Gerhard E. Herberich

Derivate des borols

Abstract Analytically pure, dark blue pentaphenylborole (PPB) can be synthesized from 1,1-dibutyl-2,3,4,5-tetraphenylstannole and C 6 H 5 BCl 2 in toluene in 95% yield. Reduction of PPB with elemental potassium in THF produces brownish red K 2 [PPB] which is derived from the new 6π-electron anion [PPB] 2− . The new complexes (C 5 H 5 )Co(PPB) and (COD)Pt(PPB) (COD = 1,5-cyclooctadiene) are obtained by irradiation of a toluene solution of (C 5 H 5 )Co(CO) 2 and PPB and by ligand substitution reaction from Pt(COD) 2 and PPB respectively.Abstract Analytically pure, dark blue pentaphenylborole (PPB) can be synthesized from 1,1-dibutyl-2,3,4,5-tetraphenylstannole and C 6 H 5 BCl 2 in toluene in 95% yield. Reduction of PPB with elemental potassium in THF produces brownish red K 2 [PPB] which is derived from the new 6π-electron anion [PPB] 2− . The new complexes (C 5 H 5 )Co(PPB) and (COD)Pt(PPB) (COD = 1,5-cyclooctadiene) are obtained by irradiation of a toluene solution of (C 5 H 5 )Co(CO) 2 and PPB and by ligand substitution reaction from Pt(COD) 2 and PPB respectively.

Derivative des borols: VI. Dehydrierende komplexierung von borolenen mit carbonylmetallen: (borol)metall-komplexe von mangan, eisen und cobalt

Abstract The reaction of 2-borolenes and 3-borolenes C4H6BR (R = Ph, Me, C6H11, OMe) with Mn, Fe, and Co carbonyls leads to dehydrogenating complexation with formation of simple, i.e. C-unsubstituted (η5-borole)metal complexes. Thus, Mn2(CO)10 gives the triple-decked complexes (μ-η5-C4H4BR)[Mn(CO)3]2 (R = Ph, OMe). By irradiation of Fe(CO)5 the half-sandwich complexes Fe(CO)3 (η5-C4H4BR) (R = Ph, Me, C6H11, OMe) are formed, whereas Co2(CO)8 yields the dinuclear complexes (μ-CO)2[Co(CO)(η5-C4H4BR)]2 (Co-Co) (R = Ph, Me). A low-temperature X-ray structure determination of Fe(CO)3(η5-C4H4BPh) is described in detail.

Derivate des borols: VIII. (η5-borol)cobalt-komplexe

Abstract A large variety of (η 5 -borole)cobalt complexes have been prepared starting with η-(CO) 2 [Co(CO)(η 5 -C 4 H 4 BR)] 2 ( CoCo ) (IIIa: R = Me, IIIb: R = Ph), including inter alia, the sandwich complexes CpCo(η 5 -C 4 H 4 BR) (VIIa, b), the triple-decked complexes η-(η 5 -C 4 H 4 BR)[Co(η 5 -C 4 H 4 BR)] 2 (VIIIa, b) and μ-(η 5 -C 4 H 4 BR)(FeCp)[Co(η 5 -C 4 H 4 BR)] (X, R = Ph), the dinuclear complex μ-(CO) 2 [Fe(CO)Cp][Co(CO)(η 5 -C 4 H 4 BPh)]( FeCo ) (IX), and salts M[Co(η 5 -C 4 H 4 BR) 2 ](XVa, b: M = Na; XVIa, b: M = NMe 4 ; XVII: M = Cs, R = Ph). The anions [Co(η 5 -C 4 H 4 BR) 2 ] − readily undergo stacking reactions to form multiple-decked complexes such as the triple-decker compounds μ-(η 5 -C 4 H 4 BR)[Mn(CO) 3 ][Co(η 5 -C 4 H 4 BR)] (XIIa, b), μ-(η 5 -C 4 H 4 BR)[Co(η 5 -C 4 H 4 BR)][Rh(η-1,5-COD)] (XVIII), [NMe 3 Ph][μ-η 5 -C 4 H 4 BPh){Cr(CO) 3 }{Co(η 5 -C 4 H 4 BPh)}] (XX), and the quadruple-decker complex Ru[μ-(η 5 -C 4 H 4 BR)Co(η 5 -C 4 H 4 BR)] 2 (XXI). The monofacially bound η 5 -borole ligands in VIIb and VIIIb shows regiospecific H/D exchange, at the α position of the boron, on treatment with CF 3 CO 2 D at room temperature. VIIb undergoes a Friedel-Crafts substitution to give the 2-acetyl derivative XXIV with MeCoCl/SnCl 4 in CH 2 Cl 2 at room temperature. The structure of VIIIa, as determined by X-ray diffraction studies is that of a typical triple-decker compound with nearly coplanar rings. The three borole rings form a helix with torsional angles of 59.8 and 72.2°. All intra-ring bond distances of the central ligand are longer than those of the outer ligands. The metal-ligand interaction is somewhat stronger for the outer ligands than for the central ligand.

Derivate des borols: VII. (η5-borol)rhodium-komplexe und nucleophiler abbau von μ-(η5-1-phenylborol)-bis[(η5-1-phenylborol)rhodium]

Abstract Dehydrogenating complexation of borolenes C 4 H 6 BR (R = Me, Ph) with [Rh(η 2 -C 2 H 4 ) 2 Cl] 2 gives the triple-decked complexes μ-L-(RhL) 2 (III) with L = η 5 -C 4 H 4 BR. Cyclopentadienide degradation of III gives the uncharged complexes CpRhL (IV) and the water-soluble salts Na[RhL 2 ] (Na + · V) which are characterized as NMe 4 + (R = Me) and Cs + salts (R = Ph). In CD 2 Cl 2 /CF 3 CO 2 D the complex CpRh(η 5 -C 4 H 4 BPh) shows fast exchange at the α-position to the boron at 0°C, thus providing the first evidence of an electrophilic substitution of an (η 5 -borole)metal complex. Protonation of V gives RhHL 2 (VII) as the first (η 5 -borole)metal hydrides. Various neutral nucleophiles effect a valence disproportionation of IIIb (R = Ph) with formation of the compounds [LRhY 3 ][RhL 2 ] (VIII) (Y = PMe 3 ), IX (Y = P(OMe) 3 ), and X (Y = CNBu t ). Cyanide degradation of IIIb in acetonitrile yields K 2 [LRh(CN) 3 ], characterized as PPh 4 + salt (XII). Further degradation in aqueous solution provides the anion [C 4 H 4 B(CN)Ph] − (XIII) isolated as the [CoCp 2 ] + salt (XIV). Anion XIII constitutes the first Lewis-base adduct of a simple, i.e. C -unsubstituted borole.

Tripeldecker-komplexe: III. Komplexierungsreaktionen von 1-phenyl-4,5-dihydroborepin unter gerüstumlagerung. Synthese und struktur von tripeldecker-komplexen des mangans und des eisens mit 2-ethyl-1-phenylborol als brückenligand☆☆☆

Abstract The thermal reaction of 1-phenyl-4,5-dihydroborepin (I) with Mn 2 (CO) 10 produces the triple-decked complex (OC) 3 Mn(μ-L)Mn(CO) 3 (III) where L is 2-ethyl-1-phenylborole. The analogous system I/[(C 5 H 5 )Fe(CO) 2 ] 2 inter alia yields the triple-decked sandwich complex (C 5 H 5 )Fe(μ-L)Fe(C 5 H 5 ) (VI) and the borabenzene derivative (C 5 H 5 )Fe(2-CH 3 C 5 H 4 BC 6 H 5 ) (VIII). The structures of the 30-electron compounds III and VI have been determined by X-ray analyses.

Derivate des borols ☆: IX. (η5-borol)metall-komplexe von ruthenium, osmium und rhodium

Abstract Dehydrogenating complexation of borolenes with carbonyls (Ru 3 (CO) 12 , Os 3 (CO) 12 ), Wilkinsons catalyst (RhCl(PPh 3 ) 3 ) and related compounds (RuCl 2 (PPh 3 ) 3 , RuHCl(PPh 3 ) 3 , OSCl 2 (PPh 3 ) 3 ), and (η 6 -arene)ruthenium complexes (Ru(η-C 6 H 6 )(η 4 -C 6 H 8 ), [Ru(η-C 6 H 6 )Cl 2 ] 2 , [Ru(η-C 6 -Me 6 )Cl 2 ] 2 ) leads to the (η 5 -borole)metal complexes of Ru, Os, and Rh. Inter alia, the preparation of the complexes Ru(CO) 3 (η 5 -C 4 H 4 BF) (R = Ph, OMe, Me), Os(CO) 3 L (L = η 5 -C 4 H 4 BPh), MHClL(PPh 3 ) 2 (M = Ru, Os), RhClL(PPh 3 ) 2 , and RuL(η-C 6 R 6 ) (R = H, Me) is described. The structures of RuHClL(PPh 3 ) 2 and RhClL(PPh 3 ) 2 have been determined by X-ray diffraction analysis.

Untersuchungen zur reaktivität organometallischer komplexe III. Über die reaktion von dicyclopentadienylkobalt mit halogenmethanen

Abstract The reaction of dicyclopentadienylcobalt, Co(C 5 H 5 ) 2 , with halomethanes RX forms 1- exo -organyl derivatives of cyclopentadienylcyclopentadienecobalt where the organyl R is a halomethyl group with one, two or three halogen atoms. The reaction rate strongly depends on X and increases in the order Cl, Br, I; it also increases with the number of halogen atoms in the halomethyl group R. Derivatives with R = CH 2 Cl, CH 2 Br, CH 2 I, CHBr 2 and the dinuclear derivative with R =- CF 2 - are described for the First time. For the dichloromethyl compound (R = CHCl 2 ) a new and convenient synthesis is reported.

Derivate des borabenzols : XII. Thalliumborinate

Abstract Thallium borinates Tl[C 5 H 5 BR] (R = CH 3 , C 6 H 5 ) have been prepared from alkalimetal borinates and TlCl in acetonitrile. These are the first borabenzene derivatives of a Main-Group metal to be isolated in pure form. Their spectral data are described in detail.

Synthesis and crystal structure of cyclopentadienyl(1,4-dimethyl-1,4-dibora-2,5-cyclohexadiene)cobalt

The synthesis of the organometallic derivative cyclopentadienyl(1,4-dimethyl-1,4-diboracyclohexa-2,5-diene)cobalt is described. This complex, [(CH 3 BC 4 H 4 BCH 3 )Co(η-C 5 H 5 )], forms red-oranged monoclinic crystals, space group P 2 1 / a with Z = 4 in a unit cell of dimensions a 11.362(7), b , 7.467(7), c 13.290(12) A, β 103.76(6)°. The structure has been elucidated by heavy-atom methods from 1732 reflections ( I > 2σ( I )) measured on a Syntex P2 1 four-circle diffractometer and refined to R = 0.055. In the coordination complex all six atoms of the cyclohexadiene ring are within bonding distance of the metal atom, but the two boron atoms bend away from the metal atom, and the ring elongates slightly in the B---B direction. As a standard of comparison the known geometry of the free ligand [1,4-difluoro-1,4-dibora-2,3,5,6-tetramethylcyclohexa-2,5-diene] is used. The terminal methyl groups on the boron atoms, by contrast, bend slightly back towards the metal atom. The cyclopentadienyl ring remains planar but is positionally disordered.

Derivate des Borols: XIII. (η5-Borol)eisen-Komplexe und (η5-Borol)-(η5-cyclopentadienyl)metallhydride von Eisen, Ruthenium und Osmium☆

Abstract The η 5 -borole complexes (C 4 H 4 BR)Fe(CO) 3 (Ia: R = Ph; Ib: R = Me) Yield a large variety of substitution products when irradiated in the presence of suitable ligands, thus affording the derivatives (C 4 H 4 BR)Fe(CO) 2 L (for R = Me: L = PMe 3 , for R = Ph: L = CNBu t , NCMe, PMe 3 ), (C 4 H 4 BR)Fe(CO)(PMe 3 ) 2 (R = Me, Ph), and (C 4 H 4 BPh)Fe(CO)L (L = butadiene, cyclopentadiene, 1,3-cyclohexadiene, 1,5-cyclooctadiene, trans -PhCHCHCOMe). Exhaustive decarbonylation produces the basic (C 4 H 4 BPh)Fe(PMe 3 ) 3 , the benzene complex (C 4 H 4 BPh)Fe(C 6 H 6 ), and hydrides (C 4 H 4 BR)FeHCp (R = Me, Ph) which are both non-rigid at low temperature (−80°C), and show a novel intramolecular proton exchange between FeH and H(2/5) above room temperature. (C 4 H 4 BPh)FeHCp is readily deprotonated to give a borataferrocene anion which can be isolated as the (TMEDAL)Li derivative and can form the triple-decked μ-(C 4 H 4 BPh)(FeCp)[Rh(COD)]. Homologous hydrides (C 4 H 4 BPh)MHCp (M = Ru, Os) can also be made photochemically from the tricarbonyls and cyclopentadiene.