New titanium and zirconium complexes with M–NH2bonds formed by facile deprotonation of H3N·B(C6F5)3

Mountford, Andrew J.; Clegg, William; Harrington, Ross W.; Humphrey, Simon M.; Lancaster, Simon

doi:10.1039/b500407a

Cited by 18 publications

(27 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The most striking feature of 5⋅ PhMe is the presence of two amidoborane ligands. Our previously characterised NH 2 B(C 6 F 5 ) 3 complexes were restricted to one amidoborane ligand 16–18. While examples are known for main group NH 2 BH 3 complexes,28 compound 5 is a rare instance of ligation by two substituted amidoborane ligands 29…”

Section: Resultsmentioning

confidence: 99%

“…The [NHB(C 6 F 5 ) 2 H] 2− ligand can be formally regarded as a Lewis acid stabilised terminal imido or imidoborane ligand, thus complementing the amidoborane and nitridoborane examples we have recently reported 16–21. The coordination sphere of 9⋅ PhMe is all the more remarkable, because imido zirconocene and hafnocene complexes have previously required stabilisation with bulky nitrogen substituents.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis and Structure of Amido‐ and Imido(pentafluorophenyl)borane Zirconocene and Hafnocene Complexes: NH and BH Activation

Jacobs

Fuller

Coles

et al. 2012

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

Treatment of Me(2)S·B(C(6)F(5))(n) H(3-n) (n=1 or 2) with ammonia yields the corresponding adducts. H(3)N·B(C(6)F(5))H(2) dimerises in the solid state through N-H···H-B dihydrogen interactions. The adducts can be deprotonated to give lithium amidoboranes Li[NH(2)B(C(6)F(5))(n)H(3-n)]. Reaction of the n=2 reagent with [Cp(2)ZrCl(2)] leads to disubstitution, but [Cp(2)Zr{NH(2)B(C(6)F(5))(2)H}(2)] is in equilibrium with the product of β-hydride elimination [Cp(2)Zr(H){NH(2)B(C(6)F(5))(2)H}], which proves to be the major isolated solid. The analogous reaction with [Cp(2)HfCl(2)] gives a mixture of [Cp(2)Hf{NH(2)B(C(6)F(5))(2)H}(2)] and the N-H activation product [Cp(2)Hf{NHB(C(6)F(5 )(2)H}]. [Cp(2)Zr{NH(2)B(C(6)F(5))(2)H}(2)]·PhMe and [Cp(2)Hf{NH(2)B(C(6)F(5))(2)H}(2)]·4(thf) exhibit β-B-agostic chelate bonding of one of the two amidoborane ligands in the solid state. The agostic hydride is invariably coordinated to the outside of the metallocene wedge. Exceptionally, [Cp(2)Hf{NH(2)B(C(6)F(5))(2)H}(2)]⋅PhMe has a structure in which the two amidoborane ligands adopt an intermediate coordination mode, in which neither is definitively agostic. [Cp(2)Hf{NHB(C(6)F(5))(2)H}] has a formally dianionic imidoborane ligand chelating through an agostic interaction, but the bond-length distribution suggests a contribution from a zwitterionic amidoborane resonance structure. Treatment of the zwitterions [Cp(2)MMe(μ-Me)B(C(6)F(5))(3)] (M=Zr, Hf) with Li[NH(2)B(C(6)F(5))(n)H(3-n)] (n=2) results in [Cp(2) MMe{NH(2)B(C(6)F(5))(2)H}] complexes, for which the spectroscopic data, particularly (1)J(B,H), again suggest β-B-agostic interactions. The reactions proceed similarly for the structurally encumbered [Cp''(2)ZrMe(μ-Me)B(C(6)F(5))(3)] precursor (Cp''=1,3-C(5)H(3)(SiMe(3))(2) , n=1 or 2) to give [Cp''(2)ZrMe{NH(2)B(C(6)F(5))(n)H(3-n)}], both of which have been structurally characterised and show chelating, agostic amidoborane coordination. In contrast, the analogous hafnium chemistry leads to the recovery of [Cp''(2)HfMe(2)] and the formation of Li[HB(C(6)F(5))(3)] through hydride abstraction.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Synthesis and Structure of Amido‐ and Imido(pentafluorophenyl)borane Zirconocene and Hafnocene Complexes: NH and BH Activation

Jacobs

Fuller

Coles

et al. 2012

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

show abstract

“…[32][33][34][35] Despite the poor solubility of 4, very small crystals were obtained at the interface between solutions of [ZrA C H T U N G T R E N N U N G (NMe 2 ) 4 ] and 1 in toluene and the solid state structure was determined by diffraction methods using synchrotron radiation. [22] Compound 4 adopts a distorted trigonal-bipyramidal geometry in which the amidoborate and amino ligands are coordinated trans to one another (N1-Zr1-N5 = 173.45(13)8; Figure 3). Of the five Zr À N bond lengths, those to the HNMe 2 (2.424(4) ) and the three equatorial NMe 2 ligands (average 2.03 ) are typical of trigonal-bipyramidal zirconium complexes containing these groups.…”

Section: Resultsmentioning

confidence: 99%

“…[2] The remaining reagents were acquired from Aldrich, Fischer, Fluorochem or Lancaster and used as supplied. The syntheses of compounds 1, [23] 2 and 4 [22] and AlA C H T U N G T R E N N U N G (C 6 F 5 ) 3 ·toluene [43] have been reported elsewhere. …”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

The Synthesis, Structure and Reactivity of B(C₆F₅)₃‐Stabilised Amide (MNH₂) Complexes of the Group 4 Metals

Mountford

Clegg

Coles

et al. 2007

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

Treatment of the homoleptic titanium amides [Ti(NR(2))(4)] (R=Me or Et) with the Brønsted acidic reagent H(3)NB(C(6)F(5))(3) results in the elimination of one molecule of amine and the formation of the four-coordinate amidoborate complexes [Ti(NR(2))(3){NH(2)B(C(6)F(5))(3)}], the identity of which was confirmed by X-ray crystallography. The reaction with [Zr(NMe(2))(4)] proceeds similarly but with retention of the amine ligand to give the trigonal-bipyramidal complex [Zr(NMe(2))(3){NH(2)B(C(6)F(5))(3)}(NMe(2)H)]. Cyclopentadienyl (Cp) amidoborate complexes, [MCp(NR(2))(2){NH(2)B(C(6)F(5))(3)}] (M=Ti, R=Me or Et; M=Zr, R=Me) can be prepared from [MCp(NR(2))(3)] and H(3)NB(C(6)F(5))(3), and exhibit greater thermal stability than the cyclopentadienyl-free compounds. H(3)NB(C(6)F(5))(3) reacts with nBuLi or LiN(SiMe(3))(2) to give LiNH(2)B(C(6)F(5))(3), which complexes with strong Lewis acids to form ion pairs that contain weakly coordinating anions. The attempted synthesis of metallocene amidoborate complexes from dialkyl or diamide precursors and H(3)NB(C(6)F(5))(3) was unsuccessful. However, LiNH(2)B(C(6)F(5))(3) does react with the highly electrophilic reagents [MCp(2)Me(mu-Me)B(C(6)F(5))(3)] to give [MCp(2)Me(mu-NH(2))B(C(6)F(5))(3)] (M=Zr or Hf). Comparison of the molecular structures of the Group 4 amidoborate complexes reveals very similar B--N, Ti--N and Zr--N bond lengths, which are consistent with a description of the bonding as a dative interaction between an {M(L)(n)(NH(2))} fragment and the Lewis acid B(C(6)F(5))(3). Each of the structures has an intramolecular hydrogen-bonding arrangement in which one of the nitrogen-bonded hydrogen atoms participates in a bifurcated FHF interaction to ortho-F atoms.

show abstract

Structural Importance of Secondary Interactions in Molecules: Origin of Unconventional Conformations of Phosphine-Borane Adducts

et al. 2007

View full text Add to dashboard Cite

The series of phosphine-borane adducts, Ph2(H3C--C[triple chemical bond]C)P--B(C6F5)3 (8 c), Ph(H3C--C[triple chemical bond]C)2P--B(C6F5)3 (8 b) and (H3C--C[triple chemical bond]C)3P--B(C6F5)3 (8 a), was prepared. The X-ray crystal structure analyses revealed close to eclipsed conformations for all members of this series with average dihedral angles theta(C-P-B-C) of 8.1 degrees (8 c), 12.3 degrees (8 b) and 20.3 degrees (8 a). Quantum chemical analysis of these compounds revealed the importance of a subtle interplay between competing attractive and repulsive secondary interactions, causing the surprising eclipsed conformational preference for systems of this degree of complexity. Some cyclic phosphine-borane adducts were studied for comparison.

show abstract

New titanium and zirconium complexes with M–NH₂bonds formed by facile deprotonation of H₃N·B(C₆F₅)₃

Abstract: Facile deprotonation of H3N.B(C6F5)3 with [M(NMe2)4](M = Zr or Ti) yields the novel amidoborate complexes [Zr(NMe2)3{NH2B(C6F5)3}(HNMe2)] and [Ti(NMe2)3{NH2B(C6F5)3}].

Cited by 18 publications

References 29 publications

Synthesis and Structure of Amido‐ and Imido(pentafluorophenyl)borane Zirconocene and Hafnocene Complexes: NH and BH Activation

Synthesis and Structure of Amido‐ and Imido(pentafluorophenyl)borane Zirconocene and Hafnocene Complexes: NH and BH Activation

The Synthesis, Structure and Reactivity of B(C₆F₅)₃‐Stabilised Amide (MNH₂) Complexes of the Group 4 Metals

Structural Importance of Secondary Interactions in Molecules: Origin of Unconventional Conformations of Phosphine-Borane Adducts

Contact Info

Product

Resources

About

New titanium and zirconium complexes with M–NH2bonds formed by facile deprotonation of H3N·B(C6F5)3

Abstract: Facile deprotonation of H3N.B(C6F5)3 with [M(NMe2)4](M = Zr or Ti) yields the novel amidoborate complexes [Zr(NMe2)3{NH2B(C6F5)3}(HNMe2)] and [Ti(NMe2)3{NH2B(C6F5)3}].

Cited by 18 publications

References 29 publications

Synthesis and Structure of Amido‐ and Imido(pentafluorophenyl)borane Zirconocene and Hafnocene Complexes: NH and BH Activation

Synthesis and Structure of Amido‐ and Imido(pentafluorophenyl)borane Zirconocene and Hafnocene Complexes: NH and BH Activation

The Synthesis, Structure and Reactivity of B(C6F5)3‐Stabilised Amide (MNH2) Complexes of the Group 4 Metals

Structural Importance of Secondary Interactions in Molecules: Origin of Unconventional Conformations of Phosphine-Borane Adducts

Contact Info

Product

Resources

About

New titanium and zirconium complexes with M–NH₂bonds formed by facile deprotonation of H₃N·B(C₆F₅)₃

The Synthesis, Structure and Reactivity of B(C₆F₅)₃‐Stabilised Amide (MNH₂) Complexes of the Group 4 Metals