Shelton A. Dias

Structural studies of steric effects in phosphine complexes. Part 6. The synthesis, characterization and molecular structure of the dinitro(trimesitylphosphine)mercury(II)dimer

Abstract The synthesis and crystal and molecular structure of the dinitro(trimesitylphosphine)mercury(II) dimer is reported. The compound [HgP(mesityl) 3 (NO 3 ) 2 ] 2 belongs to the monoclinic space group P 2 1 / c (C 5 2h , No. 14) with a = 19.940(3), b = 17.588(2), c = 16.403(2) A , β = 100.36(1)° and Z = 4; the asymmetric unit contains two independent half dimers. The structure was refined to a final R of 0.056 for 4220 observed reflections measured by diffractometer. The mercury coordination in both dimers I and II is characterized by three strong nearly coplanar bonds (in I HgP 2.395(3), HgO 2.180(12) and 2.257(8), and 2.342(9)) and three weaker HgO bonds in the range 2.58–2.90 A . Both independent trimesityl phosphine ligands have the same regular propeller conformation (HgPCC torison angles 42 to 49°) and the largest CPC angles (mean value 113.2(5)°) and cone angle (θ = 208°) yet determined. The main difference between the two independent dimers is the orientation of the non-bridging nitrato groups. Nitrato vibrational and phosphine 1 H and 31 P n.m.r. data are also presented for [HgP(mesityl) 3 (NO 3 ) 2 ] 2 .

Metal derivatives of azoles, part VII. Pyrazolato-bridged dinuclear complexes containing either cyclopalladated or -platinated trimesitylphosphine or -arsine

SummaryThe halogen bridges of the dimeric, cyclometallated trimesityl-arsine and -phosphine complexes of palladium(II) and platinum(II), where M=Pd or Pt and E=P or As have been replaced with pyrazolate groups to give the corresponding and less symmetric pyrazolato-bridged complexes, where M=Pd or Pt, E=P or As, Pz=pyrazolato anion, and M=Pd, E=As, Pz=3,5-dimethylpyrazolato anion. In the case of the palladium complexes,1H. n.m.r. clearly indicates the presence of only one isomer which is most likely to have thetrans configuration while the platinum complexes are mixtures of bothcis andtrans forms.