29484-75-1Relevant articles and documents
Different ways to distort a tetracapped tetrahedron on route to forming an E4M4 cubane: The case of [E4(Pd(PPh2Me)2)4] [Ph2EX2]2 (E = Sb, X = Cl; E = Bi, X = Br)
Stark, Joseph L.,Harms, Brian,Guzman-Jimenez, Ilse,Whitmire, Kenton H.,Gautier, Regis,Halet, Jean-Francois,Saillard, Jean-Yves
, p. 4409 - 4418 (1999)
Tetrakis(diphenylmethylphosphine)palladium reacts with diphenylantimony chloride or diphenyl-bismuth bromide to give [E4(PdL2)4][Ph2EX2] 2 (L = PPh2Me, 1: E = Sb, X = Cl; 2: E = Bi, X = Br) which have been characterized spectroscopically and by single-crystal X-ray diffraction for [Sb4(PdL2)4] [Ph2SbCl2]2· 0.5THF and [Bi4(PdL2)4] [Ph2BiBr2]2. These compounds are electron-rich based on electron counting formalisms. The additional cluster electrons can be rationalized by the ability of group 15 elements to show hypervalency, particularly those elements such as Sb and Bi which show more metal character. The electronic structure of the compounds and of related species has been examined by EHT and DFT calculations. Relationships to other cubane-derived structures are derived, and the stability of structurally related M4E4 hypothetical clusters is discussed. Compounds 1 and 2 decompose thermally to give Bi2Pd and SbPd.
Synthesis of the first carbon dioxide coordinated palladium(0) complex, Pd(η2-CO2)(PMePh2)2
Sakamoto, Masato,Shimizu, Isao,Yamamoto, Akio
, p. 407 - 409 (2008/10/08)
A new palladium(0) complex, (η2-carbon dioxide)bis(methyldiphenylphosphine)palladium(0) (Pd(CO2)(PMePh2)2; 3), has been prepared by the reaction of PdEt2(PMePh2)2 (1) with methyl acrylate followed by treatment with CO2. The complex was characterized by means of 1H, 13C{1H}, and 31P{1H} NMR and IR spectroscopy and the chemical reactions. Spectroscopic evidence indicates that complex 3 has a side-on (η2) coordination mode. Thermal decomposition of the solution of complex 3 caused cleavage of the Pd-coordinated CO2 to give CO and O=PMePh2, together with CO2. Hydrogenation of 3 yielded HCO2H. Catalytic conversion of H2 and CO2 into formic acid was found to be promoted by PdCl2L2 (L = PMe3, PMePh2, PPh3).
Synthesis of new CO complexes of palladium
Feltham,Elbaze,Ortega,Eck,Dubrawski
, p. 1503 - 1510 (2008/10/08)
The palladium(II) complexes Pd(NO2)2L2 (L = PPh3, PMePh2, PMe2Ph, PEt3) react with CO to form Pd4(CO)5L4. These reaction products have been characterized by IR and 31P, 1H, and 13C NMR spectroscopy. Pd4(CO)5(PPh3)4 crystallized in the monoclinic space group C2/c with Z = 4, a = 24.957 (5) ?, b = 16.138 (3) ?, c = 17.758 (3) ?, and β = 103.47 (2)°. The palladium atoms are at the corners of a distorted tetrahedron in which five of the six edges are bridged by the carbonyl ligands. The unbridged edge has a Pd-Pd distance of 3.209 (1) ?, indicating the absence of a metal-metal bond. The average bonding Pd-Pd distances are 2.753 (1) and 2.758 (13) ?. The average Pd-P distance is 2.318 (2) ?, and the average Pd-C-Pd angle is 82.0°. Pd(NO2)2(PEt2Ph)2 and PdCl(NO2)(PEt2Ph)2 react with CO to form the novel Pd(I) dimer Pd2(CO)Cl2(PEt2Ph)3, which was also structurally characterized by X-ray crystallography. The compound crystallized in the monoclinic space group P21/a with Z = 4, a = 20.041 (3) ?, b = 11.353 (3) ?, c = 19.920 (5) ?, and β = 129.16 (1)°. The molecule is dimeric with a Pd-Pd bond and is the first example of a semibridging carbonyl ligand in palladium complexes. Pd2 has roughly square-planar geometry with two phosphines, one chloride, and Pd1 comprising its coordination sphere. One phosphine, one chloride, Pd2, and the carbonyl ligand comprise the coordination sphere of Pd1. The semibridging carbonyl produces severe distortion in the coordination geometry of both Pd1 and Pd2. Some important distances and angles include Pd1-Pd2 = 2.6521 (3) ?, Pd1-C = 1.874 (3) ?, Pd2-C = 2.110 (3) ?, and Pd1-C-Pd2 = 83.3 (1)°.
