br(3))(SEt(2))(3)](n) (2). The crystal structure of 2 has been solved at 115, 173, 195, and 235 K. The framework of the luminescent compound 2 consists of a corrugated array with alternating Cu(mu(2)-Br)(2)Cu rhomboids, which are connected through two bridging SEt(2) ligands to a tetranuclear open-cubane Cu(4)Br(4) SBU, ligated on two external Cu atoms with one terminal SEt(2). The solid-state luminescence spectra of 1 and 2 exhibit intense halide-to-metal charge-transfer emissions centered at 565 and 550 nm, respectively, at 298 K. A correlation was also noted between the change in the full width at half-maximum of the emission band between 298 and 77 K and the relative flexibility of the bridging ligand. The emission properties of these materials are also rationalized by means of density functional theory (DFT) and time-dependent DFT calculations performed on 1.

Wide-rim and outer-face functionalizations of calix[4]arene

Abstract This review article focuses on calix[4]arene compounds in their cone conformation which exhibit organic functional groups, particularly those which are either potential soft or hard donors and halides, or organometallic-containing fragments, either at the win-rim or outer-face. This survey is presented from a structural point of view, and also includes systems involving loops and covalently bonded dimers. The attachment of various groups at these two types of sites occur mainly with carbon, nitrogen, sulfur, phosphorus, bromine, iodine, and metal atoms.

Highly efficient iridium(III) phosphors with phenoxy- substituted ligands and their high-performance OLEDs†

Two new iridium(III) cyclometallated complexes (1 and 2) based on the 2-(1-phenoxy-4-phenyl)-5-methylpyridine ligand have been developed. By attaching a flexible phenoxy group on the phenyl ring of 2-phenylpyridine (Hppy), the light-emitting properties of the resulting IrIII complexes have been improved, while the introduction of an electron-donating methyl group on the pyridyl ring of Hppy can keep the triplet emission in the green region by compensating for the reduced energy gap caused by the phenoxy group. Owing to the unique electronic structures induced by the ligand, the vacuum-evaporated organic light-emitting devices (OLEDs) of the type [ITO/NPB (40 nm)/(1 or 2):CBP (20 nm)/BCP (10 nm)/Alq3 (30 nm)/LiF (1 nm)/Al (100 nm)] furnished peak OLED efficiencies at 10.0%, 31.1 cd A−1 and 14.5 lm W−1 for 1 and 11.7%, 38.1 cd A−1 and 31.8 lm W−1 for 2. By replacing the electron-injection/electron-transporting materials (BCP and Alq3) with TPBi, the green-emitting devices based on 1 gave outstanding peak efficiencies at 22.5%, 76.2 cd A−1 and 72.8 lm W−1. Extremely high peak efficiencies of 24.5%, 84.6 cd A−1 and 77.6 lm W−1 were even obtained for the 2-doped devices and both of them are superior in performance to the benchmark dopants Ir(ppy)3 and Ir(ppy)2(acac). Moreover, polymer light-emitting devices were also fabricated using 1 and 2via the spin-coating method, and their device performances are characterized by 14.4%, 39.5 cd A−1 and 12.4 lm W−1 for 1 and 12.6%, 29.6 cd A−1 and 18.1 lm W−1 for 2. When 2 was used to make three-color white-light OLEDs, respectable device efficiencies of 15.3 cd A−1, 7.5% and 9.1 lm W−1 were achieved and their white color CIE coordinates are improved relative to Ir(ppy)3.

B,B-Diporphyrinbenzyloxy-BODIPY Dyes: Synthesis and Antenna Effect

B,B-Diporphyrinbenzyloxy-BODIPY derivatives have been prepared in high yields, and the photophysical properties are reported. Singlet energy transfers from BODIPY to the porphyrin units have been analyzed.

Nanometer Length-Dependent Triplet-Triplet Energy Transfers in Zinc(II) Porphyrin/trans-Bis(ethynylbenzene)Platinum(II) Oligomers

The synthesis and characterization of organometallic oligomers of the type [(p-C(6)H(4))C[triple bond]CPt(P(n-Bu)(3))(2)C identical withC(p-C(6)H(4))Zn(P)](n) with the corresponding models [(C(6)H(5)C[triple bond]C)Pt(P(n-Bu)(3))(2)C[triple bond]C(p-C(6)H(4))Zn(P)(p-C(6)H(4))C[triple bond]CPt(P(n-Bu)(3))(2)(C[triple bond]CC(6)H(5))], where Zn(P) is zinc(II)-10,20-di(mesityl)- (n = 4, 9) or zinc(II)-10,20-di-n-pentyl-porphyrin (n = 3, 6, 9), are reported. The electronic spectra (absorption, excitation, emission, and transient absorption) and the photophysical properties (emission lifetimes and quantum yields) of these species in 2-methyltetrahyrofuran at 298 and 77 K are presented. Rates for triplet (T(1)) energy transfer, k(ET), from the [(p-C(6)H(4)C[triple bond]C)Pt(P(n-Bu)(3))(2)(C[triple bond]C-p-C(6)H(4))] spacer to Zn(P) vary from 2.4 x 10(4) to 1.3 x 10(6) s(-1). For the n-pentyl case, a rate dependence of oligomer size is noted as k(ET) increases with the number of units, n. This phenomenon is interpreted by the presence of an excitonic process (i.e., delocalization of the energy along the Zn(P) array).