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Six rhenium(I) complexes are structurally compared, with regards to steric and electronic influences induced by the different β-diketone (benzoylacetone – Benzac, trifluoroacetylacetone – Tfaa and hexafluoroacetylacetone – Hfaa) and phosphine ligands (cyclohexyldiphenyl phosphine – PPh2Cy and dicyclohexylphenyl phosphine – PPhCy2). The complexes fac-[Re(Benzac)(CO)3(PPh2Cy)] (2), fac-[Re(Benzac)(CO)3(PPhCy2)] (3), fac-[Re(Tfaa)(CO)3(PPh2Cy)] (5), fac-[Re(Tfaa)(CO)3(PPhCy2)] (6), fac-[Re(Hfaa)(CO)3(PPh2Cy)] (8) and fac-[Re(Hfaa)(CO)3(PPhCy2)] (9) were synthesized by using the ‘2 + 1’ mixed ligand approach and characterized by means of IR, UV–Vis, 1H, 13C and 31P NMR and also X-ray diffraction, clearly showing the increase in the carbonyl stretching frequencies and downfield shifts in the 31P NMR as the fluoro atoms on the ligand backbone increases. The Tolman angles for the coordinated phosphine ligands are: 2 = 134.77°; 3 molecule A = 146.81°; 5 = 134.46°; 6 = 146.05°; 8 = 136.68° and 9 = 146.22°, illustrating the change in steric bulk as the cyclohexyl ligands on the phosphine ligands increase. A direct link is noted between the Re–P distances (2.4906(6) A for 2, 2.5213(17) A for 3 molecule A, 2.4865(16) A for 5, 2.5372(15) A for 6, 2.4906(14) A for 8 and 2.5365(16) A for 9), O,O′-bidentate ligand bite angles, O4–Re–O5, (85.12(6)° for 2, 83.34(13)° for 3 molecule A, 84.91(12)° for 5, 83.53(12)° for 6, 84.54(11)° for 8 and 83.7(2)° for 9) and the calculated dihedral angles (3.677(1)° for 2, 12.521(1)° for 3 molecule A, 1.489(7)° for 5, 12.463(11)° for 6, 2.940(7)° for 8 and 11.747(6)° for 9). The dihedral angle is calculated between the equatorial plane (Re1, C1, O1, C2, O2, O4, C5, C6, C7, O5) and the plane through Re1, O4, C5, C6, C7, O5. Dihedral angles of approximately four times larger are observed in complexes with coordinated PPhCy2 ligands compared to the PPh2Cy containing analogues, indicating the steric effect induced on the bidentate ligand by the extra cyclohexyl substituent on the PPhCy2 ligand.

The coordination polymers [ Ln ( β - dik ) 3 bpy ] ∞ 1 ·C7H8 (Ln = Eu, β-dik = dbm, tta, hfac; Ln = Tb; β-dik = dbm; Hdbm = dibenzoylmethane, Htta = thenoyltrifluoroacetone, Hhfac: hexafluoroacetylacetone) were easily assembled in mild conditions and high yields starting from the anhydrous lanthanide β-diketonates as nodes and 4,4′-bipyridine (bpy) as connector. X-ray single crystal studies have shown zigzag extended chains where lanthanide centres are 8-coordinated in a distorted square-antiprismatic geometry. Photoluminescence studies show bright red europium emission and spectral features dependent on the topology of the polymeric chains.

Lanthanide tris(β-diketonate) complexes of variant coordination numbers with the compositions [La(hfaa)3(bpy)2] (1), [Nd(hfaa)3(bpy)(H2O)]·½bpy (2), [Sm(hfaa)3(bpy)(H2O)]·bpy (3) and [Ln(hfaa)3(bpy)] (Ln = Nd (4), Sm (5), Eu (6), Ho (7), Er (8) and Yb (9); hfaa = anion of hexafluoroacetylacetone and bpy = 2,2′-bipyridine) have been synthesized and fully characterized. The single crystal analysis of (2) and (3) reveals that Nd and Sm are mononuclear and nine-coordinate (LnO7N2) with a monocapped square antiprismatic geometry. The photophysical parameters obtained are lower than their anhydrous eight-coordinated analogues. The complexes show high quantum efficiencies in the both visible and NIR regions, which could be related to the formation of highly protected coordination environments (LnO6N4 or LnO6N2) by the hfaa− and bpy ligands around the Ln(III) ions. Finally, these volatile and luminescent complexes were used to fabricate OLEDs. The best Vis–NIR devices with the structures: ITO/CuPc (15 nm)/[Sm(hfaa)3(bpy)] or [Nd(hfaa)3bpy]:CBP or [Er(hfaa)3bpy]:CBP or [Yb(hfaa)3bpy]:CBP (50 nm)/BCP (20 nm)/AlQ (30 nm)/LiF (1 nm)/Al (100 nm), show a maximum brightness of 45 cd/m2 with a current efficiency of 0.19 cd/A for visible devices, while the NIR devices exhibit a maximum NIR irradiance and a maximum external quantum efficiency (EQE) of 28 μW cm−2 and 0.022% for Nd(III), 0.50 μW cm−2 and 0.011% for Er(III) and 93 μW cm−2 and 0.18% for Yb(III), respectively, which indicate highly improved EL performance over devices reported in the literature.

The novel mixed ligand complexes [Ca(hfa)2(diglyme)(H2O)] (I), [Sr(hfa)2(diglyme)(H2O)] (II) and [Ba(hfa)2(diglyme)2] (III) (Hhfa = 1,1,1,5,5,5-hexafluoropentane-2,4-dione, diglyme = 2,5,8-trioxanonane) were synthesized by the reactions of the alkaline earth element (AEE) carbonates in n-hexane with a mixture of Hhfa and diglyme, and they were characterized by elemental analysis, 1H and 13C NMR, and FTIR spectroscopy. The crystal structures of I–III, consisting of mononuclear isolated molecules, have been determined. The thermal behavior and composition of the vapor phase have been studied for I–III by thermal analysis at low pressure and mass spectrometry using a Knudsen cell. The stability of the mixed ligand complexes [M(hfa)2(diglyme)n] to the removal of diglyme molecules under heating decreases in the row I > II ≈ III, and only I evaporates as the mixed ligand complex after water removal.

Crystal and molecular structure of the novel tetrakis hexafluoroacetyloacetonate neodymium(III) single crystal, (N(C2H5)4)[Nd(hfa)4(H2O)] (hfa – hexafluoroacetylacetone), obtained by us, has been determined by X-ray diffractometry. The complex was characterized using IR spectroscopy and thermogravimetric analysis. An absorption spectrum of the single crystal was recorded and parameterized in terms of Judd–Ofelt intensity parameters Ωλ. The experimental values of Ωλ have been compared with those calculated based on the crystallographic data and taking into account the forced electric dipole and dynamic coupling mechanisms. Our study reveals a strong effect of hydrogen bonds, formed between the ligand’s ketone oxygens and the water molecule from the neighboring complex anion, on the polarisation of the chemical environment of Nd3+ ions as well as a high value of Ω2 intensity parameter. The molecular structure of the complex can be satisfactorily predicted by the SMLC/AM1 (sparkle model for the calculation of lanthanide complexes within Austin model 1) method.

The preparation and crystal structures of four MnII carboxylate complexes containing 2-pyridinealdoxime, (py)CHNOH, are reported. The 1:1 reaction between Mn(O2CPh)2 · 2H2O and (py)CHNOH in MeCN, followed by evaporation of the resulting solution, redissolution of the residue in CHCl3 and precipitation with Et2O leads to isolation of [Mn4(O2CPh)6{(py)CO2}2{(py)CHNOH}2] · 0.6CHCl3 (1 · 0.6CHCl3). The most interesting synthetic feature is the in situ formation of the picolinate(−1) ligand, (py)CO2 −. The centrosymmetric tetranuclear cluster consists of an exactly planar zig-zag array of MnII ions and is held together by four syn, syn η1:η2:μ2 and two η1:η2:μ3 PhCO2 − groups, two η1:η2:μ2 (py)CO2 − ligands and two N,N′-bidentate chelating (py)CHNOH molecules. The 1:4:7 [Mn3 II,III, IIIO(O2CPh)6(pyr)2(H2O)]/Me3SiCl/(py)CHNOH reaction mixture in MeCN (pyr=pyridine) yields the 1D coordination polymer [Mn(O2CPh){(py)CO2}{(py)CHNOH}]n (2), in which the partial (py)CHNOH → (py)CO2 − transformation has again occurred. In each chain the MnII ions are bridged by syn, anti carboxylate groups of the η1:η1:η1:μ2 (py)CO2 − ligands, while the monodentate PhCO2 − group and the N,N′-bidentate chelating (py)CHNOH molecule complete the octahedral coordination at each metal ion. The 1:3 reaction between Mn(O2CMe)2 · 4H2O and (py)CHNOH in EtOH leads to the isolation of the dinuclear complex [Mn2(O2CMe)2{(py)CO2}2{(py)CHNOH}2] (3); crystallography reveals again the partial (py)CHNOH → (py)CO2 − transformation. The dinuclear molecule is located at a centre of symmetry; the MnII ions are bridged by two oxygen atoms from the two symmetry-related η1:η1:μ2 (py)CO2 − ligands, whose nitrogen atoms are ligated to different metal ions. Each MnII ion is further coordinated by a monodentate MeCO2 − group and a N,N′-bidentate chelating (py)CHNOH molecule. Reaction of Mn(hfac)2 · 3H2O (hfacH=hexafluoroacetylacetone) with 1 equivalent of (py)CHNOH in CH2Cl2 yields complex [Mn(O2CCF3)2{(py)CHNOH}2] (4); the CF3CO2 − ligand is one of the decomposition products of the hfac− ligand. The MnII ion in 4 is coordinated by two monodentate CF3CO2 − groups and two N,N′-bidentate chelating (py)CHNOH ligands in a cis–cis–trans fashion. The four complexes have been characterised by IR spectroscopy; characteristic bands are discussed in terms of the known structures and the coordination modes of the ligands. Variable-temperature magnetic susceptibility and EPR studies indicate weak antiferromagnetic exchange interactions in 1.

The reaction of [NnBu4][Mn4O2(O2CPh)9(H2O)] with 2 equiv. of Na(dpm) (dpm− is the anion of dipivaloylmethane) gives [NnBu4][Mn4O2(O2CPh)7(dpm)2] (1), which undergoes chelate substitution with picolinic acid (picH) or dibenzoylmethane (dbmH) to give the corresponding pic− and dbm− complexes, 2 and 3, respectively. Reaction of 1 with 1 equiv. of Me3SiCl converts it to [Mn4O2(O2CPh)6(dpm)2] (4), whose crystal structure shows a butterfly-like [Mn4O2]8+ core but with two five-coordinate MnIII ions. Compound 4 also undergoes chelate substitution with picH, dbmH, 2-(hydroxymethyl)pyridine and hexafluoroacetylacetone to give the corresponding complexes. With trans-1,2-bis(4-pyridyl)ethylene (bpe), a bridged compound [Mn4O2(O2CPh)6(dpm)2(bpe)]2 is obtained, analogous to the dbm− compound previously characterized crystallographically. Magnetic susceptibility studies of 4 in the 5.00–300 K range give Jbb=−27.5 cm−1, Jwb=−0.4 cm−1 ( H =−2J S i S j convention), and g=1.87, indicating 4 to have a quintuply degenerate (n, 0, n) ground state (n=4, 3, 2, 1, 0) as a result of the large Jbb/Jwb ratio.

The new complexes [Ru II (bpy) 2 L](PF 6 ) and [Ru III (bpy) 2 Cl 2 ]X (bpy = 2,2′-bipyridine; HL = acetylacetone, trifluoroacetylacetone, hexafluoroacetylacetone, dibenzolymethane or tropolone ; X = IO 4 and PF 6 ) have been prepared and characterized by spectroscopic measurements and also investigated by cyclic voltammetry. They effectively catalyze the oxidation of alcohols, 3,5-di-t-butycatechol and alkane in the presence of t -butyl hydroperoxide or N -methylmorpholine- N -oxide as co-oxidants.

The complex [OsIIICl3(PPh3)2MeOH] has been prepared and found to be a precursor for the synthesis of [OsIIICl2(PPh3)2L] (L = monoanions of maltol, tropolone, acetylacetone, trifluoroacetylacetone, hexafluoroacetylacetone, benzoylacetone and dibenzoylmethane). These new complexes were characterized by spectroscopic measurements and exhibited a rich redox chemistry as demonstrated by cyclic voltammetry. The catalytic oxidation of alcohols in the presence of excess N-methylmorpholine-N-oxide by [OsIIICl2(PPh3)2(acac)] has been studied and compared with that of the related ruthenium(III) complexes.

The synergistic extraction of rare-earth (RE) [La(III), Sm(III), Tb(III) and Lu(III)] complexes, with three β-diketones (HA) [hexafluoroacetylacetone (Hhfa), pivaloyl-trifluoroacetone (Hpta) and benzoylacetone] in the presence of a bidentate ligand (S), 1,10-phenanthroline, in benzene was investigated. The general composition of the adducts formed is expressed as RE(A)3S. RE(A)3(S)2 is also observed in La-Hhfa, La-Hpta and Sm-Hhfa systems. The adduct formation contains βs,1 and βs,2 and the synergistic extraction constants Kex,s,1 were determined. The trend of these constants is discussed in terms of the RE(III), β-diketone, neutral bidentate ligand and organic solvent.

Reactions of PdL2 complexes, where LH = benzoylacetone, dibenzoyl methane, or dipivaloyl methane, with pyridine and neat β-diketones (L 1H trifluoroacetylacetone, hexafluoroacetylacetone, thenoyltrifluoroacetone and pivaloyltrifluoroacetone) in toluene resulted in the formation of central carbon (C3) bonded hetero-β-diketonate complexes of the formula [Pd(L)(C3-L′)py]. These were characterized by microanalyses, IR and 1H NMR spectral data.