A simple synthesis of group 2 anthracenides and their use as reducing agents for polypnictogen ligand complexes.

By using an improved synthetic pathway, the anthracenides of the group 2 metals Ca, Sr, and Ba are straightforwardly accessible for subsequent organometallic syntheses. These highly reactive compounds are slightly soluble in tetrahydrofuran and can be used as synthons for group 2 metal transfer due to the lability of the anthracene substituent. These features were used to explore their reactivity towards the polyphosphorus ligand complexes [Cp*Fe(η-P)] (Cp* = C(CH)) and [Cp*Fe(η-(1-CH-2-PPh-P))], respectively.

Strain-Release Driven Arsenium Ion Bond Insertion.

Although it marks a cornerstone of pnictogenium ion [RPn] reactivity, the insertion of arsenium ions [RAs] into non-polar bonds remains highly challenging. Herein, a synthetic approach is developed, which circumvents the limitations of insertion reactivity of [RAs] (e.g.

Functionalization, Fragmentation, and Expansion of cyclo-PR Ligands.

In this study, three isolobal complexes of the form [{LM}(η-PR)] ({LM}  = {CpMo(CO)} (A), {Cp'''Ni} (B), {Cp'''Co} (C), R = Ph, iPr; Cp''' = 1,2,4-BuCH) are reacted with nucleophilic carbenes (L). While C does not show any reactivity, the cationic complexes A and B undergo addition reactions. The respective products [CpMo(CO)(η-PRL)] (1a - d) and [Cp'''Ni(η-PRL)] (3a - d) show different geometries for the L-PPR ligands.

Polyphosphorus Ligand Complexes of Coinage Metals for Multiple Capturing of Intact P Tetrahedra.

Two- and three-component self-assembly reactions of [CpFe(η-P)] (Cp = C(CH) (Cp*, 1a), C(4-EtCH)) (Cp, 1b)) with the coinage metal salts [Cu(CHCN)][SbF] or AgSbF were investigated to study the prerequisites for the potential coordination of white phosphorus by using a sterically encumbered Cp ligand and noncoordinating anions. In the self-assembly reactions with white phosphorus, either 0D or 1D coordination complexes are formed, all of which feature coordinated intact P tetrahedra and thus comprise an unprecedented class of mixed polyphosphorus ligand complexes capable of complete release of P in solution confirmed by NMR studies. The bulkiness of the used Cp ligand and the correctly chosen solvent allowed for obtaining more beneficial structural motifs, the first discrete tetra- and penta-coordinated cyclo-P ligand complexes, that provide the maximal content of coordinated P molecules per species known so far.

Redox mediated dimerisation of a -As complex.

Reduction as well as oxidation of the -As complex [{Cp''Ta}(μ,η-As)] (A, Cp'' = 1,3- BuCH) are demonstrated to afford controlled dimerisation to unprecedented As species. The dication [{Cp''Ta}(μ,η-As)] slowly disproportionates in solution, yielding the largest polyarsenide species in a molecular complex known to date.

Synthesis of heteropnictogen ligands P transfer.

The heterodipnictogen complexes [{CpMo(CO)}(μ,η-PE)] (E = P, As, Sb) react with the phosphorus(I) transfer reagent [(BZIMPY)P][CFSO] (BZIMPY = 2,6-bis(benzimidazole-2-yl)pyridine) in a transmetallation reaction forming the unprecedented [CpMo(CO)(η-PE)] complexes.

Nucleophilic Functionalization of a Cationic Pentaphosphole Complex-A Systematic Study of Reactivity.

The systematic nucleophilic functionalization of the cationic pentaphosphole ligand complex [Cp*Fe(η-PMe)][OTf] (A) with group 16/17 nucleophiles is reported. This method represents a highly reliable and versatile strategy for the design of novel transition-metal complexes featuring twofold substituted end-deck cyclo-P ligands, bearing unprecedented hetero-element substituents. By the reaction of A with classical group 16 nucleophiles, complexes of the type [Cp*Fe(η-PMeE)] (E=OEt (1), OBu (2), SPh (3), SePh (4)) are obtained.

Synthesis and Redox Chemistry of CoE (E=P, As) Clusters.

The synthesis of the cluster complexes [(Cp'''Co)(μ,η:η:η-E)(μ-E)] (E=P (3), As (4)) starting from the anionic triple-decker complexes [K(18cr6)(dme)][(Cp'''Co)(μ,η:η-E)] (E=P (1), As (2)) by electrophilic quenching with the Co dimer [(Cp'''CoCl)] is reported. Both complexes show a distinct redox chemistry, which was first investigated by cyclic voltammetry. Subsequently, the monoanions [K(L)(sol)][(Cp'''Co)(μ,η:η:η-E)(μ-E)] (E=P, L=18cr6, sol=dme, n=2 (5), E=As, L=2,2,2-crypt, n=0 (6)), the monocations [(Cp'''Co)(μ,η:η:η-E)(μ-E)][FAl] (E=P (7), As (8)) and the dications [(Cp'''Co)(μ,η:η:η-E)][TEF] (E=P (9), As (10)) could be realized experimentally and isolated in moderate to good yields.

Enhancing the Reactivity of an Aromatic cyclo-P Ligand via Electrophilic Activation.

Electrophilic activation of the aromatic cyclo-P ligand in [Cp*Fe(η-P)] is demonstrated to drastically enhance its reactivity towards weak nucleophiles. Unprecedented functionalized, contracted as well as complexly aggregated polyphosphorus compounds are accessed utilizing [Cp*Fe(η-PMe)][OTf] (A), highlighting the great potential of this underexplored mode of reactivity. Addition of carbenes to A affords novel 1,2- or 1,1-difunctionalized cyclo-P complexes [Cp*Fe(η-P(1-L)(2-Me)][OTf] (L=IDipp (1), CAAC (2), IPr (3 b)) and [Cp*Fe(η-P(1-IPr)(1-Me)][OTf] (3 a).

Synthesis of Sb: Crafting a Homoatomic Antimony Nanotorus.

Pure-element cyclic molecules have garnered extensive attention owing to their intriguing structures and promising applications. Among these, carbon-based cyclic molecules such as []carbon (C, = 10-26) and carbon nanotori have ignited significant interest in both experimental and theoretical investigations. However, systematic investigations of analogous cyclic counterparts of heavier main-group elements are limited, with only a few known by theoretical studies.

High-Temperature Solid-State Post-Synthetic Modification of Highly Luminescent Cu(I) Metallacycles toward New Luminescent Thermic Tracers.

A new luminescent Cu(I) tetrametallic metallacycle B is reported that features very rare semi-bridging aqua ligands. When heated markedly above room temperature, this compound undergoes a post-synthetic transformation in the solid-state, affording the new luminescent metallacycle C. Thermogravimetric analysis, IR spectroscopy and single-crystal X-ray diffraction reveal that this alteration preserves the gross tetrametallic macrocycle structure, but is caused by the release of the coordinated water molecules with the concomitant formation of cuprophilic interactions.

Synthesis of bismuthanyl-substituted monomeric triel hydrides.

The syntheses and characterizations of the first bismuthanylborane monomers stabilized only by a donor in D·BHBi(SiMe) (D = DMAP 1a, IDipp 1b, IMe1c; DMAP = 4-dimethylaminopyridine, IDipp = 1,3-bis(2,6-diisopropylphenyl)-imidazolin-2-ylidene, IMe = 1,3,4,5-tetramethylimidazol-2-ylidene) are presented. All compounds were synthesized by salt metathesis reactions between D·BHI and KBi(SiMe)(THF) and represent some of the extremely rare compounds featuring a 2c-2e B-Bi bond in a molecular compound. The products display high sensitivity towards air and light and slowly decompose in solution even at -80 °C.

Potential of Mixed Dipnictogen Molybdenum Complexes in the Self-Assembly of Thallium Coordination Compounds.

The coordination chemistry of the homo- and heterodipnictogen tetrahedrane complexes [{CpMo(CO)}(μ,η-EE')] (E, E' = P, As, Sb) () toward Tl[BArF] ([BArF] = [B(3,5-CH(CF))]) was studied. Controlled by the used tetrahedranes , and thus depending on the respective pnictogen atoms, the monomers [Tl(η-)][BArF] ([]) and [Tl(η-)][BArF] ([]), the double substituted [Tl(η-)][BArF] ([]) or the even higher aggregated compounds [Tl(η-)(μ,η-)(μ,η-)][BArF] ([]), [Tl(η-)(μ,η-)] [BArF] ([]) and [Tl(η-)(μ,η-)][BArF] ([]) were obtained. Utilization of [BArF] promises additional stabilization of Tl via η-coordination of two of its aryl rings as found in compounds [], [] and [].

Homo- and heterobimetallic transition metal cluster derived from [Cp*Fe(η-E)] (E = P, As) - unprecedented structural motifs of the resulting polypnictogen ligands.

A general synthetic procedure to neutral homo- and heterobimetallic cage compounds exhibiting various structural motifs of the polypnictogen ligands starting from [Cp*Fe(η-E)] (E = P (1), As (2); Cp* = CMe) is reported. The impact of the implemented transition metal precursors {Cp'''M} (M = Cr, Mn, Fe, Ni; Cp''' = 1,2,4-BuCH) emphasises the variability of the isolated complexes exhibiting a broad variety of structural motifs of the pnictogen ligands. Spectroscopic, crystallographic, and theoretical investigations provide insight into the structure of the partially unprecedented polypnictogen ligands.

Extension and Fusion of Cyclic Polyantimony Units.

The synthesis and characterization of a series of polyantimony anionic clusters are reported. The products [(NbCp)Sb], [MSb] (M = Ru/Fe), and [MSb] (M = Ru/Fe) were isolated as either K(18-crown-6) or K([2.2.

Synthesis and Characterization of Novel Cobalt Carbonyl Phosphorus and Arsenic Clusters.

Phosphorus- and arsenic-containing cobalt clusters are an interesting class of compounds that continue to provide new structures with captivating bonding patterns. Although the first members of this family were reported 45 years ago, the number of such species is still limited within the broad family of transition metal complexes bearing pnictogen atoms. Herein, we present the reaction of Co(CO) as a cobalt source with a number of phosphorus- and arsenic-containing compounds under variable reaction conditions.

Supramolecular compounds assembled from the heteroleptic tetrahedral complex [{CpMo(CO)}(μ,η-AsSb)] and metal salts.

The reaction of the tetrahedral complex [{CpMo(CO)}(μ,η-AsSb)] with Cu and Ag salts is presented which gives unprecedented neutral and cationic supramolecular aggregates featuring mixed As/Sb-donor molecules as ligands/linkers between metal ions.

A Ruthenophosphanorcaradiene as a Synthon for an Ambiphilic Metallophosphinidene.

Reaction of the ruthenium carbene complex Cp*(IPr)RuCl () (IPr = 1,3-bis(Dipp)imidazol-2-ylidene; Dipp = 2,6-diisopropylphenyl) with sodium phosphaethynolate (NaOCP) led to intramolecular dearomatization of one of the Dipp substituents on the Ru-bound carbene to afford a Ru-bound phosphanorcaradiene, . Computations by DFT reveal a transition state characterized by a concerted process whereby CO migrates to the Ru center as the P atom adds to the π system of the aryl group. The phosphanorcaradiene possesses ambiphilic properties and reacts with both nucleophilic and electrophilic substrates, resulting in rearomatization of the ligand aryl group with net P atom transfer to give several unusual metal-bound, P-containing main-group moieties.

Electrophilic Functionalization of a Hexaphosphabenzene Ligand in [(Cp*Mo)(μ,η-P)].

The electrophilic functionalization of the triple-decker sandwich complex [{Cp*Mo}(μ,η-P)] (A) and its mono-oxidized counterpart [{Cp*Mo}(μ,η-P)][SbF] (B) with reactive main-group electrophiles as well as radical scavengers is shown to be a reliable method for the selective functionalization of the hexaphosphabenzene ligand. Depending on the electrophile used, the regioselectivity of the functionalization can be adjusted. Using group 16 electrophiles, the trisubstituted compounds [{Cp*Mo}{(μ,η-P)(μ,η-1,3-(SePh)-2-Br-P)}][TEF] (1), [{Cp*Mo}(μ,η-P)(μ,η-1,2,3-(EPh)-P)][SbF] (E=S (2), Se (3)) as well as the side product [{Cp*Mo}(μ,η-P)(μ,η-P(SPh))][SbF] (4) are obtained.

Cu(I) Complexes Comprising tetrahedral Mo E or Mo PE units (E=P, As, Sb) as Chelating Ligands.

Novel isomorphous tetranuclear complexes, [(dppf)Cu(μ ,η -E {CpMo(CO) } ]BF [E=P (1), As (4), Sb (5), (dppf=1,1'-bis-(diphenylphosphino)-ferrocene)] and [(dppf)Cu(μ ,η -PE{CpMo(CO) } ]BF [E=As (2), Sb(3)] were synthesized from the reactions between [(dppf)Cu(MeCN) ][BF ] and tetrahedral molybdenum complexes containing unsubstituted homo- and hetero-diatomic group-15 elements [(μ,η -E {CpMo(CO) } ] [E=P (A), As (D), Sb (E)] and [(μ,η -PE{CpMo(CO) } ] [E=As (B), Sb (C)], respectively. In all these products, the {Mo E } or {Mo PE} moieties coordinate the Cu(I) center via a rare side-on η -coordination mode. The X-ray structure analyses of [(dppf)Cu(μ ,η -PSb{CpMo(CO) } ][BF ] demonstrate, for the first time, the utilization of an η -coordination mode for the ligand complex C to coordinate to the Cu(I) center.

Novel synthetic route towards heteroleptic pnictogen-rich organometallic-inorganic coordination compounds.

The reaction of the Ag(I) dimer [Ag(η-A)(μ,η:η-A)][TEF] (A = [{CpMo(CO)}(μ,η-P)]) possessing labile η-coordinated P ligands with the organometallic dipnictogen compounds [{CpMo(CO)}(μ,η-EE')] (E = E' = As, Sb; E = P, E' = As, Sb) represents a facile synthetic route towards unprecedented heteroleptic pnictogen-rich supramolecular complexes. This method can also be extended to the analogous Cu(I) dimer and is studied by DFT computations.

NHC-Stabilized Mixed Group 13/14/15 Element Hydrides.

The syntheses of novel N-heterocyclic carbene (NHC) adducts of group 13, 14 and 15 element hydrides are reported. Salt metathesis reactions between NaPH and IDipp ⋅ GeH BH OTf (1) (IDipp=1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) led to mixtures of the two isomers IDipp ⋅ GeH BH PH (2 a) and IDipp ⋅ BH GeH PH (2 b); by altering the reaction conditions an almost exclusive formation of 2 b was achieved. Attempts to purify mixtures of 2 a and 2 b by re-crystallization from THF afforded a salt [IDipp ⋅ GeH BH  ⋅ IDipp][PHGeH BH PH BH GeH ] (4) that contains the novel anionic cyclohexyl-like inorganic heterocycle [PHGeH BH PH BH GeH ] .

Reactivity of [Cp*Fe(η -As )] towards Carbenes, Silylenes and Germylenes.

The reaction behavior of [Cp*Fe(η -As )] (I) (Cp*=C Me ) towards carbenes and their heavier analogs was investigated. The reaction of I with NHCs (NHCs=N-heterocyclic carbenes) results in the first substitution products of polyarsenic ligand complexes by NHCs [Cp*Fe(η -As NHC)] (1 a: NHC=IMe=1,3,4,5-tetramethylimidazolin-2-ylidene, 1 b: NHC=IMes=1,3-bis(2,4,6-trimethylphenyl)-imidazolin-2-ylidene). In contrast, the reaction of I with CAAC ( CAAC=2,6-diisopropylphenyl)-4,4-diethyl-2,2-dimethyl-pyrrolidin-5-ylidene) leads to a fragmentation and the formation of an unprecedented As -sawhorse-type compound [As (As CAAC) ] (2).