Per a què serveix un sincrotró?

La construcció d'un modern sincrotró a Cerdanyola del Vallès costarà molts diners a la hisenda pública. Hem de tenir arguments per a respondre quan els nostres alumnes ens facin preguntes com ara: què és un sincrotró? Per a què serveix? Està justificada, aquesta despesa

Structural investigation of homonuclear Pt2 and heteronuclear PdPt complexes containing a metal-metal bond bridged by hydrido and sulfido ligands

The complex [Pt2(/.t-H)(#-S)(dppe)2](PF6) undergoes a displacive order-disorder transformation at ca 230 K. The low-temperature structure is ordered with one cation-anion pair as the asymmetric unit in space group P2Jn. At room temperature the b axis is halved and the space group is P2/n, imposing crystallographic twofold rotation symmetry on both ions; the anion shows major disorder and there is probably minor disorder in the cation, but its internal geometry remains essentially unchanged. The heteronuclear complex [PdPt(ft-H)(/.t-S)(dppe)2](PF6) is isostructural with the Pt2 complex at room temperature. All three structures have been determined crystallographically and both complexes have been extensively characterized by NMR spectroscopy, unambiguously confirming the genuine heteronuclear nature of the mixed-metal complex and the presence of the bridging hydride ligand

The structure of dichlorobis[μ-(3-dimethylamino-1-propanethiolato)-μ-S,N]-dipalladium(II), (I) [Pd2(C5H12NS)2Cl2], and ac,bd,eg, fh-tetrakis[μ-(3-piperidinemethanethiolato)-μ-S,N]-tripalladium(II) dichloride dihydrate, (II) [Pd3(C6H12NS)4]Cl2.2H2O

Mr=520.15, monoclinic, P21/n, a=7.207(2), B=20.616(4), c=5.854(1) A, β=96.05(1)º, V=864.9(6)A3, Z=2, Dx=2.00 Mg m-3, Mo Ka, = 0.71069 A, µ=2.553 mm-1, F(000)=512, 298 K, R=0.060 for 1492 reflections. (II): Mr=947.07, triclinic, Pl, a=12.666(7), b=10.595(6), c=6.572(5)A, a=98.30(2), = 97.04(2), = 99.84(2)º, V=850(2)A3, Z=1, Dx=1.85 Mg m-3, Mo Ka, =0.71069 A, µ=1.958 mm-1, F(000)=490, 298 K, R=0.071 for 1879 reflections. (I) was solved by direct methods, using MULTAN and DIRDIF, (II) by the heavy-atom method. The four-membered Pd, S, Pd, S rings have a syn-exo conformation, with dihedral angles between the S, Pd, S planes of 154.4(2) and 133.0(3)º for (I) and (II), respectively

Structural investigation of homonuclear Pt2 and heteronuclear PdPt complexes containing a metal-metal bond bridged by hydrido and sulfido ligands

The complex [Pt2(/.t-H)(#-S)(dppe)2](PF6) undergoes a displacive order-disorder transformation at ca 230 K. The low-temperature structure is ordered with one cation-anion pair as the asymmetric unit in space group P2Jn. At room temperature the b axis is halved and the space group is P2/n, imposing crystallographic twofold rotation symmetry on both ions; the anion shows major disorder and there is probably minor disorder in the cation, but its internal geometry remains essentially unchanged. The heteronuclear complex [PdPt(ft-H)(/.t-S)(dppe)2](PF6) is isostructural with the Pt2 complex at room temperature. All three structures have been determined crystallographically and both complexes have been extensively characterized by NMR spectroscopy, unambiguously confirming the genuine heteronuclear nature of the mixed-metal complex and the presence of the bridging hydride ligand

The structure of dichlorobis[μ-(3-dimethylamino-1-propanethiolato)-μ-S,N]-dipalladium(II), (I) [Pd2(C5H12NS)2Cl2], and ac,bd,eg, fh-tetrakis[μ-(3-piperidinemethanethiolato)-μ-S,N]-tripalladium(II) dichloride dihydrate, (II) [Pd3(C6H12NS)4]Cl2.2H2O

Mr=520.15, monoclinic, P21/n, a=7.207(2), B=20.616(4), c=5.854(1) A, β=96.05(1)º, V=864.9(6)A3, Z=2, Dx=2.00 Mg m-3, Mo Ka, = 0.71069 A, µ=2.553 mm-1, F(000)=512, 298 K, R=0.060 for 1492 reflections. (II): Mr=947.07, triclinic, Pl, a=12.666(7), b=10.595(6), c=6.572(5)A, a=98.30(2), = 97.04(2), = 99.84(2)º, V=850(2)A3, Z=1, Dx=1.85 Mg m-3, Mo Ka, =0.71069 A, µ=1.958 mm-1, F(000)=490, 298 K, R=0.071 for 1879 reflections. (I) was solved by direct methods, using MULTAN and DIRDIF, (II) by the heavy-atom method. The four-membered Pd, S, Pd, S rings have a syn-exo conformation, with dihedral angles between the S, Pd, S planes of 154.4(2) and 133.0(3)º for (I) and (II), respectively