Bis(organoimido)-complexes of tungsten(<scp>IV</scp>): the crystal and molecular structures of tetrachlorobis(t-butylamine)bis(t-butylimido)bis(µ-p-tolylimido)-ditungsten(<scp>VI</scp>) and tetrachlorobis(µ-phenylimido)-bis(t-butylamine) bis(t-butylimido)ditungsten(<scp>VI</scp>)

Ashcroft, Barry R.; Nielson, Alastair J.; Bradley, D. C.; Errington, R. John; Hursthouse, Michael B.; Short, Richard L.

doi:10.1039/dt9870002059

Cited by 19 publications

(8 citation statements)

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“…1.749(2) W( 5)-N( 13) 2.219(2) W( 5)-Cl (10) 2.5897(6) W( 5)-Cl( 10)#1 2.7986(6) Cl( 10)-W( 5)#1 2.7986(6) N( 13)-C( 61)…”

Section: S14unclassified

“…8 This compound has also been prepared in 30% yield in a reaction between WO 2 Cl 2 (DME) and t-BuNH(TMS) in heptane or dimethoxyethane. 9 On the basis of IR studies and by analogy with {W(N-t-Bu)(-NPh)(t-BuNH 2 )Cl 2 } 2 and {W(N-t-Bu)(-Ntolyl)(t-BuNH 2 )Cl 2 } 2 , 10 W(N-t-Bu) 2 Cl 2 (t-BuNH 2 ) was proposed to be a dimer that contains bridging t-butylimido groups. We have confirmed that W(N-t-Bu) 2 (t-BuNH 2 )Cl 2 can be prepared conveniently on a 15 g scale as described by Nielson, but have found through an X-ray structural study that it contains bridging chlorides, not bridging imido groups, as has been assumed in the literature.…”

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confidence: 99%

“…Although a cursory exploration has not looked promising, we have found that the addition of one equivalent of 2,2'bipyridine to W(NAr) 2 (CH 2 CMe 2 Ph) 2 (Ar = 2,6-Me 2 C 6 H 3 , 2,6i-Pr 2 C 6 H 3 , 2,6-Cl 2 C 6 H 3 , or 2-i-PrC 6 H 4 ) complexes followed by two equivalents of HCl in diethyl ether led to formation of W(NAr)(CHCMe 2 Ph)Cl 2 (bipy) complexes 9a-12a (equation 3). Compounds 9a-12a are essentially insoluble and therefore isolated readily in good yields and high purity simply through 1)-N(2) = 100.62 (10), N(1)-W(1)-O(1) = 125. 10(12).…”

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Syntheses of Tungsten tert-Butylimido and Adamantylimido Alkylidene Complexes Employing Pyridinium Chloride As the Acid

et al. 2012

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Routes to new tungsten alkylidene complexes that contain t-butylimido or adamantylimido ligands have been devised that begin with a reaction between WCl6 and four equivalents of HNR(TMS) to give [W(NR)2Cl(-Cl)(RNH2)]2 (R = t-Bu or 1-adamantyl). Alkylation leads to W(NR)2(CH2R')2 (R' = t-Bu or CMe2Ph) which upon treatment with pyridinium chloride yields W(NR)(CHR')Cl2py2 complexes, from which W(NR)(CHR')(Pyrrolide)2 and two W(NR)(CHR')(Pyrrolide)(OAr) complexes (OAr = hexamethyl-or hexaisopropylterphenoxide) have been prepared. Science Foundation (CHE-1111133 to R.R.S.) for financial support. The X-ray diffractometer was purchased with the help of funding from the National Science Foundation (NSF) under Grant Number CHE-0946721. We thank Professor Kit Cummins for the suggestion that hydrogen bonding is present in 1a.Supporting Information Available. Experimental details for the synthesis of all compounds and details of the X-ray structural studies. Supporting Information is available free of charge via the Internet at http://pubs.acs.org. S2 Experimental SectionGeneral. All air and moisture sensitive materials were manipulated under a nitrogen atmosphere in a Vacuum Atmospheres glovebox or on a dual-manifold Schlenk line. All glassware, including NMR tubes, was oven-dried prior to use. Diethyl ether, pentane, toluene, dichloromethane, 1,2-dimethoxyethane, and benzene were degassed and passed through activated alumina columns and stored over 4 Å Linde-type molecular sieves prior to use. Deuterated solvents were dried over 4 Å Linde-type molecular sieves prior to use. 1 H and 13 C NMR spectra were acquired at room temperature using Varian 300MHz or 500MHz spectrometers. Chemical shifts for 1 H and 13 C spectra are reported as parts per million relative to tetramethylsilane and referenced to the residual 1 H/ 13 C resonances of the deuterated solvent ( 1 H () : benzene 7.16, chloroform 7.26, methylene chloride 5.32; 13 C () : benzene 128.06, chloroform 77.16, methylene chloride 53.84). N-t-butyltrimethylsilylamine was either prepared from TMSCl and t-BuNHLi in ether or purchased from Sigma-Aldrich. The synthesis of N-trimethylsilyl(1-adamantyl)amine has been reported previously; i our preparation employed the n-butyllithium and chlorotrimethylsilane. Pyridinium chloride was purchased from Sigma-Aldrich or Alfa Aesar and sublimed before use. Ethereal solutions of HCl were prepared by bubbling HCl gas into diethyl ether; these solutions were titrated before use. Neopentyl Grignard ii , HMTOH iii , HIPTOH iv , and ZnCl 2 (dioxane) v were prepared according to literature procedures. All other reagents were used as received.[W(N-t-Bu) 2 Cl(μ-Cl)(t-BuNH 2 )] 2 (1a).The following procedure was adapted from a recent publication. vi A solution of N-t-butyltrimethylsilylamine (25 g, 172 mmol) in 30 mL toluene was added slowly over a period of 50 min to WCl 6 (15.2 g, 38.33 mmol) in 150 mL of toluene. The reaction mixture was stirred for 24 h at room temperature. The dark green mixture was filtered through a pad of Celite, a...

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“…1.749(2) W( 5)-N( 13) 2.219(2) W( 5)-Cl (10) 2.5897(6) W( 5)-Cl( 10)#1 2.7986(6) Cl( 10)-W( 5)#1 2.7986(6) N( 13)-C( 61)…”

Section: S14unclassified

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confidence: 99%

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confidence: 99%

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Syntheses of Tungsten tert-Butylimido and Adamantylimido Alkylidene Complexes Employing Pyridinium Chloride As the Acid

et al. 2012

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“…This compound proved a very attractive starting point for many studies by others in the field, as evidenced by over 100 citations of its report to date (February 2019). Don went on to further elaborate the diversity of metal imido chemistry with co-workers, including John Errington, Alastair Nielson and John Runnacles, including formation of dimeric compounds with bridging arylimido groups as in the α-H exchange reaction shown in scheme 3, equation (2) (15).…”

Section: Appointment To Chair Of Inorganic Chemistry Queen Mary College London 1965mentioning

confidence: 99%

“…However, Don wanted to probe the electronic properties further and the degree of nuclear shielding around the imido nitrogen in the different coordination modes could be revealed by 14 N and 15 N NMR. In an excellent study in collaboration with Ray Richards and Joan Mason from the Nitrogen Fixation unit at the University of Sussex, 14 N and 15 N NMR data for 37 metal imido compounds were recorded and elegantly used to elucidate periodic trends in nitrogen shielding against type of metal, the oxidation state and the charge of the complex, and nature and relative geometry of ancillary ligands. They found that there was surprisingly little de-shielding at nitrogen as the imido M-N-R unit went from linear to bent modes owing to the relatively high energy of the lowest unoccupied molecular orbitals π*(MN) and σ*(MN).…”

Section: Appointment To Chair Of Inorganic Chemistry Queen Mary College London 1965mentioning

confidence: 99%

Donald Charlton Bradley. 7 November 1924—20 December 2014

Sullivan

Thomas

2019

Biogr. Mems Fell. R. Soc.

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Don Bradley was a twentieth-century pioneer of inorganic chemistry. He opened up the field of metal alkoxides and defined the parameters controlling the aggregative and volatility properties of this class of compounds that later dictated their use as precursors for fabrication of metal oxide thin films. His legacy also included seminal contributions to our knowledge of structure and bonding in the compound classes of metal amides and metal imides. He made highly innovative contributions in the field of metal organic chemical vapour deposition (MOCVD) fabrication of III/V semiconductor thin films, both through synthesis of single source precursors and through synthesis of molecular vehicles for safe storage and delivery of pyrophoric precursors. A modest, witty and gentle man of great intellectual depth and generosity, he nurtured and encouraged the fledgling talent of his students and co-workers and enthusiastically incorporated new developments in terms of experimental and theoretical tools to provide ever deeper understanding. He was relentless in giving his time and effort to support his college, Queen Mary, and the University of London as well as scientific organizations such as the Royal Society, Royal Institution and Royal Society of Chemistry, performing a range of society- or divisional-level official roles at various times, and he even made time for board of governor roles in schools. Don was held in the highest of esteem by his friends and family, students, colleagues and fellow scientists from across the world.

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