Sandwich d/f Heterometallic Complexes [(Ln(hfac))M(acac)] (Ln = La, Pr, Sm, Dy and M = Co; Ln = La and M = Ru).

Sandwich d/f heterometallic complexes [(Ln(hfac))M(acac)] (Ln = La, Pr, Sm, Dy and M = Co; Ln = La and M = Ru) were prepared in strictly anhydrous conditions reacting the formally unsaturated fragment [Ln(hfac)] and [M(acac)] in a 2-to-1 molar ratio. These heterometallic complexes are highly sensitive to moisture. Spectroscopic observation revealed that on hydrolysis, these compounds yield dinuclear heterometallic compounds [Ln(hfac)M(acac)], prepared here for comparison purposes only.

Understanding Stabilization Factors in Heterodinuclear Ln-Al Complexes from DFT Simulations on Thermochemistry Data: A Counterintuitive Conclusion.

This study validates a computational protocol to predict the stability of heterodinuclear complexes by varying ligands on both moieties and analyzing the reaction Gibbs free energy (Δ) values. To this purpose, a series of Eu-Al complexes with the general formula [Eu()Al()], where is the ligand of europium and is an oxygen donor ligand of aluminum, is used. The nature of the bridging bonds and thermochemical characteristics (Δ, enthalpy, and entropy) of the complexes were evaluated via DFT calculations.

Mononuclear Rare-Earth Metalloligands Exploiting a Divergent Ligand.

Rare-earth tris-diketonato [RE(dike)pyterpy] metalloligands can be prepared reacting at room temperature [RE(dike)dme] (dme = 1,2-dimethoxyethane; dike = tta with Htta = 2-thenoyltrifluoroacetone and RE = La, ; Y, ; Eu, ; Dy, ; or dike = hfac with Hhfac hexafluoroacetylacetone, and RE = Eu, ; Tb, ; Yb ) with 4'-(4‴-pyridil)-2,2':6',2″-terpyridine (pyterpy). The molecular structures of , , , and have been studied through single-crystal X-ray diffraction showing mononuclear neutral complexes with the rare-earth ion in coordination number nine and with a muffin-like coordination geometry. [RE(tta)pyterpy] promptly reacts with [M(tta)dme] with formation of [Mpyterpy][RE(tta)] (M = Zn, RE = Y, ; M = Co, RE = Dy, ).

Aluminium 8-Hydroxyquinolinate -Oxide as a Precursor to Heterometallic Aluminium-Lanthanide Complexes.

A reaction in anhydrous toluene between the formally unsaturated fragment [Ln(hfac)] (Ln = Eu, Gd and Er; Hhfac = hexafluoroacetylacetone) and [Al(qNO)] (HqNO = 8-hydroxyquinoline -oxide), here prepared for the first time from [Al(OBu)] and HqNO, affords the dinuclear heterometallic compounds [Ln(hfac)Al(qNO)] (Ln = Eu, Gd and Er) in high yields. The molecular structures of these new compounds revealed a dinuclear species with three phenolic oxygen atoms bridging the two metal atoms. While the europium and gadolinium complexes show the coordination number (CN) 9 for the lanthanide centre, in the complex featuring the smaller erbium ion, only two oxygens bridge the two metal atoms for a resulting CN of 8.

Competing excitation paths in luminescent heterobimetallic Ln-Al complexes: Unraveling interactions via experimental and theoretical investigations.

The interest for heterometallic lanthanide- or- metal (Ln-M) complexes is growing because of a potential cooperative or synergistic effect related to the proximity of two different metals in the same molecular architecture affording special tunable physical properties. To exploit the potentiality of Ln-M complexes, suitable synthetic approaches, and the in-depth understanding of the effect of each building block on their properties are mandatory. Here, we report the study on a family of heterometallic luminescent complexes [Ln(hfac)Al(L)], Ln= Eu and Tb.

Size Selectivity in Heterolanthanide Molecular Complexes with a Ditopic Ligand.

The similar reactivity of lanthanides generally leads to statistically populated polynuclear complexes, making the rational design of ordered hetero-lanthanide compounds extremely challenging. Here we report on the site selectivity in hetero-lanthanide tetranuclear complexes afforded by the relatively simple ditopic pyterpyNO ligand (4'-(4-pyridil)-2,2':6',2"-terpyridine N-oxide). The sequential room temperature reaction of RE (tta) (pyterpyNO) (where RE=Y, (1); Eu, (2), Dy, (3) Htta=2-thenoyltrifluoroacetone) with La(tta) dme (dme=dimethoxyethane) yielded Y La (tta) (pyterpyNO) (4), Dy La (tta) (pyterpyNO) (5) and Eu La (tta) (pyterpyNO) (6).

-Dichloro(triphenylarsino)(,-dialkylamino)platinum(II) Complexes: In Search of New Scaffolds to Circumvent Cisplatin Resistance.

The high incidence of the resistance phenomenon represents one of the most important limitations to the clinical usefulness of cisplatin as an anticancer drug. Notwithstanding the considerable efforts to solve this problem, the circumvention of cisplatin resistance remains a challenge in the treatment of cancer. In this work, the synthesis and characterization of two -dichloro(triphenylarsino)(,-dialkylamino)platinum(II) complexes ( and ) were described.

Stoichiometrically Controlled Assembly of Lanthanide Molecular Complexes of the Heteroditopic Divergent Ligand 4'-(4-Pyridyl)-2,2':6',2″-terpyridine -Oxide in Hypodentate or Bridging Coordination Modes. Structural, Magnetic, and Photoluminescence Studies.

Mononuclear rare-earth tris-β-diketonato complexes RE(tta)dme [RE = Y (), La (), Dy (), or Eu (); Htta = 2-thenoylacetone; dme = 1,2-dimethoxyethane] react cleanly at room temperature in a 1:1 molar ratio with the heteroditopic divergent ligand 4'-(4-pyridyl)-2,2':6',2″-terpyridine -oxide (pyterpyNO) to yield RE(tta)(pyterpyNO), where = 2 for RE = Y (), Dy (), or Eu () and = 3 for RE = La (). The crystal structure of revealed a dinuclear compound with two pyterpyNO's bridging through the oxygen atom in a hypodentate mode leaving the terpyridine moieties uncoordinated. Using a metal:pyterpyNO molar ratio of 2 for RE = Y (), Dy (), or Eu (), it was possible to isolate the molecular complexes RE(tta)(pyterpyNO), while using a 5:3 molar ratio, the product La(tta)(pyterpyNO) () can be obtained.

1D-Zigzag Eu/Tb Coordination Chains as Luminescent Ratiometric Thermometers Endowed with Multicolor Emission.

Two homometallic Coordination Polymers (CPs) with composition [Ln(hfac)bipy] (Ln = Eu, , and Tb, ; hfac = hexafluoroacetylacetonato, bipy = 4,4'-bipyridine) were used to develop a family of ratiometric luminescent thermometers containing Eu and Tb as red and green emitters, respectively. The thermometric properties of pure CPs and of their mixtures having an Eu/Tb molar ratio of 1:1, 1:3, 1:5, and 1:10 (samples: , , , and ) were studied in the 83-383 K temperature range. Irrespective of the chemical composition, we observed similar thermometric responses characterized by broad applicative temperature ranges (from 100 to 165 K wide), and high relative thermal sensitivity values (S), up to 2.

New Platinum(II) Complexes Affecting Different Biomolecular Targets in Resistant Ovarian Carcinoma Cells.

Resistance to platinum-based anticancer drugs represents an important limit for their clinical effectiveness and one of the most important field of investigation in the context of platinum compounds. From our previous studies, Pt complexes containing the triphenylphosphino moiety have been emerging as promising agents, showing significant cytotoxicity to resistant ovarian carcinoma cells. Two brominated triphenylphosphino trans-platinum derivatives were prepared and evaluated on human tumor cell lines, sensitive and resistant to cisplatin.

Cytotoxicity and DNA interaction in a series of aryl terminated iminopyridine Pt(II) complexes.

A series of iminopyridine complexes of platinum(II), bearing a flexible diethereal, aryl terminated residue, where the size of aryl group is varied from phenyl to 9-anthracenyl, was synthesized. The new complexes are soluble and stable in DMSO/HO mixtures. Besides the metal center, aryl groups are available for further interactions with DNA, due to the good side chain flexibility.

Composition-Thermometric Properties Correlations in Homodinuclear Eu Luminescent Complexes.

A family of homodinuclear Ln (Ln = Gd, Eu) luminescent complexes with the general formula [Ln(β-diketonato)(-oxide)] has been developed to study the effect of the β-diketonato and -oxide ligands on their thermometric properties. The investigated complexes are [Ln(tta)(pyrzMO)] (Ln = Eu (·CH), Gd ()), [Ln(dbm)(pyrzMO)] (Ln = Eu (), Gd ()), [Ln(bta)(pyrzMO)] (Ln = Eu (), Gd ()), [Ln(hfac)(pyrzMO)] (Ln = Eu (), Gd ()) (pyrzMO = pyrazine -oxide, Htta = thenoyltrifluoroacetone, Hdbm = dibenzoylmethane, Hbta = benzoyltrifluoroacetone, Hhfac = hexafluoroacetylacetone, CH = toluene), and their 4,4'-bipyridine -oxide (bipyMO) analogues. Europium complexes emit a bright red light under UV radiation at room temperature, whose intensity displays a strong temperature () dependence between 223 and 373 K.

Platinum(II) Complexes Bearing Triphenylphosphine and Chelating Oximes: Antiproliferative Effect and Biological Profile in Resistant Cells.

Platinum(II) complexes of the type [Pt(Cl)(PPh ){(κ -N,O)-(1{C(R)=N(OH)-2(O)C H })}] with R=Me, H, (1 and 2) were synthesized and characterized. Single-crystal X-ray diffraction confirmed the proposed (SP4-3) configuration for 1. Study of the antiproliferative activity, performed on a panel of human tumor cell lines and on mesothelial cells, highlighted complex 2 as the more effective.

Single-crystal-to-single-crystal post-synthetic modifications of three-dimensional LOFs (Ln = Gd, Eu): a way to modulate their luminescence and thermometric properties.

Single-crystal-to-single-crystal post-synthetic modifications (PSMs) of Lanthanide Organic Frameworks (LOFs) {[Ln(HL)(DMF)]·2DMF} (Ln = Gd, 1 and Eu, 2; HL = 2,5-dihydroxyterephthalic acid; DMF = dimethylformamide), carried out by treatment with (a) chloroform or (b) an imidazole solution in chloroform, yielded respectively isostructural {[Ln(HL)(DMF)]·CHCl} (Ln = Gd, 3; Eu, 4) or {[Ln(HL)(Im)][Ln(HL)(Im)(HO)]·6Im·2CHCl} (Ln = Gd, 5; Eu, 6). Single crystal X-ray diffraction studies of 5 showed two different regularly alternating dimeric units in the LOF and two regularly alternating cavities with different guest molecules. All compounds revert to the parent LOF, 1 or 2, when treated with DMF at 90 °C for 8 h.

DNA interaction of a fluorescent, cytotoxic pyridinimino platinum(II) complex.

New pyridinimino complexes of platinum(II) [PtCl(N^N-R)] (N^N = 2-pyridylmethanimino, R = -(CH)O(CH)OH, -(CH)O(CH)OCHPyr), Pyr = pyren-1-yl) have been prepared. They are characterized by a dioxygenated alkyl side chain and, in one case, by a fluorescent terminal 1-pyrenyl residue. The complexes were characterized by elemental analysis, IR, H-, C-and Pt NMR spectroscopies.

1D hetero-bimetallic regularly alternated 4f-3d coordination polymers based on N-oxide-4,4'-bipyridine (bipyMO) as a linker: photoluminescence and magnetic properties.

Heterotopic divergent ligand N-oxide-4,4'-bipyridine (bipyMO) has been herein exploited for the preparation of hetero-bimetallic coordination polymers where Ln(hfac)3 and M(hfac)2 nodes regularly alternate (Hhfac = 1,1,1,5,5,5-hexafluoro-2,4-pentanedione), bipyMO being able to selectively use its two potential coordination sites to discriminate the metal ions. The synthesis of three coordination polymers, [Ln(hfac)3M(hfac)2(bipyMO)2]n (Ln = Eu, M = Zn, 1; Ln = Eu, M = Cu, 2, Ln = Dy, M = Co, 3), was carried out by reacting the appropriate [M(hfac)2(bipyMO)]n and [Ln(hfac)3] precursors in toluene in the presence of a given stoichiometric amount of bipyMO. The products were characterized by elemental analysis, X-ray powder diffraction, and FTIR spectroscopy.

Circularly Polarized Luminescence of Silica-Grafted Europium Chiral Derivatives Prepared through a Sequential Functionalization.

We describe a new organic/inorganic material emitting circularly polarized luminescence (CPL). The hybrid system was obtained by the following steps: (i) preliminary grafting of the europium N,N-dibutylcarbamate [Eu(OCNBu)] complex onto silica, (ii) substitution of the residual carbamato groups with anionic 1,3-diphenyl-1,3-propanedionato ligands (dbm), and (iii) subsequent introduction of the neutral tridentate chiral ligand 2,6-bis(isopropyl-2-oxazolin-2-yl)pyridine (Pr-PyBox) in the metal coordination sphere. The solid material is stable to air and does not leach either the metal or the ligand.

New trans dichloro (triphenylphosphine)platinum(II) complexes containing N-(butyl),N-(arylmethyl)amino ligands: Synthesis, cytotoxicity and mechanism of action.

Some new platinum(II) complexes have been prepared, of general formula trans-[PtCl2(PPh3){NH(Bu)CH2Ar}], where the dimension of the Ar residue in the secondary amines has been varied from small phenyl to large pyrenyl group. The obtained complexes, tested in vitro towards a panel of human tumor cell lines showed an interesting antiproliferative effect on both cisplatin-sensitive and -resistant cells. For the most cytotoxic derivative 2a the investigation on the mechanism of action highlighted the ability to induce apoptosis on resistant cells and interestingly, to inhibit the catalytic activity of topoisomerase II.

Smart Grafting of Lanthanides onto Silica via N,N-Dialkylcarbamato Complexes.

The grafting and the postgrafting functionalization of lanthanide ions on commercial amorphous silica have been herein carried out by using as a precursor the terbium N,N-dibutylcarbamato derivative [Tb(O2CNBu2)3]. The reaction of the complex with the surface silanols involved only a fraction of the carbamato ligands. The following protolytic substitution of the residual carbamato ligands was carried out by exploiting the Brønsted's acidity of the β-diketone dibenzoylmethane (Hdbm), in view of the antenna effect of the β-diketonato groups, which are commonly used in lanthanide photoluminescence studies.

Preparation of N,N-dialkylcarbamato lanthanide complexes by extraction of lanthanide ions from aqueous solution into hydrocarbons.

Lanthanides are easily extracted as N,N-dibutylcarbamato complexes from aqueous solutions of their chlorides into heptane solutions of dibutylamine saturated with CO2. The products are recovered in high yields and are soluble in hydrocarbons. The derivatives [Ln(O2CNBu2)3]n [Ln = Nd (1), Eu (2), Tb (3)], [NH2Bu2]2[Ln4(CO3)(O2CNBu2)12] [Ln = Tb (4), Sm (5), Eu (6)], and [Sm4(CO3)(O2CNBu2)10], 7, have thus been obtained.

Synthesis, antiproliferative and mitochondrial impairment activities of bis-alkyl-amino transplatinum complexes.

A convenient synthetic route and the characterization of complexes trans-[PtCl2(L)(PPh3)] (L=Et2NH (2), (PhCH2)2NH (3), (HOCH2CH2)2NH) (4) are reported. The antiproliferative activity was evaluated on three human tumor cell lines. The investigation on the mechanism of action highlighted for the most active complex 4 the capacity to affect mitochondrial functions.

A convenient route to dinuclear chloro-bridged platinum(II) derivatives via nitrile complexes.

The syntheses of the complexes [PtCl(2)(NCR)L] [R = Me, Et; L = PPh(3); R = Et, L = Py, CO] and [PtCl{(κ(2)-P,C)P(OC(6)H(4))(OPh)(2)}(NCEt)] are described starting from the easily available [PtCl(2)(NCR)(2)]. The stability of the products under different experimental conditions is discussed as well as their use as precursors to dinuclear complexes [Pt(μ-Cl)ClL](2). The crystal and molecular structures of cis-[PtCl(2)(NCEt)(PPh(3))], [SP-4-2]-[PtCl{(κ(2)-P,C)P(OC(6)H(4))(OPh)(2)}(NCEt)] and trans-[Pt(μ-Cl){(κ(2)-P,C)P(OC(6)H(4))(OPh)(2)}](2) are reported.

Bent dinuclear platinum(II) halo-bridged carbonyl complexes.

Crystals of trans-Pt₂(μ-X)₂X₂(CO)₂ (X = Br, I) have been grown and their molecular and crystalline structures have been solved by X-ray diffraction methods. In both cases the dinuclear molecules are bent, with a bending angle of 164.6° and 156.

Nanostructured copper oxide on silica-zirconia mixed oxides by chemical implantation.

N,N-Dialkylcarbamato complexes of copper(II), [Cu(O(2)CNR(2))(2)] (R = All = allyl, C(3)H(5); iPr, CH(CH(3))(2)) were prepared with the aim of functionalizing silica and nanostructured silica-zirconia matrices. The mixed matrices for the grafting reactions were prepared by copolymerizing MAPTMS (methacryloxypropyltrimethoxysilane), the precursor for the silica matrix, with the zirconium tetranuclear derivative [Zr(4)O(2)(OMc)(12)] (OMc = methacrylate), the precursor for the zirconia nanoparticles. Suspension of the silica and silica-zirconia matrices in a solution of the copper dialkylcarbamate led to the functionalization of the respective substrates.

N,N-Di-iso-propylcarbamato complexes of boron.

N,N-di- iso-propylcarbamato derivatives of boron(III) have been synthesized from di-iso-propylamine and boron trichloride in the presence of carbon dioxide. With a large excess of amine, a single boron product was obtained, [NH2i)Pr2][B(O2CNiPr2)4], 1, while with a lower excess a mixture of 1 and of the dinuclear derivative [B2(O2CNiPr2)6], 2, was produced. By heating in vacuo at 60 degrees C, solid 1 slowly converted to 2.