11 Jan 12:34
by Brandon L Frenette,
Jonathan Trach,
Michael J. Ferguson,
Eric Rivard
A frustrated Lewis pair (FLP) chelation approach was employed to access low-valent phosphorus centers. The resulting adducts act as P atom sources for phosphinidene (PR) transfer, indium phosphide synthesis, and neutral P2 transfer to organic substrates.
Abstract
We report phosphinidenes (PR) stabilized by an intramolecular frustrated Lewis pair (FLP) chelate. These adducts include the parent phosphinidene, PH, which is accessed via thermolysis of coordinated HPCO. The reported FLP-PH species acts as a springboard to other phosphorus-containing compounds, such as FLP-adducts of diphosphorus (P2) and InP3. Our new adducts participate in thermal- or light-induced phosphinidene elimination (of both PH and PR, R=organic group), transfer P2 units to an organic substrate, and yield the useful semiconductor InP at only 110 °C from solution.
11 Jan 08:43
Dalton Trans., 2023, 52,2098-2105
DOI: 10.1039/D3DT00069A, Paper
Open Access
Andryj M. Borys, Eva Hevia
Using diphenylacetylene as a π-accepting ligand allows access to a new family of alkali-metal nickelates, which can effectively promote the [2 + 2 + 2] cyclotrimerisation of diphenylacetylene.
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06 Jan 09:21
Chem. Commun., 2023, 59,1453-1456
DOI: 10.1039/D2CC06702A, Communication
Open Access
Kyle G. Pearce, Michael S. Hill, Mary F. Mahon
Lithium or sodium reduction of [SiNDippBe] in benzene, provides the organoberyllate products, [{SiNDippBePh}M] (M = Li or Na).
The content of this RSS Feed (c) The Royal Society of Chemistry
04 Jan 10:24
Chem. Commun., 2023, 59,503-519
DOI: 10.1039/D2CC05963K, Feature Article
Martyn P. Coles, Matthew J. Evans
The chemistry of aluminyl compounds has rapidly expanded since their discovery in 2018 and is evaluated in this summary.
The content of this RSS Feed (c) The Royal Society of Chemistry
19 Dec 13:21
by Jiancheng Li, Zhihao Lu, and Liu Leo Liu
Journal of the American Chemical Society
DOI: 10.1021/jacs.2c11878
06 Dec 08:56
by Genfeng Feng, Ka Lok Chan, Zhenyang Lin, and Makoto Yamashita
Journal of the American Chemical Society
DOI: 10.1021/jacs.2c09746
27 Nov 13:52
by Jonathan Mai,
Michael Morasch,
Dawid Jędrzkiewicz,
Jens Langer,
Bastian Rösch,
Sjoerd Harder
Attempts to isolate low-valent (BDI)Ae-Ae(BDI) complexes led to reduction of the benzene solvent and formation of (BDI)Ae-(C6H6)-Ae(BDI); BDI=β-diketiminate ligand, Ae=Ca or Sr. Reaction of bridging C6H6
2− with benzene gave (biphenyl)2− complexes. Ball-milling is an efficient synthetic tool for this dehydrogenative benzene-benzene coupling. Calculations suggest attack of C6H6
2− at benzene. This is facilitated by Ae2+⋅⋅⋅benzene coordination.
Abstract
Complex [(DIPePBDI)Ca]2(C6H6), with a C6H6
2− dianion bridging two Ca2+ ions, reacts with benzene to yield [(DIPePBDI)Ca]2(biphenyl) with a bridging biphenyl2− dianion (DIPePBDI=HC[C(Me)N-DIPeP]2; DIPeP=2,6-CH(Et)2-phenyl). The biphenyl complex was also prepared by reacting [(DIPePBDI)Ca]2(C6H6) with biphenyl or by reduction of [(DIPePBDI)CaI]2 with KC8 in presence of biphenyl. Benzene-benzene coupling was also observed when the deep purple product of ball-milling [(DIPPBDI)CaI(THF)]2 with K/KI was extracted with benzene (DIPP=2,6-CH(Me)2-phenyl) giving crystalline [(DIPPBDI)Ca(THF)]2(biphenyl) (52 % yield). Reduction of [(DIPePBDI)SrI]2 with KC8 gave highly labile [(DIPePBDI)Sr]2(C6H6) as a black powder (61 % yield) which reacts rapidly and selectively with benzene to [(DIPePBDI)Sr]2(biphenyl). DFT calculations show that the most likely route for biphenyl formation is a pathway in which the C6H6
2− dianion attacks neutral benzene. This is facilitated by metal-benzene coordination.
24 Nov 09:01
by Gerd M. Ballmann, Matthew J. Evans, Thomas X. Gentner, Alan R. Kennedy, J. Robin Fulton, Martyn P. Coles, and Robert E. Mulvey
Inorganic Chemistry
DOI: 10.1021/acs.inorgchem.2c03010
18 Nov 08:59
by Han-Ying Liu,
Samuel E. Neale,
Michael Stephen Hill,
Mary F. Mahon,
Claire L McMullin,
Emma Richards
Treatment of a low oxidation state {Mg2Na2} assembly with basic molecules that are less prone to reduction than the sodium cation itself induces the complete extrusion of the elemental alkali metal.
Abstract
Ionic compounds containing sodium cations are notable for their stability and resistance to redox reactivity unless highly reducing electrical potentials are applied. Here we report that treatment of a low oxidation state {Mg2Na2} species with non-reducible organic bases induces the spontaneous and completely selective extrusion of sodium metal and oxidation of the MgI centers to the more conventional MgII state. Although these processes are also characterized by a structural reorganisation of the initially chelated diamide spectator ligand, computational quantum chemical studies indicate that intramolecular electron transfer is abetted by the frontier molecular orbitals (HOMO/LUMO) of the {Mg2Na2} ensemble, which arise exclusively from the 3s valence atomic orbitals of the constituent sodium and magnesium atoms.
08 Nov 13:53
by Jacob S. McMullen,
Ryan Huo,
Petra Vasko,
Alison J. Edwards,
Jamie Hicks
CO has directly been transformed into small organic starting materials using earth-abundant, anionic group 2 hydride reagents.
Abstract
The synthesis, characterisation and reactivity of two isostructural anionic magnesium and calcium complexes is reported. By X-ray and neutron diffraction techniques, the anionic hydrides are shown to exist as dimers, held together by a range of interactions between the two anions and two bridging potassium cations. Unlike the vast proportion of previously reported dimeric group 2 hydrides, which have hydrides that bridge two group 2 centres, here the hydrides are shown to be “terminal”, but stabilised by interactions with the potassium cations. Both anionic hydrides were found to insert and couple CO under mild reaction conditions to give the corresponding group 2 cis-ethenediolate complexes. These cis-ethenediolate complexes were found to undergo salt elimination reactions with silyl chlorides, allowing access to small unsaturated disilyl ethers with a high percentage of their mass originating from the C1 source CO.
04 Nov 08:52
Chem. Commun., 2022, 58,13580-13583
DOI: 10.1039/D2CC05178H, Communication
Open Access
Nathan T. Coles, Lucie J. Groth, Lea Dettling, Daniel S. Frost, Massimo Rigo, Samuel E. Neale, Christian Müller
Hitherto unknown amidine-functionalized phosphabenzenes selectively form by a cascade of dehydrofluorination reactions.
The content of this RSS Feed (c) The Royal Society of Chemistry
31 Oct 10:56
by Andreu Tortajada and Eva Hevia
Journal of the American Chemical Society
DOI: 10.1021/jacs.2c09778
08 Apr 08:05
by Joseph Bedard,
Nicholas Roberts,
Mohsen Shayan,
Karlee L Bamford,
Ulrike Werner-Zwanziger,
Katherine M. Marczenko,
Saurabh S. Chitnis
The synthesis of a new air-stable and thermally robust tetrahedral tetravalent inorganic cage, (PNSiMe3)4(NMe)6 has been achieved. This cage allows four-fold functionalization reactions on its periphery to give unprecedented molecular and macromolecular constructs. This utility is shown by the synthesis of a tetrakis(bis(phosphine)iminium) ion and the first all P/N polyphazene network material.
Abstract
Tetraarylmethanes and adamantanes are important rigid covalent connectors that play a four-way scaffolding role in molecular and materials chemistry. We report the synthesis of a new tetravalent phosphaza-adamantane cage, (PNSiMe3)4(NMe)6 (2), that shows high thermal, air, and redox stability due to its geometry. It nevertheless participates in covalent four-fold functionalization reactions along its periphery. The combination of a robust core and reactive corona makes 2 a convenient inorganic scaffold upon which tetrahedral molecular and macromolecular chemistry can be constructed. This potential is demonstrated by the synthesis of a tetrakis(bis(phosphine)iminium) ion (in compound 3) and the first all P/N poly(phosphazene) network (5).
28 Mar 07:56
by Laura E English,
Aleksandra Pajak,
Claire L McMullin,
John P Lowe,
Mary F Mahon,
David Liptrot
Pyridines have been shown to mediate the release of ethene from a terphenyl supported 1,3-dioxo-2-phospholane. This generates a dioxophosphorane dimer which is an oxygen analogue of Lawesson's and Woollins’ reagents. This compound was structurally characterised and its solution behaviour interrogated. Insight into the ethene release reaction is provided by the isolation of a DMAP-coordinated dioxophosphorane
Abstract
Thermolysis of a 1,3-dioxa-2-phospholane supported by the terphenyl ligand AriPr4 (AriPr4=[C6H3-2,6-(C6H3-2,6-iPr2)]) at 150 °C gives [AriPr4PO2]2 via loss of ethene. [AriPr4PO2]2 was characterised by X-ray crystallography and NMR spectroscopy; it contains a 4-membered P−O−P−O ring and is the isostructural oxygen analogue of Lawesson's and Woollins’ reagents. The dimeric structure of [AriPr4PO2]2 was found to persist in solution through VT NMR spectroscopy and DOSY, supported by DFT calculations. The addition of DMAP to the 1,3-dioxa-2-phospholane facilitates the loss of ethene to give AriPr4(DMAP)PO2 after days at room temperature, with this product also characterised by X-ray crystallography and NMR spectroscopy. Replacement of the DMAP with pyridine induces ethene loss from the 1,3-dioxa-2-phospholane to provide gram-scale samples of [AriPr4PO2]2 in 75 % yield in 2 days at only 100 °C.
25 Feb 11:01
by Michael Stephen Hill,
Kyle G Pearce,
Chiara Dinoi,
Mary F Mahon,
Laurent Maron,
Ryan S Schwamm,
Andrew S S Wilson
Isolable and hydrocarbon-soluble β-diketiminato calcium phenyls are accessible from the reaction of Ph2Hg and [(BDI)CaH]2. The compounds were shown to react with bromoarenes through a direct SNAr displacement of halide, leading to the uncatalyzed formation of biaryl molecules.
Abstract
Hydrocarbon-soluble β-diketiminato phenylcalcium derivatives, which display various modes of Ca−μ2-Ph−Ca bridging, are accessible from reactions of Ph2Hg and [(BDI)CaH]2. Although the resultant compounds are inert toward the C−H bonds of benzene, they yield selective and uncatalyzed biaryl formation when reacted with readily available aryl bromides.
16 Feb 08:51
Dalton Trans., 2022, 51,3913-3924
DOI: 10.1039/D2DT00404F, Paper
Han-Ying Liu, Samuel E. Neale, Michael S. Hill, Mary F. Mahon, Claire L. McMullin
Reactions of the seven-membered cyclic potassium diamidoalumanyl, [K{Al(SiNDipp)}]2 (SiNDipp = {CH2SiMe2NDipp}2; Dipp = 2,6-di-isopropylphenyl), with a variety of Cu(I), Ag(I) and Au(I) chloride N-heterocyclic carbene (NHC) adducts are described.
The content of this RSS Feed (c) The Royal Society of Chemistry
03 Feb 10:16
by Dawid Jędrzkiewicz,
Jonathan Mai,
Jens Langer,
Zachary Mathe,
Neha Patel,
Serena DeBeer,
Sjoerd Harder
Ball-milling of a magnesium iodide precursor with K/KI gave a mononuclear Mg radical which is stabilized by a CAAC ligand. Although stable in the crystalline state, the complex decomposed rapidly in solution. According to calculations and EPR spectroscopy, most of the spin density is localized on the CAAC ligand.
Abstract
In order to isolate a monometallic Mg radical, the precursor (Am)MgI⋅(CAAC) (1) was prepared (Am=tBuC(N-DIPP)2, DIPP=2,6-diisopropylphenyl, CAAC=cyclic (alkyl)(amino)carbene). Reduction of a solution of 1 in toluene with the reducing agent K/KI led to formation of a deep purple complex that rapidly decomposed. Ball-milling of 1 with K/KI gave the low-valent MgI complex (Am)Mg⋅(CAAC) (2) which after rapid extraction with pentane and crystallization was isolated in 15 % yield. Although a benzene solution of 2 decomposes rapidly to give Mg(Am)2 (3) and unidentified products, the radical is stable in the solid state. Its crystal structure shows planar trigonal coordination at Mg. The extremely short Mg−C distance of 2.056(2) Å indicates strong Mg−CAAC bonding. Calculations and EPR measurements show that most of the spin density is in a π* orbital located at the C−N bond in CAAC, leading to significant C−N bond elongation. This is supported by calculated NPA charges in 2: Mg +1.73, CAAC −0.82. Similar metal-to-CAAC charge transfer was calculated for M0(CAAC)2 and [MI(CAAC)2
+] (M=Be, Mg, Ca) complexes in which the metal charges range from +1.50 to +1.70. Although the spin density of the radical is mainly located at the CAAC ligand, complex 2 reacts as a low-valent MgI complex: reaction with a I2 solution in toluene gave (Am)MgI⋅(CAAC) (1) as the major product.
20 Jan 15:49
by Yanbo Mei, Zeen Yan, and Liu Leo Liu
Journal of the American Chemical Society
DOI: 10.1021/jacs.1c11087
22 Dec 13:51
Dalton Trans., 2022, 51,831-835
DOI: 10.1039/D1DT03109K, Communication
Open Access
Rex S. C. Charman, Mary F. Mahon, John P. Lowe, David J. Liptrot
A copper(I) stannyl supported by a ring-expanded N-heterocyclic carbene has been synthesised and its reactivity towards heterocumulenes has been investigated.
The content of this RSS Feed (c) The Royal Society of Chemistry
29 Nov 13:02
Dalton Trans., 2021, Advance Article
DOI: 10.1039/D1DT03775G, Paper
Open Access
Bibian Okokhere-Edeghoghon, Samuel E. Neale, Michael S. Hill, Mary F. Mahon, Claire L. McMullin
A molecular magnesium silanide is shown through a combined synthetic and computational study to effect siloxide formation and isocyanate deoxgenation via the initial formation of magnesium silamidate intermediates.
To cite this article before page numbers are assigned, use the DOI form of citation above.
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23 Nov 20:22
Chem. Sci., 2021, Advance Article
DOI: 10.1039/D1SC04248C, Edge Article
Open Access
Andryj M. Borys, Ewan R. Clark, Paul J. Saines, Antonio Alberola, Jeremy M. Rawson
A family of 1,2,4-benzothiadiazinyl radicals are accessible from 1,2,4-benzothiadiazine 1-chlorides which can be prepared in a single step by treatment of N-arylamidines in neat thionyl chloride at reflux.
To cite this article before page numbers are assigned, use the DOI form of citation above.
The content of this RSS Feed (c) The Royal Society of Chemistry
18 Oct 09:50
by Han-Ying Liu, Ryan J. Schwamm, Samuel E. Neale, Michael S. Hill, Claire L. McMullin, and Mary F. Mahon
Journal of the American Chemical Society
DOI: 10.1021/jacs.1c09467
30 Sep 10:03
by Kyle G. Pearce,
Elinor P. F. Canham,
John F. Nixon,
Ian R. Crossley
The 1,3-diphosphaborolediide ligand motif, a hitherto missing member of the “hetero-Cp“ family, is obtained within an indenyl scaffold as its dilithium salt, as both thf and TMEDA solvates. This dianionic ligand exhibits aromaticity commensurate with its hybrid phospholide-borolediide nature, as is determined by NICS calculations and observed experimentally for both lithium salts. Additionally, coordination to zero-valent molybdenum is achieved, demonstrating a capacity to to coordinate readily as a π- and bridging π-,σ-type ligand.
Abstract
The first example of a diphosphaborolediide, the benzo-fused [C6H4P2BPh]2− (12−
), is prepared from ortho-bis(phosphino)benzene (C6H4{PH2}) and dichlorophenylborane, via a sequential lithiation approach. The dilithio-salt can be obtained as an oligomeric THF solvate or discrete TMEDA adduct, both of which are fully characterized, including by X-ray diffraction. Alongside NICS calculations, data strongly suggest some aromaticity within 12−
, which is further supported by preliminary coordination studies that demonstrate η5-coordination to a zerovalent molybdenum center, as observed crystallographically for the oligomeric [{Mo(CO)3(η5-1)}{μ-η1-Mo(CO)3(TMEDA)}2] ⋅ [μ-Li(THF)][μ-Li(TMEDA)].
02 Sep 08:05
by Andryj Borys,
Eva Hevia
Assessment of the rich co-complexation chemistry of Ni(COD)2 and PhLi has led to a new family of structurally diverse lithium nickelates being uncovered. Combined stoichiometric, catalytic, and kinetic studies reveal that these hetero-bimetallic complexes may be the key intermediates that facilitate the smooth C−O bond cleavage and cross-coupling of aryl ethers under mild conditions.
Abstract
The Ni-catalysed cross-coupling of aryl ethers is a powerful method to forge new C−C and C−heteroatom bonds. However, the inert C(sp2)−O bond means that a canonical mechanism that relies on the oxidative addition of the aryl ether to a Ni0 centre is thermodynamically and kinetically unfavourable, which suggests that alternative mechanisms may be involved. Here, we provide spectroscopic and structural insights into the anionic pathway, which relies on the formation of electron-rich hetero-bimetallic nickelates by adding organometallic nucleophiles to a Ni0 centre. Assessing the rich co-complexation chemistry between Ni(COD)2 and PhLi has led to the structures and solution-state chemistry of a diverse family of catalytically competent lithium nickelates being unveiled. In addition, we demonstrate dramatic solvent and donor effects, which suggest that the cooperative activation of the aryl ether substrate by Ni0-ate complexes plays a key role in the catalytic cycle.
27 Aug 09:08
by Andryj M. Borys, Ella F. Rice, Gary S. Nichol, and Michael J. Cowley
Journal of the American Chemical Society
DOI: 10.1021/jacs.1c06228
01 Jul 08:15
by Daniel W. N. Wilson, Stephanie J. Urwin, Eric S. Yang, and Jose M. Goicoechea
Journal of the American Chemical Society
DOI: 10.1021/jacs.1c04417
15 Jun 08:44
Dalton Trans., 2021, 50,8685-8689
DOI: 10.1039/D1DT01532J, Communication
Jacob S. McMullen, Alison J. Edwards, Jamie Hicks
A series of neutral magnesium and calcium complexes that display various novel group 2⋯arene interaction have been synthesised and structurally characterised.
The content of this RSS Feed (c) The Royal Society of Chemistry
04 May 12:42
by Michael Stephen Hill,
Han-Ying Liu,
Ryan Schwamm,
Claire McMullin,
Mary Mahon,
Nasir Rajabi
Cu(ts) both ways: Carbene-supported copper-alumanyl complexes, [LCu-Al(SiNDipp)], display divergent reactivity with carbodiimides and CO2, implying an ambiphilicity in the Cu–Al interaction that is dependent on the identity of the carbene co-ligand.
Abstract
Copper-alumanyl complexes, [LCu-Al(SiNDipp)], where L=carbene=NHCiPr (N,N′-diisopropyl-4,5-dimethyl-2-ylidene) and Me2CAAC (1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene) and featuring unsupported Al−Cu bonds, have been prepared. Divergent reactivity observed with carbodiimides and CO2 implies an ambiphilicity in the Cu–Al interaction that is dependent on the identity of the carbene co-ligand.
04 May 12:33
by Stephan Hagspiel,
Felipe Fantuzzi,
Rian D. Dewhurst,
Annalena Gärtner,
Felix Lindl,
Anna Lamprecht,
Holger Braunschweig
The first examples of Lewis base adducts of the parent boraphosphaketene (H2B−PCO) are prepared, and their dimerization, decarbonylation and use as synthons for phosphinidenes is explored, leading to a number of different B/P-containing heterocycles and transition-metal complexes thereof.
Abstract
The first examples of Lewis base adducts of the parent boraphosphaketene (H2B-PCO) and their cyclodimers are prepared. One of these adducts is shown to undergo mild decarbonylation and phosphinidene insertion into a B−C bond of a borole, forming very rare examples of 1,2-phosphaborinines, B/P isosteres of benzene. The strong donor properties of these 1,2-phosphaborinines are confirmed by the synthesis of their π complexes with the Group 6 metals.
19 Jan 13:52
by Andryj M. Borys and Eva Hevia
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Organometallics
DOI: 10.1021/acs.organomet.0c00785
