Roberto Pattacini

Temperature‐Dependent Fluorescence of Cu5 Metal Clusters: A Molecular Thermometer

The accurate measurement of temperature is of increasing importance as it is required for widespread applications (electronic devices, biology, medical diagnostics). In this context, fluorescence thermometry has already shown great potential, and a variety of molecules have been proposed as luminescent molecular thermometers. Herein, we describe Cu5 metal cluster 1 (Figure 1) that presents remarkable photophysical properties, both in solution and as the solid, characterized by temperature-dependent emission intensity and lifetime that change significantly in the range between 45 and + 80 8C. These properties allow for an unprecedented accuracy in temperature determination by fluorescence measurements, with the high sensitivity and the high temporal (sub-millisecond) and spatial (sub-micrometer) resolution typical of photoluminescence spectroscopy. Complex 1 can be seen as a metal nanoparticle composed of five copper atoms bound to three highly conjugated dianionic cationic ligands (EtNC(S)PPh2NPPh2C(S)NEt) ; Figure 1A). 14] Its absorption spectrum presents a broad and unstructured band below 450 nm (Figure 2A). The system is luminescent in all phases, both at room temperature and at 77 K (Figure 2B) and no dependence on the solvent was observed. A summary of the photophysical properties is shown in Table 1.

Sulfido-.carbonyl ruthenium clusters derived from tertiary phosphine sulfides

Abstract The reactions of Ru3(CO)12 with 2,4,6 tris-(trimethoxy)phenylphosphino sulfide (ttmppS) and with 1,2 bis-[(diphenylphosphino)methyl]benzene disulfide (dpmbS2) afford a variety of phosphine substituted sulfido carbonyl clusters. These belong to three different families of clusters showing, respectively, (i) the Ru3S (compound 4), (ii) the Ru3S2 (compound 3), and (iii) the Ru4S2 cores (compounds 1 and 2). Similar distributions of products have been observed in the case of the reactions between M3(CO)12 (M=Ru or Fe) and phosphine and diphosphine selenides. The structures of complexes 1–4 have been determined by X-ray diffraction methods.

Stepwise selenium transfer from tertiary phosphine selenides to [Ru3(CO)12]. Structural characterization of the primary product [Ru3(μ3-Se)(μ3-CO)(CO)7(PPh3)2]

The monoselenido clusters [Ru3(μ3-Se)(μ3-CO)(CO)7(PR′R2)2] (R = Ph, R′ = Ph or CH2Ph; R = R′ = p-C6H4OMe) obtained by the reaction of phosphine selenides R2R′PSe with [Ru3(CO)12], undergo the second attack by R2R′PSe affording, under appropriate conditions, the corresponding diselenido derivative [Ru3(μ3-Se)2(CO)7(PR′R2)2]. The crystal structure of [Ru3(μ3-Se)(μ3-CO)(CO)7(PPh3)2] 4 showing the first triruthenium triangle bicapped by a selenium atom and a carbonyl ligand, is also reported.

Polynuclear selenido–carbonyl manganese complexes derived from tertiary phosphine selenides

Abstract The reactions of some phosphine selenides with mononuclear and dinuclear manganese complexes have been investigated. The reactions of Cp′Mn(CO)2(THF) (1) with bis(diphenylphosphino)ethane diselenide (dppeSe2) affords [(Cp′Mn)2(μ-Se)2(CO)2(dppe)] (4), identified by spectroscopic techniques. Complex CpMn(CO)2(THF) (2), by reacting with bis(diphenylphsphino)methane monoselenide (dppmSe) gives a variety of products, [(CpMn)2(μ-Se)2(CO)3(dppm)] (5), [CpMn(CO)2(dppm)] (6), [(CpMn)2(CO)4(μ-dppm)] (7), [CpMn(CO)2(dppmSe)] (8) have been identified (Cp=η5-C5H5, Cp′=η5-C5H4Me, THF=tetrahydrofuran). Finally the reactions of [Mn2(CO)8(MeCN)2] (3) with diphenylmethylphosphine selenide (dpmpSe) and triphenylphosphine selenide (tppSe) afford clusters with molecular formula [Mn4(μ3-Se)2(μ-CO)(CO)14(dpmp)2] (9) and [Mn4(μ3-Se)2(μ-CO)(CO)14(tpp)2] (10), respectively. The structure of 9 has been determined by X-ray diffraction methods.

Anchoring selenido-carbonyl ruthenium clusters to functionalised silica xerogels

Xerogeis de silica contendo carbonilas metalicas polinucleares (clusters) com estrutura nido Ru3Se2 foram preparadas atraves de tres rotas diferentes. A simples dispersao do cluster [Ru3(m3-Se)2(CO)7(PPh 3)2] pelo processo sol gel produz um material nao homogeneo. Xerogeis homogeneos foram obtidos atraves da reacao de [Ru3(m3-Se)2(CO)8(PPh 3)] com xerogeis funcionalizados contendo fragmentos difenilfosfino enxertados, e pela reacao do [Ru3(CO)12] com um xerogel contendo grupos fosfinoseleneto enxertados. A reacao entre [Ru3(CO)12] e seleneto de dodecildifenilfosfinoseleneto resultou na formacao de quatro clusters contendo ligantes carbonil e seleneto, soluveis em solventes apolares e que podem ser empregados na confeccao de filmes.

Reactivity of the zwitterionic ligand EtNHC(S)Ph2P[double bond, length as m-dash]NPPh2C(S)NEt towards [Ru3(CO)12]. Sulfur transfer and ligand fragmentation leading to the methideylamide [-N(Et)-CH(R)-] micro3-bridging moiety.

The reaction of EtNHC(S)Ph2P[double bond, length as m-dash]NP+Ph2C(S)N(-)Et (HEtSNS) with [Ru3(CO)12] has been carried out under two different experimental conditions: in the first case [Ru3(CO)12], previously turned into the labile intermediate [Ru3(CO)10(CH3CN)2], afforded, at room temperature in dichloromethane, the trinuclear clusters [Ru3(CO)11(CNEt)] (1), [Ru3(CO)9(micro-H)[(micro-S:kappa-P)Ph2PN[double bond, length as m-dash]PPh2C(S)NEt]] (2), [Ru3(CO)9(micro-H)[(micro-S:kappa-P)Ph2PN[double bond, length as m-dash]P(S)Ph2]] (3) and [Ru3(CO)10[(micro-kappa2P)Ph2PNHPPh2]] (3). Ligand fragmentation occurs via loss of EtNC or EtNCS, without sulfur transfer to the cluster core. In the second case, [Ru3(CO)12] reacted with HEtSNS in toluene at 70 degrees C, giving the trinuclear clusters , [Ru3(CO)7(CNEt)(micro3-S)[(micro2-N:eta1-C:kappa1-P)Ph2PN[double bond, length as m-dash]PPh2C(H)NEt]] (6), [Ru3(CO)8)(micro3-S)[(micro2-N:eta-C:kappa-P)Ph2PN[double bond, length as m-dash]PPh2C(H)NEt]] (6) and [Ru3(CO)6(micro3-CO)(micro3-S)(EtNC)[(micro-kappa2P) Ph2PNHPPh2]] (7). The last three compounds derive from ligand fragmentation and sulfur transfer to the metal cluster. All compounds were characterized by spectroscopy (NMR, IR) and the molecular structures of , and were determined by single-crystal X-ray diffraction. Cluster preserves the original Ru3 triangular core in which an edge is bridged by a hydride ligand and by the sulfur atom of the Ph2PN[double bond, length as m-dash]PPh2C(S)NEt ligand. Cluster shows an open triangle of Ru atoms capped by a micro3-sulfide and by the unprecedented methideylamide -N(Et)CH(R)-micro3-bridging moiety of the Ph2PN[double bond, length as m-dash]PPh2C(H)NEt ligand. It formally derives from cluster by substitution of ethyl isonitrile with one CO molecule. Finally, cluster displays a Ru3(micro3-S)(micro3-CO) trigonal bipyramidal core.