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1.
Simon J. Bonyhady Cameron Jones Prof. Sharanappa Nembenna Dr. Andreas Stasch Dr. Alison J. Edwards Dr. Garry J. McIntyre Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(3):938-955
The preparation and characterization of a series of magnesium(II) iodide complexes incorporating β‐diketiminate ligands of varying steric bulk and denticity, namely, [(ArNCMe)2CH]? (Ar=phenyl, (PhNacnac), mesityl (MesNacnac), or 2,6‐diisopropylphenyl (Dipp, DippNacnac)), [(DippNCtBu)2CH]? (tBuNacnac), and [(DippNCMe)(Me2NCH2CH2NCMe)CH]? (DmedaNacnac) are reported. The complexes [(PhNacnac)MgI(OEt2)], [(MesNacnac)MgI(OEt2)], [(DmedaNacnac)MgI(OEt2)], [(MesNacnac)MgI(thf)], [(DippNacnac)MgI(thf)], [(tBuNacnac)MgI], and [(tBuNacnac)MgI(DMAP)] (DMAP=4‐dimethylaminopyridine) were shown to be monomeric by X‐ray crystallography. In addition, the related β‐diketiminato beryllium and calcium iodide complexes, [(MesNacnac)BeI] and [{(DippNacnac)CaI(OEt2)}2] were prepared and crystallographically characterized. The reductions of all metal(II) iodide complexes by using various reagents were attempted. In two cases these reactions led to the magnesium(I) dimers, [(MesNacnac)MgMg(MesNacnac)] and [(tBuNacnac)MgMg(tBuNacnac)]. The reduction of a 1:1 mixture of [(DippNacnac)MgI(OEt2)] and [(MesNacnac)MgI(OEt2)] with potassium gave a low yield of the crystallographically characterized complex [(DippNacnac)Mg(μ‐H)(μ‐I)Mg(MesNacnac)]. All attempts to form beryllium(I) or calcium(I) dimers by reductions of [(MesNacnac)BeI], [{(DippNacnac)CaI(OEt2)}2], or [{(tBuNacnac)CaI(thf)}2] have so far been unsuccessful. The further reactivity of the magnesium(I) complexes [(MesNacnac)MgMg(MesNacnac)] and [(tBuNacnac)MgMg(tBuNacnac)] towards a variety of Lewis bases and unsaturated organic substrates was explored. These studies led to the complexes [(MesNacnac)Mg(L)Mg(L)(MesNacnac)] (L=THF or DMAP), [(MesNacnac)Mg(μ‐AdN6Ad)Mg(MesNacnac)] (Ad=1‐adamantyl), [(tBuNacnac)Mg(μ‐AdN6Ad)Mg(tBuNacnac)], and [(MesNacnac)Mg(μ‐tBu2N2C2O2)Mg(MesNacnac)] and revealed that, in general, the reactivity of the magnesium(I) dimers is inversely proportional to their steric bulk. The preparation and characterization of [(tBuNacnac)Mg(μ‐H)2Mg(tBuNacnac)] has shown the compound to have different structural and physical properties to [(tBuNacnac)MgMg(tBuNacnac)]. Treatment of the former with DMAP has given [(tBuNacnac)Mg(H)(DMAP)], the X‐ray crystal structure of which disclosed it to be the first structurally authenticated terminal magnesium hydride complex. Although attempts to prepare [(MesNacnac)Mg(μ‐H)2Mg(MesNacnac)] were not successful, a neutron diffraction study of the corresponding magnesium(I) complex, [(MesNacnac)MgMg(MesNacnac)] confirmed that the compound is devoid of hydride ligands. 相似文献
2.
Dr. K. Yuvaraj Iskander Douair Prof. Laurent Maron Prof. Cameron Jones 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(64):14665-14670
Reactions of a series of magnesium(I) compounds with ethylene, in the presence of an N-heterocyclic carbene (NHC), have been explored. Treating [{(MesNacnac)Mg}2] (MesNacnac=[HC(MeCNMes)2]−, Mes=mesityl) with an excess of ethylene in the presence of two equivalents of :C{(MeNCMe)2} (TMC) leads to the formal reductive coupling of ethylene, and formation of the 1,2-dimagnesiobutane complex, [{(MesNacnac)(TMC)Mg}2(μ-C4H8)]. In contrast, when the reaction is repeated in the presence of three equivalents of TMC, a mixture of the β-diketiminato magnesium ethyl, [(MesNacnac)(TMC)MgEt], and the NHC coordinated magnesium diamide, [(MesNacnac-H)Mg(TMC)2], results. Four related products, [(ArNacnac)(TMC)MgEt] (Ar=2,6-dimethylphenyl (Xyl) or 2,6-diisopropylphenyl (Dip)) and [(ArNacnac-H)Mg(TMC)2] (Ar=Xyl or Dip), were similarly synthesised and crystallographically characterized. Computational studies have been employed to investigate the mechanisms of the two observed reaction types, which appear dependent on the substitution pattern of the magnesium(I) compound, and the stoichiometric equivalents of TMC used in the reactions. 相似文献
3.
Cameron Jones David P. Mills Richard P. Rose Andreas Stasch William D. Woodul 《Journal of organometallic chemistry》2010,695(22):2410-2417
Reactions of the anionic gallium(I) heterocycle salt, [K(tmeda)][Ga(DAB)] (DAB = {N(Dip)C(H)}2; Dip = C6H3Pri2-2,6), with a series of groups 6-9 and 11 metal halide complexes have given rise to the metal gallyl complexes, [CpCr(IMes){Ga(DAB)}] (IMes = :C{(Mes)NC(H)}2; Mes = mesityl), [M(tmeda){Ga(DAB)}2] (M = Mn, Fe or Co) and [Cu(dppe){Ga(DAB)}] (dppe = 1,2-bis(diphenylphosphino)ethane). The majority of the complexes have been crystallographically characterized. The reactivity of the previously reported copper(I) gallyl complex, [(IPr)Cu{Ga(DAB)}] (IPr = :C{(Dip)NC(H)}2), towards a variety of unsaturated substrates has been explored. Three crystallographically characterized complexes have arisen from this phase of the study, viz. [(IPr)CuCCPh], [(IPr)Cu{Ga(DAB)}(CNBut)] and [(IPr)Cu{κ1-OC(O)C(CNHDip)(NHDip)}]. The results of these investigations show that the reactivity of [(IPr)Cu{Ga(DAB)}] is significantly different to that of related copper boryl complexes. 相似文献
4.
K. Yuvaraj Iskander Douair Dafydd D. L. Jones Laurent Maron Cameron Jones 《Chemical science》2020,11(13):3516
An extremely bulky, symmetrical three-coordinate magnesium(i) complex, [{(TCHPNacnac)Mg}2] (TCHPNacnac = [{(TCHP)NCMe}2CH]−, TCHP = 2,4,6-tricyclohexylphenyl) has been prepared and shown to have an extremely long Mg–Mg bond (3.021(1) Å) for such a complex. It was shown not to react with either DMAP (4-dimethylaminopyridine) or CO. Three unsymmetrical 1 : 1 DMAP adducts of less bulky Mg–Mg bonded species have been prepared, viz. [(ArNacnac)Mg–Mg(DMAP)(ArNacnac)] (ArNacnac = [(ArNCMe)2CH]− Ar = 2,6-xylyl (Xyl), mesityl (Mes) or 2,6-diethylphenyl (Dep)), and their reactivity toward CO explored. Like the previously reported bulkier complex, [(DipNacnac)Mg–Mg(DMAP)(DipNacnac)] (Dip = 2,6-diisopropylphenyl), [(DepNacnac)Mg–Mg(DMAP)(DepNacnac)] reductively trimerises CO to give a rare example of a deltate complex, [{(DepNacnac)Mg(μ-C3O3)Mg(DMAP)(DepNacnac)}2]. In contrast, the two smaller adduct complexes react with only two CO molecules, ultimately giving unusual ethenediolate complexes [{(ArNacnac)Mg{μ-OC(H) C(DMAP−H)O}Mg(ArNacnac)}2] (Ar = Xyl or Mes). DFT calculations show the latter reactions to proceed via reductive dimerizations of CO, and subsequent intramolecular C–H activation of Mg-ligated DMAP by “zig–zag” [C2O2]2− fragments of reaction intermediates. Calculations also suggest that magnesium deltate complexes are kinetic products in these reactions, while the magnesium ethenediolates are thermodynamic products. This study shows that subtle changes to the bulk of the reacting 1 : 1 DMAP–magnesium(i) adduct complexes can lead to fine steric control over the products arising from their CO reductive oligomerisations. Furthermore, it is found that the more activated nature of the adduct complexes, relative to their symmetrical, three-coordinate counterparts, [{(ArNacnac)Mg}2], likely derives more from the polarisation of the Mg–Mg bonds of the former, than the elongated nature of those bonds.Subtle changes to the bulk of 1 : 1 adducts of DMAP with magnesium(i) complexes leads to steric control over the products arising from their reductive oligomerisations of carbon monoxide. 相似文献
5.
Albert Paparo Cory D. Smith Cameron Jones 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(33):11581-11585
Additions of beryllium–halide bonds in the simple beryllium dihalide adducts, [BeX2(tmeda)] (X=Br or I, tmeda=N,N,N′,N′‐tetramethylethylenediamine), across the metal center of a neutral aluminum(I) heterocycle, [:Al(DipNacnac)] (DipNacnac=[(DipNCMe)2CH]?, Dip=2,6‐diisopropylphenyl), have yielded the first examples of compounds with beryllium–aluminum bonds, [(DipNacnac)(X)Al‐Be(X)(tmeda)]. For sake of comparison, isostructural Mg–Al and Zn–Al analogues of these complexes, viz. [(DipNacnac)(X)Al‐M(X)(tmeda)] (M=Mg or Zn, X=I or Br) have been prepared and structurally characterized. DFT calculations reveal all compounds to have high s‐character metal–metal bonds, the polarity of which is consistent with the electronegativities of the metals involved. Preliminary reactivity studies of [(DipNacnac)(Br)Al‐Be(Br)(tmeda)] are reported. 相似文献
6.
Two extremely bulky boryl/silyl-substituted amide ligands, –N{B(DipNCH)2}(SiR3) (R = Me TBoL, R = Ph PhBoL; Dip = 2,6-diisopropylphenyl) were used in the preparation of the group 12 metal halide complexes, PhBoLZnBr, {TBoLCd(μ-I)}2, TBoLHgI, and PhBoLHgI. The reduction of these, and two previously reported compounds, PhBoLZnBr(THF) and {PhBoLCd(μ-I)}2, using a magnesium(I) compound, {(MesNacnac)Mg}2 (MesNacnac = [(MesNCMe)2CH]–, Mes = mesityl), were carried out, leading to mixed results. In several cases these reactions led to decomposition, and deposition of the group 12 metal. However, in two instances the homobimetallic metal(I) complexes, TBoLM–MTBoL (M = Zn or Hg), were isolated and crystallographically characterized. The reduction of {PhBoLCd(μ-I)}2 afforded the known cadmium(I) complex, PhBoLCd–CdPhBoL, but also gave a very low yield of the thermally unstable complex, PhBoLCd–Mg(THF)(MesNacnac). The X-ray crystal structure of this compound reveals it to contain the first example of a Cd–Mg bond in a molecular compound. 相似文献
7.
A Mixed‐Valence Tri‐Zinc Complex, [LZnZnZnL] (L=Bulky Amide), Bearing a Linear Chain of Two‐Coordinate Zinc Atoms
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Jamie Hicks Emma J. Underhill Dr. Christos E. Kefalidis Prof. Laurent Maron Prof. Cameron Jones 《Angewandte Chemie (International ed. in English)》2015,54(34):10000-10004
Reduction of a variety of extremely bulky amido Group 12 metal halide complexes, [LMX(THF)0,1] (L=amide; M=Zn, Cd, or Hg; X=halide) with a magnesium(I) dimer gave a homologous series of two‐coordinate metal(I) dimers, [L′MML′] (L′=N(Ar?)(SiMe3), Ar?=C6H2{C(H)Ph2}2Pri‐2,6,4); and the formally zinc(0) complex, [L*ZnMg(MesNacnac)] (L*=N(Ar*)(SiPri3); Ar*=C6H2{C(H)Ph2}2Me‐2,6,4; MesNacnac=[(MesNCMe)2CH]?, Mes=mesityl), which contains the first unsupported Zn? Mg bond. Two equivalents of [L*ZnMg(MesNacnac)] react with ZnBr2 or ZnBr2(tmeda) to give the mixed valence, two‐coordinate, linear tri‐zinc complex, [L*ZnIZn0ZnIL*], and the first zinc(I) halide complex, [L*ZnZnBr(tmeda)], respectively. The analogues [L*ZnMZnL*] (M=Cd or Hg), were also prepared, the Cd species contains the first Zn? Cd bond in a molecular compound. Metal–metal bonding was studied by DFT calculations. 相似文献
8.
Magnesium(I) Dimers Bearing Tripodal Diimine–Enolate Ligands: Proficient Reagents for the Controlled Reductive Activation of CO2 and SO2
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Aaron J. Boutland Dr. Indrek Pernik Dr. Andreas Stasch Prof. Cameron Jones 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(44):15749-15758
The first examples of magnesium(I) dimers bearing tripodal ligands, [(Mg{κ3‐N,N′,O‐(ArNCMe)2(OCCPh2)CH})2] [Ar=2,6‐iPr2C6H3 (Dip) 7 , 2,6‐Et2C6H3 (Dep) 8 , or mesityl (Mes) 9 ] have been prepared by post‐synthetic modification of the β‐diketiminato ligands of previously reported magnesium(I) systems, using diphenylketene, O?C?CPh2. In contrast, related reactions between β‐diketiminato magnesium(I) dimers and the isoelectronic ketenimine, MesN?C?CPh2, resulted in reductive insertion of the substrate into the Mg?Mg bond of the magnesium(I) reactant, and formation of [{(Nacnac)Mg}2{μ‐κ2‐N,C‐(Mes)NCCPh2}] (Nacnac=[(ArNCMe)2CH]?; Ar=Dep 10 or Mes 11 ). Reactions of the four‐coordinate magnesium(I) dimer 8 with excess CO2 are readily controlled, and cleanly give carbonate [(LMg)2(μ‐κ2:κ2‐CO3)] 12 (L=[κ3‐N,N′,O‐(DepNCMe)2(OCCPh2)CH]?; thermodynamic product), or oxalate [(LMg)2(μ‐κ2:κ2‐C2O4)] 13 (kinetic product), depending on the reaction temperature. Compound 12 and CO are formed by reductive disproportionation of CO2, whereas 13 results from reductive coupling of two molecules of the gas. Treatment of 8 with an excess of N2O cleanly gives the μ‐oxo complex [(LMg)2(μ‐O)] 14 , which reacts facilely with CO2 to give 12 . This result presents the possibility that 14 is an intermediate in the formation of 12 from the reaction of 8 and CO2. In contrast to its reactions with CO2, 8 reacts with SO2 over a wide temperature range to give only one product; the first example of a magnesium dithionite complex, [(LMg)2(μ‐κ2:κ2‐S2O4)] 16 , which is formed by reductive coupling of two molecules of SO2, and is closely related to f‐block metal dithionite complexes derived from similar SO2 reductive coupling processes. On the whole, this study strengthens previously proposed analogies between the reactivities of magnesium(I) systems and low‐valent f‐block metal complexes, especially with respect to small molecule activations. 相似文献
9.
A Systematic Study of Structure and E−H Bond Activation Chemistry by Sterically Encumbered Germylene Complexes
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Matthew Usher Dr. Andrey V. Protchenko Dr. Arnab Rit Dr. Jesús Campos Dr. Eugene L. Kolychev Dr. Rémi Tirfoin Prof. Dr. Simon Aldridge 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(33):11685-11698
A series of new germylene compounds has been synthesized offering systematic variation in the σ‐ and π‐capabilities of the α‐substituent and differing levels of reactivity towards E?H bond activation (E=H, B, C, N, Si, Ge). Chloride metathesis utilizing [(terphenyl)GeCl] proves to be an effective synthetic route to complexes of the type [(terphenyl)Ge(ERn)] ( 1 – 6 : ERn=NHDipp, CH(SiMe3)2, P(SiMe3)2, Si(SiMe3)3 or B(NDippCH)2; terphenyl=C6H3Mes2‐2,6=ArMes or C6H3Dipp2‐2,6=ArDipp; Dipp=C6H3iPr2‐2,6, Mes=C6H2Me3‐2,4,6), while the related complex [{(Me3Si)2N}Ge{B(NDippCH)2}] ( 8 ) can be accessed by an amide/boryl exchange route. Metrical parameters have been probed by X‐ray crystallography, and are consistent with widening angles at the metal centre as more bulky and/or more electropositive substituents are employed. Thus, the widest germylene units (θ>110°) are found to be associated with strongly σ‐donating boryl or silyl ancillary donors. HOMO–LUMO gaps for the new germylene complexes have been appraised by DFT calculations. The aryl(boryl)‐germylene system [ArMesGe{B(NDippCH)2}] ( 6 ‐Mes), which features a wide C‐Ge‐B angle (110.4(1)°) and (albeit relatively weak) ancillary π‐acceptor capabilities, has the smallest HOMO–LUMO gap (119 kJ mol?1). These features result in 6 ‐Mes being remarkably reactive, undergoing facile intramolecular C?H activation involving one of the mesityl ortho‐methyl groups. The related aryl(silyl)‐germylene system, [ArMesGe{Si(SiMe3)3}] ( 5 ‐Mes) has a marginally wider HOMO–LUMO gap (134 kJ mol?1), rendering it less labile towards decomposition, yet reactive enough to oxidatively cleave H2 and NH3 to give the corresponding dihydride and (amido)hydride. Mixed aryl/alkyl, aryl/amido and aryl/phosphido complexes are unreactive, but amido/boryl complex 8 is competent for the activation of E?H bonds (E=H, B, Si) to give hydrido, boryl and silyl products. The results of these reactivity studies imply that the use of the very strongly σ‐donating boryl or silyl substituents is an effective strategy for rendering metallylene complexes competent for E?H bond activation. 相似文献
10.
Jeremy C. Mullins Dr. K. Yuvaraj Yixiao Jiang Dr. Gerard P. Van Trieste III Dr. Asim Maity Prof. David C. Powers Prof. Cameron Jones 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(65):e202202103
UV irradiation of solutions of a guanidinate coordinated dimagnesium(I) compound, [{(Priso)Mg}2] 3 (Priso=[(DipN)2CNPri2]−, Dip=2,6-diisopropylphenyl), in either benzene, toluene, the three isomers of xylene, or mesitylene, leads to facile activation of an aromatic C−H bond of the solvent in all cases, and formation of aryl/hydride bridged magnesium(II) products, [{(Priso)Mg}2(μ-H)(μ-Ar)] 4 – 9 . In contrast to similar reactions reported for β-diketiminate coordinated counterparts of 3 , these C−H activations proceed with little regioselectivity, though they are considerably faster. Reaction of 3 with an excess of the pyridine, p-NC5H4But (pyBut), gave [(Priso)Mg(pyButH)(pyBut)2] 10 , presumably via reduction of the pyridine to yield a radical intermediate, [(Priso)Mg(pyBut⋅)(pyBut)2] 11 , which then abstracts a proton from the reaction solvent or a reactant. DFT calculations suggest two possible pathways to the observed arene C−H activations. One of these involves photochemical cleavage of the Mg−Mg bond of 3 , generating magnesium(I) doublet radicals, (Priso)Mg⋅. These then doubly reduce the arene substrate to give “Birch-like” products, which subsequently rearrange via C−H activation of the arene. Circumstantial evidence for the photochemical generation of transient magnesium radical species includes the fact that irradiation of a cyclohexane solution of 3 leads to an intramolecular aliphatic C−H activation process and formation of an alkyl-bridged magnesium(II) species, [{Mg(μ-Priso−H)}2] 12 . Furthermore, irradiation of a 1 : 1 mixture of 3 and the β-diketiminato dimagnesium(I) compound, [{(DipNacnac)Mg}2] (DipNacnac=[HC(MeCNDip)2]−), effects a “scrambling” reaction, and the near quantitative formation of an unsymmetrical dimagnesium(I) compound, [(Priso)Mg−Mg(DipNacnac)] 13 . Finally, the EPR spectrum (77 K) of a glassed solution of UV irradiated 3 is dominated by a broad featureless signal, indicating the presence of a doublet radical species. 相似文献
11.
Surprisingly Different Reaction Behavior of Alkali and Alkaline Earth Metal Bis(trimethylsilyl)amides toward Bulky N‐(2‐Pyridylethyl)‐N′‐(2,6‐diisopropylphenyl)pivalamidine
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Diana Kalden Ansgar Oberheide Dr. Claas Loh Dr. Helmar Görls Dr. Sven Krieck Prof. Dr. Matthias Westerhausen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(31):10944-10959
N‐(2,6‐Diisopropylphenyl)‐N′‐(2‐pyridylethyl)pivalamidine (Dipp‐N=C(tBu)‐N(H)‐C2H4‐Py) ( 1 ), reacts with metalation reagents of lithium, magnesium, calcium, and strontium to give the corresponding pivalamidinates [(tmeda)Li{Dipp‐N=C(tBu)‐N‐C2H4‐Py}] ( 6 ), [Mg{Dipp‐N=C(tBu)‐N‐C2H4‐Py}2] ( 3 ), and heteroleptic [{(Me3Si)2N}Ae{Dipp‐N=C(tBu)‐N‐C2H4‐Py}], with Ae being Ca ( 2 a ) and Sr ( 2 b ). In contrast to this straightforward deprotonation of the amidine units, the reaction of 1 with the bis(trimethylsilyl)amides of sodium or potassium unexpectedly leads to a β‐metalation and an immediate deamidation reaction yielding [(thf)2Na{Dipp‐N=C(tBu)‐N(H)}] ( 4 a ) or [(thf)2K{Dipp‐N=C(tBu)‐N(H)}] ( 4 b ), respectively, as well as 2‐vinylpyridine in both cases. The lithium derivative shows a similar reaction behavior to the alkaline earth metal congeners, underlining the diagonal relationship in the periodic table. Protonation of 4 a or the metathesis reaction of 4 b with CaI2 in tetrahydrofuran yields N‐(2,6‐diisopropylphenyl)pivalamidine (Dipp‐N=C(tBu)‐NH2) ( 5 ), or [(thf)4Ca{Dipp‐N=C(tBu)‐N(H)}2] ( 7 ), respectively. The reaction of AN(SiMe3)2 (A=Na, K) with less bulky formamidine Dipp‐N=C(H)‐N(H)‐C2H4‐Py ( 8 ) leads to deprotonation of the amidine functionality, and [(thf)Na{Dipp‐N=C(H)‐N‐C2H4‐Py}]2 ( 9 a ) or [(thf)K{Dipp‐N=C(H)‐N‐C2H4‐Py}]2 ( 9 b ), respectively, are isolated as dinuclear complexes. From these experiments it is obvious, that β‐metalation/deamidation of N‐(2‐pyridylethyl)amidines requires bases with soft metal ions and also steric pressure. The isomeric forms of all compounds are verified by single‐crystal X‐ray structure analysis and are maintained in solution. 相似文献
12.
Maryam Tayebani Sandro Gambarotta Glenn P. A. Yap 《Angewandte Chemie (International ed. in English)》1998,37(21):3002-3005
A nitrogen center was abstracted from a pyrrolyl ring to form the dinuclear nitrido- and dienyl-bridged complex 1 during the reaction of [{(tmeda)NbIICl}2(μ-Cl)3Li(tmeda)] with the lithium salt of 2,5-dimethylpyrrole (tmeda=N,N,N′,N′-tetramethylethylenediamine). A second product from this reaction is the amido-carbene-hydride niobium complex 2 , which likewise forms under C−N bond cleavage. 相似文献
13.
Dr. Shenglai Yao M. Sc. Nils Lindenmaier Dr. Yun Xiong Prof. Dr. Shigeyoshi Inoue Dr. Tibor Szilvási Dipl.‐Chem. Mario Adelhardt Dr. Jörg Sutter Prof. Dr. Karsten Meyer Prof. Dr. Matthias Driess 《Angewandte Chemie (International ed. in English)》2015,54(4):1250-1254
The unusual reactivity of the newly synthesized β‐diketiminato cobalt(I) complexes, [(LDepCo)2] ( 2 a , LDep=CH[C(Me)N(2,6‐Et2C6H3)]2) and [LDippCo ? toluene] ( 2 b , LDipp=CH[CHN(2,6‐iPr2C6H3)]2), toward white phosphorus was investigated, affording the first cobalt(I) complexes [(LDepCo)2(μ2:η4,η4‐P4)] ( 3 a ) and [(LDippCo)2(μ2:η4,η4‐P4)] ( 3 b ) bearing the neutral cyclo‐P4 ligand with a rectangular‐planar structure. The redox chemistry of 3 a and 3 b was studied by cyclic voltammetry and their chemical reduction with one molar equivalent of potassium graphite led to the isolation of [(LDepCo)2(μ2:η4,η4‐P4)][K(dme)4] ( 4 a ) and [(LDippCo)2(μ2:η4,η4‐P4)][K(dme)4] ( 4 b ). Unexpectedly, the monoanionic Co2P4 core in 4 a and 4 b , respectively, contains the two‐electron‐reduced cyclo‐P42? ligand with a square‐planar structure and mixed‐valent cobalt(I,II) sites. The electronic structures of 3 a , 3 b , 4 a , and 4 b were elucidated by NMR and EPR spectroscopy as well as magnetic measurements and are in agreement with results of broken‐symmetry DFT calculations. 相似文献
14.
Samuel R. Lawrence Matthew de Vere-Tucker Alexandra M. Z. Slawin Andreas Stasch 《Molecules (Basel, Switzerland)》2021,26(23)
The reaction of [{(Arnacnac)Mg}2] (Arnacnac = HC{MeC(NAr)}2, Ar = 2,6-diisopropylphenyl, Dip, or 2,6-diethylphenyl, Dep) with 4-dimethylaminopyridine (DMAP) at elevated temperatures afforded the hexameric magnesium 4-pyridyl complex [{(Arnacnac)Mg(4-C5H4N)}6] via reductive cleavage of the DMAP C-N bond. The title compound contains a large s-block organometallic cyclohexane-like ring structure comprising tetrahedral (Arnacnac)Mg nodes and linked by linear 4-pyridyl bridging ligands, and the structure is compared with other ring systems. [(Dipnacnac)Mg(DMAP)(NMe2)] was structurally characterised as a by-product. 相似文献
15.
Sneha Mullassery K. Yuvaraj Deepak Dange Dafydd D. L. Jones Iker del Rosal Ross O. Piltz Alison J. Edwards Laurent Maron Cameron Jones 《Angewandte Chemie (International ed. in English)》2023,62(30):e202305582
Reduction of a range of amido- and aryloxy-aluminum dihydride complexes, e.g. [AlH2(NR3){N(SiMe3)2}] (NR3=NMe3 or N-methylpiperidine (NMP)), with β-diketiminato dimagnesium(I) reagents, [{(ArNacnac)Mg}2] (ArNacnac=[HC(MeCNAr)2]−, Ar=mesityl (Mes) or 2,6-xylyl (Xyl)), have afforded deep red mixed valence aluminum hydride cluster compounds, [Al6H8(NR3)2{Mg(ArNacnac)}4], which have an average Al oxidation state of +0.66, the lowest for any well-defined aluminum hydride compound. In the solid-state, the clusters are shown to have distorted octahedral Al6 cores, having zero-valent Al axial sites and mono-valent AlH2− equatorial units. Several novel by-products were isolated from the reactions that gave the clusters, including the Mg−Al bonded magnesio-aluminate complexes, [(ArNacnac)(Me3N)Mg−Al(μ-H)3[{Mg(ArNacnac)}2(μ-H)]]. Computational analyses of one aluminum hydride cluster revealed its Al6 core to be electronically delocalized, and to possess one unoccupied, and six occupied, skeletal molecular orbitals. 相似文献
16.
Dr. Anne‐Frédérique Pécharman Prof. Michael S. Hill Dr. Mary F. Mahon 《Angewandte Chemie (International ed. in English)》2018,57(33):10688-10691
Reactions of readily accessible magnesium‐centered pinacolatoboryl nucleophiles with [(Ph2B)2O] result in B?O bond activation of the diphenylborinic anhydride. Although [pinBBPh2] is apparently generated when the nucleophilic boron unit is derived in situ from a magnesium diboranate, it cannot be isolated owing to its onward derivatization by a further {Bpin}? equivalent. A reaction with a terminal magnesium boryl species similarly provides a boryloxide byproduct. In this case, however, the unsymmetrical B(sp2)?B(sp3) diborane may be intercepted as its DMAP adduct. 相似文献
17.
Platinum Oxoboryl Complexes as Substrates for the Formation of 1:1, 1:2, and 2:1 Lewis Acid–Base Adducts and 1,2‐Dipolar Additions
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Dr. Stefanie Bertsch Johannes Brand Prof. Dr. Holger Braunschweig Florian Hupp Krzysztof Radacki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(16):6278-6285
The oxoboryl complex trans‐[(Cy3P)2BrPt(B?O)] ( 2 ) reacts with the Group 13 Lewis acids EBr3 (E=Al, Ga, In) to form the 1:1 Lewis acid–base adducts trans‐[(Cy3P)2BrPt(B?OEBr3)] ( 6 – 8 ). This reactivity can be extended by using two equivalents of the respective Lewis acid EBr3 (E=Al, Ga) to form the 2:1 Lewis acid–base adducts trans‐[(Cy3P)2(Br3Al‐Br)Pt(B?OAlBr3)] ( 18 ) and trans‐[(Cy3P)2(Br3Ga‐Br)Pt(B?OGaBr3)] ( 15 ). Another reactivity pattern was demonstrated by coordinating two oxoboryl complexes 2 to InBr3, forming the 1:2 Lewis acid–base adduct trans‐[{(Cy3P)2BrPt(B?O)}2InBr3] ( 20 ). It was also possible to functionalize the B?O triple bond itself. Trimethylsilylisothiocyanate reacts with 2 in a 1,2‐dipolar addition to form the boryl complex trans‐[(Cy3P)2BrPt{B(NCS)(OSiMe3)}] ( 27 ). 相似文献
18.
Reinald Fischer Heiner Schmidt Fadi M. Younis Helmar Görls Regina Suxdorf Matthias Westerhausen 《无机化学与普通化学杂志》2020,646(4):207-214
The reaction of MCl4(thf)2 (M = Zr, Hf) with 1,4-dilitiobutane in diethyl ether at –25 °C or at 0 °C with a molar ratio of 1 : 3 yields the homoleptic “ate” complexes [(thf)4Li] [{(thf)Li}M(C4H8)3] 1 - Zr (M = Zr) and 1 - Hf (M = Hf). The crystalline compounds form ion lattices with solvent-separated [(thf)4Li]+ cations and [{(thf)Li}M(C4H8)3]– anions. The NMR spectra at –20 °C show magnetic equivalence of the M–CH2 and of the β-CH2 groups of the butane-1,4-diide ligands on the NMR time scale. Analogous reactions of MCl4(thf)2 with 1,4-dilithiobutane with a molar ratio of 1 : 2 proceed unclear. However, single crystals of [Li(thf)4] [HfCl5(thf)] ( 2 ) can be isolated with the hafnium atom in a distorted octahedral coordination sphere of five chloro and one thf ligand. NMR spectra allow to elucidate the time-dependent degradation of 1-Hf and 1-Zr in THF and toluene at 25 °C via THF cleavage. Addition of tmeda to a solution of 1-Zr allows the isolation of intermediately formed [{(tmeda)Li}2Zr(nBu)2(C4H8)2] ( 3 ). 相似文献
19.
Dr. Louis J. Morris Dr. Thayalan Rajeshkumar Prof. Dr. Laurent Maron Prof. Dr. Jun Okuda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(56):e202201480
In the presence of TMEDA (N,N,N’,N’-tetramethylethylenediamine), partially deaggregated zinc dihydride as hydrocarbon suspensions react with the gallium(I) compound [(BDI)Ga] ( I , BDI={HC(C(CH3)N(2,6-iPr2-C6H3))2}−) by formal oxidative addition of a Zn−H bond to the gallium(I) centre. Dissociation of the labile TMEDA ligand in the resulting complex [(BDI)Ga(H)−(H)Zn(tmeda)] ( 1 ) facilitates insertion of a second equiv. of I into the remaining Zn−H to form a thermally sensitive trinuclear species [{(BDI)Ga(H)}2Zn] ( 2 ). Compound 1 exchanges with polymeric zinc dideuteride [ZnD2]n in the presence of TMEDA, and with compounds I and 2 via sequential and reversible ligand dissociation and gallium(I) insertion. Spectroscopic and computational studies demonstrate the reversibility of oxidative addition of each Zn−H bond to the gallium(I) centres. 相似文献
20.
Self‐Assembly of Water‐Soluble Platinum(II)‐Based Metallacalixarenes and Tuning Their Conformational Interconversion via Synergistic Effects between Solvents and Anions
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《化学:亚洲杂志》2018,13(19):2805-2811
The aqueous self‐assembly of the flexible ligand L bis(1H‐benz[d]imidazole‐1‐yl)methane and cis‐coordinated PtII precursors [(en)Pt2+, (tmeda)Pt2+, en=ethylenediamine, tmeda=N,N,N′,N′‐tetramethylethylenediamine)] led to the formation of the metallacalixarenes with full alternative conformations (e.g., two novel water‐soluble metallacalixarenes [M2L2]4+ and [M3L3]6+ with D2 and D3 symmetry, respectively). Their molecular structures were determined by single crystal X‐ray analyses in solid state. The two metallacalixarenes present different cavity sizes and the [M3L3]6+ cavity encapsulates one NO3−. NOESY NMR revealed that the conformational interconversion between 1,3‐alternate conformer in methanol and cone conformer in DMSO was tuned via the synergistic effect between solvent and anion. Guest encapsulation is also discussed. 相似文献