Organodiborate Ring Transformations Promoted by Zirconocene and Hafnocene Dichlorides. Preparation and Structure of (η⁵-C₅H₅)₂ZrCl{(μ-H)₂BC₄H₈}

Abstract

The anion [H2B2(μ-H)(μ-C4H8)2]- reacts with zirconocene dichloride or hafnocene dichloride to form (η5-C5H5)2ZrCl{(μ-H)2BC4H8} or (η5-C5H5)2HfCl{(μ-H)2BC4H8}, complexes which contain a borocyclopentane ring that is bound to the metal through hydrogen bridges. In these reactions the organodiborate anion disproportionates to form 1/2 mol of B2(μ-H)2(μ-C4H8)2 as well as the 5-membered borocyclopentane ring.

Syntheses, structures, and properties of phenyltrihydroborate complexes of zirconocene and titanocene

“…The Zr-Cl distance is 2.4148(17) Å and the Zr-O distance is 2.211(3) Å . The Zr-Cl distance is slightly shorter than that in compounds 1, 4, and other organohydroborate compound [2a, 10,22]. The Zr-O distance was consistent with that observed in [Cp 2 Zr(OEt 2 )-(OEt)][HB(C 6 F 5 )] (2.209(8) Å ) [15] and is slightly longer than the sum of the covalent radii, 2.16 Å [26].…”

“…These results are different compared with those were observed in the tetrahydroborate complexes where the bridge B-H bond distances are 0.06-0.10 Å longer than the terminal B-H bond distances [1a,21].The Zr-Cl distance is 2.4844(13) Å in 1 and 2.460(2) Å in 4. It is comparable to the Zr-Cl distances observed in other hydroborate complexes [2a,10,22].…”

Cyclic Hydroborate Complexes of Metallocenes. 1. Organodiborate Ring Transformations Promoted by Zirconocene and Hafnocene Dichlorides. Syntheses and Structures of Zirconocene and Hafnocene Boracyclopentane Derivatives

“…In our attempts to isolate such complexes, a unique type of ring transformation occurred in reaction of II with zirconocene and with hafnocene dichlorides. Earlier, in a preliminary report, we described the zirconocene complex (η 5 -C 5 H 5 ) 2 ZrCl{(μ-H) 2 BC 4 H 8 }, III , which was isolated from this reaction. Presented here are details of syntheses and structural characterizations of III and (η 5 -C 5 H 5 ) 2 HfCl{(μ-H) 2 BC 4 H 8 }, IV , formed from the reaction of II with zirconocene dichloride and with hafnocene dichloride.…”

Ferrocenyl(trihydro)borates: building blocks for the synthesis of heterooligonuclear metallocene complexes

“…6 Numerous transition metal complexes of the parent tetrahydroborate ligand have been thoroughly studied. 7 In contrast, organo (hydro)borate metal complexes have received much less attention 6,[8][9][10][11][12][13][14][15][16][17][18][19][20] and corresponding compounds featuring Fig. 1 Ferrocene-based tris( pyrazol-1-yl)borates (Ia, Ib; pz = pyrazol-1-yl) as well as phenyl-and ferrocene-based trihydroborates (IIa-IIIb).…”