Ruthenium complex boryl

B2(cal)2 adds readily to the ruthenium zero oxidation state compounds, Ru(CO)L(PPh3)3 (L = CO, CN-p-tolyl), to give six coordinate bis(boryl)-complexes in which both the two phosphine ligands, and the two boryl ligands, arc mutually cix (see Scheme 2).6 This reaction is not general since the corresponding osmium complexes do not react directly with B2(cat)2, however, bis(boryl)-osmium... 

Part of the intense interest in M-B compounds derives from the participation of these species in various catalytic processes.1,2 Scheme 6 depicts proposed catalytic cycles for metal-catalysed alkene hydroboration and alkyne diborylation. Key steps involve the insertion of unsaturated organic substrates into M-B bonds and a key intermediate involved in the formation of product is molecule A in which there are ad jacent M-C and M-B bonds. The ruthenium and osmium boryl complexes described in this section provide models for these steps and intermediates. 

Table 6 Selected spectroscopic and structural parameters for ruthenium boryl complexes ...

Ruthenium boryl complexes containing catecholate, pinacolate and dithi-olate substituents have been analyzed as potential alkane functionalization... 

The first ruthenium dihaloboryl Cp/Ru(CO)2BCl2 (8.102) has recently been spectroscopically characterized, although no structural data were reported [60]. As with the related iron complex CpFe(CO)2BCl2 (8.35), 8.102 exhibits the relatively downfield-shifted 11B resonance (5b 81.0) and high frequency carbonyl stretching bands (2012, 1958 cm-1), expected for a boryl system featuring poorly 7r-donating substituents. The ferrocenyl(bromo)boryl complex Cp/Ru(CO)2B(Fc)Br (8.101) has also been synthesized recently and has spectroscopic properties similar to those of the closely related iron systems 8.63 and 8.64 [92]. 

A range of five- and six-coordinate osmium boryl complexes has been synthesized making use of similar approaches to those reported above for ruthenium. In particular, the reaction of phenylosmium(II) precursors with boranes, which proceed via elimination of benzene, has been shown to be a useful entry point into octahedral and square pyramidal osmium boryl complexes. Significant further chemistry has been reported on these systems, including substitution at both boron and metal centres, which has shed light on fundamental issues of structure/bonding and reactivity [12]. 

Fig. 37 A symmetrically bridged homodinuclear ruthenium boryl complex...

Iron, Ruthenium, and Osmium - In this section of work Fp = Fe(CO)2Cp - and Rp = Ru(CO)2Cp is used throughout. The inclusion compounds of aromatic ruthenium complexes, e.g. (Bn)Ru(Cp) PF in a-cyclodextrin has been investigated and die mentioned example has been crystallographically characterised. Two transition m boryl complexes, FpB(OCeH40) and FpBPh2 have been reported the reaction of the former complex with Et2NH results in the formation of FpH and die aminoborane. Gas phase and solution studies have been carried out on the first pentafluorocyclopentadienyl complex ICp Rufn-CsFs)]. The redox chemistry of this complex is not unusual in any way. ... 

The isomerization of multifunctionalized allyl silyl or allyl boryl ethers is efficiently catalyzed by a ruthenium complex in high yield (Scheme 38).23,24... 

For each case we will also present catalytic analogues, namely (1) the activation of methane to form methanol with platinum, the reaction of certain aromatics with palladium to give alkene-substituted aromatics, and (2) the alkylation of aromatics with ruthenium catalysts, and the borylation of alkanes and arenes with a variety of metal complexes. 

Fig. 26 Ruthenium boryl and related complexes bearing amino substituents...

Borylated pyrrole 88 was prepared by Oestreich by treatment of the corresponding pyrrole with pinacolborane and a ruthenium(II) thiolate complex. The direct synthesis of 88 promises to find wide utility in medicinal chemistry and was applied to a variety of substituted indoles (13JA10978). N-Methylpyrrole was directly arylated at room temperature by photoredox catalysis with diaryliodonium salts to furnish 89 in 84% yield (13SL507). 

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