Linda S. Benner

Addition of tin(II) chloride to Pd2(Ph2PCH2PPh2)2CI2. The crystal and molecular structure of Pd2(Ph2PCH2PPh2)2(SnCl3)Cl

Abstract Addition of tin(II) chloride to Pd2(dpm)2Cl2 (dpm is Ph2PCH2PPh2) produces Pd2(dpm)2(SnCl3)Cl. The crystal structure of the latter complex reveals that the tin(II) chloride has inserted into the PdCI bond and that a nearly linear PdPdSn unit it present infrared and electronic spectral evidence indicates that carbon monoxide and sulfur dioxide insert into the Pd-Pd bond of Pd2(dpm)2(SnCl3)Cl. Spectroscopic evidence for the formation of Pd2(dpm)2(SnCl3)2 is described.

Dinuclear rhodium complexes with three and four bridging ligands. The preparation and crystal structure of [Rh2(Ph2PCH2PPh2)2(μ-Cl)(μ-CO)(CO)2][Rh(CO)2Cl2] · CH2Cl2

Abstract The reaction of four moles of bis(diphenylphosphino)methane (dpm) or bis(diphenylarsino)methane (dam) with three moles of Rh2(CO)4Cl2 produces [Rh2(dpm)2(μ-Cl)(CO)2][Rh(CO)2Cl2] or [Rh2(dam)2(μ-Cl)(CO)2][Rh(CO)2Cl2]. Reaction of Rh2(dam)2(CO)2Cl2 with Rh2(CO)4Cl2 proceeds by halide ion abstraction to give [Rh2(dam)2(μ-Cl)(CO)2][Rh(CO)2Cl2]. Carbon monoxide adds to [Rh2(dpm)2(μ-Cl)(CO)2][Rh(CO)2Cl2] to give [Rh(dpm)2(μ-Cl)(μ-CO)(CO)2][Rh(CO)2Cl2]. The crystal structure of [Rh2(dpm)2(μ-CO)(μ-Cl)(CO)2] [Rh(CO)2Cl2] · CH2Cl2 has been determined by X-ray diffraction. The crystals are monoclinic, space group P21/c, with lattice constants: a 16.302(4) A, b 18.370(3) A, c 19.189(3) A, β 91.11(2)°, Z = 4. Positional and isotropic thermal parameters of the non-hydrogen atoms were refined using a full-matrix least-squares method to a final R index of 0.085 for 6401 reflections with Inet > 3σ(Inet). Bond distances: RhRh, 2.838(1) A; RhC (bridged), 2.094(11), 2.051(11) A; RhC (terminal), 1.813(1), 1.839(1) A; P⋯P(av.), 3.055(6) A. Correlations between P⋯P or As⋯As distances and M⋯M distances are noted for dpm or dam as bridging ligands.

Spin Trapping of Radicals Produced by Thermal Homolysis of L2Mn2(CO)8

Abstract The reaction of L 2 Mn 2 (CO) 8 (L = PPh 3 , P(OMe) 2 Ph, PEt 3 , PMePh 2 , P(p-CH 3 C 6 H 4 ) 3 , P(m-CH 3 C 6 H 4 ) 3 , P(OEt) 3 , PEt 2 Ph) with nitroso-t-butane at 23°C in a variety of solvents (dichloromethane, toluene, tetrahydrofuran, acetonitrile, acetone) in the dark produces stable nitroxide radicals which have been detected by electron spin resonance spectroscopy. The radicals are identified as the spin adducts L(OC) 4 MnN(O)C(CH 3 ) 3 . In pyridine solution substitution of the phosphine ligands of the radicals rapidly occurs so that the species trapped from L 2 Mn 2 (CO) 8 (L = PPh 3 , PEt 3 , PPh(OMe) 2 , AsPh 3 ) is (C 5 H 5 N)(OC) 4 MnN(O)C(CH 3 ) 3 .

Structural characterization of a four-electron donating, doubly-bridging isocyanide in (μ-p-CH3C6H4NC)Mn2(Ph2PCH2PPh2)2(CO)4

Abstract X-Ray crystallographic analysis of (μ- p -CH 3 C 6 H 4 NC)Mn 2 (Ph 2 PCH 2 PPh 2 ) 2 (CO) 4 is reported. The molecule consists of two manganese atoms joined by a single bond and bridged by two trans diphosphine ligands and the isocyanide. There are two terminal CO groups per Mn. The isocyanide carbon donates a pair of electrons to one Mn (MnC = 1.81 A) while the CN unit donates a second pair of electrons to the other Mn (MnN = 2.12 A, MnC = 2.14 A). The isocyanide is strongly bent with a CNC(phenyl) angle of 137°. The bonding of the isocyanide ligand is discussed.

Reversible insertion of sulfur dioxide into palladiumpalladium bonds. The preparation and structure of Pd2(μ-SO2)(Ph2PCH2PPh2)2 Cl2

Abstract Addition of sulfur dioxide to Pd 2 (dpm) 2 X 2 , (dpm = (C 6 H 5 ) 2 PCH 2 P(C 6 H 5 ) 2 , X = Cl or Br), Pt 2 (dpm) 2 Cl 2 or Pd 2 [(C 6 H 5 ) 2 As(CH 2 As(C 6 H 5 ) 2 ]Cl 2 produces 1/1 adducts. The crystal structure of Pd 2 (μ-SO 2 )(dpm) 2 Cl 2 shows two approximately planar palladium centers with coordination sites occupied by two phosphorus atoms from two bridging dpm ligands, a terminal halide ligand, and a bridging SO 2 ligand. The unit cell contains two crystallographically independent molecules. In most aspects the dimensions of the two molecules are similar. However, the ability of crystal packing forces to alter the PdPd distance (3.383 and 3.221 for the two different molecules) reflects the lack of a direct PdPd bond.

Isocyanide addition to MN2(CO)5(Ph2PCH2PPh2)2 and the formation of a four-electron doubly-bridging isocyanide

Summary Addition of RNC (R = p-CH3C6H4, C6H5CH2, or CH3) to Mn2(CO)5(dpm)2 (dpm = Ph2PCH2PPh2) produces Mn2(CO)5(CNR)(dpm)2 with a terminal isocyanide. Heating of this complex produces Mn2(CO)5(dpm)2 (R = CH3 or C6H5CH2) or Mn2(CO)4(CNR)(dpm)2 (R = p-CH3C6H4). The latter probably contains a four-electron doubly-bridging isocyanide ligand.