The synthesis and structure of mercuric halide complexes of triphenylphosphonium cyclopentadienylide. The first x-ray structure of a mercury cyclopentadienyl

Abstract

Sir:We wish to report the synthesis and characterization of the initial examples of a new class of metallocenes, the cationic metal halide complexes of triphenylphosphinium cyclopentadienylide, I.-hPh, -CpPPh, I Stirring 0.2401 g (0.736 mmol) of CpPPh3 with 0.3360 g (0.738 mmol) of mercuric iodide in 50 ml of dry, deoxygenated (N2) tetrahydrofuran (THF) a t room temperature resulted in the formation of a dark yellow precipitate after a few minutes. Upon filtration 0.3155 g (55%) of the 1:l adduct, CpPPh3HgI2, mp 191-192 'C dec, was obtained. More of the product could be precipitated by addition of petroleum ether (60-90 'C), but it was of slightly lesser quality. The complex has been air-stable at room temperature for more than a year.

Coordination complexes of aryl- and alkylphosphonium cyclopentadienylides (cyclopentadienylidene ylides), C5R4PR′R′′R′′′ (R=H, alkyl, aryl; R′, R′′, R′′′=alkyl, aryl)

“…This was the first report of C 5 H 4 PPh 3 being bound in this way. The P-C 5 bond distance (1.748(7)Å) in this compound is elongated relative to the P-C 5 bond distance in C 5 H 4 PPh 3 (1.718(3)Å) [7,28,63], but the C 5 ring bond distances are only nominally shorter than in the free ligand. The bonding at the ␤-carbon (see Fig.…”

“…The structure of the phosphonium bridged permethylcyclopentadienyl ligand. Acetone-d 6 6.96 (m), 7.10 (m) - [22] Group 12 [( 1 -C 5 H 4 PPh 3 )HgI 2 ] 2 CDCl 3 6.0-6.6 (m) - [28] ture of type Ib would be isoelectronic with benzene, the ylide might be expected to form compounds of the type ( 5 -C 5 H 4 PPh 3 )M(CO) 3 (M = Cr, Mo, W), analogous to the known arene compounds ( 6 -C 6 H 6 )M(CO) 3 [9]. Successful attempts to prepare the group 6 compounds were carried out and the molybdenum compound was obtained analytically pure [9].…”

“…In 1976, Holy et al reported that C 5 H 4 PPh 3 reacts with HgX 2 (X = Cl, Br, I) in THF to form compounds of the type [(C 5 H 4 PPh 3 )HgX 2 ] 2 ( Fig. 57) [28,63]. The X-ray structure of the iodido compound was determined, and it was found that the C 5 ring is bound to the mercury atom in an 1 coordination mode through a -bond as in Fig.…”

X-ray and Spectroscopy Studies of Mercury (II) and Silver (I) Complexes of α-Ketostabilized Phosphorus Ylides

“…Failure to observe satellites in the above spectra was previously noted in the ylide complexes of Hg (II) 33 and Ag (I), 34 which had been explained by fast exchange of the ylide with the metal. In other hand it is possible that a fast equilibrium between complexes and free ylides is responsible for the failure observed either the NMR couplings or presence of two diastereoisomers.…”

trans-Di-μ-iodo-diiodobis(triphenylphosphonium-cyclopentadienylide)dimercury(II)

“…The crystal structure was investigated because NMR solution data did not unequivocally differentiate between a a and n type of complex. The solution NMR data could best be interpreted as a fluxional a-type complex with the Hg-C bond having roughly equal probability of being at C(2) or C(3) (Holy, Baenziger, Flynn & Swenson, 1976). 8532 reflections were measured (sin 0/2ma x < 0-481 /k -1) using graphite-monochromatized Mo Ka radiation (2 = 0.7107 A) with an automated FACS-I diffractometer, yielding the 4052 independent reflections (3571 > 30) which were used in the least-squares refinement.…”