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We describe the synthesis of N-functionalised phosphinecarboxamides obtained by reaction of the 2-phosphaethynolate anion (PCO−) with diamines, specifically hydrazine, methylenediamine and ethylenediamine, in the presence of acid. The resulting neutral compounds can be deprotonated to generate phosphide anions that, when further reacted with electrophiles, form secondary phosphines. [ABSTRACT FROM AUTHOR]

A series of gallium phosphaketenyl complexes supported by a 1,2-bis(aryl-imino)acenaphthene ligand (Dipp-Bian) are reported. Photolysis of one such species induced decarbonylation to afford a gallium substituted diphosphene. Addition of Lewis bases, specifically trimethylphosphine and the gallium carbenoid Ga(Nacnac) (Nacnac = HC[C(Me)N-(C6H3)-2,6-iPr2]2), resulted in displacement of the phosphaketene carbonyl to yield base-stabilised phosphinidenes. In several of these transformations, the redox non-innocence of the Dipp-Bian ligand was found to give rise to radical intermediates and/or side-products. [ABSTRACT FROM AUTHOR]

The synthesis of two novel ferrocenyl-substituted phosphinecarboxamides, FcNHC(O)PH2 (1; Fc = ferrocenyl) and FcCH2NHC(O)PH2 (2), is reported. These two primary phosphines were obtained by the reaction of aminoferrocene with sodium 2-phosphaethynolate in the presence of a proton source or, directly, from aminomethylferrocene hydrochloride and sodium 2-phosphaethynolate. Their ability to act as ligands was probed via reactions of 1 with rhodium(III) and ruthenium(II) precursors. The isoelectronic metal complexes [(η5-C5Me5)RhCl2(1-κP)] and [(η6-mes)RuCl2(1-κP)] were obtained. Treatment of these compounds with a base resulted in HCl elimination to afford phosphide-bridged dirhodium and diruthenium complexes highlighting that on coordination to a metal, the P–H bonds of these phosphinecarboxamides become increasingly protic. [ABSTRACT FROM AUTHOR]

A series of novel β-diketiminate stabilised aluminium borohydrides of the type (Nacnac)Al(R){H2(9-BBN)} has been synthesised offering variation in both the auxiliary R substituent and in the Nacnac backbone itself. A number of these complexes show unusual dissociation of the borane from the aluminium hydride in solution under ambient conditions. The lability of the borane is shown (by variable temperature NMR analyses) to be influenced by the electronic character of both the aluminium-bound R substituent and the Nacnac ligand itself, such that electron-withdrawing substituents lead to greater dissociation of the borane. Comparison of these complexes with related systems featuring the tetrahydroborate [BH4]− ligand illustrates the impact of the boron-bound substituents on the ability of the borane fragment to dissociate from the aluminium hydride. This dissociative behaviour is shown to be highly influential on the ability of the borohydride complexes to reduce carbon dioxide in a stoichiometric manner. [ABSTRACT FROM AUTHOR]

Sterically demanding primary phosphanes of the type RBhp-PH2 (Bhp = 2,6-bis(benzhydryl)-4-R-phenyl; R = Me, tBu) could be prepared in high yields by modification of synthetic protocols of established bulky phosphanes. The Bhp substituents simultaneously exhibit extensive steric expansiveness and high degrees of flexibility compared to other 2,6-substituted phenyl backbones, enabling a range of different-sized atoms and functionalities to be located between the flanking benzhydryl moieties. Therefore, it was also possible to isolate and fully characterize several halogenated precursors, a diazonium intermediate, as well as a dihalostibane. [ABSTRACT FROM AUTHOR]

Over the course of the last six years, research on the synthesis and reactivity of molecular metal phosphaketenes (M–PCO) has gained increasing attention. However, lanthanide complexes of the heavier group 15 cyanate analogue PCO− have not been investigated so far. Herein we present exemplar studies on the nature and reactivity of rare-earth phosphaethynolato-complexes using three characteristic representatives of the rare-earth metals: Y, Nd and Sm. Our investigations comprise both +2 and +3 redox states, and one defined amidinate-based ligand set, as well as novel reaction pathways in the presence of the sequestering agents 18-crown-6 and 2,2,2-crypt. [ABSTRACT FROM AUTHOR]

This paper demonstrates the use of phosphinecarboxamide as a facile phosphorus precursor, which can be used alongside zinc acetate for the chemical vapour deposition (CVD) of adherent and crystalline zinc phosphide films. Thin films of Zn3P2 have a number of potential applications and phosphinecarboxamide is a safer and more efficient precursor than the highly toxic, corrosive and flammable phosphine used in previous CVD syntheses. [ABSTRACT FROM AUTHOR]

The synthesis of a novel heterocubane [RSnE]4 was successful for E = As, while for E = P differing behaviour was observed. Aryl-substituted chlorostannylenes were treated with salts of heavy cyanate homologues PCO− and AsCO−. The reaction with AsCO− salts afforded primarily [TerSnAs]4 (Ter = 2,6-dimesitylphenyl). In contrast, the reaction of TerSnCl with NaPCO proceeded considerably less cleanly affording a mixture of products. The main product was putatively a neutral [Ter4Sn4P4] compound, however, it is not a cubane. A variety of by-products of this reaction could be characterised crystallographically. [ABSTRACT FROM AUTHOR]

The synthesis of a novel heterocubane [RSnE]4 was successful for E = As, while for E = P differing behaviour was observed. Aryl-substituted chlorostannylenes were treated with salts of heavy cyanate homologues PCO− and AsCO−. The reaction with AsCO− salts afforded primarily [TerSnAs]4 (Ter = 2,6-dimesitylphenyl). In contrast, the reaction of TerSnCl with NaPCO proceeded considerably less cleanly affording a mixture of products. The main product was putatively a neutral [Ter4Sn4P4] compound, however, it is not a cubane. A variety of by-products of this reaction could be characterised crystallographically. [ABSTRACT FROM AUTHOR]

The reactivity of the heavier group 15 tribromides, SbBr3 and BiBr3, towards 1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene (IPr) is described. These reactions quantitatively afford Lewis acid–base adducts, (IPr)EBr3 (E = Sb 1; Bi 2), which readily react with AlBr3 yielding cationic species [(IPr)EBr2]+ (E = Sb 3; Bi 4). Under thermal treatment, the N-heterocyclic carbene ligands in 1 and 2 will readily isomerise to afford the abnormally-bonded (or mesoionic) complexes (aIPr)EBr3 (E = Sb 5; Bi 6). As with 1 and 2, bromide abstraction from such compounds readily affords the cationic complexes [(aIPr)EBr2]+ (E = Sb 7; Bi 8). Finally, in an effort to elucidate the isomerisation process which allows for the conversion of 1 and 2 to the abnormally bonded systems (compounds 5 and 6), compound 1 was reacted with a further equivalent of IPr to afford the cationic species [(aIPr)2SbBr2]+ (9). This strongly suggests that the normal to abnormal isomerisation of the N-heterocylic carbene ligands in compounds 1 and 2 is mediated by the presence of free IPr. Compound [9]Br can be used to access the dicationic species [(aIPr)2SbBr]2+ (10), which we have identified spectroscopically. Single crystal X-ray structures and spectroscopic data for all compounds are discussed. [ABSTRACT FROM AUTHOR]

Reactions of the protonated heptaphosphide dianion, [HP7]2−, with one equivalent of E[N(SiMe3)2]2 (E = Ge, Sn, Pb) give rise to novel derivatized cluster anions [P7EN(SiMe3)2]2− (E = Ge (1), Sn (2) and Pb (3)). All three species were characterized by multi-element solution-phase NMR spectroscopy and electrospray ionization mass spectrometry. In addition, 1 and 2 were structurally authenticated by means of single crystal X-ray diffraction in [K(18-crown-6)]2[P7EN(SiMe3)2]·2py. Interestingly, while 2 appears to be indefinitely stable in solution for prolonged periods of time, the germanium-containing analogue, 1, readily decomposes at room temperature giving rise to the dimeric species [(P7Ge)2N(SiMe3)2]3− (4) and [K(18-crown-6)][N(SiMe3)2]. A low quality single crystal X-ray structure of the former allowed for the confirmation of its composition and connectivity which is consistent with the 31P NMR spectrum obtained for the anion. [ABSTRACT FROM AUTHOR]

Reaction of the lithiated N-heterocyclic carbene [:C[N(2,6-iPr2C6H3)]2(CH)CLi]n (LiIPr) with KOtBu in diethylether (Et2O) afforded the novel organo-potassium compound [:C[N(2,6-iPr2C6H3)]2(CH)CK(THF)2] (KIPr·2THF). Both LiIPr and KIPr can be interpreted as ditopic carbanionic carbenes (or alkali metal salts of anionic "dicarbenes") and are interesting precursors for the synthesis of novel metal complexes bearing carbanionic carbenes as ligands. Reaction of KIPr with M[N(SiMe3)2]2 (M = Zn, Sn) afforded salts of the anionic three coordinate complexes [M{C(CH)[N(2,6-iPr2C6H3)]2C:}{N(SiMe3)2}2]- (M = Zn (1) and Sn (2)). Contrasting reactivity was observed for the other group 14 bis-amide compounds M[N(SiMe3)2]2 (M = Ge, Pb), which initially appear to yield analogous 1:1 complexes (M = Ge (3) and Pb (4)), however over time give rise to compounds bearing two ditopic carbanionic carbenes ([M{C(CH)[N(2,6-iPr2C6H3)]2C:}2-{N(SiMe3)2}]-; Ge (5) and Pb (6)) and the tris-amide anions ([M{N(SiMe3)3}]-), presumably via a Schlenktype equilibrium. Compounds 5 and 6 can be directly synthesized by reacting M[N(SiMe3)2]2 (M = Ge, Pb) with two equivalents of KIPr, respectively. [ABSTRACT FROM AUTHOR]

Reaction of dimesityliron(II) (Fe2(mes)4) with the N-heterocyclic carbenes 1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene (IPr) and 1,3-bis(2,6-dimethylphenyl)hexahydropyrimidin-2-ylidene (6-Xyl) afforded the novel trigonal planar complexes [Fe(IPr)(mes)2] (1) and [Fe(6-Xyl)(mes)2] (2), respectively. Both species were structurally characterized by single crystal X-ray diffraction and display structures and magnetic responses consistent with a quintet ground state (S = 2). Reaction of 1 with KC8 in THF afforded K+ salts of the anionic complex [{:C[N(2,6-iPr2C6H3)]2(CH)C}2Fe(mes)]- (3) and the homoleptic organometallic anion [Fe(mes)3]- (4). By contrast, reduction of 2 resulted in extensive decomposition and intractable product mixtures. Complex 3 is coordinated by two ditopic carbanionic carbenes via the C4/C5 position while the C2 position retains unquenched carbenic character and remains vacant for further coordination. This was corroborated by reacting solutions of 3 with one and two equivalents of triethylaluminium (AlEt3) which resulted in the formation of [{Et3Al:C[N(2,6-iPr2C6H3)]2(CH)C}{:C[N(2,6-iPr2C6H3)]2- (CH)C}Fe(mes)]- (5) and [{Et3Al:C[N(2,6-iPr2C6H3)]2(CH)C}2Fe(mes)]- (6), respectively. Both of these species were structurally characterized as [K(2,2,2-crypt)]+ salts. [ABSTRACT FROM AUTHOR]

The synthesis of a new endohedral ten-vertex Zintl ion cluster, [Fe@Sn10]3−, isoelectronic with [Fe@Ge10]3−, is reported. In an attempt to place this new cluster within the context of the known structural chemistry of the M@E10 family (M = transition metal, E = main group element), we have carried out a detailed electronic structure analysis of the different structural types: viz bicapped square antiprismatic ([Ni@Pb10]2−, [Zn@In10]8−), tetra-capped trigonal prismatic ([Ni@In10]10−) and the remarkable pentagonal prismatic [Fe@Ge10]3− and [Co@Ge10]3−. We establish that the structural trends can be interpreted in terms of a continuum of effective electron counts at the E10 cage, ranging from electron deficient (＜4n + 2) in [Ni@In10]10− to highly electron rich (＞4n + 2) in [Fe@Ge10]3−. The effective electron count differs from the total valence electron count in that it factors in the increasingly active role of the metal d electrons towards the left of the transition series. The preference for a pentagonal prismatic geometry in [Fe@Ge10]3− emerges as a natural consequence of backbonding to the cage from four orthogonal 3d orbitals of the low-valent metal ion. Our calculations suggest that the new [Fe@Sn10]3− cluster should also exhibit structural consequences of backbonding from the metal to the cage, albeit to a less extreme degree than in its Ge analogue. The global minimum lies on a very flat surface connecting D4d, C2v and C3v-symmetric minima, suggesting a very plastic structure that may be easily deformed by the surrounding crystal environment. If so, then this provides a new and quite distinct structural type for the M@E10 family. [ABSTRACT FROM AUTHOR]

Salt metathesis reactions between ethylenediamine (en) solutions of the K3E7(E = P, As) Zintl phases and post-transition metal halides (InCl3, TlCl, SnI2and PbI2) have yielded a family of novel heteroatomic cluster anions, [In(E7)2]3−, [TlE7]2−and [E′E15]3−(E′ = Sn, Pb; E = P, As). Several of these new species have been characterized by single-crystal X-ray diffraction as salts of sequestered potassium cations in [K(2,2,2-crypt)]3[In(P7)2]·3.5py (1), [K(2,2,2-crypt)]2[TlP7]·py (3), [K(18-crown-6)]2[TlAs7] (4b), [K(2,2,2-crypt)]3[E′P15]·en (E′ = Sn (5), Pb (6)) and [K(2,2,2-crypt)]3[SnAs15]·2en (7). The presence of all of the cluster anions in solution was confirmed by electrospray mass-spectrometry and by 1H and 31P{1H} NMR spectroscopy when pertinent. [ABSTRACT FROM AUTHOR]

The reaction of Li2(C14H18)(TMEDA)xwith UCl4yields U(η8-C14H18)2, (UPn*2; Pn* = C14H18) an analogue of CePn*2and U{η8-C8H4(1,4-SiiPr3)2}2. The UPn*2molecule is structurally characterised viaa variety of techniques, its magnetism is probed in the solution and solid phase and the redox properties are investigated using cyclic voltammetry. During this study it was shown to be reducible and the reduced species reacted with N2to form a stable complex. An analogous complex was not found under Ar. [ABSTRACT FROM AUTHOR]

The reaction of ethylenediamine solutions of K4E9 (E = Ge, Sn, Pb) with diaryl and dialkyl organozinc reagents ZnMes2 and ZniPr2 yielded the functionalized Zintl ions, closo-[E9ZnR]3- (R = Mes: E = Ge (1), Sn (2), Pb (3); R = iPr: E = Ge (4), Sn (5), Pb (6)). These reactions proceed via reductive zinc-carbon bond activation of the organometallic reagents by the free solvated electrons present in ethylenediamine solutions of intermetallic Zintl phases. The functionalized cluster anions 1, 2 and 4-6 were characterized in the solid-state as [K(2,2,2-crypt)]+ salts by single-crystal X-ray diffraction and elemental analysis, while the presence of all six cluster anions in solution was confirmed by 1H and 13C{1H} NMR spectroscopy and electrospray mass spectrometry. [ABSTRACT FROM AUTHOR]

Correction for ‘Increasing steric demand through flexible bulk – primary phosphanes with 2,6-bis(benzhydryl)phenyl backbones’ by Jonas Bresien et al., Dalton Trans., 2019, 48, 3786–3794. [ABSTRACT FROM AUTHOR]

The synthesis of a new endohedral ten-vertex Zintl ion cluster, [Fe@Sn10]3−, isoelectronic with [Fe@Ge10]3−, is reported. In an attempt to place this new cluster within the context of the known structural chemistry of the M@E10 family (M = transition metal, E = main group element), we have carried out a detailed electronic structure analysis of the different structural types: viz bicapped square antiprismatic ([Ni@Pb10]2−, [Zn@In10]8−), tetra-capped trigonal prismatic ([Ni@In10]10−) and the remarkable pentagonal prismatic [Fe@Ge10]3− and [Co@Ge10]3−. We establish that the structural trends can be interpreted in terms of a continuum of effective electron counts at the E10 cage, ranging from electron deficient (＜4n + 2) in [Ni@In10]10− to highly electron rich (＞4n + 2) in [Fe@Ge10]3−. The effective electron count differs from the total valence electron count in that it factors in the increasingly active role of the metal d electrons towards the left of the transition series. The preference for a pentagonal prismatic geometry in [Fe@Ge10]3− emerges as a natural consequence of backbonding to the cage from four orthogonal 3d orbitals of the low-valent metal ion. Our calculations suggest that the new [Fe@Sn10]3− cluster should also exhibit structural consequences of backbonding from the metal to the cage, albeit to a less extreme degree than in its Ge analogue. The global minimum lies on a very flat surface connecting D4d, C2v and C3v-symmetric minima, suggesting a very plastic structure that may be easily deformed by the surrounding crystal environment. If so, then this provides a new and quite distinct structural type for the M@E10 family. [ABSTRACT FROM AUTHOR]