A nano-sized supramolecule beyond the fullerene topology

Cu(I) Complexes Comprising tetrahedral Mo2 E2 or Mo2 PE units (E=P, As, Sb) as Chelating Ligands

Novel isomorphous tetranuclear complexes, [(dppf)Cu(μ3 ,η2 : 2 : 2 -E2 {CpMo(CO)2 }2 ]BF4 [E=P (1), As (4), Sb (5), (dppf=1,1'-bis-(diphenylphosphino)-ferrocene)] and [(dppf)Cu(μ3 ,η2 : 2 : 2 -PE{CpMo(CO)2 }2 ]BF4 [E=As (2), Sb(3)] were synthesized from the reactions between [(dppf)Cu(MeCN)2 ][BF4 ] and tetrahedral molybdenum complexes containing unsubstituted homo- and hetero-diatomic group-15 elements [(μ,η2 : 2 -E2 {CpMo(CO)2 }2 ] [E=P (A), As (D), Sb (E)] and [(μ,η2 : 2 -PE{CpMo(CO)2 }2 ] [E=As (B), Sb (C)], respectively. In all these products, the {Mo2 E2 } or {Mo2 PE} moieties coordinate the Cu(I) center via a rare side-on η2 -coordination mode. The X-ray structure analyses of [(dppf)Cu(μ3 ,η2 : 2 : 1 -PSb{CpMo(CO)2 }2 ][BF4 ] demonstrate, for the first time, the utilization of an η1 -coordination mode for the ligand complex C to coordinate to the Cu(I) center. All the products were characterized by X-ray crystallography, NMR and IR spectroscopy, mass spectrometry and elemental analysis. Electrochemical studies also revealed the formation of 1-5, and, further, to understand the structure and bonding of the products, theoretical calculations using density functional theory (DFT) were conducted.

Snapshots of sequential polyphosphide rearrangement upon metallatetrylene addition

Insertion and functionalization of gallasilylenes [LPhSi-Ga(Cl)LBDI] (LPh = PhC(NtBu)2; LBDI = [{2,6-iPr2C6H3NCMe}2CH]) into the cyclo-E5 rings of [Cp*Fe(η5-E5)] (Cp* = η5-C5Me5; E = P, As) are reported. Reactions of [Cp*Fe(η5-E5)] with gallasilylene result in E-E/Si-Ga bond cleavage and the insertion of the silylene in the cyclo-E5 rings. [(LPhSi-Ga(Cl)LBDI){(η4-P5)FeCp*}], in which the Si atom binds to the bent cyclo-P5 ring, was identified as a reaction intermediate. The ring-expansion products are stable at room temperature, while isomerization occurred at higher temperature, and the silylene moiety further migrates to the Fe atom, forming the corresponding ring-construction isomers. Furthermore, reaction of [Cp*Fe(η5-As5)] with the heavier gallagermylene [LPhGe-Ga(Cl)LBDI] was also investigated. All the isolated complexes represent rare examples of mixed group 13/14 iron polypnictogenides, which could only be synthesized by taking advantage of the cooperativity of the gallatetrylenes featuring low-valent Si(ii) or Ge(ii) and Lewis acidic Ga(iii) units/entities.

Diantimony Complexes [CpR 2 Mo2 (CO)4 (μ,η2 -Sb2 )] (CpR =C5 H5 , C5 H4 t Bu) as Unexpected Ligands Stabilizing Silver(I)n (n=1-4) Monomers, Dimers and Chains

Synthesis and reactivity of transition metal compounds bearing "naked" pnictogen atoms is an active research area with remarkable bonding patterns observed in the formed compounds. Within this field, intense investigations on the coordination behavior of complexes possessing P_n and As_n (2≤n≤5) moieties have been conducted. However, studies on heavier analogues have been ignored so far due to arduous challenges related to low yields and moderate air stability. Herein, we present the first in-depth study addressing the reactivity of organometallic complexes containing Sb-donor atoms with several Ag^I salts. These reactions afforded twelve unprecedented aggregates as monomers, dimers as well as three- and four-membered chains of Ag^I ions claimed in the literature to be inaccessible. Interatomic distances as well as computational evidence obtained with help of several different methods suggest the presence of Ag⋅⋅⋅Ag interactions in all complexes containing more than one Ag^I ion.

Versatile Coordination of AgI and CuI Ions towards cyclo-As5 Ligands

The reactions of the cyclo‐As₅ complex [Cp*Fe(η⁵‐As₅)] (B) with the Ag^I and Cu^I salts of the weakly coordinating anion (WCA) [FAl{OC₆F₁₀(C₆F₅)}₃]⁻ ([FAl]⁻) are studied. These reactions allow the synthesis of the mononuclear complexes [M(η⁵ : η²‐B)₂][FAl] (M=Ag (1), Cu (2)) when a ratio of B/M(FAl) 2 : 1 is used. Compound 1 shows an unusual disorder of the central Ag^I cation between two π‐coordinating cyclo‐As₅ ligands, which is absent in 2 pointing to a weak interaction of the Ag center towards the cyclo‐As₅ ligands in B. When the ratio of B/Ag(FAl) is changed to 3 : 1 or 1 : 1, the respective coordination compounds [Ag(η²‐B)₃][FAl] (3) and [Ag₂(η² : η²‐B)₂][FAl]₂ (4) are accessible. The coordination modes of the cyclo‐As₅ units in 1, 3 and 4 are all different, reflecting the adaptive coordination behavior of B towards Ag^I ions. The optimized geometries in the gas phase of 1–4 are determined by DFT calculations to support the bonding situation observed in their solid‐state structures.

The Missing Parent Compound [(C5 H5 )Fe(η5 -P5 )]: Synthesis, Characterization, Coordination Behavior and Encapsulation

The so far missing parent compound of the large family of pentaphosphaferrocenes [CpFe(η5 -P5 )] (1 b) was synthesized by the thermolysis of [CpFe(CO)2 ]2 with P4 using the very high-boiling solvent diisopropylbenzene. It was comprehensively characterized by, inter alia, NMR spectroscopy, single crystal X-ray structure analysis, cyclic voltammetry and DFT computations. Moreover, its coordination behavior towards CuI halides was explored, revealing the unprecedented 2D polymeric networks [{CpFe(η5:1:1:1:1 -P5 )}Cu2 (μ-X)2 ]n (2 a: X=Cl, 2 b: X=Br) and [{CpFe(η5:1:1 -P5 )}Cu(μ-I)]n (3) and even the first cyclo-P5 -containing 3D coordination polymer [{CpFe(η5:1:1 -P5 )}Cu(μ-I)]n (4). The sandwich complex 1 b can also be incorporated in nano-sized supramolecules based on [Cp*Fe(η5 -P5 )] (1 a) and CuX (X=Cl, Br, I): [CpFe(η5 -P5 )]@[{Cp*Fe(η5 -P5 )}12 (CuX)20-n ] (5 a: X=Cl, n=2.4; 5 b: X=Br, n=2.4; 5 c: X=I, n=0.95). Thereby, the formation of the CuI-containing fullerene-like sphere 5 c is found for the first time.

Au-Containing Coordination Polymers Based on Polyphosphorus Ligand Complexes

Whereas the self-assembly of pentaphosphaferrocenes [Cp^RFe(η⁵-P₅)] (Cp^R = Cp*, Cp^×, and Cp^Bn) with Cu and Ag salts has been well-studied in the past, the coordination chemistry toward Au complexes has been left untouched so far. Herein, the results of the self-assembly processes of [Cp^RFe(η⁵-P₅)] with Au salts of different anions (GaCl₄^-, SbF₆^-, and Al(OC(CF₃)₃)₄ (TEF^-)) are reported. Next to a variety of molecular coordination products, the first coordination polymers based on polyphosphorus ligand complexes and Au salts are also obtained. Thereby, a 2D coordination polymer comprising metal vacancies is isolated. In all products, the Au centers are coordinated in a linear or a trigonal planar environment. In solution, highly dynamic processes are observed. Variable-temperature NMR spectroscopy, solid-state NMR spectroscopy, and X-ray powder diffraction were applied to gain further insight into selected coordination compounds.

Mixed Organometallic-Organic Hybrid Assemblies Based on the Diarsene Complex [Cp2 Mo2 (CO)4 (μ,η2 -As2 )], AgI Salts and N-Donor Organic Molecules

The reaction of the organometallic diarsene complex [Cp2 Mo2 (CO)4 (η2 -As2 )] (1) with Ag[Al{OC(CF3 )3 }4 ] (Ag[TEF]) yielded the AgI monomer [Ag(η2 -1)3 ][TEF] (2). This compound exhibits dynamic behavior in solution, which allows directed selective synthesis of unprecedented organometallic-organic hybrid assemblies upon its reaction with N-donor organic molecules by a stepwise pathway, which is supported by DFT calculations. Accordingly, the reaction of 2 with 2,2'-bipyrimidine (L1) yielded the dicationic molecular compound [{(η2 -1)2 Ag}2 (μ-L1)][TEF]2 (3) or the 1D polymer [{(η2 -1)Ag}(μ-L1)]n [TEF]n (4) depending on the ratio of the reactants. However, its reactions with the pyridine-based linkers 4,4'-bipyridine (L2), 1,2-bis(4-pyridyl)ethylene (L3) and 1,2-bis(4-pyridyl)ethyne (L4) allowed the formation of the 2D polymers [{(η2 -1)Ag}2 (μ-Lx)3 ]n [TEF]2n [Lx=L2 (5), L3 (6), L4 (7), respectively]. Additionally, this concept was extended to step-by-step one-pot reactions of 1, [Ag(CH3 CN)3 ][Al{OC(CF3 )2 (CCl3 )}4 ] ([Ag(CH3 CN)3 ][TEFCl ]) and linkers L2-L4 to produce the 2D polymers [{(η2 -1)Ag}2 (μ,Lx)3 ]n [TEFCl ]2n [Lx=L2 (8), L3 (9), L4 (10), respectively].

A construction guide for high-nuclearity (≥50 metal atoms) coinage metal clusters at the nanoscale: bridging molecular precise constructs with the bulk material phase

Synthesis remains a major strength in chemistry and materials science and relies on the formation of new molecules and diverse forms of matter. The construction and identification of large molecules poses specific challenges and has historically lain in the realm of biological (organic)-type molecules with evolved synthesis methods to support such endeavours. But with the development of analytical tools such as X-ray crystallography, new synthesis methods toward large metal-based (inorganic) molecules and clusters have come to the fore, making it possible to accurately determine the precise distribution of hundreds of atoms in large clusters. In this review, we focus on different synthesis protocols used to form new metal clusters such as templating, alloying and size-focusing strategies. A specific focus is on group 11 metals (Cu, Ag, Au) as they currently predominate large metal cluster investigations and related Au and Ag bulk surface phenomena. This review focuses on metal clusters that have very high-nuclearity, i.e. with 50 or more metal centers within the isolated cluster. This size domain, it is believed, will become increasingly important for a variety of applications as these metal clusters are positioned at the interface between the molecular and bulk phases, whilst remaining a classic nanomaterial and retaining unique nano-sized properties.

Linking of CuI Units by Tetrahedral Mo2 E2 Complexes (E=P, As)

The reaction of [Cp2 Mo2 (CO)4 (μ,η2:2 -E2 )] (A: E=P, B: E=As, Cp=C5 H5 ) with the WCA-containing CuI salts ([Cu(CH3 CN)4 ][Al{OC(CF3 )3 }4 ] (CuTEF, C), [Cu(CH3 CN)4 ][BF4 ] (D) and [Cu(CH3 CN)3.5 ][FAl{OC6 F10 (C6 F5 )}3 ] (CuFAl, E)) affords seven unprecedented coordination compounds. Depending on the E2 ligand complex, the counter anion of the copper salt and the stoichiometry, four dinuclear copper dimers and three trinuclear copper compounds are accessible. The latter complexes reveal first linear Cu3 arrays linked by E2 units (E=P, As) coordinated in an η2:1:1 coordination mode. All compounds were characterized by X-ray crystallography, NMR and IR spectroscopy, mass spectrometry and elemental analysis. To define the nature of the Cu⋅⋅⋅Cu⋅⋅⋅Cu interactions, DFT calculations were performed.

The Potential of the Diarsene Complex [(C5 H5 )2 Mo2 (CO)4 (μ,η2 -As2 )] as a Connector Between Silver Ions

The reaction of the organometallic diarsene complex [Cp₂Mo₂(CO)₄(μ,η²‐As₂)] (B) (Cp = C₅H₅) with Ag[FAl{OC₆F₁₀(C₆F₅)}₃] (Ag[FAl]) and Ag[Al{OC(CF₃)₃}₄] (Ag[TEF]), respectively, yields three unprecedented supramolecular assemblies [(η²‐B)₄Ag₂][FAl]₂ (4), [(μ,η¹:η²‐B)₃(η²‐B)₂Ag₃][TEF]₃ (5) and [(μ,η¹:η²‐B)₄Ag₃][TEF]₃ (6). These products are only composed of the complexes B and Ag^I. Moreover, compounds 5 and 6 are the only supramolecular assemblies featuring B as a linking unit, and the first examples of [Ag^I]₃ units stabilized by organometallic bichelating ligands. According to DFT calculations, complex B coordinates to metal centers through both the As lone pair and the As−As σ‐bond thus showing this unique feature of this diarsene ligand.

Use of a cyclo-P4 building block - a way to networks of host-guest assemblies

Despite the proven ability to form supramolecular assemblies via coordination to copper halides, organometallic building blocks based on four-membered cyclo-P4 ligands find only very rare application in supramolecular chemistry. To date, only three types of supramolecular aggregates were obtained based on the polyphosphorus end-deck complexes CpRTa(CO)2(η4-P4) (1a: CpR = Cp''; 1b: CpR = Cp'''), with none of them, however, possessing a guest-accessible void. To achieve this target, the use of silver salts of the weakly coordinating anion SbF6 - was investigated as to their self-assembly in the absence and in the presence of the template molecule P3Se4. The two-component self-assembly of the building block 1a and the coinage-metal salt AgSbF6 leads to the formation of 1D or 3D coordination polymers. However, when the template-driven self-assembly was attempted in the presence of an aliphatic dinitrile, the unprecedented barrel-like supramolecular host-guest assembly P3Se4@[{(Cp''Ta(CO)2(η4-P4))Ag}8]8+ of 2.49 nm in size was formed. Moreover, cyclo-P4-based supramolecules are connected in a 2D coordination network by dinitrile linkers. The obtained compounds were characterised by mass-spectrometry, 1H and 31P NMR spectroscopy and X-ray structure analysis.

The Potential of the Diphosphorus Complex [Cp2W2(CO)4(η2-P2)] as an Organometallic Connecter in Supramolecular Chemistry

For the first time, the tetrahedral diphosphorus complex [Cp2W2(CO)4(µ,η2:η2-P2)] (Cp = C5H5) (3) is used as a connecter in supramolecular chemistry. The treatment of 3 with CuI halides leads to the formation of the new one-dimensional (1D) linear polymers [Cu(µ-X){Cp2W2(CO)4(µ,η2:η2:η1:η1-P2)}] n {X = Cl (4), Br (5), I (6)}. The coordination polymers (CPs) 4-6 are almost insoluble in organic solvents, thus, their 31P MAS-NMR spectra were recorded and found to be remarkably influenced by their solid-state structures. Additionally, we demonstrate that by reacting the Cp-substituted diphosphorus complex [Cp'2W2(CO)4(µ,η2:η2-P2)] {Cp' = C5H4{C(CH3)3}} (7) with CuBr, the unprecedented soluble 1D CP [Cu(µ-Br){Cp'2W2(CO)4(µ,η2:η2:η1:η1-P2)}] n (8) is obtained. Furthermore, the reactions of 3 with the AgI salts Ag[CF3SO3] and Ag[PF6] result in the formation of the oligomeric dicationic species [Ag2{Cp2W2(CO)4(µ,η2:η2:η2-P2)}2 {Cp2W2(CO)4(µ,η2:η2:η1:η1-P2)}2][X']2 {X' = [CF3SO3]- (9), [PF6]- (10)}.

The Potential of Molybdenum Complexes Bearing Unsubstituted Heterodiatomic Group 15 Elements as Linkers in Supramolecular Chemistry

The reactions of tetrahedral molybdenum complexes bearing unsubstituted heterodiatomic Group 15 elements, [Cp₂ Mo₂ (CO)₄ (μ,η² :η² -PE)] (Cp=C₅ H₅ ; E=As (1), Sb (2)), with Cu^I halides afforded seven unprecedented neutral supramolecular assemblies. Depending on the Mo₂ PE units and the Cu^I halide, the oligomers [⟨{Cp₂ Mo₂ (CO)₄ }{μ₄ ,η² :η² :η² :η¹ -PE}⟩₄ ⟨{CuX}{Cu(μ-X)}⟩₂ ] (E=As (X=Cl (3), Br (4)); E=Sb (X=Cl (6), Br (7))) or the 1D coordination polymers [{Cp₂ Mo₂ (CO)₄ }{μ₄ ,η² :η² :η¹ :η¹ -PAs}{Cu(μ-I)}]_n (5) and [{Cp₂ Mo₂ (CO)₄ }{μ₄ ,η² :η² :η² :η¹ -PSb}₂ {Cu(μ-X)}₃ ]_n (X=I (8), Br (9)) are accessible. These solid-state aggregates are the first and only examples featuring the organometallic heterodiatomic Mo₂ PE complexes 1 and 2 as linking moieties. DFT calculations demonstrate that complexes 1 and 2 present a unique class of mixed-donor ligands coordinating to Cu^I centers via the P lone pair and the P-E σ-bond, revealing an unprecedented coordination mode.

From nano-balls to nano-bowls

Pentaphosphaferrocene [Cp*Fe(η5-P5)] in combination with Cu(i) halides is capable of a template-directed synthesis of fullerene-like spheres. Herein, we present the use of a triple decker complex as template that leads to the formation of unprecedented 'nano-bowls'. These spherical domes resemble the truncated fullerenes I h-C80 and represent a novel spherical arrangement in the chemistry of spherical molecules.

Highly soluble Cu(i)-acetonitrile salts as building blocks for novel phosphorus-rich organometallic-inorganic compounds

The synthesis of the air-stable and highly soluble Cu(i)-acetonitrile salts [Cu(CH3CN)3.5][FAl] (1) ([FAl] = FAl{OC(C6F10)(C6F5)}3) and [Cu(CH3CN)4][TEF] (2) ([TEF] = Al{OC(CF3)3}4) is presented. Compound 1 reacts with the organometallic polyphosphorus complexes [Cp2Mo2(CO)4(η2-P2)] (A) and [(Cp*Fe(η5-P5)] (B) and salt 2 reacts with B to form one new (3) and three unprecedented (4-6) phosphorus-rich Cu(i) dimers with the general formulas [Cu2(μ,η1:η1-A)2(η2-A)2][FAl]2 (3), [Cu2(μ,η1:η1-A)2(η1-CH3CN)4][FAl]2 (4), [Cu2(μ,η1:η1-B)2(η1-CH3CN)4][FAl]2 (5) and [Cu2(μ,η1:η1-B)2(η1-CH3CN)4][TEF]2 (6).

Organometallic-Organic Hybrid Polymers Assembled from Pentaphosphaferrocene, Bipyridyl Linkers, and CuI Ions

A multicomponent approach of the P n ligand complex [Cp*Fe(η5-P5)] (1: Cp* = η5-C5Me5) with the ditopic organic linkers 4,4'-bipyridine (2) or trans-1,2-di(pyridine-4-yl)ethene (3) in the presence of CuI salts of the anions [BF4]- and [PF6]- or the coordinating anion Br-, leads to the formation of four novel organometallic-organic hybrid polymers: the cationic 1D polymeric compounds [Cu4{Cp*Fe(µ3,η5:1:1-P5)}2(µ,η1:1-C10H8N2)4(CH3CN)4] n [BF4]4n (4) and [Cu4{Cp*Fe(µ3,η5:1:1-P5)}2(µ,η1:1-C10H8N2)4(CH3CN)4] n [PF6]4n (5) as well as the unique neutral threefold 2D → 2D interpenetrated networks [Cu2Cl2{Cp*Fe(µ3,η5:1:1-P5)}(µ,η1:1-C12H10N2)] n (6) and [Cu2Br2{Cp*Fe(µ3,η5:1:1-P5)}(µ,η1:1-C10H8N2)] n (7).

Synthesis and Reactivity of an End-Deck cyclo-P4 Iron Complex

Reduction of the Fe^II complex [(^Ph PP₂^Cy )FeCl₂ ] (2) generated an electron-rich and unsaturated Fe⁰ species, which was reacted with white phosphorus. The resulting new complex, [(^Ph PP₂^Cy )Fe(η⁴ -P₄ )] (3), is the first iron cyclo-P₄ complex and the only known stable end-deck cyclo-P₄ complex outside Group V. Complex 3 features an Fe^II center, as shown by Mössbauer spectroscopy, associated to a P₄^2- fragment. The distinct reactivity of complex 3 was rationalized by analysis of the molecular orbitals. Reaction of complex 3 with H⁺ afforded the unstable complex [(^Ph PP₂^Cy )Fe(η⁴ -P₄ )(H)]⁺ (4), whereas with CuCl and BCF, the complexes [(^Ph PP₂^Cy )Fe(η⁴ :η¹ -P₄ )(μ-CuCl)]₂ (5) and [(^Ph PP₂^Cy )Fe(η⁴ :η¹ -P₄ )B(C₆ F₅ )₃ ] (6) were formed.

Neutral two-dimensional organometallic–organic hybrid polymers based on pentaphosphaferrocene, bipyridyl linkers and CuCl

The reaction of the P_n ligand complex [Cp*Fe(η⁵-P₅)] (1: Cp* = η⁵-C₅Me₅) with CuCl in the presence of 4,4′-bipyridine or 1,2-di(4-pyridyl)ethylene leads to the formation of three unprecedented neutral 2D organometallic–organic hybrid networks.

Tuning the dimensionality of organometallic–organic hybrid polymers assembled from [Cp2Mo2(CO)4(η2-P2)], bipyridyl linkers and AgI ions

The first of its kind study of the effect of the organic linker length and reaction temperature on aggregation reactions leading to organometallic–organic hybrid polymers is presented.

Preorganized AgI Bimetallic Precursor with Labile Diphosphorus Ligands for a Programmed Synthesis of Organometallic-Organic Hybrid Polymers

An AgI dimer capped with labile organometallic diphosphorus ligands [Cp2 Mo2 (CO)4 (η2 -P2 )] (Cp=C5 H5 ) acts as a highly pre-organized molecular precursor to direct the construction of 1D or 2D, and 3D organometallic-organic hybrid coordination polymers upon reaction with ditopic pyridine-based linkers. The formation of the supramolecular aggregates can be controlled by the stoichiometry of the organic molecules, and the mechanism is supported by DFT calculations.

An Icosidodecahedral Supramolecule Based on Pentaphosphaferrocene: From a Disordered Average Structure to Individual Isomers

Pentaphosphaferrocenes [CpR Fe(η5 -P5 )] (1) and CuI halides are excellent building blocks for the formation of discrete supramolecules. Herein, we demonstrate the potential of Cu(CF3 SO3 ) for the construction of the novel 2D polymer [{Cp*Fe(μ4 ,η5:1:1:1 -P5 )}{Cu(CF3 SO3 )}]n (2) and the unprecedented nanosphere (CH2 Cl2 )1.4 @[{CpBn Fe(η5 -P5 )}12 {Cu(CF3 SO3 )}19.6 ] (3). The supramolecule 3 has a unique scaffold beyond the fullerene topology, with 20 copper atoms statistically distributed over the 30 vertices of an icosidodecahedron. Combinatorics was used to interpret the average disordered structure of the supramolecules. In this case, only two pairs of enantiomers with D5 and D2 symmetry are possible for bidentate bridging coordination of the triflate ligands. DFT calculations showed that differences in the energies of the isomers are negligible. The benzyl ligands enhance the solubility of 3, enabling NMR-spectroscopic and mass-spectrometric investigations.

Strategies for the Construction of Supramolecular Dimers versus Homoleptic 1D Coordination Polymers Starting from the Diphosphorus [Cp2Mo2(CO)4(η2-P2)] Complex and Silver(I) Salts

The reactions of the tetrahedral diphosphorus [Cp₂Mo₂(CO)₄(η²‐P₂)] (1; Cp = C₅H₅) complex with Ag[Al{OC(CF₃)₃}₄] (AgTEF) (A) and Ag[FAl{OC(C₆F₅)(C₆F₁₀)}₃] (AgFAl) (B) were studied. The first reaction led to the formation of the [Ag₂(η²‐1)₂(η¹:η¹‐1)₂][TEF]₂ (2) dimer and the [Ag₂(η¹:η¹‐1)₃]_n[TEF]_2n (3) coordination polymer, whereas the second reaction afforded the [Ag₂(η¹:η¹‐1)₂(η¹‐CH₂Cl₂)₂(η²‐C₇H₈)₂][FAl]₂ (4) or the [Ag₂(η²‐1)₂(η¹:η¹‐1)₂][FAl]₂ (5) dimer and the [Ag₂(η¹:η¹‐1)₄]_n[FAl]_2n (6) coordination polymer. In each case, the products obtained depended on the ratio of the reactants and/or the synthetic procedure.

The Cobalt cyclo-P4 Sandwich Complex and Its Role in the Formation of Polyphosphorus Compounds

A synthetic approach to the sandwich complex [Cp′′′Co(η⁴‐P₄)] (2) containing a cyclo‐P₄ ligand as an end‐deck was developed. Complex 2 is the missing homologue in the series of first‐row cyclo‐P_n sandwich complexes, and shows a unique tendency to dimerize in solution to form two isomeric P₈ complexes [(Cp′′′Co)₂(μ,η⁴:η²:η¹‐P₈)] (3 and 4). Reactivity studies indicate that 2 and 3 react with further [Cp′′′Co] fragments to give [(Cp′′′Co)₂(μ,η²:η²‐P₂)₂] (5) and [(Cp′′′Co)₃P₈] (6), respectively. Furthermore, complexes 2, 3, and 4 thermally decompose forming 5, 6, and the P₁₂ complex [(Cp′′′Co)₃P₁₂] (7). DFT calculations on the P₄ activation process suggest a η³‐P₄ Co complex as the key intermediate in the synthesis of 2 as well as in the formation of larger polyphosphorus complexes via a unique oligomerization pathway.

The Diphosphorus Complex [Cp2Mo2(CO)4(η2-P2)] as a Building Block for the Synthesis of Mixed-Hybrid Coordination Polymers

The three-component reaction of the tetrahedral diphosphorus complex [Cp2Mo2(CO)4(η2-P2)] (1), with Ag[BF4] (2) in the presence of 2,2'-bipyrimidine (3) leads to the formation of the two novel two-dimensional networks 4 and 5. Compound 4 is a new two-dimensional organometallic-organic hybrid polymer, while derivative 5 represents a unique two-dimensional organometallic-inorganic-organic hybrid polymer. These results show the possibility of synthesizing a new class of coordination polymers, which could not be obtained from two-component reactions with organic molecules in addition of metal ions.

A cyclo-P6 Ligand Complex for the Formation of Planar 2D Layers

The all-phosphorus analogue of benzene, stabilized as middle deck in triple-decker complexes, is a promising building block for the formation of graphene-like sheet structures. The reaction of [(CpMo)2 (μ,η(6) :η(6)-P6)] (1) with CuX (X=Br, I) leads to self-assembly into unprecedented 2D networks of [{(CpMo)2P6}(CuBr)4 ]n (2) and [{(CpMo)2 P6}(CuI)2]n (3). X-ray structural analyses show a unique deformation of the previously planar cyclo-P6 ligand. This includes bending of one P atom in an envelope conformation as well as a bisallylic distortion. Despite this, 2 and 3 form planar layers. Both polymers were furthermore analyzed by (31)P{(1)H} magic angle spinning (MAS) NMR spectroscopy, revealing signals corresponding to six non-equivalent phosphorus sites. A peak assignment is achieved by 2D correlation spectra as well as by DFT chemical shift computations.

Acid-Base-Triggered Structural Transformation of a Polyoxometalate Core Inside a Dodecahedrane-like Silver Thiolate Shell

Self-assembly of metavanadate and organosilver(I) salts leads to a novel dodecahedrane-like [Ag30 ((t) BuS)20 ](10+) silver(I) thiolate nanocage that tightly wraps an unusual C2h polyoxovanadate anion. The polyoxovanadate core undergoes transformation to a D3d configuration upon acidification, and reverts back to its original C2h structure upon addition of base. Chromism was observed for the silver(I) thiolate cluster during the configurational change of the central polyoxovanadate core; the color of the solution changes reversibly from green to dark yellow. This work represents the first reported example of chromic polyoxometalate-templated silver(I) thiolate shells that respond to external acid-base stimuli. It also represents an important advance in providing crystallographic proof that structural transformations occur in a nanoscale core-shell cluster.

Low temperature isolation of a dinuclear silver complex of the cyclotetraphosphane [ClP(μ-PMes*)]2

The reaction of the cyclotetraphosphane [ClP(μ-PMes*)]2 (, Mes* = 2,4,6-tri-tert-butylphenyl) with Ag[Al(OR(F))4] (R(F) = CH(CF3)2) resulted in a labile, dinuclear silver complex of , which eliminates AgCl above -30 °C. Its properties were investigated by spectroscopic methods, single crystal X-ray diffraction and DFT calculations.

Giant Spherical Cluster with I-C140 Fullerene Topology

We report on an effective cluster expansion of CuBr-linked aggregates by the increase of the steric bulk of the Cp(R) ligand in the pentatopic molecules [Cp(R)Fe(η(5)-P5)]. Using [Cp(BIG)Fe(η(5)-P5)] (Cp(BIG)=C5(4-nBuC6H4)5), the novel multishell aggregate [{Cp(BIG)Fe(η(5:2:1:1:1:1:1)-P5)}12(CuBr)92] is obtained. It shows topological analogy to the theoretically predicted I-C140 fullerene molecule. The spherical cluster was comprehensively characterized by various methods in solution and in the solid state.

Redox and Coordination Behavior of the Hexaphosphabenzene Ligand in [(Cp*Mo)2 (μ,η(6) :η(6) -P6 )] Towards the "Naked" Cations Cu(+) , Ag(+) , and Tl(.)

Although the cyclo-P₆ complex [(Cp*Mo)₂(μ,η⁶:η⁶-P₆)] (1) was reported 30 years ago, little is known about its chemistry. Herein, we report a high-yielding synthesis of 1, the complex 2, which contains an unprecedented cyclo-P₁₀ ligand, and the reactivity of 1 towards the “naked” cations Cu⁺, Ag⁺, and Tl⁺. Besides the formation of the single oxidation products 3 a,b which have a bisallylic distorted cyclo-P₆ middle deck, the [M(1)₂]⁺ complexes are described which show distorted square-planar (M=Cu(4 a), Ag(4 b)) or distorted tetrahedral coordinated (M=Cu(5)) M⁺ cations. The choice of solvent enabled control over the reaction outcome for Cu⁺, as proved by powder XRD and supported by DFT calculations. The reaction with Tl⁺ affords a layered two-dimensional coordination network in the solid state.

E4 Butterfly Complexes (E=P, As) as Chelating Ligands

The coordination properties of new types of bidentate phosphane and arsane ligands with a narrow bite angle are reported. The reactions of [{Cp'''Fe(CO)2 }2 (μ,η(1:1) -P4 )] (1 a) with the copper salt [Cu(CH3 CN)4 ][BF4 ] leads, depending on the stoichiometry, to the formation of the spiro compound [{{Cp'''Fe(CO)2 }2 (μ3 ,η(1:1:1:1) -P4 )}2 Cu](+) [BF4 ](-) (2) or the monoadduct [{Cp'''Fe(CO)2 }2 (μ3 ,η(1:1:2) -P4 ){Cu(MeCN)}](+) [BF4 ](-) (3). Similarly, the arsane ligand [{Cp'''Fe(CO)2 }2 (μ,η(1:1) -As4 )] (1 b) reacts with [Cu(CH3 CN)4 ][BF4 ] to give [{{Cp'''Fe(CO)2 }2 (μ3 ,η(1:1:1:1) -As4 )}2 Cu](+) [BF4 ](-) (5). Protonation of 1 a occurs at the "wing tip" phosphorus atoms, which is in line with the results of DFT calculations. The compounds are characterized by spectroscopic methods (heteronuclear NMR spectroscopy and IR spectrometry) and by single-crystal X-ray diffraction studies.