18 research outputs found

    Ag<sub>13</sub>-Centered Cuboctahedral Architecture in Inorganic Cluster Chemistry: A DFT Investigation

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    The bonding in the [Ag<sub>13</sub>{Ī¼<sub>3</sub>-FeĀ­(CO)<sub>4</sub>}<sub>8</sub>]<sup>3ā€‘/5ā€‘</sup> clusters, which exhibit an Ag<sub>13</sub>-centered cuboctahedral core, has been analyzed and rationalized by DFT calculations. Not considering the interaction with its encapsulated atom, the empty [Ag<sub>12</sub>{Ī¼<sub>3</sub>-FeĀ­(CO)<sub>4</sub>}<sub>8</sub>]<sup>4ā€“</sup> cage can be considered as the assembly of 12 linearly coordinated 14-electron Ag<sup>I</sup> metal centers. Adding a supplementary Ag<sup>+</sup> at the center allows some covalent delocalized bonding which to some extent tends to reduce the electron deficiency of the 14-electron centers. Adding now two electrons strengthens the delocalized bonding between the encapsulated atom and its host, making [Ag<sub>13</sub>{Ī¼<sub>3</sub>-FeĀ­(CO)<sub>4</sub>}<sub>8</sub>]<sup>5ā€“</sup> a superatom with two jellium (5s-type) electrons. TDDFT calculations predict near-IR absorption for this penta-anion, because of the presence of an a<sub>1g</sub> HOMO in the middle of an energy gap. Luminescence in the same optical range is also suggested. Other related cubococtahedral species, such as [Ag<sub>23</sub>(SH)<sub>16</sub>]<sup>āˆ’</sup>, a model for the known 8-electron [Au<sub>23</sub>(SR)<sub>16</sub>]<sup>āˆ’</sup> species which exhibits a bicapped centered dodecahedral kernel structure, have also been investigated

    Ag<sub>13</sub>-Centered Cuboctahedral Architecture in Inorganic Cluster Chemistry: A DFT Investigation

    No full text
    The bonding in the [Ag<sub>13</sub>{Ī¼<sub>3</sub>-FeĀ­(CO)<sub>4</sub>}<sub>8</sub>]<sup>3ā€‘/5ā€‘</sup> clusters, which exhibit an Ag<sub>13</sub>-centered cuboctahedral core, has been analyzed and rationalized by DFT calculations. Not considering the interaction with its encapsulated atom, the empty [Ag<sub>12</sub>{Ī¼<sub>3</sub>-FeĀ­(CO)<sub>4</sub>}<sub>8</sub>]<sup>4ā€“</sup> cage can be considered as the assembly of 12 linearly coordinated 14-electron Ag<sup>I</sup> metal centers. Adding a supplementary Ag<sup>+</sup> at the center allows some covalent delocalized bonding which to some extent tends to reduce the electron deficiency of the 14-electron centers. Adding now two electrons strengthens the delocalized bonding between the encapsulated atom and its host, making [Ag<sub>13</sub>{Ī¼<sub>3</sub>-FeĀ­(CO)<sub>4</sub>}<sub>8</sub>]<sup>5ā€“</sup> a superatom with two jellium (5s-type) electrons. TDDFT calculations predict near-IR absorption for this penta-anion, because of the presence of an a<sub>1g</sub> HOMO in the middle of an energy gap. Luminescence in the same optical range is also suggested. Other related cubococtahedral species, such as [Ag<sub>23</sub>(SH)<sub>16</sub>]<sup>āˆ’</sup>, a model for the known 8-electron [Au<sub>23</sub>(SR)<sub>16</sub>]<sup>āˆ’</sup> species which exhibits a bicapped centered dodecahedral kernel structure, have also been investigated

    [M<sub>16</sub>Ni<sub>24</sub>(CO)<sub>40</sub>]<sup>4ā€“</sup>: Coinage Metal Tetrahedral Superatoms as Useful Building Blocks Related to Pyramidal Au<sub>20</sub> Clusters (M = Cu, Ag, Au). Electronic and Bonding Properties from Relativistic DFT Calculations

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    Characterization of the tetrahedral Au<sub>20</sub> structure in the gas phase remains a major landmark in gold cluster chemistry, where further efforts to stabilize this bare 20-electron superatom in solution to extend and understand its chemistry have failed so far. Here, we account for the structural, electronic, and bonding properties of [M<sub>16</sub>Ni<sub>24</sub>(CO)<sub>40</sub>]<sup>4ā€“</sup> (M = Cu, Ag, Au) observed in solution for gold and silver. Our results show a direct electronic relationship with Au<sub>20</sub>, owing that such species share a common tetrahedral [M<sub>16</sub>]<sup>4ā€“</sup> central core with a 1S<sup>2</sup>1P<sup>6</sup>1D<sup>10</sup>2S<sup>2</sup> jellium configuration. In the case of Au<sub>20</sub>, the [Au<sub>16</sub>]<sup>4ā€“</sup> core is capped by four Au<sup>+</sup> ions, whereas in [M<sub>16</sub>Ni<sub>24</sub>(CO)<sub>40</sub>]<sup>4ā€“</sup> it is capped by four Ni<sub>6</sub>(CO)<sub>10</sub> units. In both cases, the capping entities are a full part of the superatom entity, where it appears that the free (uncapped) [M<sub>16</sub>]<sup>4ā€“</sup> species must be capped for further stabilization. It follows that the Ni<sub>6</sub>(CO)<sub>10</sub> units in [M<sub>16</sub>Ni<sub>24</sub>(CO)<sub>40</sub>]<sup>4ā€“</sup> should not be considered as external ligands as their bonding with the [M<sub>16</sub>]<sup>4ā€“</sup> core is mainly associated with a delocalization of the 20 jellium electrons onto the Ni atoms. Thus, the [M<sub>16</sub>Ni<sub>24</sub>(CO)<sub>40</sub>]<sup>4ā€“</sup> species can be seen as the solution version of tetrahedral M<sub>20</sub> clusters, encouraging experimental efforts to further develop the chemistry of such complexes as M(111) finite surface section structures, with M = Ag and Au and, particularly promising, with M = Cu. Furthermore, optical properties were simulated to assist future experimental characterization

    New Main-Group-Element-Rich <i>nido</i>-Octahedral Cluster System: Synthesis and Characterization of [Et<sub>4</sub>N][Fe<sub>2</sub>(CO)<sub>6</sub>(Ī¼<sub>3</sub>ā€‘As){Ī¼<sub>3</sub>ā€‘EFe(CO)<sub>4</sub>}<sub>2</sub>]

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    A series of clusters of the form [Et<sub>4</sub>N]Ā­[Fe<sub>2</sub>Ā­(CO)<sub>6</sub>Ā­(Ī¼<sub>3</sub>-As)}Ā­(Ī¼<sub>3</sub>-EFeĀ­(CO)<sub>4</sub>)], where E is either P or As, were synthesized from [Et<sub>4</sub>N]<sub>2</sub>Ā­[HAsĀ­{FeĀ­(CO)<sub>4</sub>}<sub>3</sub>] and ECl<sub>3</sub>. AsCl<sub>3</sub> gives the As-only compound; PCl<sub>3</sub> produces compounds having two As atoms with one P atom, or one As atom and two P atoms, and they can exist as two possible isomers, one of which is chiral. The As<sub>2</sub>P and AsP<sub>2</sub> clusters cocrystallize, and their structure as determined by single-crystal X-ray diffraction is given along with the structure of the As-only cluster. Analytical data as well as density functional theory calculations support the formation and geometries of the new molecules

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

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    The structure of a nanospheric polyhydrido copper cluster, [Cu<sub>20</sub>(H)<sub>11</sub>{S<sub>2</sub>PĀ­(O<sup><i>i</i></sup>Pr)<sub>2</sub>}<sub>9</sub>], was determined by single-crystal neutron diffraction. The Cu<sub>20</sub> cluster consists of an elongated triangular orthobicupola constructed from 18 Cu atoms that encapsulate a [Cu<sub>2</sub>H<sub>5</sub>]<sup>3ā€“</sup> ion with an exceptionally short Cuā€“Cu distance. The 11 hydrides in the cluster display three different coordination modes to the Cu atoms: six Ī¼<sub>3</sub>-hydrides in a pyramidal geometry, two Ī¼<sub>4</sub>-hydrides in a tetrahedral cavity, and three Ī¼<sub>4</sub>-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 Ɨ 0.50 mm Ɨ 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

    No full text
    The structure of a nanospheric polyhydrido copper cluster, [Cu<sub>20</sub>(H)<sub>11</sub>{S<sub>2</sub>PĀ­(O<sup><i>i</i></sup>Pr)<sub>2</sub>}<sub>9</sub>], was determined by single-crystal neutron diffraction. The Cu<sub>20</sub> cluster consists of an elongated triangular orthobicupola constructed from 18 Cu atoms that encapsulate a [Cu<sub>2</sub>H<sub>5</sub>]<sup>3ā€“</sup> ion with an exceptionally short Cuā€“Cu distance. The 11 hydrides in the cluster display three different coordination modes to the Cu atoms: six Ī¼<sub>3</sub>-hydrides in a pyramidal geometry, two Ī¼<sub>4</sub>-hydrides in a tetrahedral cavity, and three Ī¼<sub>4</sub>-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 Ɨ 0.50 mm Ɨ 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

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

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    Three new halide-centered octanuclear silverĀ­(I) complexes, [Ag<sub>8</sub>(X)Ā­{S<sub>2</sub>PĀ­(CH<sub>2</sub>CH<sub>2</sub>Ph)<sub>2</sub>}<sub>6</sub>]Ā­(PF<sub>6</sub>), X = F<sup>ā€“</sup>, <b>1</b>; Cl<sup>ā€“</sup>, <b>2</b>; Br<sup>ā€“</sup>, <b>3</b>; were prepared in the presence of the corresponding halide anions with silverĀ­(I) salts and dithiophosphinate ligands. Structure analyses displayed that a Ag<sub>8</sub> cubic core can be modulated by the size effect of the central halide; however, an iodide-centered Ag<sub>8</sub> cluster was not found under similar reaction conditions. Interestingly, a luminescent dodecanuclear silverĀ­(I) cluster, [Ag<sub>12</sub>(Ī¼<sub>12</sub>-I)Ā­(Ī¼<sub>3</sub>-I)<sub>4</sub>{S<sub>2</sub>PĀ­(CH<sub>2</sub>CH<sub>2</sub>Ph)<sub>2</sub>}<sub>6</sub>]Ā­(I), <b>4</b>; was then synthesized. The structure of <b>4</b> contains a novel Ī¼<sub>12</sub>-I at the center of a cuboctahedral silverĀ­(I) atom cage, which is further stabilized by four additional Ī¼<sub>3</sub>-I and six dithiophosphinate ligands. To the best of our knowledge, the Ī¼<sub>12</sub>-I revealed in <b>4</b> is the highest coordination number for a halide ion authenticated by both experimental and computational studies. Previously, the Ī¼<sub>12</sub>-I was only observed in [PyH]Ā­[{TpMoĀ­(Ī¼<sub>3</sub>-S)<sub>4</sub>Cu<sub>3</sub>}<sub>4</sub>(Ī¼<sub>12</sub>-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

    Hydrido Copper Clusters Supported by Dithiocarbamates: Oxidative Hydride Removal and Neutron Diffraction Analysis of [Cu<sub>7</sub>(H){S<sub>2</sub>C(aza-15-crown-5)}<sub>6</sub>]

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    Reactions of CuĀ­(I) salts with NaĀ­(S<sub>2</sub>CR) (R = N<sup><i>n</i></sup>Pr<sub>2</sub>, NEt<sub>2</sub>, aza-15-crown-5), and (Bu<sub>4</sub>N)Ā­(BH<sub>4</sub>) in an 8:6:1 ratio in CH<sub>3</sub>CN solution at room temperature yield the monocationic hydride-centered octanuclear Cu<sup>I</sup> clusters, [Cu<sub>8</sub>(H)Ā­{S<sub>2</sub>CR}<sub>6</sub>]Ā­(PF<sub>6</sub>) (R = N<sup><i>n</i></sup>Pr<sub>2</sub>, <b>1</b><sub><b>H</b></sub>; NEt<sub>2</sub>, <b>2</b><sub><b>H</b></sub>; aza-15-crown-5, <b>3</b><sub><b>H</b></sub>). Further reactions of [Cu<sub>8</sub>(H)Ā­{S<sub>2</sub>CR}<sub>6</sub>]Ā­(PF<sub>6</sub>) with 1 equiv of (Bu<sub>4</sub>N)Ā­(BH<sub>4</sub>) produced neutral heptanuclear copper clusters, [Cu<sub>7</sub>(H)Ā­{S<sub>2</sub>CR}<sub>6</sub>] (R = N<sup><i>n</i></sup>Pr<sub>2</sub>, <b>4</b><sub><b>H</b></sub>; NEt<sub>2</sub>, <b>5</b><sub><b>H</b></sub>; aza-15-crown-5, <b>6</b><sub><b>H</b></sub>) and clusters <b>4</b>ā€“<b>6</b> can also be generated from the reaction of CuĀ­(BF<sub>4</sub>)<sub>2</sub>, NaĀ­(S<sub>2</sub>CR), and (Bu<sub>4</sub>N)Ā­(BH<sub>4</sub>) in a 7:6:8 molar ratio in CH<sub>3</sub>CN. Reformation of cationic Cu<sup>I</sup><sub>8</sub> clusters by adding 1 equiv of Cu<sup>I</sup> salt to the neutral Cu<sub>7</sub> clusters in solution is observed. Intriguingly, the central hydride in [Cu<sub>8</sub>(H)Ā­{S<sub>2</sub>CN<sup><i>n</i></sup>Pr<sub>2</sub>}<sub>6</sub>]Ā­(PF<sub>6</sub>) can be oxidatively removed as H<sub>2</sub> by CeĀ­(NO<sub>3</sub>)<sub>6</sub><sup>2ā€“</sup> to yield [Cu<sup>II</sup>(S<sub>2</sub>CN<sup><i>n</i></sup>Pr<sub>2</sub>)<sub>2</sub>] exploiting the redox-tolerant nature of dithiocarbamates. Regeneration of hydride-centered octanuclear copper clusters from the [Cu<sup>II</sup>(S<sub>2</sub>CN<sup><i>n</i></sup>Pr<sub>2</sub>)<sub>2</sub>] can be achieved by reaction with CuĀ­(I) ions and borohydride. The hydride release and regeneration of Cu<sup>I</sup><sub>8</sub> was monitored by UVā€“visible titration experiments. To our knowledge, this is the first time that hydride encapsulated within a copper cluster can be released as H<sub>2</sub> via chemical means. All complexes have been fully characterized by <sup>1</sup>H NMR, FT-IR, UVā€“vis, and elemental analysis, and molecular structures of <b>1</b><sub><b>H</b></sub>, <b>2</b><sub><b>H</b></sub>, and <b>6</b><sub><b>H</b></sub> were clearly established by single-crystal X-ray diffraction. Both <b>1</b><sub><b>H</b></sub> and <b>2</b><sub><b>H</b></sub> exhibit a tetracapped tetrahedral Cu<sub>8</sub> skeleton, which is inscribed within a S<sub>12</sub> icosahedron constituted by six dialkyl dithiocarbamate ligands in a tetrametallic-tetraconnective (Ī¼<sub>2</sub>, Ī¼<sub>2</sub>) bonding mode. The copper framework of <b>6</b><sub><b>H</b></sub> is a tricapped distorted tetrahedron in which the four-coordinate hydride is demonstrated to occupy the central site by single crystal neutron diffraction. Compounds <b>1</b>ā€“<b>3</b> exhibit a yellow emission in both the solid state and in solution under UV irradiation at 77 K, and the structureless emission is assigned as a <sup>3</sup>metal to ligand charge transfer (MLCT) excited state. Density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations on model compounds match the experimental structures and provide rationalization of their bonding and optical properties

    [Ag<sub>7</sub>(H){E<sub>2</sub>P(OR)<sub>2</sub>}<sub>6</sub>] (E = Se, S): Precursors for the Fabrication of Silver Nanoparticles

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    Reactions of AgĀ­(I) salt, NH<sub>4</sub>(E<sub>2</sub>PĀ­(OR)<sub>2</sub>) (R = <sup>i</sup>Pr, Et; E = Se, S), and NaBH<sub>4</sub> in a 7:6:1 ratio in CH<sub>2</sub>Cl<sub>2</sub> at room temperature, led to the formation of hydride-centered heptanuclear silver clusters, [Ag<sub>7</sub>(H)Ā­{E<sub>2</sub>PĀ­(OR)<sub>2</sub>}<sub>6</sub>] (R = <sup>i</sup>Pr, E = Se (<b>3</b>): R = Et; E = SĀ­(<b>4</b>). The reaction of [Ag<sub>10</sub>(E)Ā­{E<sub>2</sub>PĀ­(OR)<sub>2</sub>}<sub>8</sub>] with NaBH<sub>4</sub> in CH<sub>2</sub>Cl<sub>2</sub> produced [Ag<sub>8</sub>(H)Ā­{E<sub>2</sub>PĀ­(OR)<sub>2</sub>}<sub>6</sub>]Ā­(PF<sub>6</sub>) (R = <sup>i</sup>Pr, E = Se (<b>1</b>): R = Et; E = SĀ­(<b>2</b>)), which can be converted to clusters <b>3</b> and <b>4</b>, respectively, via the addition of 1 equiv of borohydride. Intriguingly clusters <b>1</b> and <b>2</b> can be regenerated via adding 1 equiv of AgĀ­(CH<sub>3</sub>CN)<sub>4</sub>PF<sub>6</sub> to the solution of compounds <b>3</b> and <b>4</b>, respectively. All complexes have been fully characterized by NMR (<sup>1</sup>H, <sup>77</sup>Se, <sup>109</sup>Ag) spectroscopy, UVā€“vis, electrospray ionization mass spectrometry (ESI-MS), FT-IR, thermogravimetric analysis (TGA), and elemental analysis, and molecular structures of <b>3</b><sub><b>H</b></sub> and <b>4</b><sub><b>H</b></sub> were clearly established by single crystal X-ray diffraction. Both <b>3</b><sub><b>H</b></sub> and <b>4</b><sub><b>H</b></sub> exhibit a tricapped tetrahedral Ag<sub>7</sub> skeleton, which is inscribed within an E<sub>12</sub> icosahedron constituted by six dialkyl dichalcogenophosphate ligands in a tetrametallic-tetraconnective (Ī¼<sub>2</sub>, Ī¼<sub>2</sub>) bonding mode. Density functional theory (DFT) calculations on the models [Ag<sub>7</sub>(H)Ā­(E<sub>2</sub>PH<sub>2</sub>)<sub>6</sub>] (E = Se: <b>3ā€²</b>; E = S: <b>4ā€²</b>) yielded to a tricapped, slightly elongated tetrahedral silver skeleton, and time-dependent DFT (TDDFT) calculations reproduce satisfyingly the UVā€“vis spectrum with computed transitions at 452 and 423 nm for <b>3ā€²</b> and 378 nm for <b>4ā€²</b>. Intriguingly further reactions of [Ag<sub>7</sub>(H)Ā­{E<sub>2</sub>PĀ­(OR)<sub>2</sub>}<sub>6</sub>] with 8-fold excess amounts of NaBH<sub>4</sub> produced monodisperse silver nanoparticles with an averaged particle size of 30 nm, which are characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), and UVā€“vis absorption spectrum

    Hydrido Copper Clusters Supported by Dithiocarbamates: Oxidative Hydride Removal and Neutron Diffraction Analysis of [Cu<sub>7</sub>(H){S<sub>2</sub>C(aza-15-crown-5)}<sub>6</sub>]

    No full text
    Reactions of CuĀ­(I) salts with NaĀ­(S<sub>2</sub>CR) (R = N<sup><i>n</i></sup>Pr<sub>2</sub>, NEt<sub>2</sub>, aza-15-crown-5), and (Bu<sub>4</sub>N)Ā­(BH<sub>4</sub>) in an 8:6:1 ratio in CH<sub>3</sub>CN solution at room temperature yield the monocationic hydride-centered octanuclear Cu<sup>I</sup> clusters, [Cu<sub>8</sub>(H)Ā­{S<sub>2</sub>CR}<sub>6</sub>]Ā­(PF<sub>6</sub>) (R = N<sup><i>n</i></sup>Pr<sub>2</sub>, <b>1</b><sub><b>H</b></sub>; NEt<sub>2</sub>, <b>2</b><sub><b>H</b></sub>; aza-15-crown-5, <b>3</b><sub><b>H</b></sub>). Further reactions of [Cu<sub>8</sub>(H)Ā­{S<sub>2</sub>CR}<sub>6</sub>]Ā­(PF<sub>6</sub>) with 1 equiv of (Bu<sub>4</sub>N)Ā­(BH<sub>4</sub>) produced neutral heptanuclear copper clusters, [Cu<sub>7</sub>(H)Ā­{S<sub>2</sub>CR}<sub>6</sub>] (R = N<sup><i>n</i></sup>Pr<sub>2</sub>, <b>4</b><sub><b>H</b></sub>; NEt<sub>2</sub>, <b>5</b><sub><b>H</b></sub>; aza-15-crown-5, <b>6</b><sub><b>H</b></sub>) and clusters <b>4</b>ā€“<b>6</b> can also be generated from the reaction of CuĀ­(BF<sub>4</sub>)<sub>2</sub>, NaĀ­(S<sub>2</sub>CR), and (Bu<sub>4</sub>N)Ā­(BH<sub>4</sub>) in a 7:6:8 molar ratio in CH<sub>3</sub>CN. Reformation of cationic Cu<sup>I</sup><sub>8</sub> clusters by adding 1 equiv of Cu<sup>I</sup> salt to the neutral Cu<sub>7</sub> clusters in solution is observed. Intriguingly, the central hydride in [Cu<sub>8</sub>(H)Ā­{S<sub>2</sub>CN<sup><i>n</i></sup>Pr<sub>2</sub>}<sub>6</sub>]Ā­(PF<sub>6</sub>) can be oxidatively removed as H<sub>2</sub> by CeĀ­(NO<sub>3</sub>)<sub>6</sub><sup>2ā€“</sup> to yield [Cu<sup>II</sup>(S<sub>2</sub>CN<sup><i>n</i></sup>Pr<sub>2</sub>)<sub>2</sub>] exploiting the redox-tolerant nature of dithiocarbamates. Regeneration of hydride-centered octanuclear copper clusters from the [Cu<sup>II</sup>(S<sub>2</sub>CN<sup><i>n</i></sup>Pr<sub>2</sub>)<sub>2</sub>] can be achieved by reaction with CuĀ­(I) ions and borohydride. The hydride release and regeneration of Cu<sup>I</sup><sub>8</sub> was monitored by UVā€“visible titration experiments. To our knowledge, this is the first time that hydride encapsulated within a copper cluster can be released as H<sub>2</sub> via chemical means. All complexes have been fully characterized by <sup>1</sup>H NMR, FT-IR, UVā€“vis, and elemental analysis, and molecular structures of <b>1</b><sub><b>H</b></sub>, <b>2</b><sub><b>H</b></sub>, and <b>6</b><sub><b>H</b></sub> were clearly established by single-crystal X-ray diffraction. Both <b>1</b><sub><b>H</b></sub> and <b>2</b><sub><b>H</b></sub> exhibit a tetracapped tetrahedral Cu<sub>8</sub> skeleton, which is inscribed within a S<sub>12</sub> icosahedron constituted by six dialkyl dithiocarbamate ligands in a tetrametallic-tetraconnective (Ī¼<sub>2</sub>, Ī¼<sub>2</sub>) bonding mode. The copper framework of <b>6</b><sub><b>H</b></sub> is a tricapped distorted tetrahedron in which the four-coordinate hydride is demonstrated to occupy the central site by single crystal neutron diffraction. Compounds <b>1</b>ā€“<b>3</b> exhibit a yellow emission in both the solid state and in solution under UV irradiation at 77 K, and the structureless emission is assigned as a <sup>3</sup>metal to ligand charge transfer (MLCT) excited state. Density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations on model compounds match the experimental structures and provide rationalization of their bonding and optical properties
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