Heteroleptic Tris Research Articles

The synthesis and structure of heteroleptic tris(diimine)ruthenium(II) complexes.

The reactions of bidentate diimine ligands (L2) with cationic bis(diimine)[Ru(L)(L1)(CO)Cl]+ complexes (L, L1, L2 are dissimilar diimine ligands), in the presence of trimethylamine-N-oxide (Me3NO) as a decarbonylation reagent, lead to the formation of heteroleptic tris(diimine) ruthenium(II) complexes, [Ru(L)(L1)(L2)]2+. Typically isolated as hexafluorophosphate or perchlorate salts, these complexes were characterised by UV-visible, infrared and mass spectroscopy, cyclic voltammetry, microanalyses and NMR spectroscopy. Single crystal X-ray studies have elucidated the structures of K[Ru(bpy)(phen)(4,4'-Me(2)bpy)](PF(6))(3).1/2H(2)O, [Ru(bpy)(5,6-Me(2)phen)(Hdpa)](ClO(4))(2), [Ru(bpy)(phen)(5,6-Me(2)phen)](ClO(4))(2), [Ru(bpy)(5,6'-Me(2)phen)(4,4'-Me(2)bpy)](PF(6))(2).EtOH, [Ru(4,4'-Me(2)bpy)(phen)(Hdpa)](PF(6))(2).MeOH and [Ru(bpy)(4,4'-Me(2)bpy)(Hdpa)](ClO(4))(2).1/2Hdpa (where Hdpa is di(2-pyridyl)amine). A novel feature of the first complex is the presence of a dinuclear anionic adduct, [K(2)(PF(6))(6)](4-), in which the two potassium centres are bridged by two fluorides from different hexafluorophosphate ions forming a K(2)F(2) bridging unit and by two KFPFK bridging moieties.

Infrared spectra of phthalocyanine and naphthalocyanine in sandwich-type (na)phthalocyaninato and porphyrinato rare earth complexes: Part 4. The infrared characteristics of phthalocyanine in heteroleptic tris(phthalocyaninato) rare earth complexes

The infrared (IR) spectroscopic data for a series of heteroleptic tris(phthalocyaninato) rare earth complexes (Pc)M(OOPc)M(OOPc) (M=Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Y) and (Pc)Tm(OOPc)Tm(Pc) [H 2Pc=unsubstituted phthalocyanine, H 2OOPc=2,3,9,10,16,17,24,25-octakis(octyloxy)phthalocyanine] have been collected with 2 cm −1 resolution. The IR spectra for (Pc)M(OOPc)M(OOPc) are more complicated than those of bis(phthalocyaninato) rare earth analogues, revealing the relatively lower symmetry of these triple-decker compounds. For both types of heteroleptic tris(phthalocyaninato) rare earth compounds, the characteristic phthalocyanine dianion IR bands for both Pc 2− and OOPc 2−at ca. 1329 and 1380 cm −1 attributed, respectively, to the pyrrole stretching and the symmetric CH bendings of CH 3 groups in octyloxy side chains of OOPc rings together with contribution from the isoindole stretching vibrations are observed in these spectra. The frequencies of the vibration at 1312–1318, attributed to pyrrole stretchings, are dependent on the central rare earth size, shifting slightly to higher energy along with the decrease of rare earth radius across the series. The decreased sensitivity of the frequency of the vibration at 1463–1465 cm −1 and rare earth metal size compared with that of the corresponding isoindole stretching band at 1439–1454 cm −1 for bis(phthalocyaninato) rare earth counterparts indicates that the π–π interactions in these heteroleptic triple-deckers are weaker than those in the double-deckers.

Isolation of Geometric Isomers within Diastereoisomers of Dinuclear Ligand-Bridged Complexes of Ruthenium(II)

The individual diastereoisomeric forms [meso (ΔΛ) and rac (ΔΔ and ΛΛ)] of the ligand-bridged dinuclear species [{Ru(phen)(Me₄bpy)}₂(μ-bpm)]⁴⁺ [phen = 1,10-phenanthroline; Me₄bpy = 4,4',5,5'-tetramethyl-2,2'-bipyridine; bpm = 2,2'-bipyrimidine] have been synthesized using chiral forms of the precursors [Ru(phen)(Me₄bpy)(bpm)]²⁺ and [Ru(phen)(Me₄bpy)(py)₂]²⁺. The cis and trans geometric isomers of both diastereoisomeric forms have been separated by cation exchange chromatography and characterized by NMR spectroscopy. We also report the first chiral resolutions of a heteroleptic tris(bidentate)ruthenium(II) complex, [Ru(phen)(Me₄bpy)(bpm)]²⁺, and a heteroleptic bis(bidentate)bis(pyridine)ruthenium(II) complex, [Ru(phen)(Me₄bpy)(py)₂]²⁺, in both cases using cation exchange chromatography.

1,2-bis(dimethylamino) ethan-komplexe von heteroleptischen alkylzink-verbindungen: Zusammenhang zwischen ZnN-abstand und RZnR′-bindungswinkel

The synthesis and isolation of heteroleptic diorganylzinc compounds enforces the use of either sterically demanding substituents or the formation of a tmeda complex. The occupation of the coordination sites at the zinc atom prevents the dismutation to the homoleptic derivatives. These tmeda adducts show a linear dependency of the RZnR′ bond angle and the ZnN distance, which is discussed in detail for two examples. ZnN bond lengths of 215 pm and a CZnCl angle of 122.2° are observed for [1,2-bis(dimethylamino)ethane-N,N′]zinc chloride phenyl(trimethylsilyl)methanide (triclinic, P l, a = 974.9(3), b = 985.2(3), c = 1262.6(3) pm, α = 67.35(2)°, β = 78.42(2)°, γ = 63.02(2)°, Z = 2 ), whereas the substitution of the chlorine substituent by a methyl group (triclinic, P l, a = 974.74(8), b = 998.03(8), c = 1276.21(9) pm, α = 67.492(5)°, β = 77.880(6)°, γ = 63.291(5)°, Z = 2 ) leads to a ZnN bond length of 224 pm with a widened CZnC angle of 131.1°. The extrapolation of the linear relation predicts a ZnN distance of 290 pm for a linear RZnR′ moiety, a bond length of 190 pm for an angle of 109°. This last mentioned value corresponds to a ZnN single bond such as, for example, in the heteroleptic tris(trimethylsilyl)methylzinc bis(trimethylsilyl)amide (monoclinic, P2 1/ n, a = 904.74(7), b = 1668.72(9), c = 1806.76(8) pm, β = 94.670(5)°, Z = 4) with a value of 184.6 pm.

Black MLCT Absorbers

[Extract] A general approach has been developed for the preparation of heteroleptic tris(bidentate)ruthenium(II) complexes which exhibit significant continuous light absorption throughout the UV and visible regions. It utilizes separate metal-to-ligand charge transfer (MLCT) transitions to different heterocyclic ligands and the incorporation of the diethyldithiocarbamate anion (Et₂dtc-) to shift the MLCT bands uniformly to the red. In the spectrum of [Ru{(EtCO₂)₂bpy}(dpa)(Et₂dtc)]⁺ ((EtCO₂)₂bpy is 4,4'-bis(carboxyethyl)-2,2'-bipyridine) significant absorption (e > 3000) extends past 700 nm. These complexes can be photochemically inert and exhibit near-IR emission with appreciable excited state lifetimes.