Deep red phosphorescence of cyclometalated iridium complexes by o-carborane substitution.

Heteroleptic (C(∧)N)2Ir(acac) (C(∧)N = 5-MeCBbtp (5a); 4-BuCBbtp (5b); 5-BuCBbtp (5c); 5-(R)CBbtp = 2-(2'-benzothienyl)-5-(2-R-ortho-carboran-1-yl)-pyridinato-C(2),N, R = Me and n-Bu; 4-BuCBbtp = 2-(2'-benzothienyl)-4-(2-n-Bu-ortho-carboran-1-yl)-pyridinato-C(2),N, acac = acetylacetonate) complexes supported by o-carborane substituted C(∧)N-chelating ligand were prepared, and the crystal structures of 5a and 5b were determined by X-ray diffraction. While 5a and 5c exhibit a deep red phosphorescence band centered at 644 nm, which is substantially red-shifted compared to that of unsubstituted (btp)2Ir(acac) (6) (λem = 612 nm), 5b is nonemissive in THF solution at room temperature. In contrast, all complexes are emissive at 77 K and in the solid state.

Through-space charge transfer and emission color tuning of di-o-carborane substituted benzene.

1,4-Di-(1-Ar-o-carboran-2-yl)benzene (Ar = 3,5-bis(trifluoromethyl)phenyl (1), phenyl (2), 4-n-butylphenyl (3), 4-N,N-dimethylaniline (4)) compounds that are electronically modulated at the C1-position of o-carborane with the electron-withdrawing or -donating aryl groups were prepared and characterized. The X-ray crystal structures of 1, 3, and 4 reveal that the two aryl groups on the C1-carborane carbon atoms are oppositely positioned, featuring overall C2-symmetry, and the C1-C2 bond length of carborane increases with the increasing order of electron-donating effect of an aryl group. UV-vis absorption spectra exhibit small low-energy absorption bands at around 275-300 nm for 1-3 while 4 shows a broad absorption tail at 350-400 nm.

Heteroleptic tris-cyclometalated iridium(III) complexes supported by an o-carboranyl-pyridine ligand.

Heteroleptic tris-cyclometalated Ir(III) complexes supported by the o-carboranyl-pyridine (CBpy) as a novel C^N chelating ligand were synthesized and characterized. While the CBpy ligand contributes to the electronic stabilization of complexes, their photophysical properties are dominated by 2-arylpyridine ligands.

Synthesis and electron transporting properties of methanofullerene-o-carborane dyads in organic field-effect transistors.

A series of methanofullerene-o-carborane dyads (PCB-Ph-CB, PCB-Cn-CB, n = 1, 3, 6, 11) were synthesized via esterification of [6,6]-phenyl-C61-butyric acid (PCBA) with 2-alcohol functionalized o-carborane derivatives, 1-(4-n-BuC6H4)-2-R-1,2-closo-C2B10H10 (R = p-C6H4OH, (CH2)nOH, n = 1, 3, 6, 11). All the dyads are highly soluble in chlorinated and aromatic solvents under ambient conditions. UV-vis absorption and electrochemical reduction of the dyads exhibited features almost identical to each other, as well as to their parent PCBM, suggesting that the electronic properties of the dyads would be dominated by the methanofullerene moiety.

Dual sensing of fluoride ions by the o-carborane-triarylborane dyad.

The o-carborane-triarylborane dyad shows high fluoride ion affinity through the trigonal-planar boron center while degradation to nido-carborane leads to a turn-on fluorescence response toward fluoride.

Vinyl-type polynorbornenes with pendant PCBM: a novel acceptor for organic solar cells.

Vinyl addition homo- and copolymerization of norbornene monomer (M1) functionalized with a PCBM moiety using a Pd(II) catalyst in combination with a 1-octene chain transfer agent efficiently produces polynorbornenes with side-chain PCBM groups. Characterization by NMR spectroscopy and elemental analysis reveals that the copolymers constitute a well-defined polymer structure with controlled incorporation of M1. Although the homopolymer is insoluble in organic solvents, the copolymers containing 62 mol% (P2) and 50 mol% (P3) of the PCBM moiety are soluble in chlorinated solvents such as o-dichlorobenzene.

A highly Lewis acidic triarylborane bearing peripheral o-carborane cages.

A triarylborane (2) bearing three o-carborane cages at peripheral positions on the aryl groups was prepared and its crystal structure was determined from X-ray diffraction study. Treatment of 2 with KF in the presence of 18-crown-6 led to the potassium salt, [2F](-). A UV-vis titration experiment carried out in THF/H(2)O (9/1 v/v) showed that 2 binds fluoride ions with a binding constant (K) of 4.

o-Carborane-assisted Lewis acidity enhancement of triarylboranes.

The introduction of an o-carborane cage into the triarylborane significantly enhances the Lewis acidity of the boron atom leading to large increase in fluoride ion affinity.

Polymorphism-induced dual phosphorescent emission from solid-state iridium(III) complex.

Different molecular packing structures in the solid-state iridium(III) complex (1) induce unprecedented dual phosphorescent emission through 3M(LLLL)CT and 3M(LL)CT transitions.

Synthesis of stable platinum complexes containing carborane in a carrier group for potential BNCT agents.

A series of stable platinum complexes containing closo-carborane cages in a 'carrier group', which could be potentially utilized for boron neutron capture therapy (BNCT), was successfully synthesized and characterized by various spectroscopic methods. Two ortho-closo-carborane cages were connected to the 3,3' or 4,4'-positions of 2,2'-bipyridine through ester bonds to give three carborane-linked bipyridine ligands, 3,3'-(3-(1,2-dicarba-closo-dodecaborane-1-yl)propoxycarbonyl)-2,2'-bipyridine (3) and n,n-(3-(1-methyl-1,2-dicarba-closo-dodecaborane-1-yl)propoxycarbonyl)-2,2-bipyridine (n = 3 4; n = 4 5). The prepared ligands successfully replaced the labile benzonitrile groups of [Pt(PhCN)2Cl2] to afford three cisplatin analogs [Pt(L)Cl2] (L = 3-5).

Synthesis and properties of salen-aluminum complexes as a novel class of color-tunable luminophores.

Showing their true colors? Full emission color tuning in the visible region can be achieved with salen-aluminum complexes that are electronically modulated at C5 of the phenoxide ring in the salen moiety. Emission spectra for various substituents R(5) are shown (EWG: electron-withdrawing group, EDG: electron-donating group).A series of salen-aluminum complexes, [{(R(5))(2)-salen(3-tBu)(2)}Al(OC(6)H(4)-p-C(6)H(5))] (salen=N,N'-bis(salicylidene)ethylenediamine; R(5)=H (1), tBu (2), Br (3), Ph (4), OMe (5), NMe(2) (6)) and [{5,5'-(NMe(3))(2)-salen(3-tBu)(2)}Al(OC(6)H(4)-p-C(6)H(5))][OTf](2) (7; OTf=CF(3)SO(3)) that are electronically modulated directly at C5 of the phenoxide ring in the salen moiety has been prepared.

Aqueous fluorometric and colorimetric sensing of phosphate ions by a fluorescent dinuclear zinc complex.

A fluorescent dinuclear zinc complex (1) has been prepared by an easy "one pot" method in which the lysine-based Schiff base ligand is generated in situ. The compound is characterized in detail by various spectroscopic techniques and single-crystal X-ray diffraction. Crystal data: monoclinic, C2, a = 18.

Highly selective fluorescence detection of Cu2+ in water by chiral dimeric Zn2+ complexes through direct displacement.

Fluorescent dinuclear chiral zinc complexes were synthesized in a "one-pot" method in which the lysine-based Schiff base ligand was generated in situ. This complex acts as a highly sensitive and selective fluorescent ON-OFF probe for Cu(2+) in water at physiological pH. Other metal ions such as Hg(2+), Cd(2+), and Pb(2+) gave little fluorescence change.

Synthetic utility of ammonium salts in a Cu-catalyzed three-component reaction as a facile coupling partner.

Ammonium salts were found to be a convenient and inexpensive reagent in the Cu-catalyzed three-component reaction with terminal alkynes and sulfonyl or phosphoryl azides leading to N-unprotected amidines. Thus obtained amidines bearing 2-bromobenzenesulfonyl moiety were efficiently cyclized by the Cu-catalyzed intramolecular N-arylation to give an important pharmacophore skeleton of 2H-1,2,4-benzothiadiazine 1,1-dioxides. Conveniently, two tandem catalytic procedures could be readily operated in one pot.

Elaboration of rac-like active species from Lewis base functionalized unbridged zirconocenes for isospecific propylene polymerization.

A series of ortho or meta Lewis base functionalized unbridged zirconocenes, [{1-(E(n)-Ph)-3,4-Me(2)C(5)H(2)}(2)ZrCl(2)] (E = NMe(2), OMe; n = 1, 2), and a half-functionalized zirconocene, [{1-(p-Me(2)NC(6)H(4))-3,4-Me(2)C(5)H(2)}{1-(p-tolyl)-3,4-Me(2)C(5)H(2)}ZrCl(2)], were prepared. The crystal structures of these compounds determined by X-ray diffraction revealed the presence of only C(2)-symmetric rac-like isomers in the asymmetric units. In combination with methylaluminoxane (MAO) cocatalyst, the meta-functionalized complexes afforded mixtures of polymers that exhibit multimelting transition temperatures and broad molecular-weight distributions (MWDs) in propylene polymerization at atmospheric monomer pressure, whereas the ortho-functionalized complexes did not give rise to polymerization.

A novel solution-processible heterodinuclear AlIII/IrIII complex for host-dopant assembly OLEDs.

A discrete heterodinuclear Al (III)/Ir (III) complex shows bright-orange light emission when used as an active layer in host-dopant assembly organic light-emitting diodes based on a solution process.

Aluminium-salen luminophores as new hole-blocking materials for phosphorescent OLEDs.

The organic light-emitting diodes (OLEDs) employing complex [salen(tBu)4Al(OC6H4-p-C6H5)] (4) as a hole-blocking layer produced stable green EL emission of Ir(ppy)3 irrespective of changing current density and showed higher brightness and device efficiency than the BAlq-based device.

Novel chlorotitanium complexes containing chiral tridentate schiff base ligands for ring-opening polymerization of lactide.

The selective synthesis of tri- and dichlorotitanium species containing chiral tridentate Schiff base ligands, derived from (1R,2S)-(-)-1-aminoindanol, was achieved by changing the solvent. Single-crystal X-ray analyses reveal that chlorotitanium complexes are monomeric and octahedral with the meridional occupation of the Schiff base. Although the chlorotitanium complexes lack typical initiating groups such as alkoxides or amides, they are effective catalysts for the controlled ring-opening polymerization of L-lactide (L-LA) as shown by the linearity of the molecular weight vs [L-LA]/[Ti] ratio plot as well as very narrow polydispersity index values.

Novel synthetic strategy for developing an isospecific unbridged metallocene system for propylene polymerization.

New unbridged zirconocenes functionalized with a Lewis base, [{1-(E-C(6)H(4))-3,4-Me(2)C(5)H(2)}(2)ZrCl(2)] (E = p-NMe(2) (3); p-OMe (4); p-SMe (5)) were prepared and their propylene polymerization behavior was examined. Under methylaluminoxane (MAO) activation at atmospheric monomer pressure, these complexes afford mixtures of polymers exhibiting multimelting transition temperatures and broad molecular weight distribution, whereas they produce completely atactic polypropylenes under [Ph(3)C][B(C(6)F(5))(4)] activation. Stepwise solvent extraction of the polymer mixtures reveals that the polymers consist of amorphous, moderately isotactic, as well as, highly isotactic portions and the weight ratio of each portion is dependent upon reaction temperature.

Hydrogen-bond-directed highly stereoselective synthesis of Z-enamides via Pd-catalyzed oxidative amidation of conjugated olefins.

An efficient procedure for the preparation of Z-enamides has been developed, involving the reaction of primary amides with conjugated olefins using a Pd/Cu cocatalyst system. It was found that certain additives, such as phosphine oxides and phosphonates, increase the efficiency of the reaction in nonpolar solvents under an oxygen atmosphere, thus producing a variety of Z-enamides in high yields with excellent stereoselectivity under Wacker-type conditions. The oxidative amidation reaction has a broad substrate scope, allowing alkyl, aryl, and vinyl amides to react with olefins conjugated with ester, amide, phosphonate, and ketone groups.

Trimanganese complexes bearing bidentate nitrogen ligands as a highly efficient catalyst precursor in the epoxidation of alkenes.

A series of trinuclear manganese complexes coordinated with neutral bidentate nitrogen ligands, [Mn3L2(OAc)6], were prepared from manganese acetate and the corresponding ligands. Using peracetic acid as the oxidant, the air- and moisture-stable manganese clusters exhibited excellent catalytic activity and selectivity in the epoxidation of olefins under mild conditions. The highest activity was observed with a trinuclear complex containing a 2-pyridylimino ligand, [Mn3(ppei)2(OAc)6] (ppei = 2-pyridinal-1-phenylethylimine).

Fabrication of color-tunable luminescent silica nanotubes loaded with functional dyes using a sol-gel cocondensation method.

Luminescent silica nanotubes SNT-2 (loaded with coumarion laser dye 2) and SNT-3 (loaded with anthracene laser dye 3) were prepared by sol-gel cocondensation of functional dyes and TEOS in a cholesterol-based organogel system. The emission colors of silica nanotubes were tuned by using different functional dyes. Interestingly, there is a great difference in PL spectrum of silica nanotubes loaded with functional dyes between ethanol and the solid state.