Bis boryl Complexes

The structure of a further iridium bis(boryl) complex, the cationic species [(tbbpy)(cod)Ir(Bpin)2]+[OTf] (9.33), together with that of a related neutral tris(boryl) system (vide infra), has been reported as part of a study to elucidate the mechanism and intermediates of arene borylation chemistry [136]. 9.33 features an approximately octahedral coordination geometry with mutually cis pairs of bipyridyl, diene and Bpin ligands. The two Ir-B bond lengths [2.06(2) and 2.12(1) A] are effectively identical within the standard 3a limit. 

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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... 

Scheme 21 Synthetic routes to the crystallographically characterized rhodium boryl hydride and bis (boryl) complexes 9.8-9.13...

Fig. 36 Crystallographically characterized square planar platinum(II) bis(boryl) complexes 10.16-10.30...

In the bis-boryl complexes 7, 8, and 9 [49-52], the cis arrangements of the two boryl ligands prevent the very strong trans influence ligands from being trans to each other. In the tris-boiyl complexes 10,11, and 12 [53-55], the facial arrangements of the three boryl ligands do the same. 

To complement the activation study of tetra(alkoxy)diboron with Pt(0) complexes. Smith and Iverson disclosed their findings on the reactivity of B2cat2 with [Pt(ri -CH2=CH2)(PPh3)2], which resulted in the loss of ethylene, even at —80 °C, followed by oxidative addition of the B—B bond to give the bis(boryl) complex as-[Pt(Bcat)2(PPh3)2] (10b) (Scheme... 

Scheme 35 Formation of the bis(boryl) complex frans,c/s,c/s-[Os(CO)2(PPh3)2(Bcat)J (32) and trans,c/s,c/s-[Ru CO)2 PPh3)2(Bcat)2] (33).

Dai C, Stringer G, Corrigan JF, Taylor NJ, Marder TB, Norman NC. Synthesis and molecular structure of paramagnetic Co(II) bis(boryl) complex [Co(PMe3)3(Bcat)2] (cat = l,2-02C6H4).J Organomet Chem. 1996 513 273-275. 

He X, Hartwig JF. Boryls bound to iron carbonyl. Stmcture of a rare bis(boryl) complex, synthesis of the first anionic boryl, and reaction chemistry that includes the synthetic equivalent of horyl anion transfer. Organometallics. 1996 15 400-407. 

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