Synthetic control of excited-state properties in cyclometalated Ir(III) complexes using ancillary ligands.

The synthesis and photophysical characterization of a series of (N,C(2')-(2-para-tolylpyridyl))2 Ir(LL') [(tpy)2 Ir(LL')] (LL' = 2,4-pentanedionato (acac), bis(pyrazolyl)borate ligands and their analogues, diphosphine chelates and tert-butylisocyanide (CN-t-Bu)) are reported. A smaller series of [(dfppy)2 Ir(LL')] (dfppy = N,C(2')-2-(4',6'-difluorophenyl)pyridyl) complexes were also examined along with two previously reported compounds, (ppy)2 Ir(CN)2- and (ppy)2 Ir(NCS)2- (ppy = N,C(2')-2-phenylpyridyl). The (tpy)2 Ir(PPh2CH2)2 BPh2 and [(tpy)2 Ir(CN-t-Bu)2](CF3SO3) complexes have been structurally characterized by X-ray crystallography.

Organometallic complexes as hole-transporting materials in organic light-emitting diodes.

The use of metal complexes fac-tris(1-phenylpyrazolato-N,C(2)('))cobalt(III) [fac-Co(ppz)(3)], fac-tris(2-phenylpyridinato-N,C(2)(') cobalt(III) [fac-Co(ppy)(3)], and [tris[2-((pyrrole-2-ylmethylidene)amino)ethyl]amine]gallium(III) [Ga(pma)] as materials for hole-transporting layers (HTL) in organic light-emitting diodes (OLEDs) is reported. Co(ppz)(3) and Co(ppy)(3) were prepared by following literature procedures and isolated as mixtures of facial (fac) and meridional (mer) isomers. The more stable fac isomers were separated from the unstable mer forms via column chromatography and thermal gradient sublimation.

Synthesis and characterization of facial and meridional tris-cyclometalated iridium(III) complexes.

The synthesis, structures, electrochemistry, and photophysics of a series of facial (fac) and meridional (mer) tris-cyclometalated Ir(III) complexes are reported. The complexes have the general formula Ir(C'N)(3) [where C'N is a monoanionic cyclometalating ligand; 2-phenylpyridyl (ppy), 2-(p-tolyl)pyridyl (tpy), 2-(4,6-difluorophenyl)pyridyl (46dfppy), 1-phenylpyrazolyl (ppz), 1-(4,6-difluorophenyl)pyrazolyl (46dfppz), or 1-(4-trifluoromethylphenyl)pyrazolyl (tfmppz)]. Reaction of the dichloro-bridged dimers [(C'N(2)Ir(mu-Cl)(2)Ir(C'N)(2)] with 2 equiv of HC( wedge )N at 140-150 degrees C forms the corresponding meridional isomer, while higher reaction temperatures give predominantly the facial isomer.

Comparative Study of the Luminescence Properties of the Europium(III) Complexes of the Squarate, Phenylsquarate, and (Diphenylamino)squarate Ligands.

Reaction of EuCl(3).6H(2)O with 3-phenyl-4-hydroxycyclobut-3-ene-1,2-dione (phenylsquarate) in methanol produces the polymeric complex {Eu(&mgr;-C(6)H(5)C(4)O(3))(2)(C(6)H(5)C(4)O(3))(2)(CH(3)OH)(2)(H(2)O)(2).(CH(3)OH)}(n)() (1) which crystallizes in the space group P2(1)/n with a = 13.

First-Row Transition-Metal Complexes of the 1-Methoxycyclobutenedionate(1-) Ion.

The synthesis and characterization by single-crystal X-ray crystallography of a series of monomeric first-row transition-metal complexes with the 1-methoxycyclobutenedionate(1-) ligand are described. The isomorphous compounds [M(CH(3)OC(4)O(3))(2)(H(2)O)(4)] (M = Mn, Co, Ni, Zn) are C(2) symmetric and crystallize in the monoclinic space group C2/c. The metal atom in each of these complexes is six-coordinate with two cis 1-methoxycyclobutenedionate(1-) ligands, the methoxy substituent being oriented cis with respect to the ligating oxygen atom.