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Phosphorescence in the liquid crystal state with one of the highest quantum yield values, 42%, at room temperature is reported. This property is achieved with cyclic trinuclear copper(I) complexes prepared using 3,5-dimethyl-4-(trialkoxyphenyl)pyrazolate ligands. The compounds show well-organized hexagonal columnar mesophases that are stable at room temperature or near room temperature with intracolumnar order at distances of 3.6 Å, red emission and lifetimes consistent with the excimeric metal-centered phosphorescence typical of copper trinuclear pyrazolato complexes. A non-mesogenic analogue shows similar properties, and the single crystal structure is formed by stacked molecules forming a supramolecular extended structure with two different intermolecular Cu⋯Cu contacts, 3.368 Å and 3.666 Å, which are in the range of previously reported weak cuprophilic interactions. The results demonstrate that metallomesogens with efficient room temperature phosphorescence can be obtained with metal complexes other than the widely explored and precious metal-based iridium or platinum complexes. [ABSTRACT FROM AUTHOR]

New complexes with the DAFO (4,5-diazafluoren-9-one) ligand of stoichiometry [Ag(DAFO)(P-P)]OTf [P-P = dppe, 1,2-bis(diphenylphosphane)ethane; dppp, 1,3-bis(diphenylphosphane)propane; dppph, ortho-bis(diphenylphosphane)benzene; dppcc, 1,2-bis(diphenylphosphane)-1,2-dicarba-closo-dodecaborane; dipcc, 1,2-bis(diisopropylphosphane)-1,2-dicarba-nido-dodecaborane], [Ag(DAFO)(P-P*)] [P-P* = dppnc, 7,8-bis(diphenylphosphane)-7,8-dicarba-nido-undecaborate(-1); dipnc, 7,8-bis(diisopropylphosphane)-7,8-dicarba-closo-undecaborate(-1)] and [Ag(DAFO)(OTf)L] [L = PPh3; dpccMe, 1-diphenylphosphane-2-methyl-1,2-dicarba-closo-dodecaborane] are reported. The structures of the complexes depend on the skeleton of the diphosphane. Most of these compounds are luminescent and their emissions seem to have originated from IL (DAFO) transitions, modified upon coordination to silver. [ABSTRACT FROM AUTHOR]

Gold complexes with selenolate and tellurolate carborane ligands [E2C2B10H10]2− (E = Se, Te) have been synthesized by reaction of a freshly prepared solution of [1,2-(LiE)2C2B10H10] (E = Se, Te) with [AuClL] (L = PPh3, PPh2Me, PPh2py) in a 1 : 2 molar ratio or [Au2Cl2(P∼P)] [P∼P = dppf, 1,1′-bis(diphenylphosphano)ferrocene; dppe, 1,2-bis(diphenylphosphano)ethane; dppc, 1,2-bis(diphenylphosphano)-o-carborane] in a 1 : 1 molar ratio affording complexes [Au2(μ-1,2-E2C2B10H10)L2] or [Au2(μ-1,2-E2C2B10H10)(P∼P)], respectively. The gold(iii) species PPN[Au(E2C2B10H10)2] (PPN = bis(triphenylphosphano)iminium) have been afforded by reaction of PPN[AuCl4] with [1,2-(LiE)2C2B10H10]. Complex [Au4(μ-1,2-Se2C2B10H10)2(μ-dppc)2] displays a tetranuclear structure, different from the dinuclear cyclic arrangement proposed for other complexes with diphosphanes of [Au2(μ-1,2-Se2C2B10H10)(P∼P)] stoichiometry. [ABSTRACT FROM AUTHOR]

Reaction of the yellow-green emitters [Au{(PPh2)2C2B9H10}(PR3)] with [Au(C6F5)(tht)] affords orange-red emissive gold complexes [Au2{μ-(PPh2)2C2B9H10}(C6F5)(PR3)] which contain different neutral (PR3) and anionic (C6F5) auxiliary ligands and an anionic diphosphine. The resulting complexes are among the few reported in which an ortho-carborane diphosphine acts in a bridging mode, and are unique in containing not a closo- (neutral), but a nido-carborane (anionic) cluster. DFT and TDDFT calculations led to the prediction of the origin of the two first singlet–triplet transitions, which is consistent with the experimental results. Although the blue emissive nido-diphosphine plays a key role in the transitions of the three-coordinate precursors and the final dinuclear complexes, it is the environment around the gold centre that controls the emission energy. [ABSTRACT FROM AUTHOR]

The synthesis and X-ray analysis of complexes [(μ-1,12-C2B10H10){Au(PPh3)}2] and [(μ-1,2-C2B10H10)- {Au(PMe3)}2] have provided the experimental data needed to analyse two points. The first point is the use of these data to carry out a computational study with the aim of comparing the electronic structures and relative stabilities of the organometallic isomers [(μ-1,n-C2B10H10){Au(PR3)}2] (n = 2, 7, 12; R = Ph, Me) with those of the parent carborane clusters ortho-, meta- and para-carborane and the influence of the monophosphine substituents. The second point is focused in the influence of the steric demand of the monophosphine in the presence or not of aurophilic interactions in the ortho derivatives [(μ-1,2-C2B10H10){Au(PR3)}2] (R= Me, Ph). The photoluminescent behaviour of both the carboranes and the organometallic complexes is presented. [ABSTRACT FROM AUTHOR]

The synthesis and X-ray analysis of complexes [(μ-1,12-C2B10H10){Au(PPh3)}2] and [(μ-1,2-C2B10H10){Au(PMe3)}2] have provided the experimental data needed to analyse two points. The first point is the use of these data to carry out a computational study with the aim of comparing the electronic structures and relative stabilities of the organometallic isomers [(μ-1,n-C2B10H10){Au(PR3)}2] (n= 2, 7, 12; R = Ph, Me) with those of the parent carborane clusters ortho-, meta- and para-carborane and the influence of the monophosphine substituents. The second point is focused in the influence of the steric demand of the monophosphine in the presence or not of aurophilic interactions in the orthoderivatives [(μ-1,2-C2B10H10){Au(PR3)}2] (R = Me, Ph). The photoluminescent behaviour of both the carboranes and the organometallic complexes is presented. [ABSTRACT FROM AUTHOR]

The metal atoms in group 11 complexes [M{(PR2)2C2B9H10}L] [R = Ph, (i)Pr; L = tertiary phosphane; M = Au, Ag, Cu] play an important role in the emissive properties of these compounds. The influence of the metal follows the order Au ≫ Ag ≥ Cu. The three-coordinated complexes are obtained from the reaction of [AuClL], [Ag(OTf)L], or [Cu(NO3)(PPh3)2] with the closo carborane diphosphane in refluxing ethanol. For L = PPh2NHPy, cleavage of the P-N bond and the formation of the monophosphane PPh2OEt are observed, depending on the metal and the nido carborane diphosphane substituent ((i)Pr or Ph).

Unsaturated [Tp(Me2)Ir(III)] fragments, readily generated from compounds [Tp(Me2)Ir(C(6)H(5))(2)(N(2))], (1a) and [Tp(Me2)Ir(η(4)-CH(2)=C(Me)C(Me)=CH(2)] (1b) (Tp(Me2) = hydrotris(3,5-dimethylpyrazolyl)borate), induce the isomerisation of the polypyridines, 2,2'-bipyridine, 1,10-phenanthroline and 2,2':6'2''-terpyridine, to form complexes that contain the carbene tautomer of these ligands. For terpy, a binuclear compound has also been isolated, in which this molecule bridges two Ir(III) centres, thanks to its coordination as a bidentate N-heterocyclic carbene. The new compounds have been structurally authenticated by X-ray crystallography and their photophysical properties have been investigated.

Reaction of the diphosphanes P∼P [PPh(2)(C(6)H(4))(n)PPh(2) (n = 1-5) and PPh(2)C[triple bond, length as m-dash]C(C(6)H(4))C[triple bond, length as m-dash]CPPh(2)] with [AuX(tht)] (X = Cl, C(6)F(5)) in a 1 : 2 molar ratio affords dinuclear luminescent complexes of formula [(AuX)(2)(P∼P)]. The photoemissive properties of these complexes are mainly controlled by the presence of the diphosphane ligand, specifically by the phenylene spacers of the diphosphanes. At room temperature fluorescent (IL) processes dominate the emissions, both in solution and in the solid state. Frozen solutions or solids at 77 K display dual emissions or only one emission attributed to ligand to ligand charge transfer (LL'CT) transitions from the auxiliary ligand (L) to phenylene spacers of the diphosphane (L').

[6]-Azaosmahelicenes, the first d(4)-heterometallahelicenes, have been synthesised and fully characterised. Their optical properties (UV-Vis absorption and luminescence) are reported., (This journal is © The Royal Society of Chemistry 2012)

A series of luminescent dinuclear neutral complexes of stoichiometry [(AuSPh)(2)(PPh(2)-(C(6)H(4))(n)-PPh(2))] (n = 1, 2, 3) as well as their tetranuclear cationic derivatives [(Au(2)SPh)(2)(PPh(2)-(C(6)H(4))(n)-PPh(2))(2)](PF(6))(2) are reported. Their crystal structures have been elucidated by X-ray studies. These studies indicate that, for the dinuclear species, only when n = 1 the molecules exhibit intermolecular aurophilic interactions. None of the tetranuclear species crystallizes in their molecular form, due to the formation of aggregates through Au···Au interactions. The origin of the luminescence has been analyzed by computational studies indicating that the presence or absence of aurophilic interactions does not affect the luminescent behavior and that intraligand charge transfer processes which involve the thiolate and the diphosphine are responsible for the emissions. The result is in contrast with the thiolate-gold charge transfer processes which dominate the photophysics of gold-thiolate compounds and reveals the influence of the phenylene spacers in the emissive behavior of these compounds., (This journal is © The Royal Society of Chemistry 2011)

The coordination properties of the 1,1'-bis[((6-methyl)-2-pyridyl)amido]ferrocene ligand () towards group 11 and palladium complexes have been studied. coordinates as the bridging ligand, through the pyridinic nitrogen atoms, when reacting with the gold(i) compounds [Au(OTf)(PPh(3))] and [Au(C(6)F(5))(tht)] or with the gold(iii) species [Au(C(6)F(5))(3)(tht)] leading to linear or square planar derivatives, respectively. The reaction of with [O(AuPPh(3))(3)]ClO(4) affords the tetranuclear compound [Au(4)(L-H)(2)(PPh(3))(4)](ClO(4))(2) in which the amide groups have been deprotonated and the ligand acts as dianionic, N,N,N,N-tetradentate. The treatment of the ligand with silver salts leads to mononuclear complexes with the ligand acting as N,N,O or N,N chelating in [AgL]OTf, or [AgL(2)]OTf, or to dinuclear species with an N,N bridging ligand in [Ag(2)(PPh(3))(2)(mu-L)](OTf)(2). Tetracoordination around the copper atom is proposed for the copper complexes [CuL(PPh(3))(2)]PF(6), [CuL]PF(6), or [CuL(2)]PF(6) with the ligand coordinated in an NH,NH,N,N or an N,N chelating fashion. Finally the palladium compound [PtCl(2)L] has been synthesized with a trans-chelating ligand. In the structures of some of these derivatives the presence of secondary interactions such as weak hydrogen bonds of the type C-HO, C-HN or C-HX (X = F, Cl) or even MO interactions leads to supramolecular networks.

The complexation properties of the ligand bis(3,5-dimethylpyrazol-1-yl)methane (L) towards group 11 metals have been studied. The reaction in a 1 : 1 molar ratio with [Cu(NCMe)4]PF6 or Ag(OTf) complexes gives the mononuclear [CuL(NCMe)]PF6 (1), with crystallographic mirror symmetry, or dinuclear [Ag2(mu-L)2](OTf)2 (2) (OTf = trifluoromethanesulfonate) in which the ligand bridges both silver centres, an unprecedented mode of coordination for this type of ligands. Compound 2 crystallizes with two water molecules and forms a supramolecular structure through classical hydrogen bonding. The reaction in a 2 : 1 ratio affords in both cases the four-coordinated derivatives [ML2]X (M = Cu, X = PF6 (3); Ag, X = OTf 4). The treatment of [Ag(OTf)(PPh3)] with the ligand L gives [AgL(PPh3)]OTf (5). The gold(I) derivative [Au2(C6F5)2(mu-L)] (6) has also been obtained by reaction of L with two equivalents of [Au(C6F5)(tht)]. These complexes present a luminescent behaviour at low temperature; the emissions being mainly intraligand but enhanced after coordination of the metal. Compounds 1-4 have been characterized by X-ray crystallography. DFT studies showed that, in the silver complex 2, coordination of H2O to Ag in the binuclear complex is favoured by formation of a hydrogen-bonding network, involving the triflato anion, and releasing enough energy to allow distortion of the Ag2 framework.