Structural correlations and NMR properties of mononuclear cyclic triphosphorus complexes

The [(triphos)Ni(η-P₃)BF₄ · C₂H₅OH compound has been synthesized by treating Ni(BF₄)₂ · 6H₂O with P₄S₃, in the presence of the triphos ligand (triphos = 1,1,1-tris(diphenylphosphinomethyl)ethane). The crystal structure of the complex and that of the previously obtained platinum isomorph have been investigated by X-ray diffraction.Correlations are drawn within the series of the monocationic [(triphos)M(η³-P₃)]⁺ (M = Ni, Pd, Pt) complexes and that of the neutral [(triphos)M(η³-P₃)] (M = Co, Rh, Ir) compounds, as well as between the two series. Phosphorus NMR data are reported for the compounds of the two sets and trends are analyzed in terms of simple models of the bonding.     

π-Polyolefin and π-acetylene cobalt(I) complexes with the tris(tertiary phosphine) 1,1,1-tris(diphenylphosphinomethyl)ethane. X-ray structure of [(triphos)Co(η4-C7H8)]ClO4 · O.5 CH2Cl2

Cationic cobalt(I) complexes with the general formula [(triphos)Co(L)]Y (triphos  1,1,1-tris(diphenylphosphinomethyl) ethane; L  1,3-butadiene, isoprene, 1,3-cyclohexadiene, 1,3,5-cycloheptatriene, 1,3,5,7-cyclooctatetraene, phenylacetylene, diphenylacetylene) have been obtained by reaction of cobalt perchlorate with a variety of conjugated polyolefins or with acetylenes in the presence of the triphos ligand. The crystal structure of the complex [(triphos)Co(C₇H₈)]ClO₄ · 0.5 CH₂Cl₂ has been determined by an X-ray analysis using diffractometric data. The crystals are monoclinic, space group P2₁/c with cell dimensions a 10.514(3), b 15.041(5), c 54.795(12) Å, β 92.61(3)°, Z  8. The structure was solved by direct methods and refined by least-squares techniques to a final conventional R factor of 0.091. The structure, which consists of [(triphos)Co(C₇H₈)]⁺ cations, perchlorate anions, and interposed CH₂-Cl₂ solvent molecules, shows that the cycloheptatriene molecule acts as a tetrahapto ligand. The coordination polyhedron can be regarded either as a distorted square pyramid or as a distorted octahedron. The coordination geometries of all complexes have been assigned on the basis of this structure determination and of IR and NMR data.     

Synthesis of (CH3C(CH2PPh2)3)CoL complexes (L = O2CO,S2CO,O2SO) through metal-assisted CO2, CS2, SO2 oxidation. Crystal structure of (CH3C(CH2PPh2)3)CO(O2SO)

The solution obtained by reduction of [(triphos)CO(μ-Cl)₂Co(triphos)]⁺² (triphos = CH₃C(CH₂PPh₂)₃) with Na/Hg reacts with CO₂, CS₂ and SO₂ to give (triphos)Co(O₂CO), (triphos)Co(S₂CO), and (triphos)Co(O₂SO), respectively. The molecular structure of the last has been established by X-ray difraction.     

Hydrogenation of White Phosphorus to Phosphane with Rhodium and Iridium Trihydrides

Only one of the four P atoms of P₄ reacts with rhodium and iridium trihydrides [(triphos)MH₃] to provide phosphane [Eq. (a)]. The resulting cyclo-P₃ fragment is efficiently scavenged by the metal fragment to give the complexes [(triphos)M(η³-P₃)]. A mechanism accounting for the hydrogenation reaction is proposed in which the complexes [(triphos)MH(η¹:η¹-P₄)] and [(triphos)M(η¹:η²-HP₄] are intermediates. The latter complex contains the unprecedented hydridotetraphosphane ligand HP₄⁻.     

Paramagnetic carbonyl cobalt(II) complexes. Molecular structure of bromocarbonyl-1,1,1-tris(diphenylphosphinomethyl)ethanecobalt(II) tetraphenylborate

Carbon monoxide or cyclohexyl isonitrile (L) react with the dinuclear five-coordinated derivatives of 1,1,1-tris(diphenylphosphinomethyl)ethane, (triphos), [(triphos)Co(μ-X)₂Co(triphos)](BPh₄)₂ (X = halide) to give complexes of formula [(triphos)Co(L)X]BPh₄. The latter are rare examples of paramagnetic cobalt(II) carbonyl complexes. The molecular structure of [(triphos)Co(CO)Br]BPh₄ has been determined from counter diffraction data. The crystals are monoclinic, space group P2₁/a with cell dimensions a 20.225(8), b 20.664(9), c 13.301(5); β 97.24(5)°, D_c = 1.338 g cm^?3 for Z = 4. Full-matrix least squares refinement led to the conventional R factor of 0.057 for 3648 observed reflections. The molecular structure consists of five-coordinate [(triphos)Co(CO)Br]⁺ cations of intermediate geometry and BPh^?₄ anions.     

Insertion of the Pt(PPh3)2 unit into inorganic triatomic rings coordinated to metal—ligand moieties

Reaction of the [(triphos)Co(E₂S)]BF₄ complexes (triphos = 1,1,1-tris(di-phenylphosphinomethyl)ethane, E = P or As) containing the P₂S or As₂S cyclic units trihapto(η³-bonded to the metal, with (C₂H₄)Pt(PPh₃)₂ involves insertion of the Pt(PPh₃)₂ moiety into a bond of the inorganic ring, yielding the compounds [(triphos)Co(E₂S)Pt(PPh₃)₂]BPh₄ (E = P or As), whose structures have been determined by X-ray diffraction studies.     

Ring Contraction by NHC‐Induced Pnictogen Abstraction

The reaction of [Cp′′′Co(η⁴‐P₄)] ( 1 ) (Cp′′′=1,2,4‐tBu₃C₅H₂) with ^MeNHC (^MeNHC=1,3,4,5‐tetramethylimidazol‐2‐ylidene) leads through NHC‐induced phosphorus cation abstraction to the ring contraction product [(^MeNHC)₂P][Cp′′′Co(η³‐P₃)] ( 2 ), which represents the first example of an anionic CoP₃ complex. Such NHC‐induced ring contraction reactions are also applicable for triple‐decker sandwich complexes. The complexes [(Cp*Mo)₂(μ,η^6:6‐E₆)] ( 3 a , 3 b ) (Cp*=C₅Me₅; E=P, As) can be transformed to the complexes [(^MeNHC)₂E][(Cp*M)₂(μ,η^3:3‐E₃)(μ,η^2:2‐E₂)] ( 4 a , 4 b ), with 4 b representing the first structurally characterized example of an NHC‐substituted As^I cation. Further, the reaction of the vanadium complex [(Cp*V)₂(μ,η^6:6‐P₆)] ( 5 ) with ^MeNHC results in the formation of the unprecedented complexes [(^MeNHC)₂P][(Cp*V)₂(μ,η^6:6‐P₆)] ( 6 ), [(^MeNHC)₂P][(Cp*V)₂(μ,η^5:5‐P₅)] ( 7 ) and [(Cp*V)₂(μ,η^3:3‐P₃)(μ,η^1:1‐P{^MeNHC})] ( 8 ).     

Cationic η3-Triphenylcyclopropenylnickel complexes with tridentate ligands containing N,P, As as the donor atoms. Molecular structure of η3-triphenylcyclopropenyl-1,1,1-tris(diphenylphosphinomethyl)ethanenickel perchlorate

The [(C₃Ph₃)Ni(PPh₃)₂]ClO₄ complex reacts with the tridentate ligands, 1,1,1-tris(dimethylphosphinomethyl)ethane, 1,1,1-tris(diphenylphosphinomethyl)ethane, (bis(2-diphenylphosphino)ethyl)phenylphosphine, (bis(2-diphenylphosphino)ethyl)-n-propylamine, and 1,1,1-tris(diphenylarsinomethyl)ethane to give cationic η³-triphenylcyclopropenyl complexes of formula [(C₃Ph₃)NiL]Y (Y = ClO₄, BPh₄). An uncharged derivative with the formula [(C₃Ph₃)Ni(hb(3,5-me₂Pz)₃)] (hb(3,5-me₂Pz)₃ = hydrotris(3,5-dimethyl-1-pyrazolyl)borate) has also been prepared. The molecular structure of [(C₃Ph₃)Ni(triphos)]ClO₄ has been determined from counter diffraction data. The crystals are monoclinic, space group P2₁/n with cell dimensions: a 17.750(5), b 17.629(5), c 16.509(4) Å; β 92-59(9)°, D_c = 1.359 g cm^?3 for Z = 4. Full matrix least-squares refinement led to the conventional R factor of 0.064 for 2556 observed reflections. The molecular structure consists of [(C₃Ph₃)Ni(triphos)]⁺ cations and ClO₄^? anions. The nickel atom is coordinated to the three phosphorus atoms of the triphos ligand, and to the C₃Ph₃ fragment in a symmetric η³ fashion.     

Reversible lithium uptake by CoP3 at low potential: role of the anion

Although various transition metal compounds in Group V (nitrides and antimonides) have been reported to act as low potential Li insertion hosts, the phosphides have remained unexplored to date. We show here that lithium uptake and extraction in the metal phosphide, CoP₃, provides a reversible capacity of 400 mAh/g at an average potential of 0.9 V vs Li/Li⁺, via a novel mechanism. The latter was revealed using a combination of X-ray diffraction, electron microscopy, and potentiodynamic and galvanostatic intermittent measurements coupled with X-ray photoelectron spectroscopy (XPS). Initial uptake of Li forms highly dispersed cobalt clusters embedded in a matrix of Li₃P; extraction of Li from this ion-conductive matrix on charge yields nano-particles of LiP, with little change evident in the oxidation state of the Co site. This shows that contrary to the case of metal oxides here the anion plays the major role in reduction and oxidation. We expect this is a general phenomenon for phosphides, and to be of fundamental interest and future importance in the search for new negative electrode materials.     

Ringkontraktion durch NHC‐induzierte Pnictogen‐Abstraktion

Die Reaktion von [Cp′′′Co(η⁴‐P₄)] ( 1 ) (Cp′′′=1,2,4‐tBu₃C₅H₂) mit ^MeNHC (^MeNHC=1,3,4,5‐tetramethylimidazol‐2‐ylidene) führt über eine NHC‐induzierte Phosphorkationen‐Abstraktion zum Ringkontraktionsprodukt [(^MeNHC)₂P][Cp′′′Co(η³‐P₃)] ( 2 ), welches das erste Beispiel eines anionischen CoP₃‐Komplexes repräsentiert. Solche von NHCs induzierten Ringkontraktionsreaktionen lassen sich ebenfalls auf Tripeldecker‐Sandwich‐Komplexe anwenden. So werden die Komplexe [(Cp*Mo)₂(μ,η^6:6‐E₆)] ( 3 a , 3 b ) (Cp*=C₅Me₅; E=P, As) zu den Komplexen [(^MeNHC)₂E][(Cp*M)₂(μ,η^3:3‐E₃)(μ,η^2:2‐E₂)] ( 4 a , 4 b ) transformiert, wobei 4 b das erste strukturell charakterisierte Beispiel eines NHC‐substituierten As^I‐Kations darstellt. Darüber hinaus führt die Reaktion des Vanadium‐Komplexes [(Cp*V)₂(μ,η^6:6‐P₆)] ( 5 ) mit ^MeNHC zur Bildung der neuartigen Komplexe [(^MeNHC)₂P][(Cp*V)₂(μ,η^6:6‐P₆)] ( 6 ), [(^MeNHC)₂P][(Cp*V)₂(μ,η^5:5‐P₅)] ( 7 ) bzw. [(Cp*V)₂(μ,η^3:3‐P₃)(μ,η^1:1‐P{^MeNHC})] ( 8 ).     

Fine Control of the Redox Reactivity of a Nonheme Iron(III)–Peroxo Complex by Binding Redox-Inactive Metal Ions

Redox-inactive metal ions are one of the most important co-factors involved in dioxygen activation and formation reactions by metalloenzymes. In this study, we have shown that the logarithm of the rate constants of electron-transfer and C−H bond activation reactions by nonheme iron(III)–peroxo complexes binding redox-inactive metal ions, [(TMC)Fe^III(O₂)]⁺-Mⁿ⁺ (Mⁿ⁺=Sc³⁺, Y³⁺, Lu³⁺, and La³⁺), increases linearly with the increase of the Lewis acidity of the redox-inactive metal ions (ΔE), which is determined from the g_zz values of EPR spectra of O₂^.−-Mⁿ⁺ complexes. In contrast, the logarithm of the rate constants of the [(TMC)Fe^III(O₂)]⁺-Mⁿ⁺ complexes in nucleophilic reactions with aldehydes decreases linearly as the ΔE value increases. Thus, the Lewis acidity of the redox-inactive metal ions bound to the mononuclear nonheme iron(III)–peroxo complex modulates the reactivity of the [(TMC)Fe^III(O₂)]⁺-Mⁿ⁺ complexes in electron-transfer, electrophilic, and nucleophilic reactions.     

Fine Control of the Redox Reactivity of a Nonheme Iron(III)–Peroxo Complex by Binding Redox‐Inactive Metal Ions

Redox‐inactive metal ions are one of the most important co‐factors involved in dioxygen activation and formation reactions by metalloenzymes. In this study, we have shown that the logarithm of the rate constants of electron‐transfer and C−H bond activation reactions by nonheme iron(III)–peroxo complexes binding redox‐inactive metal ions, [(TMC)Fe^III(O₂)]⁺‐M^{n +} (M^{n +}=Sc³⁺, Y³⁺, Lu³⁺, and La³⁺), increases linearly with the increase of the Lewis acidity of the redox‐inactive metal ions (ΔE ), which is determined from the g_zz values of EPR spectra of O₂^.−‐M^{n +} complexes. In contrast, the logarithm of the rate constants of the [(TMC)Fe^III(O₂)]⁺‐M^{n +} complexes in nucleophilic reactions with aldehydes decreases linearly as the ΔE value increases. Thus, the Lewis acidity of the redox‐inactive metal ions bound to the mononuclear nonheme iron(III)–peroxo complex modulates the reactivity of the [(TMC)Fe^III(O₂)]⁺‐M^{n +} complexes in electron‐transfer, electrophilic, and nucleophilic reactions.     

S-, O-, O,O′- p-toluenesulfinato complexes of iron(II), cobalt(II) and nickel(II) with polydentate tripod-like phosphines,crystal structure of 1,1,1-tris(diphenylphosphinomethyl)ethane p-toluenesulfinatocobalt(II) perchlorate

Reaction of sodium p-toluenesulfinate with iron(II), cobalt(II) and nickel(II) aquo ions in the presence of the poly(tertiary phosphines) 1,1,1-tris(diphenylphosphinomethyl)ethane (triphos), tris(2-diphenylphosphinoethyl)amine (np₃) and tris(2-diphenylphosphinoethyl)phosphine (pp₃) gives five-coordinated p-toluenesulfinato complexes of formulae [(triphos)Co(p-tolSO₂)]ClO₄ and [LM(p-tolSO₂)]BPh₄ (L = pp₃, M = Fe, Co, Ni; L = np₃, M = Co, Ni). The nickel derivatives are diamagnetic with the p-toluenesulfinate ligand bonded to the metal through the sulfur atom. The iron and cobalt complexes are paramagnetic, low or high spin, with the _p-toluenesulfinate ion linked to the metal via one oxygen (np₃ and pp₃ derivatives) or both oxygen atoms (cobalt-triphosderivative).The structure of [(triphos)Co(p-tolSO₂)]ClO₄ has been determined from three-dimensional X-ray data collected by counter methods. The crystals are monoclinic, space group P2₁/n with a = 20.942(9), b =, 9.652(4), c= 22.040(8), Å, β, = 96.86(5)°, d_c = 1.407 gcm^?3 for Z = 4. Full-matrix least-squares refinements converged at the conventional R factor of 0.063 for 5573 observed reflections. The complex cation has a distorted square pyramidal geometry with the sulfinate group acting as a bidentate ligand through the two oxygen atoms.     

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.     

Kinetics of nucleophilic attack on coordinated organic moieties : XII. Addition of triphenylphosphine to [(C8H11)Co(C5H5)]BF4

A stopped-flow investigation of the reversible addition of Ph₃P to [(C₈H₁₁)Co(C₅H₅)]⁺ indicates the rate law, k_obs = k₁[Ph₃P] + k_?1. The low Δ2 of 21.0 ± 1.2 kJ mol^?1 and the negative ΔS2 of ?114 ± 5 J K^?1 mol^?1 are consistent with rapid addition to the enyl ligand. The higher Δ2 of 86.2 ± 5.1 kJ mol^?1 and the positive ΔS2 of +60 ± 17 J K^?1 mol^?1are as expected for the reverse dissociation. Preliminary studies show that the related complex [(C₇H₉)Co(C₅H₅)]⁺ is at least 65 times more electrophilic towards Ph₃P.     

Synthesis and reactions of a nucleophilic bis(μ-dimethylphosphido)dicobalt complex. The crystal and molecular structure of [C5H5Co(μ-PMe2)]2 and [(C5H5Co)2(μ-H)(μ-PMe2)2]BPh4

The bis(μ-dimethylphosphido)dicobalt complex [C₅H₅Co(μ-PMe₂)]₂ (II) has been prepared from Co(C₅H₅ and PMe₂H on almost quantitative yield. It has also been made by reduction of [C₅H₅Co(PMe₂H)₃]I₂ (IV) with NaH and from the reaction of [C₅H₅(PMe₃)Co(μ-CO)₂Mn(CO)C₅H₄Me] with PMe₂H. Protonation of II with CF₃CO₃H in the presence of NH₄PF₆ produces the PF₆^? salt of the (μ-hydrido)dicobalt cation [(C₅H₅Co)₂(μ-H)(μ-PMe₂)₂]⁺ (V) which reacts with aqueous NaOH to give II. Similar treatment of [C₅H₅Co(μ-SMe]₂ with CF₃CO₂H/NH₄PF₆ leads to the formation of [(C₅H₅Co)₂(μ-SMe)₃]PF₆ (VI). The nucleophilic character of complex II has also been demonstrated in the reaction with SO₂, which gives [(C₅H₅Co)₂ (μ-PMe₂)₂(μ-SO₂)] (VII). The crystal and molecular structures of II, the corresponding bis(μ-diphenylphosphido) compound [C₅H₅Co(μ-PPh₂)]₂ (III) and the BPh₄^? salt of V have been determined. In both neutral complexes the Co₂P₂ cores are similarly puckered, as reflected in the dihedral angle between the CoP₂ and P₂Co′ planes of 108.1 and 105.0° for R = Me and Ph, respectively. The CoCo bond length and the PP interatomic separations are essentially identical for both dimers. The CoCo bond length in V, 2.517(1) Å, is lower than that in II, 2.542(2) Å. The only obvious structural variation between the unprotonated and the protonated species is the large difference in the degree of canting of the C₅H₅ rings with respect to each other. The angles between the C₅(ring)-centroid and the CoCo line are ca. 150 and 167° in II and V, respectively, which reflects the influence of the bridging hydride ligand in the cationic complex.     

Interaction of bivalent transition metal ions with iminodiacetato-(pentaammine/tetraammine)cobalt(III) ions. A kinetic and equilibrium study

Summary The kinetics of reversible complexation of Ni^II and Co^II with iminodiacetato(pentaammine)cobalt(III), [(NH₃)₅-Co(idaH₂)]³⁺ and Ni^II with iminodiacetato(tetraammine)-cobalt(III), [(NH₃)₄Co(idaH)]²⁺, have been investigated by the stopped-flow technique at 25 °C, pH = 5.7–6.9 and I = 0.3 mol dm ^–3. The reaction paths (NH₃)₅Co(idaH)²⁺+M²⁺(NH₃)₅Co(ida)M³⁺+H⁺ (NH₃)₅Co(ida)⁺+M²⁺(NH₃)₅Co(ida)M³⁺ (NH₃)₄Co(ida)⁺+Ni²⁺(NH₃)₄Co(ida)Ni³⁺ have been identified (idaH = N⁺H₂(CH₂CO₂)₂H, ida = NH(CH₂COO)^2–]. The rate parameters for the formation and dissociation of the binuclear species are reported. The data are essentially consistent with an I _d mechanism. The dissociation rate constants of the binuclear species indicate that Ni²⁺ and Co²⁺ are chelated by the coordinated iminodiacetate moiety.     

Complex Topology of Uranyl Polyphosphate Frameworks: Crystal Structures of α‐, β‐K[(UO2)(P3O9)] and K[(UO2)2(P3O10)]

Three new uranyl polyphosphates, α‐K[(UO₂)(P₃O₉)] ( 1 ), β‐K[(UO₂)(P₃O₉)] ( 2 ), and K[(UO₂)₂(P₃O₁₀)] ( 3 ), were prepared by high‐temperature solid‐state reactions. The crystal structures of the compounds have been solved by direct methods: 1 – monoclinic, P2₁/m, a = 8.497(1), b = 15.1150(1), c = 14.7890(1) Å, β = 91.911(5)°, V = 1898.3(3) ų, Z = 4, R₁ = 0.0734 for 4181 unique reflections with |F₀| ≥ 4σ_F; 2 – monoclinic, P2₁/n, a = 8.607(1), b = 14.842(2), c = 14.951(1) Å, β = 95.829(5)°, V = 1900.0(4) ų, Z = 4, R₁ = 0.0787 for 3185 unique reflections with |F₀| ≥ 4σ_F; 3 – Pbcn, a = 10.632(1), b = 10.325(1), c = 11.209(1) Å, V = 1230.5(2) ų, Z = 4, R₁ = 0.0364 for 1338 unique reflections with |F₀| ≥ 4σ_F. In the structures of 1 and 2 , phosphate tetrahedra share corners to form infinite [PO₃]^? chains, whereas, in the structure of 3 , tetrahedra form linear [P₃O₁₀]^5? trimers. The structures are based upon 3‐D frameworks of U and P polyhedra linked by sharing common O corners. The infinite [PO₃]^? chains in the structures of 1 and 2 are parallel to [100] and [–101], respectively. The uranyl polyphosphate frameworks are occupied by host K⁺ cations.     

A Neutral Tetraphosphacyclobutadiene Ligand in Cobalt(I) Complexes

The unusual reactivity of the newly synthesized β‐diketiminato cobalt(I) complexes, [(L^DepCo)₂] ( 2 a , L^Dep=CH[C(Me)N(2,6‐Et₂C₆H₃)]₂) and [L^DippCo ? toluene] ( 2 b , L^Dipp=CH[CHN(2,6‐ⁱPr₂C₆H₃)]₂), toward white phosphorus was investigated, affording the first cobalt(I) complexes [(L^DepCo)₂(μ₂:η⁴,η⁴‐P₄)] ( 3 a ) and [(L^DippCo)₂(μ₂:η⁴,η⁴‐P₄)] ( 3 b ) bearing the neutral cyclo‐P₄ ligand with a rectangular‐planar structure. The redox chemistry of 3 a and 3 b was studied by cyclic voltammetry and their chemical reduction with one molar equivalent of potassium graphite led to the isolation of [(L^DepCo)₂(μ₂:η⁴,η⁴‐P₄)][K(dme)₄] ( 4 a ) and [(L^DippCo)₂(μ₂:η⁴,η⁴‐P₄)][K(dme)₄] ( 4 b ). Unexpectedly, the monoanionic Co₂P₄ core in 4 a and 4 b , respectively, contains the two‐electron‐reduced cyclo‐P₄^2? ligand with a square‐planar structure and mixed‐valent cobalt(I,II) sites. The electronic structures of 3 a , 3 b , 4 a , and 4 b were elucidated by NMR and EPR spectroscopy as well as magnetic measurements and are in agreement with results of broken‐symmetry DFT calculations.     

Highly Kinked Uranyl Chromate Nitrate Layers in the Crystal Structures of A[(UO2)(CrO4)(NO3)] (A = K,Rb)

Two first uranyl chromate nitrates, K[(UO₂)(CrO₄)(NO₃)] ( 1 ) and Rb[(UO₂)(CrO₄)(NO₃)] ( 2 ), were prepared by solid‐state reactions and characterized by electron microprobe analysis and single‐crystal X‐ray diffraction. The compounds are isotypic [ 1 : monoclinic, P2₁/c, a = 9.881(5), b = 7.215(4), c = 14.226(6) Å, β = 124.85(3)°, V = 832.3(7) ų; 2 : monoclinic, P2₁/c, a = 9.804(1), b = 7.359(1), c = 14.269(1) Å, β = 122.048(4), V = 872.6(1) ų]. The structures of 1 and 2 are based upon the complex [(UO₂)(CrO₄)(NO₃)]^– layers with unprecedented structural topology, which consist of the UrO₃NO₃ units linked through CrO₄ tetrahedra. The resulted kinked layer can be divided into chains arranged in the ladder fashion. The layers are parallel to (100) and are linked by A⁺ (A = K, Rb) cations located between the layers.