Daniele Belletti

Synthesis and spectroscopic studies of ruthenium complexes with poly(pyrazol-1-yl) methane ligands. Crystal structure of [RuCl(cod)(tpzm)]Cl·EtOH [cod = cycloocta-1,5-diene, tpzm = tris(pyrazol-1-yl)methane]

Neutral six-co-ordinate complexes of RuII, [RuCl2(btpzm)(cod)]1 and [RuCl2(btpzm)(cod)]2 with bis(pyrazol-1-yl)methane (bpzm) or bis (5-trimethylsilylpyrazol-1-yl)methane (btpzm) were synthesised from [{RuC2(cod)}n](cod = cycloocta-1,5-diene) and the corresponding ligand. Complex 1 reacts with LiBEt3H to give the hydride [RuH(Cl)(bpzm)(cod)]3. The reactitivity of 2 allowed the synthesis of the new complex [RuCl2(btpzm)2]·0.5thf 4(thf = tetrahydrofuran) with two bidentate btpzm ligands. The reaction of [{RuCl2(cod)}n] with the tris(pyrazol-1-yl)methane ligand (tpzm) yielded the six-co-ordinate cationic complex [RuCl(cod)(tpzm)]Cl·-EtOH 5. Finally, the reaction of [RuCl3(tpzm)] with both pyridine and triethylamine afforded [RuCl2(py)(tpzm)]6. Spectroscopic data are provided for all these compounds. The crystal structure of compound 5 has ben determined by X-ray diffraction methods: monoclinic, space group P21/c, with a= 9.330(2), b= 15.579(4), c= 15.667(4)A, β= 97.79(2)° and Z= 4. The structure has been solved from diffractometer data by direct and Fourier methods and refined by full-matrix least squares to R= 0.0414 for 3362 observed reflections. It consists of complex cations, chloride anions and ethanol molecules of solvation linked by strong hydrogen bonds. The ruthenium is approximately octahedrally co-ordinated to one tridentate tpzm ligand, one chloride ion and two η2-CC olefinic groups of the cod ligand.

Single-crystal X-ray and Raman investigation on melanophlogite from Varano Marchesi (Parma, Italy)

Abstract The results of a new single-crystal structure refinement and of a Raman spectroscopy investigation on melanophlogite, a clathrate structure of SiO2, are reported. The studied sample comes from a new finding at Varano Marchesi (Parma, Italy), and occurs in small veins and pockets along fractures in a siliceous marl from a chaotic complex. Melanophlogite is invariably separated from the host rock by a thin crust of opal-CT. Raman spectroscopy was done to investigate the guest molecules that are hosted in the cages of the structure. In the Varano Marchesi melanophlogite, only CH4 is present in the clathrate structure. During a comparative investigation of melanophlogite from different geological setting (Racalmuto, Sicily, Italy), H2S also was found, together with CH4, in the cavities of the structure. A single-crystal X-ray refinement of the Varano Marchesi sample was done using the Pm3̅n symmetry of β-melanophlogite [a = 13.399(2), R4σ = 4.7%]. According to the site refinement from X-ray diffraction results, CH4 occupies 71 and 91% of the 512 and 51262 site cavities, respectively. The Varano Marchesi melanophlogite formed as a result of low-temperature hydrothermal activity. The mineral growth occurred at the expense of opal, in connection with CH4 flux through the porous material.

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.

Synthesis and crystal structure of [Ru2(CO)6(µ-PPh2)(µ-PCHCHC6H4)], a complex with an unprecedented phospha-bicyclic ligand, obtained from [Ru3(µ-H)(CO)8(Ph2PCHCH2)(µ3-Ph2PCHCH)]via reductive elimination reactions

The complex [Ru2(CO)6(µ-PPh2)(µ-[graphic omitted]H4)] has been obtained by thermal treatment of [Ru3(µ-H)(CO)8(Ph2PCHCH2)(µ3-Ph2PCHCH)]via reductive elimination of ethylene and benzene and metal–metal cleavage. The heterocyclic [graphic omitted]H4 bridging ligand, obtained upon activation of co-ordinated diphenyl(vinyl)phosphine, is unprecedented. The complex has been identified by spectroscopic methods and its structure fully elucidated by X-ray diffraction methods.

Reactivity of Ph2(2-C5H4N)PSe towards Ru3(CO)12 and mononuclear MCl2(PhCN)2 (M = Pd or Pt) complexes

Abstract The behavior of the Ph2(2-C5H4N)PSe ligand in the reactions with Ru3(CO)12 and the mononuclear complexes MCl2(PhCN)2 (M=Pd or Pt) has been investigated. The reaction with Ru3(CO)12 is characterized by PSe bond cleavage, affording the 48-electron compound [Ru3(μ3-Se)(μ-PPh2)2(μ-C5H4N)(μ3-C5H4N)(CO)6] (1), the open triangular 50-electron nido clusters [Ru3(μ3-Se)2(CO)9−n{P(2-C5H4N)Ph2}n] (2 and 3, for n=1 and 2, respectively) and the octahedral 62-electron closo cluster [Ru4(μ4-Se)2(CO){μ-P,N-Ph2(2-C5H4N)P}] (4). The cluster 1 derives by the multiple fragmentation of two phosphine ligands on the metal triangle involving the PSe and PC bond cleavages. The molecular structure of 4 shows a short Ru⋯P non-bonding separation that can be viewed as a preliminary step towards the PC bond cleavage. In the reactions with MCl2(PhCN)2 (M=Pd, Pt) Ph2(2-C5H4N)PSe remains intact affording mononuclear neutral complexes of the type MCl2{N,Se-Ph2(2-C5H4N)PSe}. The crystal structure of the palladium derivative 5 has been determined by X-ray diffraction methods.

Crystal structure of a seven-coordinate cobalt(II) complex with a new polyfunctional hydrazonic ligand, [Co(H4dapis)(OH2)2]Cl2·9/2H2O

A seven-coordinate cobalt(II) complex has been synthesized with a new hydrazonic ligand, H4dapis, and its crystal structure determined by X-ray diffraction methods and refined toR 0.0564 for 2763 independent reflections. The structure consists of [Co(H4dapis)(OH2)2] cations, Cl anions, and lattice H2O molecules interlinked by hydrogen bonds. The cobalt atom has a distorted pentagonal bipyramidal environment with two axial H2O molecules and the H4dapis ligand forming the basal plane.

Trapping a pseudo-Hofmann rearrangement on a ruthenium cluster

In the clusters [Ru3(micro(3)-NPPh(3))(micro(3)-OSiMe(3))(micro-X)(micro(C,O)-OC[double bond]NPPh(3))(micro-CO)(CO)6] (X = NCO, 2; X = Cl, 3), which were prepared by a pyrolytic reaction of Ph(3)PNSiMe(3) with Ru(3)(CO)12, the ligands result from a cluster-mediated pseudo-Hofmann rearrangement involving the micro-NCO, micro(C,O)-Ph(3)P[double bond]N-CO and micro(3)-NPPh(3) fragments.

Crystal and molecular structure of (−)-1,2-O-isopropylidene-3-O-methyl-7,8-dideoxy-β-l-glycero-d-gluco-non-7-enofuranurono-9,6-lactone, C13H18O7

The crystal structure of the title lactone, C13H18O7, has been determined by single crystal diffraction methods. The compound crystallizes in the monoclinic space groupP21 witha=13.231(2),b=10.248(2),c=5.348(1) Å,β=96.66(2)°, andZ=2. A total of 1055 reflection intensities were recorded on a Siemens AED single-crystal diffractometer (CuKα radiation) at room temperature. The structure was solved by direct methods and electron density calculations. Full-matrix least-squares refinement gaveR=0.055 for 946 unique reflections above 2σ(I). The absolute configuration of the six chiral carbon atoms was deduced as 4S, 5R, 6R, 7S, 9R, 10R (crystallographic numbering corresponds to C-6, 5, 4, 3, 2, 1 in the title compound). An intermolecular O-H⋯O hydrogen bond joins the molecules in chains which run along the twofold screw axis.