Metalloxane des Siliciums und Germaniums mit dem 2‐(Dimethylaminomethyl)ferrocenyl‐Liganden (FcN): Darstellung und Molekülstrukturen von (FcN)4M4O4(OH)4(M = Si,Ge), (FcN)6Ge6O8(OH)2 und von (FcN)2Si(OH)2

Metalloxanes of Silicon and Germanium with the 2‐(Dimethylaminomethyl)‐ferrocenyl Ligand (FcN): Synthesis and Molecular Structures of (FcN)₄M₄O₄(OH)₄(M = Si, Ge), (FcN)₆Ge₆O₈(OH)₂ and of (FcN)₂Si(OH)₂ (FcN)₄M₄O₄(OH)₄ · H₂O [FcN = 2‐(dimethylaminomethyl)ferrocenyl, M = Si ( 2 ) und Ge ( 3 )] are prepared by hydrolysis of FcNSiCl₃ or FcNGeCl₃ ( 1 ) in Et₂O in the presence of (NH₄)₂CO₃. The tricyclic compound (FcN)₆Ge₆O₈(OH)₂ ( 4 ) is formed after treatment of the hydrolysis solution of FcNGeCl₃ with CaH₂. (FcN)₂Si(OH)₂ ( 5 ) was sythesized by hydrolysis of (FcN)₂SiCl₂ under similar conditions. Compounds 1 — 5 are obtained as yellow orange crystals, the molecular structures of 1 — 5 were determinated by X‐ray diffraction. 2 and 3 are 8‐membered Si‐O/Ge‐O cycles with one OH and one FcN‐ligand on each Si or Ge atom, respectively. Compound 4 represents a stair‐like tricyclic Ge‐O structure whereas 5 is a discrete Silanediol. 2 — 5 show O‐H···N hydrogene bridges of the OH groups to the nitrogen atoms of the FcN substituents.     

Expansion of Germanato‐Polyoxovanadate Cluster Cores: Solvothermal Syntheses and Selected Properties of (trenH2)2[{M(tren)}4V15Ge6O48(H2O)] (M = Co and Zn)

Two germanato‐polyoxovanadates with the {V₁₅Ge₆O₄₈} cluster core are extended by covalent bonds to four transition metal amine complexes [M(tren)]²⁺ (M = Co and Zn, tren = tris(2‐aminoethyl)amine). The complexes have bonds to terminal atoms of the Ge₂O₇ units and such expansion of a germanato‐polyxovanadate was never observed before. The characterization of these compounds revealed the presence of two protonated tren molecules charge balancing the negative charges of the [{M(tren)}₄V₁₅Ge₆O₄₈(H₂O)]^4– anion.     

μ-Oxalato Complexes du Molybdène(V) et (VI) et du Niobium(V)

Molybdenum(V) and (VI) and Niobium (V) μ-Oxalato Complexes The complexation of the « oxalato » ligand as bis-(bidentate) bridge in the solid compounds {(C₂H₅)₄N}₂ {M₂^VO₂X₆(C₂O₄)} or {(C₂H₅)₄N}₂ {M^VIO₄X₄(C₂O₄)} (with M^V = Mo or Nb; M^VI = Mo and X = F, Cl, Br) is characterized on the basis of their infrared spectra and analytical data. The behaviour, of the Mo^V dimer compounds in near corresponding mononuclear species at room temperature, because of the low interaction between metallic ions.     

A series of Wells-Dawson and Keggin-based compounds with uncoordinated S donors as fluorescence sensors to Hg2+

Abstract

Through using a S-containing ligand 2,2’-dimethyl-4,4’-bithiazole (dbt), a series of Wells-Dawson and Keggin-based compounds, {Zn(dbt)₃}{Zn(dbt)₂(H₂O)}₂{HP₂W^VW^VI₁₇O₆₂}·4H₂O (1), {Cd(dbt)₂(H₂O) (HP₂W^VW^VI₁₇O₆₂)}{Cd(dbt)₃}{Cd(dbt)₂(H₂O)}·13H₂O (2), {Cd₂(dbt)₄Cl} {PW₁₂O₄₀} (3) and {Cd₂(dbt)₄}{SiW₁₂O₄₀} (4), were synthesized under hydrothermal conditions and structurally characterized. In 1, there are three dissociated subunits: Wells-Dawson anion, {Zn(dbt)₃}²⁺ and {Zn(dbt)₂(H₂O)}²⁺. In 2, the mono-supporting Wells-Dawson anions exhibit abundant hydrogen bonding interactions with discrete {Cd(dbt)₃}²⁺ and {Cd(dbt)₂(H₂O)}²⁺ mononuclear coordination complexes, constructing a supramolecular layer. Compound 3 has a binuclear Cd cluster {Cd₂(dbt)₄Cl}⁴⁺ with a Cl as a bridging atom. The Keggin anions link these binuclear Cd clusters alternately to build a 1D chain. In 4, a pair of {Cd(dbt)₂}²⁺ subunits connect adjacent Keggin anions and a 1D chain is formed. In these four compounds, only the N donors coordinate with Zn or Cd and the S atoms are uncoordinated. These compounds show good fluorescence sensing performance to Hg²⁺. We also studied the electrochemical and photocatalytic properties of 1–4. These compounds also can act as electrochemical sensors for the detection of nitrite.     

A Novel Expansion Mode of Polyoxovanadate Clusters: Synthesis,Crystal Structure and Properties of {[Cu(H2O)(C5H14N2)2]2[V16O38(Cl)]}·4(C5H16N2)

The new polyoxovanadate (POV) compound {[Cu(H₂O)(C₅H₁₄N₂)₂]₂[V₁₆O₃₈(Cl)]} · 4(C₅H₁₆N₂) was synthesized under solvothermal conditions and crystallizes in the tetragonal space group I4₁/amd with a = 13.8679(6), c = 45.558(2) Å, V = 8761.7(7) ų. The central structural motif is a {V₁₆O₃₈(Cl)} cluster constructed by condensation of 16 square‐pyramidal VO₅ polyhedra. The cluster hosts a central Cl^– anion. According to valence bond sum calculations, chemical analysis and magnetic properties the cluster anion may be formulated as [V₁₅^IVV^VO₃₈(Cl)]^12–, i.e., only one vanadium atom is not reduced. To the best of our knowledge this is the first reported {V₁₆O₃₈(X)} cluster in this V^IV:V^V ratio. The presence of the two different vanadium oxidation states is clearly seen in the IR spectrum. An unusual and hitherto never observed structural feature is the binding mode between the [Cu(H₂O)(C₅H₁₄N₂)₂]²⁺ complexes and the [V₁₅^IVV^VO₃₈(Cl)]^12– anion. The Cu²⁺ ion binds to a μ₂‐O atom of the cluster anion whereas in all other transition metal complex‐augmented POVs bonding between the transition metal cation and the anion occurs through terminal oxygen atoms of the POV. The magnetic properties are dominated by strong antiferromagnetic exchange interactions between the V⁴⁺ d¹ centers, whereas the Cu²⁺ d⁹ cations are magnetically decoupled from the cluster anion. Upon heating, the title compound decomposes in a complex fashion.     

NiII36-Containing 54-Tungsto-6-Silicate: Synthesis,Structure, Magnetic and Electrochemical Studies

The 36-Ni^II-containing 54-tungsto-6-silicate, [Ni₃₆(OH)₁₈(H₂O)₃₆(SiW₉O₃₄)₆]⁶⁻ ( Ni₃₆ ) was synthesized by a simple one-pot reaction of the Ni₂-pivalate complex [Ni₂(μ-OH₂)(O₂CCMe₃)₄(HO₂CCMe₃)₄] with the trilacunary [SiW₉O₃₄]¹⁰⁻ polyanion precursor in water and structurally characterized by a multitude of physicochemical techniques including single-crystal XRD, FTIR, TGA, elemental analysis, magnetic and electrochemical studies. Polyanion Ni₃₆ comprises six equivalent {Ni^II₆SiW₉} units which are linked by Ni−O−W bridges forming a macrocyclic assembly. Magnetic studies demonstrate that the {Ni₆} building blocks in Ni₃₆ remain magnetically intact while forming a hexagonal ring with antiferromagnetic exchange interactions between adjacent {Ni₆} units. Electrochemical studies indicate that the first reduction is reversible and associated with the W^VI/V couple, whereas the second reduction is irreversible attributed to the Ni^II/0 couple.     

High Nuclearity Antimonato‐Polyoxovanadate Cluster {V15Sb6O42} as a Synthon for the Solvothermal in situ Generation of α‐ and β‐{V14Sb8O42} Isomers

New heteroatom polyoxovanadates (POVs) were synthesized by applying a water‐soluble high‐nuclearity cluster as new synthon. The [V₁₅Sb₆O₄₂]^6? cluster shell exhibiting D₃ symmetry was in situ transformed into completely different cluster shells, namely, the α‐[V₁₄Sb₈O₄₂]^4? isomer with D_2d and the β‐[V₁₄Sb₈O₄₂]^4? isomer with D_2h symmetry. The solvothermal reaction of {Ni(en)₃}₃[V₁₅Sb₆O₄₂(H₂O)_x] ? 15 H₂O (x=0 or 1; en=ethylenediamine) in water led to the crystallization of [{Ni(en)₂}₂V₁₄Sb₈O₄₂] ? 5.5 H₂O containing the β‐isomer. The addition of [Ni(phen)₃](ClO₄)₂ ? 0.5 H₂O (phen=1,10‐phenanthroline) to the reaction slurry gave the new compound {Ni(phen)₃}₂[V₁₄Sb₈O₄₂] ? phen ? 12 H₂O with the α‐isomer. Both transformation reactions are complex due the change of symmetry, the chemical composition, and rearrangement of the VO₅ square pyramids and Sb₂O₅ handle‐like moieties.     

Hydrothermal synthesis and structural characterization of two new reduced phosphomolybdates based on an organoamine template and copper ion

Two new compounds, (H₂en)₃(H₂enMe)₄(H₃O){Cu^I[Mo^V ₆O₁₂(OH)₃(HPO₄)(PO₄)₃]₂}?·?6H₂O (1) and (H₂enMe)₄{Cu^ICu^II[Mo^V ₆O₁₂(OH)₃(PO₄)(HPO₄)₂(H₂PO₄)]₂}?·?3H₂O (2), were hydrothermally synthesized and characterized by elemental analysis, IR, TGA, and single-crystal X-ray diffraction analysis. Crystallographic analysis reveals that 1 is constructed from cluster anions {Cu^I[Mo^V ₆O₁₂(OH)₃(HPO₄)(PO₄)₃]₂}^15?, protonated organic amines, and water molecules. Each cluster is bridged through hydrogen bonds to form a 3-D supermolecular structure. For 2, {Cu^I[Mo^V ₆O₁₂(OH)₃(PO₄)(HPO₄)₂(H₂PO₄)]₂}^11? are connected by Cu^II cations to form an infinite chain. The formation of 1 and 2 reveals that organoamines influence the structures of the crystals.     

Hydrothermal syntheses and crystal structures of two organic–inorganic hybrid molybdovanadates based on [V2Mo6(OH)2O24]4− and [VMo12O40]3− polyoxoanions

Two new organic–inorganic hybrid cobalt-molybdovanadates [Co(phen)₃]H₂[H₂V₂Mo₆O₂₆] · 7H₂O (1) and [Co(2,2′-bipy)₃][Na(H₂O)₇][VMo₁₂O₄₀] (2) have been hydrothermally synthesized and structurally characterized by elemental analyses, IR, UV, XPS spectroscopy, thermogravimetric (TG) analyses, and X-ray single crystal diffraction. The molecular structure of 1 consists of a [V₂Mo₆(OH)₂O₂₄]^4? polyoxoanion, a [Co(phen)₃]²⁺, two H⁺ and seven lattice water molecules. The structure of [V₂Mo₆(OH)₂O₂₄]^4? consists of six MoO₆ octahedra and two VO₄ tetrahedra; six MoO₆ octahedra are linked by edge-sharing oxygens forming a {Mo₆} ring, and two VO₄ tetrahedra cap opposite sides of the {Mo₆} ring. The molecular structural unit of 2 is constructed from a typical Keggin-type [VMo₁₂O₄₀]^3? polyoxoanion and a [Co(2,2′-bipy)₃]²⁺ cation and a Na⁺ countercation; Co²⁺ is coordinated by six nitrogens from three 2,2′-bipyridines forming a distorted octahedron.     

Solvatothermal Syntheses and Structural Characterizations of Polyoxoalkoxometalates: The Heptanuclear [{Fe(OH)(CH3CN)2} Fe6OCl6{(OCH2)3CCH2OH}4], the Decanuclear [Fe10O2Cl8{(OCH2)3CCH2CH3}6], and the Bimetallic [(VO)2Fe8O2Cl6{(OCH2)3CCH2CH3}6]

Solvatothermal syntheses have been exploited to effect the isolation of three novel polyoxoalkoxometalate clusters, [{Fe(OH)(CH₃CN)₂} Fe₆OCl₆{(OCH₂)₃CCH₂OH}₄] (1), [Fe₁₀O₂Cl₈{(OCH₂)₃CCH₂CH₃}₆] (2), and [(VO)₂Fe₈O₂Cl₆{(OCH₂)₃CCH₂CH₃}₆] (3). The structure of 1 may be described as a hexametalate core {Fe₆OCl₆}¹⁰⁺, consisting of a octahedral arrangement of chloride ligands encasing an octahedron of six Fe(III) sites, with a central oxo group. The remaining four coordination sites at each octahedral iron center are occupied by doubly bridging oxygen donors from the trisalkoxo ligands. One triangular face of this substructure, defined by three oxygen atoms, from three adjacent trisalkoxo ligands, is capped by the {Fe(OH)(CH₃CN)₂}²⁺ subunit. The structure of 2 is based on the decametalate core of edge-sharing octahedra. The eight peripheral Fe(III) sites of the cluster bond to four oxygen donors from the trisalkoxo ligands, a terminal Cl^– ligand, and one of the ⁶-oxo groups. The two central iron sites are linked to four oxygen donors from the trisalkoxo ligands and to both of the ⁶-oxo groups. Cluster 3 is structurally related to 2 with two {FeCl}²⁺ units replaced by {VO}²⁺ groups.     

Hydrothermal synthesis and structural characterization of organically-templated copper vanadium phosphates: the two-dimensional [{Cu2(bisterpy)}V3O5(HPO4)2(PO4)] (1) and the three-dimensional [{Cu2(bisterpy)}V2O5(HPO4)2] (2) (bisterpy=2,2′:4′,4″:2″,2‴-quarterpyridyl, 6′,6″-dipyridine)

The hydrothermal reactions of appropriate vanadium oxides and copper(II) salts with bisterpy in the presence of phosphoric acid or fluorophosphoric acid yield the Cu(II)-bisterpy/oxovanadium phosphate materials [{Cu₂(bisterpy)}V₃O₅(HPO₄)₂(PO₄)] (1) and [{Cu₂(bisterpy)}V₂O₅(HPO₄)₂] (2). Compound 1 is layered material, consisting of inorganic {V₃O₅(HPO₄)₂(PO₄)}_n⁴ⁿ⁻ chains propagating parallel to the crystallographic a-axis, linked in the second dimension through binuclear {Cu₂(bisterpy)}⁴⁺ units. The chain is constructed from corner-sharing {V₄O₁₀(PO₄)₂}⁶⁻ and {V₂O₂(PO₄)₄}⁶⁻ cluster building blocks. There are two distinct vanadium sites: a tetrahedral {V(V)O₄} site and a square pyramidal {V(IV)O₅} center. The Cu(II)-bisterpy subunits are linked to the vanadophosphate chains through phosphate oxygen atoms exclusively. In contrast, the structure of 2 is three-dimensional, exhibiting inorganic {Cu₂V₂O₅(HPO₄)₂}_n networks linked through bisterpy bridges to provide the overall three-dimensional connectivity. The oxovanadium subunit consists of the well-documented {V₂O₇} binuclear unit of corner-sharing tetrahedral.     

Synthesis and Characterization of a 3-D Framework Constructed from [V12B18O54(OH)6(H2O)]10− Clusters and K+ Cations

An organic–inorganic hybrid polyoxovanadoborate K₆(CH₃NH₃)₄[V₁₂B₁₈O₅₄(OH)₆-(H₂O)]·2en·12H₂O (1, en = ethylenediamine) has been synthesized under hydrothermal conditions and characterized by IR spectroscopy, element analyses, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and single-crystal X-ray diffraction. Single-crystal structure analysis reveals that 1 consists of a cage-like polyoxovanadium borate [V₁₂B₁₈O₅₄(OH)₆(H₂O)]^10? cluster that is constructed from a puckered {B₁₈O₃₆(OH)₆} ring sandwiched by two triangle {V₆O₁₈} units, in which a water molecule is confined in the middle of the cage-like cluster. Interestingly, 1 represents the rare example of extended 3-D framework constructed from [V₁₂B₁₈O₅₄(OH)₆-(H₂O)]^10? clusters through K⁺ cations.     

Thermogravimetric,Cyclovoltammetric, and Mössbauer Spectroscopic Investigations on Heterobimetallic Organo Derivatives of Silicon and Germanium with the 2‐(Dimethylaminomethyl)ferrocenyl Ligand (η5‐C5H5)Fe[η5‐C5H3(CH2NMe2)], FcN

The thermic decomposition of the cyclotetrametaloxanetetrols [(FcN)₄M₄O₄(OH)₄] (M= Si( 1 ), Ge( 2 )) as well as the cyclohexagermoxanediol [(FcN)₆Ge₆O₈(OH)₂] ( 3 ) takes place in three defined steps. At the monomer silandiol [(FcN)₂Si(OH)₂] ( 4 ) only two such steps are observed. The cyclovoltammetric oxidation of the metaloxanes 1 ‐ 2 occurs in two two‐electron steps and following two one‐electron transitions. The oxidation of 3 occurs in a four‐electron process and a following two‐electron transition. Silandiol 4 is oxidized via two one‐electron transitions. The oxidation of the educt [FcNGeCl₃] ( 5 ) occurs in a one‐electron step. Temperature depending ⁵⁷Fe‐Mössbauer‐measurements confirm as well intervalent electron transitions in 1 ‐ 5 as the chelate stucture in 5 .     

Solid state coordination chemistry of the copper(II)/bisterpy/vanadate system: The structures of [Cu2(bisterpy)V4O12]·2H2O and [Cu2(bisterpy)V4F2O11] (bisterpy = 2,2′:4′,4′′:2′′,2′′′-quarter-pyridyl, 6′,6′′-di-2-pyridine)

Hydrothermal methods were exploited in the preparation of bimetallic organic–inorganic hybrid materials of the metal-bisterpy/vanadate class. [Cu₂(bisterpy)V₄O₁₂]·2H₂O exhibits a two-dimensional structure constructed from {Cu₂V₄O₁₂}_n chains linked through bisterpy ligands. The isomorphous materials [M₂(bisterpy)V₄F₂O₁₁] (M = Cu, Zn) are also two-dimensional. In these cases, {M₂V₄F₂O₁₁}_n chains are linked through bisterpy ligands to generate the two-dimensional network.     

Two New Polyoxovanadate‐supported Transition Metal Complexes: [Zn(en)2][Zn(en)2(H2O)2][{Zn(en)(enMe)}As6V15O42(H2O)]·4H2O and [Zn2(enMe)2(en)3][{Zn(enMe)2}As6V15O42(H2O)]·4H2O

Two novel As‐V‐O cluster supported transition metal complexes, [Zn(en)₂][Zn(en)₂(H₂O)₂][{Zn(en)(enMe)}As₆V₁₅O₄₂(H₂O)]·4H₂O ( 1 ) and [Zn₂(enMe)₂(en)₃][{Zn(enMe)₂}As₆V₁₅O₄₂(H₂O)]·4H₂O ( 2 ), have been hydrothermally synthesized. The single X‐ray diffraction studies reveal that both compounds consist of discrete noncentral polyoxoanions [{Zn(en)(enMe)}As₆V₁₅O₄₂(H₂O)]^4? or [{Zn(enMe)₂}As₆V₁₅O₄₂(H₂O)]^4? cocrystallized with respective zinc coordination complexes. Interestingly, compounds 1 and 2 exhibit the first two polyoxovanadates containing As₈V₁₅O₄₂‐(H₂O)]^6? cluster decorated by only one transition metal complex. Crystal data: 1 , monoclinic, P2₁/n, a = 14.9037(4) Å, b = 18.1243(5) Å, c = 27.6103(7) Å, β = 105.376(6)°, Z = 4; 2 monoclinic, P2₁/n, a = 14.9786(7) Å, b = 33.0534(16) Å, c = 14.9811(5) Å, Z = 4.     

Heterodinuclear M1M2 Complexes (M1=Ni,Pd, Pt; M2=Rh,Ir) Supported by a Tetradentate Phosphine Ligand and Their Application for Hydrosilylation

A new series of cationic heterodinuclear complexes, [M¹M²Cl₂(meso-dpmppp)(RNC)₂]PF₆ (M¹=Ni, M²=Rh, R=^tBu ( 1 a ); M¹=Pd, M²=Rh, R=^tBu ( 2 a ), Xyl ( 2 b ); M¹=Pt, M²=Rh, R=^tBu ( 3 a ), Xyl ( 3 b ); M¹=Pd, M²=Ir, R=^tBu ( 4 a )), supported by a tetradentate phosphine ligand, meso-Ph₂PCH₂P(Ph)(CH₂)₃P(Ph)CH₂PPh₂ (meso-dpmppp), were synthesized by stepwise reactions of meso-dpmppp with NiCl₂ ⋅ 6H₂O or MCl₂(cod) (M=Pd, Pt), forming mononuclear metalloligands of [M¹Cl₂(meso-dpmppp)], and with [M²Cl(cod)]₂ (M²=Rh, Ir) and RNC (R=^tBu, Xyl) in the presence of [NH₄][PF₆]. The related neutral PdRh complex, [PdRhCl₃(meso-dpmppp)(XylNC)] ( 5 ), was also prepared. The structures of 1 – 5 were determined by X-ray analyses to contain two square planar d⁸ metal centers with face-to-face arrangement, where meso-dpmppp supports M¹ and M² metal ions in cis/trans-P,P coordination mode, combining cis-{M¹P₂Cl₂} and trans-{M²P₂(CNR)₂} units. Complexes 1 – 4 showed an intence characteristic absorption around 422–464 nm derived from Rh^I→RNC MLCT transition (HOMO→LUMO+1), which are influenced by changing M¹ (Ni^II, Pd^II, Pt^II) metal ions since HOMO composed of dσ* orbitals appreciably destabilized by changing M¹ from Ni to Pd, and Pt. The electronic structures of 1 a – 4 a were investigated on the basis of DFT calculations and NBO analyses to show weak but noticeable d⁸–d⁸ metallophilic interaction as empirical dispersion energy of 0.9–1.5 kcal/mol without M¹–M² covalent bonding interaction. In addition, 1 – 5 were utilized as catalysts for hydrosilylation of styrene, and the NiRh complex 1 a was found to show higher activity and chemo- and regioselectivity compared with 2 – 5 .     

Coordination Properties of Perfluoroethyl‐ and Perfluorophenyl‐Substituted Phosphonous acids,RfP(OH)2

Phosphinic acids, R^fP(O)(OH)H (R^f=CF₃, C₂F₅, C₆F₅), turned out to be excellent preligands for the coordination of phosphonous acids, R^fP(OH)₂. Addition of C₂F₅P(O)(OH)H to solid PtCl₂ under different reaction conditions allows the isolation and full characterization of the mononuclear complexes [ClPt{P(C₂F₅)(OH)O}{P(C₂F₅)(OH)₂}₂] and [Pt{P(C₂F₅)(OH)O}₂{P(C₂F₅)(OH)₂}] containing hydrogen‐bridged [R^fP(OH)O]^? and R^fP(OH)₂ units. Further deprotonation of [Pt{P(C₂F₅)(OH)O}₂{P(C₂F₅)(OH)₂}₂] leads to the formation of the dianionic platinate, [Pt{P(C₂F₅)(OH)O}₄]^2?, revealing four intramolecular hydrogen bridges. With PdCl₂ the dinuclear complex [Pd₂(μ‐Cl)₂{[P(C₂F₅)(OH)O]₂H}₂] was isolated and characterized. The Cl^? free complex [Pd{P(C₂F₅)(OH)O}₂{P(C₂F₅)(OH)₂}₂] was also prepared and deprotonated to the dianionic palladate, [Pd{P(C₂F₅)(OH)O}₄]^2?. Both compounds were characterized by NMR spectroscopy, IR spectroscopy, and X‐ray analyses. In addition, the C₆F₅ derivatives [ClPt{P(C₆F₅)(OH)O}{P(C₆F₅)(OH)₂}₂] and [Pd₂(μ‐Cl)₂{[P(C₆F₅)(OH)O]₂H}₂] as well as the CF₃ derivative [Pd₂(μ‐Cl)₂{[P(CF₃)(OH)O]₂H}₂] were synthesized and fully characterized. Phosphonous acid complexes are inert towards air and moisture and can be stored for several months without decomposition. The catalytic activity of the palladium complexes in the Suzuki cross‐coupling reaction between 1‐bromo‐3‐fluorobenzene and phenyl boronic acid was demonstrated.     

[M3V18O42(H2O)12(XO4)]⋅24 H2O (M=Fe,Co; X=V,S): Metal Oxide Based Framework Materials Composed of Polyoxovanadate Clusters

New framework materials composed of well-defined vanadium oxide clusters were prepared by low-temperature reactions and characterized by X-ray crystal structure analysis. The structures of these solids contain {V₁₈O₄₂} cages linked into two interpenetrating three-dimensional networks by bridging {M(H₂O)₄} groups (M=Fe^II, Co^II; see picture).     

Chemical Bonding in Homoleptic Carbonyl Cations [M{Fe(CO)5}2]+ (M=Cu,Ag, Au)

Syntheses of the copper and gold complexes [Cu{Fe(CO)₅}₂][SbF₆] and [Au{Fe(CO)₅}₂][HOB{3,5-(CF₃)₂C₆H₃}₃] containing the homoleptic carbonyl cations [M{Fe(CO)₅}₂]⁺ (M=Cu, Au) are reported. Structural data of the rare, trimetallic Cu₂Fe, Ag₂Fe and Au₂Fe complexes [Cu{Fe(CO)₅}₂][SbF₆], [Ag{Fe(CO)₅}₂][SbF₆] and [Au{Fe(CO)₅}₂][HOB{3,5-(CF₃)₂C₆H₃}₃] are also given. The silver and gold cations [M{Fe(CO)₅}₂]⁺ (M=Ag, Au) possess a nearly linear Fe-M-Fe’ moiety but the Fe-Cu-Fe’ in [Cu{Fe(CO)₅}₂][SbF₆] exhibits a significant bending angle of 147° due to the strong interaction with the [SbF₆]⁻ anion. The Fe(CO)₅ ligands adopt a distorted square-pyramidal geometry in the cations [M{Fe(CO)₅}₂]⁺, with the basal CO groups inclined towards M. The geometry optimization with DFT methods of the cations [M{Fe(CO)₅}₂]⁺ (M=Cu, Ag, Au) gives equilibrium structures with linear Fe-M-Fe’ fragments and D₂ symmetry for the copper and silver cations and D_4d symmetry for the gold cation. There is nearly free rotation of the Fe(CO)₅ ligands around the Fe-M-Fe’ axis. The calculated bond dissociation energies for the loss of both Fe(CO)₅ ligands from the cations [M{Fe(CO)₅}₂]⁺ show the order M=Au (D_e=137.2 kcal mol⁻¹)>Cu (D_e=109.0 kcal mol⁻¹)>Ag (D_e=92.4 kcal mol⁻¹). The QTAIM analysis shows bond paths and bond critical points for the M−Fe linkage but not between M and the CO ligands. The EDA-NOCV calculations suggest that the [Fe(CO)₅]→M⁺←[Fe(CO)₅] donation is significantly stronger than the [Fe(CO)₅]←M⁺→[Fe(CO)₅] backdonation. Inspection of the pairwise orbital interactions identifies four contributions for the charge donation of the Fe(CO)₅ ligands into the vacant (n)s and (n)p AOs of M⁺ and five components for the backdonation from the occupied (n-1)d AOs of M⁺ into vacant ligand orbitals.     

{ReCl2(NO)2[Sb(C6H5)3]2}; Synthese,Kristallstruktur, Infrarot- und 121Sb-Mößbauer-Spektrum

{ReCl₂(NO)₂[Sb(C₆H₅)₃]₂}; Preparation, Crystal Structure, Infrared and ¹²¹Sb Mössbauer Spectrum The title compound yields from treatment of ReCl₃(NO)₂ with excess Sb(C₆H₅)₃ in a dichloromethane suspension forming green crystals. The structure of {ReCl₂(NO)₂[Sb(C₆H₅)₃]₂} was solved by X-ray methods; the complex crystallizes in the triclinic space group P1 with three formula units per unit cell (9522 undependent, observed reflexions, R = 5.0%). The lattice constants are a = 1251, b = 1414, c = 1671 pm, α = 66.2, β = 83.0, γ = 89.1°. The Rhenium atom is coordinated octahedrally by two NO groups, two Cl atoms, which are in cis-position to one another and two antimony atoms of the SbPh₃ ligands, which are in trans positions. The NO and Cl ligands are statistically disordered in the equatorial plane. The I.R. spectrum as well as the ¹²¹Sb-Mössbauer spectrum, the latter obtained at 4.2 K, are recorded.