A Twelve-Coordinated Iodide in a Cuboctahedral Silver(I) Skeleton

Three new halide-centered octanuclear silver­(I) complexes, [Ag₈(X)­{S₂P­(CH₂CH₂Ph)₂}₆]­(PF₆), X = F^–, <b>1</b>; Cl^–, <b>2</b>; Br^–, <b>3</b>; were prepared in the presence of the corresponding halide anions with silver­(I) salts and dithiophosphinate ligands. Structure analyses displayed that a Ag₈ cubic core can be modulated by the size effect of the central halide; however, an iodide-centered Ag₈ cluster was not found under similar reaction conditions. Interestingly, a luminescent dodecanuclear silver­(I) cluster, [Ag₁₂(μ₁₂-I)­(μ₃-I)₄{S₂P­(CH₂CH₂Ph)₂}₆]­(I), <b>4</b>; was then synthesized. The structure of <b>4</b> contains a novel μ₁₂-I at the center of a cuboctahedral silver­(I) atom cage, which is further stabilized by four additional μ₃-I and six dithiophosphinate ligands. To the best of our knowledge, the μ₁₂-I revealed in <b>4</b> is the highest coordination number for a halide ion authenticated by both experimental and computational studies. Previously, the μ₁₂-I was only observed in [PyH]­[{TpMo­(μ₃-S)₄Cu₃}₄(μ₁₂-I)]. The synthetic details, spectroscopic studies including multinuclear NMR and ESI-MS, structure elucidations by single crystal X-ray diffraction, and photoluminescence of <b>4</b> are reported herein

Neutron Diffraction Studies of a Four-Coordinated Hydride in Near Square-Planar Geometry

The structure of a nanospheric polyhydrido copper cluster, [Cu₂₀(H)₁₁{S₂P­(O^<i>i</i>Pr)₂}₉], was determined by single-crystal neutron diffraction. The Cu₂₀ cluster consists of an elongated triangular orthobicupola constructed from 18 Cu atoms that encapsulate a [Cu₂H₅]^3– ion with an exceptionally short Cu–Cu distance. The 11 hydrides in the cluster display three different coordination modes to the Cu atoms: six μ₃-hydrides in a pyramidal geometry, two μ₄-hydrides in a tetrahedral cavity, and three μ₄-hydrides in an unprecedented near square-planar geometry. The neutron data set was collected for 7 days on a small crystal with dimensions of 0.20 mm × 0.50 mm × 0.65 mm using the Spallation Neutron Source TOPAZ single-crystal time-of-flight Laue diffractometer at Oak Ridge National Laboratory. The final <i>R</i>-factor was 8.63% for 16,014 reflections

Neutron Diffraction Studies of a Four-Coordinated Hydride in Near Square-Planar Geometry

The structure of a nanospheric polyhydrido copper cluster, [Cu₂₀(H)₁₁{S₂P­(O^<i>i</i>Pr)₂}₉], was determined by single-crystal neutron diffraction. The Cu₂₀ cluster consists of an elongated triangular orthobicupola constructed from 18 Cu atoms that encapsulate a [Cu₂H₅]^3– ion with an exceptionally short Cu–Cu distance. The 11 hydrides in the cluster display three different coordination modes to the Cu atoms: six μ₃-hydrides in a pyramidal geometry, two μ₄-hydrides in a tetrahedral cavity, and three μ₄-hydrides in an unprecedented near square-planar geometry. The neutron data set was collected for 7 days on a small crystal with dimensions of 0.20 mm × 0.50 mm × 0.65 mm using the Spallation Neutron Source TOPAZ single-crystal time-of-flight Laue diffractometer at Oak Ridge National Laboratory. The final <i>R</i>-factor was 8.63% for 16,014 reflections

Ferrocene-Functionalized Cu(I)/Ag(I) Dithiocarbamate Clusters

A series of compounds, namely, [Cu₈(μ₄-H)­{S₂CN­MeCH₂Fc}₆]­(PF₆) (<b>1</b>), [Cu₇(μ₄-H) {S₂CN^<i>i</i>PrCH₂Fc}₆] (<b>2</b>), [Cu₃{S₂CN­(Bz) (CH₂Fc)}₂(dppf)₂]­(PF₆) (<b>3</b>), and [Ag₂{S₂CNMe­(CH₂Fc)}₂(PPh₃)₂] (<b>4</b>) (dppf = 1,1′-bis­(diphenylphosphino)­ferrocene), supported by multiferrocene assemblies, were synthesized. All the compounds were characterized by ¹H NMR, Fourier transform infrared, elemental analysis, and electrospray ionization mass spectrometry techniques. Single-crystal X-ray structural analysis revealed that <b>1</b> is a monocationic octanuclear Cu^I cluster and that <b>2</b> is a neutral heptanuclear Cu^I cluster with tetracapped tetrahedral (<b>1</b>) and tricapped tetrahedral (<b>2</b>) geometries entrapped with an interstitial hydride, anchored by six ferrocene units at the periphery of the core. Compounds <b>3</b> and <b>4</b> comprise trimetallic Cu^I and dimetallic Ag^I cores enfolded by four and two ferrocene moieties. Interestingly both chelating and bridging modes of binding are observed for dppf ligand in <b>3</b>. Further the formation and isolation of polyhydrido copper clusters [Cu₂₈H₁₅{S₂CN^<i>i</i>PrCH₂Fc}₁₂]­(PF₆) (<b>5</b>) and [Cu₂₈H₁₅{S₂CN^<i>n</i>Bu₂}₁₂]­(PF₆) (<b>7</b>), stabilized by bulky ferrocenyl and <i>n</i>-butyl dithiocarbamate ligands, was demonstrated. They are readily identified by ²H NMR studies on their deuterium analogues, [Cu₂₈D₁₅{S₂CN^<i>i</i>PrCH₂Fc}₁₂]­(PF₆) (<b>6</b>) and [Cu₂₈D₁₅{S₂CN^<i>n</i>Bu₂}₁₂]­(PF₆) (<b>8</b>). Though the structure details as well as spectroscopic characterizations of <b>5</b> are yet to be investigated, the compound <b>7</b> is fully characterized by variety of spectroscopy including single-crystal X-ray diffraction. The cyclic voltammetry studies for compounds <b>1</b>, <b>2</b>, and <b>4</b> display irreversible redox peaks for Fe²⁺/Fe³⁺ couple wherein the reduction peaks are not well-resolved due to some adsorption of the complex onto the electrode surface

A Nanospheric Polyhydrido Copper Cluster of Elongated Triangular Orthobicupola Array: Liberation of H₂ from Solar Energy

An unprecedented air-stable, nanospheric polyhydrido copper cluster, [Cu₂₀H₁₁(S₂P­(OⁱPr)₂)₉] (<b>1</b>_<b>H</b>), which is the first example of an elongated triangular orthobicupola array of Cu atoms having <i>C</i>_3<i>h</i> symmetry, was synthesized and characterized. Its composition was primarily determined by electrospray ionization mass spectrometry, and it was fully characterized by ¹H, ²H, and ³¹P NMR spectroscopy and single-crystal X-ray diffraction (XRD). The structure of complex <b>1</b>_<b>H</b> can be expressed in terms of a trigonal-bipyramidal [Cu₂H₅]^3– unit anchored within an elongated triangular orthobicupola containing 18 Cu atoms, which is further stabilized by 18 S atoms from nine dithiophosphate ligands and six capping hydrides. The positions of the 11 hydrides revealed by low temperature XRD were supported by a density functional theory investigation on the simplified model [Cu₂₀H₁₁(S₂PH₂)₉] with <i>C</i>_3<i>h</i> symmetry. <b>1</b>_<b>H</b> is capable of releasing H₂ gas upon irradiation with sunlight, under mild thermal conditions (65 °C), or in the presence of acids at room temperature

A Nanospheric Polyhydrido Copper Cluster of Elongated Triangular Orthobicupola Array: Liberation of H₂ from Solar Energy

An unprecedented air-stable, nanospheric polyhydrido copper cluster, [Cu₂₀H₁₁(S₂P­(OⁱPr)₂)₉] (<b>1</b>_<b>H</b>), which is the first example of an elongated triangular orthobicupola array of Cu atoms having <i>C</i>_3<i>h</i> symmetry, was synthesized and characterized. Its composition was primarily determined by electrospray ionization mass spectrometry, and it was fully characterized by ¹H, ²H, and ³¹P NMR spectroscopy and single-crystal X-ray diffraction (XRD). The structure of complex <b>1</b>_<b>H</b> can be expressed in terms of a trigonal-bipyramidal [Cu₂H₅]^3– unit anchored within an elongated triangular orthobicupola containing 18 Cu atoms, which is further stabilized by 18 S atoms from nine dithiophosphate ligands and six capping hydrides. The positions of the 11 hydrides revealed by low temperature XRD were supported by a density functional theory investigation on the simplified model [Cu₂₀H₁₁(S₂PH₂)₉] with <i>C</i>_3<i>h</i> symmetry. <b>1</b>_<b>H</b> is capable of releasing H₂ gas upon irradiation with sunlight, under mild thermal conditions (65 °C), or in the presence of acids at room temperature

Anion Encapsulation and Geometric Changes in Hepta- and Hexanuclear Copper(I) Dichalcogeno Clusters: A Theoretical and Experimental Investigation

Whereas stable octanuclear clusters of the type M^I₈(E^∩E)₆ (M = Cu, Ag; E^∩E = dithio or diseleno ligand) are known for being able to encapsulate a hydride or main-group anion under some circumstances, only the related hydride-containing heptanuclear [M^I]₇(H)­(E^∩E)₆ and empty hexanuclear [M^I]₆(E^∩E)₆ species have been characterized so far. In this paper we investigate by the means of theoretical calculations and experiments the viability of empty and anion-centered clusters of the type [Cu^I]₇(X)­(E^∩E)₆ and [Cu^I]₆(X)­(E^∩E)₆ (X = vacancy, H or a main-group atom). The theoretical prediction for the existence of anion-containing heptanuclear species, the shape of which is modulated by the anion nature and size, have been fully confirmed by the synthesis and characterization of [Cu₇(X)­{S₂P­(OⁱPr)₂}₆] (X = H, Br). This consistency between experiment and theory allows us to predict the stability and shape-modulated structure of a whole series of [Cu^I]₇(X)­(E^∩E)₆ (X = vacancy, H, O, S, halogen) and [Cu^I]₆(X)­(E^∩E)₆ (X = H, halogen) clusters

Structure and Spectroscopic Properties of Gold(I) Diselenophosph(in)ate Complexes: A Joint Experimental and Theoretical Study

The structure and optical properties of several polynuclear gold­(I) species, namely, diselenophosphate [Au­{μ-Se₂P­(OR)₂}]₂ complexes (R = ^<i>i</i>Pr, Et, ^<i>n</i>Pr) respectively numbered <b>1</b>, <b>2</b>, and <b>3</b> and number <b>4</b> [Au­{μ-Se₂P­(CH₂)₂Ph)₂}]₂, exhibiting interesting structural, absorption, and emission properties have been studied. The synthesis, full characterization, and experimental spectroscopic study of <b>3</b> and <b>4</b> have first been carried out, <b>1</b> and <b>2</b> being previously studied. In the solid state, <b>3</b> gives polymers, like <b>1</b> and <b>2</b>, whereas <b>4</b> exists under a dinuclear monomeric form. The absorption and phosphorescence properties of <b>4</b> have been rationalized using DFT and TDDFT computations. In particular, Au–Au bonding seems to appear in its first singlet and triplet states, whereas such a bond does not exist in the ground state. Then, the influence of polymerization through aurophilic bonding on the optical properties of <b>2</b> is investigated (<b>1</b> and <b>3</b> behave as <b>2</b>). It is shown using TDDFT computations that its observed UV–visible excitation spectrum in solution is due to high oligomers and not to monomers or low size oligomers. ESI-MS molecular weight measurements confirm the occurrence of such oligomers of <b>2</b> in solution. An assignment of the observed bands of <b>2</b> is proposed. The transition corresponding to the first excitation band, which is mainly a HOMO to LUMO one, exhibits metal-centered character, i.e., a gold 5d to 6p orbital transition, but concomitantly transfers significant electron density from gold to phosphorus atoms so that it is also a MLCT one

Anion Encapsulation and Geometric Changes in Hepta- and Hexanuclear Copper(I) Dichalcogeno Clusters: A Theoretical and Experimental Investigation

Whereas stable octanuclear clusters of the type M^I₈(E^∩E)₆ (M = Cu, Ag; E^∩E = dithio or diseleno ligand) are known for being able to encapsulate a hydride or main-group anion under some circumstances, only the related hydride-containing heptanuclear [M^I]₇(H)­(E^∩E)₆ and empty hexanuclear [M^I]₆(E^∩E)₆ species have been characterized so far. In this paper we investigate by the means of theoretical calculations and experiments the viability of empty and anion-centered clusters of the type [Cu^I]₇(X)­(E^∩E)₆ and [Cu^I]₆(X)­(E^∩E)₆ (X = vacancy, H or a main-group atom). The theoretical prediction for the existence of anion-containing heptanuclear species, the shape of which is modulated by the anion nature and size, have been fully confirmed by the synthesis and characterization of [Cu₇(X)­{S₂P­(OⁱPr)₂}₆] (X = H, Br). This consistency between experiment and theory allows us to predict the stability and shape-modulated structure of a whole series of [Cu^I]₇(X)­(E^∩E)₆ (X = vacancy, H, O, S, halogen) and [Cu^I]₆(X)­(E^∩E)₆ (X = H, halogen) clusters

A μ₉-Iodide in a Tricapped Trigonal-Prismatic Geometry

Two luminescent, undecanuclear silver complexes [Ag₁₁(μ₉-I)­(μ₃-I)₃{E₂P­(OⁱPr)₂}₆]­(PF₆) [E = S (yellow), <b>1</b>; Se (orange), <b>2</b>], containing the first μ₉-iodine inscribed at the center of a pentacapped trigonal-prismatic silver skeleton, were reported