Synthesis and Characterisation of Stable Bis(phosphonio)isophosphindolyliumcarbonylmetallates and a Cationic Bis(phosphonio)isophosphindolylium-GoldComplex* Reaction of 1,3-bis(triphenylphosphonio)isophosphindolylium bromide, [L+][Br-] (la), with TI[Co(CO),], Na[MoCp-(CO)3], or Na[WCp(C0)3] (5a-c) yields the corresponding ionic isophosphindolylium-carbonylmetallates, 6a-c. Whereas l a fails to react with neutral metal carbonyls, a mixture of ionic complexes of the type [LAuX+][AuYZ-] (7a, X, Y, Z = C1 or Br) is formed by reaction with two equivalents of AuC1. Treatment of AuCl with the triflate [L+][OTf-] (lb), which is accessible from l a via anion metathesis, furnishes

Key Words-Bis(phosphonio)isophosphindolide cations I Silver complexes I 31P NMR I "'Ag NMR 2 1 X C1(3a), Br (3b)

Bis(triphenylphosphonio)isophosphindolide triflate (1[CF(3)SO(3)]) reacted with HgCl(2) and H(2)O or MeOH to give a phosphinito complex which was converted with excess HgCl(2) into the dimercury complex 5. In contrast, methanolysis of 1[X] (X = CF(3)SO(3), Br) in the presence of Hg(OAc)(2) afforded the phosphonium cation 9. A mercury complex 8 was isolated for X = Br as a reaction intermediate. Salts of a macrocyclic cation with a constitution similar to that of 9 were obtained by reaction of 1[CF(3)SO(3)] with Hg(OAc)(2) and triethylene glycol. The products were characterised by (1)H, (13)C, and (31)P NMR spectroscopy; in addition, (199)Hg NMR data of some complexes were obtained from 2D (31)P,(199)Hg shift correlations. Complexes 5 (space group P2(1)2(1)2(1), Z = 4, a = 12.449(2) Å, b = 17.583(3) Å, c = 23.111(3) Å, V = 5058.8(14) Å(3), 8917 reflections refined to R(w2) = 0.103) and 8 (space group C2/c, Z = 8, a = 20.028(2) Å, b = 15.513(2) Å, c = 30.247(8) Å, beta = 91.91(1) degrees, V = 9392(3) Å(3), 7955 reflections refined to R(w2) = 0.177) were further characterized by single crystal X-ray diffractommetry. Compound 8 is the first example of a monomeric complex of the type LHgX(2) (L = phosphine donor, X = halogen); formation of a halide bridged dimer is presumably prevented by the extraordinarily sterically demanding ligand. A reaction mechanism for the formation of 5 and 8 is proposed which involves the formation of mercury complexes of 1 as the initial step.

Phosphorus Heterocycles, Copper Complexes, Crystal Structure, '' P NMR Data Bis-triphenylphosphonio-isophosphindolide salts 1[X] react with Cu(I)-halides CuX to give isolable products of composition [(l)Cu2X3]. X-ray crystal structure analyses confirmed that for X = Br, Cl dinuclear complexes [(/y-1 )(/i-X)Cu2X2] with /i2j;'(P)-bridging cations 1 are formed, while for X = I a solid phase containing a salt (l^lC u*^] and a complex [(l^C u .^] with a terminal ?/(P)-coordinated ligand 1 was obtained. The bonding parameters in the two types of complexes suggest that l i s a hybrid between a phosphenium cation and a phospholide anion whose 7T-system is less nucleophilic than the phosphorus lone-pair.31P NMR studies revealed that in solution in all cases binuclear complexes [(l)Cu2X3] are in dynamic equilibrium with small amounts of mononuclear species and free 1. The same equilibria were detected in the system l[OTf]/CuOTf. NMR studies of ligand exchange reactions indicated that the stability of complexes [(l)Cu2X3] increases in the order X = OTf < 1 < Br, Cl, and titration of [(l)Cu2Bn] with EuNBr allowed to determine the equilibrium constant of the complex formation reaction.

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