Mononuclear structures rhenium complexes

There are three rhenium xanthate structures in the literature and two of these are binuclear. The mononuclear complex of formula (Me5C5)ReCl3(S2COCy) (46) is represented in Fig. 26. The rhenium atom is considered to exist in a... 

Suspected Si H—M interactions were also discussed in connection with the mononuclear complexes HReCp(CO)2(SiPh3) 161), HMnCp(CO)2(SiPh3) 161,162> and HFeCp(CO)2(SiF2Me)2 163>. From an analysis of known or estimated Si — H distances, it was concluded that Si — H interactions were most likely absent in the rhenium and iron complexes. In the case of HMnCp(CO)2(SiPh3), it was originally believed that a true example of Mn—H Si interaction existed162), but a subsequent re-assessment of the problem indicates that the structural evidence is, at best, inconclusive 161.163). 

It is in this oxidation state that the known chemistry of the two elements is most different. For rhenium di- and trinuclear cluster species predominate (Section 18-D-5), whereas for Tc there are only a few Tc and no Tc3+ complexes. Mononuclear Tc3+ species do occur. The only simple [MXJ3- complex known for either element is the [Tc(NCS)6]3 ion, but the mer-MCl3(PR3)3, MCl3py3, and [MX2(LL)2]+ complexes with X = halide, NCS , or MeS" and LL a diphosphine or diarsine are important.41 Some of these complexes can be reduced with retention of structure in the II and even I oxidation states.42... 

Follow-up products may include metal oxides, be it in a mononuclear or in a di-and oligonuclear form (Eqs. 2-4). The tetranuclear rhenium(I) complex formed by photolysis (Eq. 4) has a cubane-type structure [7]. Related complexes 2a-d were made according to Scheme 2 [8],... 

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