Reactivity of B(C₆F₅)₃ with Simple Early Transition Metal Alkoxides: Alkoxide-Aryl Exchange, THF Ring-Opening, or Acetonitrile CC Coupling

Abstract

Treatment of the titanium(IV) and vanadium(IV) alkoxide complexes M(OPr i )4 [M = Ti, V] with B(C6F5)3 results in alkoxide−aryl exchange and formation of the organometallic dimer complexes [M(OPr i )2(μ-OPr i )(C6F5)]2 (M = Ti (1), V (2)). In comparison, the reaction between B(C6F5)3 and Zr(OBu t )4 in pentane, followed by recrystallization in acetonitrile−THF solutions, affords the unexpected trimeric zirconium salt [Zr3(OBu t )6(μ2-OBu t )3(μ3-OBu t )(μ3-OCH2CH2CH2CH3)][B(C6F5)4] (3), which proceeds through a redox reaction involving the borane and the THF solvent. In the presence of CH3CN, a tetranuclear complex formulated as [Zr2(OBu t )5(μ-OBu t )2(μ-N,N′-N(H)C(CH3)C(H)CN)]2 (5) is obtained, which results from a C,C coupling reaction between two acetonitrile molecules. When Zr(OBu t )4 is treated with (HO)B(C6F5)2, a dimer complex formulated as [Zr(OBu t )2{μ-O-OB(OBu t )(C6F5)2-κ2-O,O}]2 (7) is formed that contains an unusual ligand bonding mode. The molecular structures of 1, 2, 3, 5, and 7 as well as the adduct B(C6F5)3·THF (4) and [Zr(OBu t )3(μ-OBu t )]2(μ-NCCH3) (6) have been determined by X-ray diffraction.

Metal‐Free Hydrogenation Catalyzed by an Air‐Stable Borane: Use of Solvent as a Frustrated Lewis Base

“…The reversibility of the binding is clear from variable‐temperature (VT) NMR analysis of THF solutions of 1 b ; below 0 °C the 11 B NMR shift remains constant at δ=3.8 ppm, consistent with the four‐coordinate 1 b ⋅THF adduct (c.f. δ=3.3 ppm for 1 a ⋅THF in CD 2 Cl 2 ) 15. Upon warming, however, the resonance signal moves progressively downfield, reaching δ=23.9 ppm at 60 °C, indicative of a shift in the equilibrium towards free, uncoordinated 1 b (c.f.…”

Structural and Energetic Features of Group 13 Element Trispentafluorophenyl Complexes with Diethyl Ether

“…Reported in this work crystal parameters of 1 and 3 are in good agreement with previous data. [16,34,35] The X-ray crystallographic analysis of 1-4 reveals a distorted tetrahedral geometry on the central atom ( Figure 1). The sum of C-E-C valence angles increases in order B < Al < Ga < In from 336°to 349°, indicating a lesser pyramidalization of heavier group 13 elements.…”

“…In light with the fact that molecular hydrogen activation can be achieved using B(C 6 F 5 ) 3 -Et 2 O FLP, [33] diethyl ether was chosen as a reference Lewis base for this study. The solid-state structures of boron B(C 6 F 5 ) 3 •Et 2 O [34,35] and gallium Ga(C 6 F 5 ) 3 • Et 2 O [16] derivatives are known. In this work we report the synthesis, crystal structures and thermal stability of complexes of group 13 element trispentafluorophenyl derivatives E(C 6 F 5 ) 3 (E = B, Al, Ga, In) with diethyl ether.…”

A non-oxo methanolate-bridged divanadium(IV) complex with tris(2-sulfanidylphenyl)phosphane ligands: synthesis, structural characterization and magnetic investigation

“…In a continuation of this research, a ISSN 2053ISSN -2296 # 2016 International Union of Crystallography non-oxo divanadium(IV) complex with methanolate bridges has been synthesized and characterized, namely tetraphenylphosphonium tri--methanolato-bis({tris[2-sulfanidyl-3-(trimethylsilyl)phenyl]phosphane}vanadium(IV)) methanol disolvate, (Ph 4 P) [V 2 (-OMe) 3 (PS3 00 ) 2 ]Á2MeOH, (I). Several examples of divanadium(IV) and divanadium(V) complexes with bis-(alkoxide) bridges have been reported (Westrup et al, 2011;Scales et al, 2010;Romero-Fernandez et al, 2010;Nishina et al, 2010;Arbaoui et al, 2009;Zhang & Nomura, 2008;Lorber et al, 2008;Homden et al, 2008;Nunes et al, 2005;Preuss, Vogel et al, 2001;Lutz et al, 1999;Castellano et al, 1999;Kempe & Spannenberg, 1997;Devore et al, 1987), but, to the best of our knowledge, a tris(alkoxide) divanadium core structure is unprecedented in the literature.…”