Dinuclear rhenium complexes with

Fletcher et al. reported another interesting neutral dinuclear rhenium complex 28 (see Fig. 15) which interacts strongly with H2P04 , reasonably with Cl" but only... 

The dinuclear rhenium disulfido complex with n,rj -S2 ligands (ReCp )2(/U-S2)2 (Cp =7j -C5Me4Et) (type IIa2 complex in Fig. 2) undergoes an insertion reaction of acetylene and ethylene into the S-S bond according to Scheme 57. 

Binuclear complexes of naphthalene (VIII) and of benzene (IX) with [Os(NH3)5]2+ and [Ru(NH3)5]2+ moieties were reported by Taube et al. (19), in which anti- //-1,2-rj2 3,4- 2) coordination of the arene is present. This bonding mode was first observed by Pasman et al. (20) in the binuclear Rhenium complex X. Wolczanski et al. (21) obtained complex XI from the mononuclear complex [Ta(0—Si Bu3)3 2-(N,C)-pyridine ] and benzene. Each tantalum atom is bound unsymmetrically to one C=C bond of benzene with a weak interaction to a third carbon atom the bonding may be described as a distorted tj3-enyl. In the dinuclear cobalt complex XII, the xylene functions as a bis(enyl)-ligand (12,22). 

A number of complexes can be derived from the trinuclear and dinuclear rhenium(m) halides and halo complexes (page 979) with retention of the Re3 and Re2 units. 

SCH2), 36.6 (SCH2), 13.2 (Re—Me). Analogous dithiolate complexes can be prepared in a variety of ways. For example, direct treatment of MTO with 2-(mercaptomethyl)thiophenol gives the corresponding dithiolate complex. In addition, MTO can be converted to [MeReO(SPh)2l2, which can be treated with 1,3-propanedithiol to give the 1,3-propanedithiolate complex. These dinuclear rhenium(V) dithiolate complexes can be converted into monomeric complexes of stoichiometry MeReO(K -dithiolate)L with Lewis bases such as pyridine, 2-ethyl-pyridine, 4-ferf-butylpyridine, tetramethylthiourea, triphenylphosphine, or methyldiphenylphosphine. 

Rate laws and rate constants have been determined for the reactions of the dinuclear rhenium(ni) complexes [RcaXg] with thiourea or tris-n-butyl-phosphine in methanol. The kinetic pattern suggests the reaction sequence shown in Scheme 3. The reaction of [Re2Brg] - with chloride ion was also studied. ... 

The [TcO(OH2)(CN)4] complex is, as shown by the complex formation constants in Table II, more reactive than the corresponding complexes of either the Re(V) or W(IV). This, coupled with the fact that the dinuclear species [Tc203(CN)8]4 is formed rapidly whenever there are appreciable amounts of the [TcO(OH)(CN)4]2 complex present (71), i.e., below pH ca. 5.5, prohibits any experiment around these acidic conditions. A marked difference in the [H+] dependence for the Tc(V) compared to the above-mentioned Re(V) and W(IV) systems originates from the fact that the Tc(V) is much more reactive and had to be studied at pH values significantly higher than the )Ka2 value of ca. 4. This yielded results similar to the insert (a) in Fig. 16 for the rhenium(V) and only the exchange rate constants and the activation parameters for the hydroxo oxo complex for Tc(V) could thus be obtained (Table V). 

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