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Modifying atomically precise nanocluster surfaces while maintaining the cluster core remains a key challenge. Herein, the synthesis, structure, and properties of two targeted Ag 20 nanoclusters (NCs) with eight surface azide moieties, [CO 3 @Ag 20 (S t Bu) 10 (m-N 3 -C 6 H 4 COO) 8 (DMF) 4 ] (1-m) and [CO 3 @Ag 20 (S t Bu) 10 (p-N 3 -C 6 H 4 COO) 8 (DMF) 4 ] (1-p) are reported, where DMF is N,N-dimethylformamide. These AgNCs are designed to undergo cluster surface strain-promoted azide-alkyne cycloaddition (CS-SPAAC) reactions, introducing new functionality to the cluster surface. Reactivity is screened using model strained cyclooctynes. Reaction products and parent clusters are characterized by UV-vis, FT-IR, and NMR spectroscopies. The structure of the parent clusters and presence of surface azides is confirmed by single crystal X-ray diffraction (SCXRD) analysis. Clusters 1-m and 1-p are found to be amenable to CS-SPAAC reactions with retention of the NC frameworks, opening new routes for efficient modification of AgNC for applications., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)

To fine-tune structure-property correlations of thiolate-protected gold nanoclusters through post-assembly surface modifications, we report the synthesis of the o, m, and p regioisomeric forms of the anionic azide-functionalized [Au 25 (SCH 2 CH 2 -C 6 H 4 -N 3 ) 18 ] 1- platform. They can undergo cluster-surface strain-promoted alkyne-azide cycloaddition (CS-SPAAC) chemistry with complementary strained-alkynes. Although their optical properties are similar, the electrochemical properties appear to correlate with the position of the azido group. The ability to conduct CS-SPAAC chemistry without altering the parent nanocluster structure is different as the isomeric form of the surface ligand is changed, with the [Au 25 (SCH 2 CH 2 -p-C 6 H 4 -N 3 ) 18 ] 1- isomer having the highest reaction rates, while the [Au 25 (SCH 2 CH 2 -o-C 6 H 4 -N 3 ) 18 ] 1- isomer is not stable following CS-SPAAC. Single-crystal X-ray diffraction provide the molecular structure of the neutral forms of the three regioisomeric clusters, [Au 25 (SCH 2 CH 2 -o/m/p-C 6 H 4 -N 3 ] 0 , which illustrates correlated structural features of the central core as the position of the azido moiety is changed., (© 2022 Wiley-VCH GmbH.)

A hexadeca-nuclear, N-heterocyclic carbene stabilized gold(i)-copper(i)-sulfido cluster is reported, which emits yellow-orange in the solid state. The nature of this emission is examined, supported by combined theoretical and spectroscopic studies.

The selective synthesis of the zinc-acetato-phosphinidene cluster [Zn 6 (μ 3 -PSiMe 3 ) 4 (OAc) 4 (NC 5 H 5 ) 5 ] 1 is presented. The cluster serves as a stable, single-source precursor to yield soluble zinc phosphide nanoparticles via P-Si bond activation and AcOSiMe 3 elimination when heated in oleylamine or other donor solvents.

Ultrasmall atomically precise monolayer-protected gold thiolate nanoclusters are an intensely researched nanomaterial framework, but there is a lack of a system that can be directly synthesized and undergo interfacial surface chemistry. We report an [Au 25 (SCH 2 CH 2 - p -C 6 H 4 -N 3 ) 18 ] - nanocluster platform with azide moieties appended onto each surface ligand. The structure of this surface reactive cluster has been confirmed by single-crystal X-ray crystallography, mass spectrometry and ultraviolet visible, infrared and nuclear magnetic resonance spectroscopies. We show that all surface azide moieties are amenable to cluster-surface strain-promoted alkyne-azide cycloaddition chemistry with a strained cyclooctyne, opening this as a new platform to allow functional, postassembly surface modifications to this very prominent nanocluster.

Highly accelerated inverse-electron-demand strain-promoted alkyne-nitrone cycloaddition (IED SPANC) between a stable cyclooctyne (bicyclo[6.1.0]nonyne (BCN)) and nitrones delocalized into a C α -pyridinium functionality is reported, with the most electron-deficient "pyridinium-nitrone" displaying among the most rapid cycloadditions to BCN that is currently reported. Density functional theory (DFT) and X-ray crystallography are explored to rationalize the effects of N - and C α -substituent modifications at the nitrone on IED SPANC reaction kinetics and the overall rapid reactivity of pyridinium-delocalized nitrones.

A series of phosphorescent homo- and heterometallic copper(I)-chalcogenide clusters stabilized by cyclic (alkyl)(amino)carbene ligands [Cu 4 M 4 (μ 3 -E) 4 (CAAC Cy ) 4 ] (M = Cu, Ag, Au; E = S, Se) has been synthesized by the reaction of the new copper(I) trimethylsilylchalcogenolate compounds [(CAAC Cy )CuESiMe 3 ] with ligand-supported group 11 acetates. The clusters are emissive at 77 K in solution and the solid state, with emission colors that depend on the metal/chalcogen composition. Electronic structure calculations point to a common 3 [(M + +E 2- )LCT] emissive state for the series.

The reaction of N-heterocyclic carbene (NHC) Group 11 metal complexes, [(NHC)M-X] (X = chloride, acetate), with the new azide-modified arylthiol 1-HSCH 2 -2,5-Me 2 -4-N 3 CH 2 -C 6 H 2 , 1 (for M = Au; X = Cl), or 1-Me 3 SiSCH 2 -2,5-Me 2 -4-N 3 CH 2 -C 6 H 2 , 2 (for M = Cu, X = Cl; M = Ag, X = OAc), affords the "clickable" NHC-metal thiolates [( i Pr 2 -bimy)Au-(1-SCH 2 -2,5-Me 2 -4-N 3 CH 2 -C 6 H 2 )], 5; [(IPr)Au-(1-SCH 2 -2,5-Me 2 -4-N 3 CH 2 -C 6 H 2 )], 6; [(IPr)Ag-(1-SCH 2 -2,5-Me 2 -4-N 3 CH 2 -C 6 H 2 )], 7; and [(IPr)Cu-(1-SCH 2 -2,5-Me 2 -4-N 3 CH 2 -C 6 H 2 )], 8 ( i Pr 2 -bimy = 1,3-di-isopropylbenzimidazol-2-ylidene, IPr = 1,3-bis(2,6-di-iso-propylphenyl)imidazol-2-ylidene). Single-crystal X-ray analysis of all metal complexes show that they are two-coordinate, nearly linear, with a terminally bonded thiolate ligand possessing an accessible azide (-N 3 ) moiety. The strain-promoted alkyne-azide cycloaddition (SPAAC) reaction of complex 6 with bicyclo[6.1.0]non-4-yn-9-ylmethanol (BCN-OH) and dibenzocyclooctyne-amine (DBCO-NH 2 ) illustrated the reactivity of the azide moiety toward strain-promoted cycloaddition. The rate of the SPAAC reaction between complex 6 and BCN-OH was determined via 1 H NMR spectroscopy under second order conditions, and was compared to that of BCN-OH with PhCH 2 N 3 .

The novel binary P 4 analogue (Ge 2 P 2 ) 2- proved to be a suitable precursor for heteroatomic cluster synthesis. Over time in solution, it rearranges to form (Ge 7 P 2 ) 2- , as shown by NMR studies and X-ray diffraction. Reactions of (Ge 2 P 2 ) 2- with CdPh 2 afford [K(crypt-222)] 3 [Cd 3 (Ge 3 P) 3 ], containing an unprecedented ternary cluster anion with a triangular Cd 3 moiety.

Systematic 111 Cd solid-state (SS) NMR experiments were performed to correlate X-ray crystallographic data with SSNMR parameters for a set of CdS-based materials, varying from molecular crystals of small complexes [Cd(SPh) 4 ] 2- and [Cd 4 (SPh) 10 ] 2- to superlattices of large monodisperse clusters [Cd 54 S 32 (SPh) 48 (dmf) 4 ] 4- and 1.9 nm CdS. Methodical data analysis allowed for assigning individual resonances or resonance groups to particular types of cadmium sites residing in different chemical and/or crystallographic environments. For large CdS frameworks, 111 Cd resonances were found to form three groups. This result is noteworthy, since for related systems with size polydispersity and variations in composition, such as CdS or CdSe nanoparticles protected with an organic ligand shell, typically only two groups of resonances were observed. The generalized information obtained in this work can be used for the interpretation of 111/113 Cd SSNMR data for large CdS clusters and nanoparticles, for which crystal structure analysis remains inaccessible. Comparison of the powder X-ray diffraction patterns for freshly prepared and dried superlattices of large CdS clusters revealed an interesting superstructure rearrangement that was not observed for the smaller frameworks.

A new class of coinage-metal chalcogenide compounds [Au 4 M 4 (μ 3 -E) 4 (IPr) 4 ] (M = Ag, Au; E = S, Se, Te) has been synthesized from the combination of N-heterocyclic carbene-ligated gold(I) trimethylsilylchalcogenolates [(IPr)AuESiMe 3 ] and ligand-supported metal acetates. Phosphorescence is observed from these clusters in glassy 2-methyltetrahydrofuran and in the solid state at 77 K, with emission energies that depend on the selection of metal/chalcogen ion composition. The ability to tune the emission is attributed to electronic transitions of mixed ligand-to-metal-metal-charge-transfer (IPr → AuM 2 ) and interligand (IPr → E) phosphorescence character, as revealed by time-dependent density functional theory computations.N-heterocyclic carbenes (NHCs) have been applied as ancillary ligands in the synthesis of luminescent gold(I) chalcogenide clusters and this approach allows for unprecedented selectivity over the metal and chalcogen ions present within a stable octanuclear framework.

Superstructures, combining nanoscopic constituents into micrometer-size assemblies, have a great potential for utilization of the size-dependent quantum-confinement properties in multifunctional electronic and optoelectronic devices. Two diverse superstructures of nanoscopic CdSe were prepared using solvothermal conversion of the same cadmium selenophenolate precursor (Me 4 N) 2 [Cd(SePh) 4 ]: the first is a superlattice of monodisperse [Cd 54 Se 32 (SePh) 48 (dmf) 4 ] 4- nanoclusters; the second is a unique porous CdSe crystal. Nanoclusters were crystallized as cubic crystals (≤0.5 mm in size) after solvothermal treatment at 200 °C in DMF. UV-vis absorption and PLE spectra of the reported nanoclusters are consistent with previously established trends for the known families of tetrahedral CdSe frameworks. In contrast to these, results of PL spectra are rather unexpected, as distinct room temperature emission is observed both in solution and in the solid state. The porous CdSe crystals were isolated as red hexagonal prisms (≤70 μm in size) via solvothermal treatment under similar conditions but with the addition of an alkylammonium salt. The presence of a three-dimensional CdSe network having a coherent crystalline structure inside hexagonal prisms was concluded based on powder X-ray diffraction, selected area electron diffraction and electron microscopy imaging. Self-assembly via oriented attachment of crystalline nanoparticles is discussed as the most probable mechanism of formation.

The first examples of gold(I) trimethylsilylchalcogenolate complexes were synthesized and their reactivity showcased in the preparation of a novel gold-copper-sulfur cluster [Au 4 Cu 4 S 4 (dppm) 2 ] (dppm=bis(diphenylphosphino)methane). The unprecedented structural chemistry of this compound gives rise to interesting optoelectronic properties, including long-lived orange luminescence in the solid state. Through time-dependent density functional theory calculations, this emission is shown to originate from ligand-to-metal charge transfer facilitated by Au⋅⋅⋅Cu metallophilic bonding., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In this work, the synthesis of nanoscale CuInS 2 and CuInSe 2 was developed using molecular precursors of the type [(Ph 3 P) 2 CuIn(ER) 4 ] (E = S, Se) and solvothermal reactions. Various conditions were investigated including the use of different precursors, reaction temperatures, reaction times and the addition of a secondary chalcogen source to mixtures. After optimizing conditions, nanoparticles of CuInS 2 and CuInSe 2 were isolated with controlled sizes in the range of 2-5 nm (wurtzite structure), which ultimately tuned the band gap energies of the materials. Characterization methods including powder X-ray diffraction, electron microscopy, and optical spectroscopy were used to investigate their structures and photophysical properties.

As a part of efforts to prepare new "metallachalcogenolate" precursors and develop their chemistry for the formation of ternary mixed-metal chalcogenide nanoclusters, two sets of thermally stable, N-heterocyclic carbene metal-chalcogenolate complexes of the general formula [(IPr)Ag-ESiMe3] (IPr=1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene; E=S, 1; Se, 2) and [(iPr2-bimy)Cu-ESiMe3]2 (iPr2-bimy=1,3-diisopropylbenzimidazolin-2-ylidene; E=S, 4; Se, 5) are reported. These are prepared from the reaction between the corresponding carbene metal acetate, [(IPr)AgOAc] and [(iPr-bimy)CuOAc] respectively, and E(SiMe3 )2 at low temperature. The reaction of [(IPr)Ag-ESiMe3] 1 with mercury(II) acetate affords the heterometallic complex [{(IPr)AgS}2Hg] 3 containing two (IPr)Ag-S(-) fragments bonded to a central Hg(II), representing a mixed mercury-silver sulfide complex. The reaction of [(iPr2-bimy)Cu-SSiMe3]2, which contains a smaller N-heterocyclic-carbene, with mercuric(II) acetate affords the high nuclearity cluster, [(iPr2-bimy)6Cu10S8Hg3]6. The new N-heterocyclic carbene metal-chalcogenolate complexes 1, 2, 4, 5 and the ternary mixed-metal chalcogenolate complex 3 and cluster 6 have been characterized by multinuclear NMR spectroscopy ((1)H and (13)C), elemental analysis and single-crystal X-ray diffraction., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Ferrocene-based phosphines constitute an important auxiliary ligand in inorganic chemistry. Utilizing the (ferrocenylethyl)phosphines (FcCH2CH2)3-nHnP (Fc = ferrocenyl; n = 2, 1; n = 1, 2; n = 0, 3) the synthesis of a series of coordination complexes [(FcCH2CH2)3-nHnPCuCl]4 (n = 2, 1-CuCl; n = 0, 3-CuCl), [(FcCH2CH2)2HPCuCl] (2-CuCl), {[(FcCH2CH2)H2P]2AgCl}2 (1-AgCl), [(FcCH2CH2)2HPAgCl] (2-AgCl), [(FcCH2CH2)3PAgCl]4 (3-AgCl), [(FcCH2CH2)3PM(OAc)]4 (M = Cu, 3-CuOAc M = Ag, 3-AgOAc), [(FcCH2CH2)3-nHnPAuCl] (n = 1, 2-AuCl; n = 0, 3-AuCl), via the reaction between the free phosphine and MX (M = Cu, Ag and Au; X = Cl, OAc), is described. The reaction between the respective phosphine with a suspension of metal-chloride or -acetate in a 1 : 1 ratio in THF at ambient temperature affords coordinated phosphine-coinage metal complexes. Varying structural motifs are observed in the solid state, as determined via single crystal X-ray analysis of 1-CuCl, 3-CuCl, 1-AgCl, 3-AgCl, 3-CuOAc, 3-AgOAc, 2-AuCl and 3-AuCl. Complexes 1-CuCl and 3-CuCl are tetrameric Cu(i) cubane-like structures with a Cu4Cl4 core, whereas silver complexes with primary and tertiary phosphine reveal two different structural types. The structure of 1-AgCl, unlike the rest, displays the coordination of two phosphines to each silver atom and shows a quadrangle defined by two Ag and two Cl atoms. In contrast, 3-AgCl is distorted from a cubane structure via elongation of one of the ClAg distances. 3-CuOAc and 3-AgOAc are isostructural with step-like cores, while complexes 2-AuCl and 3-AuCl reveal a linear geometry of a phosphine gold(i) chloride devoid of any aurophilic interactions. All of the complexes were characterized in solution by multinuclear (1)H, (13)C{(1)H} and (31)P NMR spectroscopic techniques; the redox chemistry of the series of complexes was examined using cyclic voltammetry. This class of complexes has been found to exhibit one reversible Fe(ii)/Fe(iii) oxidation couple, suggesting the absence of electronic communication between the ferrocenyl units on individual phosphine ligands as well as between different phosphines on the polymetallic cores.

The facile preparation and structural characterization of [M6{P(SiMe3)2}6] (M = Ag, Cu) is reported. These complexes show limited stability towards solvent loss at ambient temperature; however, N-heterocyclic carbene (NHC) ligands were used to synthesize more thermally stable metal-silylphosphido compounds. 1,3-Di-isopropylbenzimidazole-2-ylidene ((i)Pr2-bimy) and 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) are found to be excellent ligands to stabilize silylphosphido-copper compounds that show higher stability when compared to [Cu6{P(SiMe3)2}6].

A series of thermally stable N-heterocyclic copper-chalcogenolate complexes of the general formula [(IPr)Cu-ESiMe3] (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene; E = S, Se, Te) have been prepared from [(IPr)CuOAc] and E(SiMe3)2 at low temperature. The reaction of [(IPr)Cu-SSiMe3] with mercuric(II) acetate affords the heterometallic [{(IPr)CuS}2Hg] complex containing two (IPr)Cu-S(-) fragments to a central Hg(II).

The silylated organochalcogen reagents 1,2-(Me3SiSCH2)2C6H4, and 1,2-(Me3SiSeCH2)2C6H4, were prepared from the corresponding organobromides and lithium trimethylsilanechalcogenolate Li[ESiMe3] (E = S, Se). They have been characterized by multinuclear NMR spectroscopy ((1)H, (13)C, (77)Se) and electrospray ionization mass spectrometry. and react under mild conditions with (1,3-bis(diphenylphosphino)propane)palladium(ii) chloride, [PdCl2(dppp)], to provide the dinuclear organochalcogenolate-bridged complexes [(dppp)2Pd2-μ-κ(2)S-{1,2-(SCH2)2C6H4}]X2, []X2 and [(dppp)2Pd2-μ-κ(2)Se-{1,2-(SeCH2)2C6H4}]X2, []X2 (X = Cl, Br) in good yield, respectively. Furthermore, the tetranuclear palladium complex [(dppp)4Pd4-μ-κ(4)S-{1,2,4,5-(SCH2)4C6H2}]X4, []X4 (X = Cl, Br) can be synthesized from the reaction of the tetrathiotetrasilane 1,2,4,5-(Me3SiSCH2)4C6H2, and [PdCl2(dppp)]. The structures of []X2, []X2 and []X4 were determined by single crystal X-ray diffraction methods. A variety of NMR experiments including two-dimensional homonuclear and heteronuclear correlated spectra were used to probe the solution behaviour of the dinuclear complexes in more detail. These complexes were further characterized by electrospray ionization (ESI) mass spectrometry, and for []X2 and []X2, UV-Vis absorption spectroscopy.

A ferrocene-based dithiol 1,1'-[fc(C{O}OCH2CH2SH)2] has been prepared and treated with a Ag(I) salt to form the stable dithiolate compound [fc(C{O}OCH2CH2SAg)2]n (fc=[Fe(η(5)-C5H4)2]). This is used as a reagent for the preparation of the nanocluster [Ag74S19(dppp)6(fc(C{O}OCH2CH2S)2)18] which was obtained in good yield (dppp=1,3-bis(diphenylphosphino)propane)., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The N-heterocyclic carbene (NHC) 1,3-di-isopropylbenzimidazole-2-ylidene ((i)Pr2-bimy) is found to be an excellent ligand for the stabilization of silver-phosphorus polynuclear complexes. The straightforward preparation and characterization of the clusters [Ag12(PSiMe3)6((i)Pr2-bimy)6] (1) and [Ag26P2(PSiMe3)10((i)Pr2-bimy)8] (2) are described, representing the first examples of such structurally characterized, higher nuclearity complexes obtained using this class of ligands.

A series of polychalcogenotrimethylsilane complexes Ar(CH2ESiMe3)n, (Ar = aryl; E = S, Se; n = 2, 3, and 4) can be prepared from the corresponding polyorganobromide and M[ESiMe3] (M = Na, Li). These represent the first examples of the incorporation of such a large number of reactive -ESiMe3 moieties onto an organic molecular framework. They are shown to be convenient reagents for the preparation of the polyferrocenylseleno- and thioesters from ferrocenoyl chloride. The synthesis, structures, and spectroscopic properties of the new silyl chalcogen complexes 1,4-(Me3SiECH2)2(C6Me4) (E = S, 1; E = Se, 2), 1,3,5-(Me3SiECH2)3(C6Me3) (E = S, 3; E = Se, 4) and 1,2,4,5-(Me3SiECH2)4(C6H2) (E = S, 5; E = Se, 6) and the polyferrocenyl chalcogenoesters [1,4-{FcC(O)ECH2}2(C6Me4)] (E = S, 7; E = Se, 8), [1,3,5-{FcC(O)ECH2}3(C6Me3)] (E = S, 9; E = Se, 10) and [1,2,4,5-{FcC(O)ECH2}4(C6H2)] (E = S, 11 illustrated; E = Se, 12) are reported. The new polysilylated reagents and polyferrocenyl chalcogenoesters have been characterized by multinuclear NMR spectroscopy ((1)H, (13)C, (77)Se), electrospray ionization mass spectrometry and, for complexes 1, 2, 3, 4, 7, 8, and 11, single-crystal X-ray diffraction. The cyclic voltammograms of complexes 7-11 are presented., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The ligation of N-heterocyclic carbenes (NHCs) to [CuS(t)Bu] and [AgS(t)Bu] was developed as an alternative to PR3 ligands as solubilizing reagents for these coordination polymers in order to form polynuclear copper and silver t-butylthiolate clusters. 1,3-Di-isopropylbenzimidazol-2-ylidene ((i)Pr2-bimy) and 1,3-di-isopropyl-4,5-dimethylimidazol-2-ylidene ((i)Pr2-mimy) were ligated to [CuS(t)Bu] and [AgS(t)Bu] forming [Cu4(S(t)Bu)4((i)Pr2-bimy)2] 1, [Cu4(S(t)Bu)4((i)Pr2-mimy)2] 2, [Ag4(S(t)Bu)4((i)Pr2-bimy)2] 5 and [Ag5(S(t)Bu)6][Ag((i)Pr2-mimy)2] 6. For comparison, the trialkyl phosphines P(n)Pr3 and P(i)Pr3 were also used to solubilize [AgS(t)Bu] and [CuS(t)Bu] to form copper and silver t-butylthiolate clusters. [Cu4(S(t)Bu)4(P(n)Pr3)2] 3, [Cu4(S(t)Bu)4(P(i)Pr3)2] 4, [Ag4(S(t)Bu)4(P(n)Pr3)2] 7 and [Ag6(S(t)Bu)6(P(i)Pr3)2] 8 were thus formed upon reaction with [CuS(t)Bu] and [AgS(t)Bu]. The synthesized complexes have been characterized via spectroscopic and crystallographic methods. The molecular structures of the clusters, which can vary according to the ligand type, are described.

The redox-active diphosphine ligand 1,1'-bis(diphenylphosphino)ferrocene (dppf) has been used to stabilize the copper(I) chalcogenide clusters [Cu12(μ4-S)6(μ-dppf)4] (1), [Cu8(μ4-Se)4(μ-dppf)3] (2), [Cu4(μ4-Te)(μ4-η(2)-Te2)(μ-dppf)2] (3), and [Cu12(μ5-Te)4(μ8-η(2)-Te2)2(μ-dppf)4] (4), prepared by the reaction of the copper(I) acetate coordination complex (dppf)CuOAc (5) with 0.5 equiv of E(SiMe3)2 (E = S, Se, Te). Single-crystal X-ray analyses of complexes 1-4 confirm the presence of {Cu(2x)E(x)} cores stabilized by dppf ligands on their surfaces, where the bidentate ligands adopt bridging coordination modes. The redox chemistry of cluster 1 was examined using cyclic voltammetry and compared to the electrochemistry of the free ligand dppf and the corresponding copper(I) acetate coordination complex 5. Cluster 1 shows the expected consecutive oxidations of the ferrocene moieties, Cu(I) centers, and phosphine of the dppf ligand.

Electrospray ionization (ESI) mass spectrometry (MS) is a widely used tool for the characterization of organometallic nanoclusters. By matching experimental mass spectra with calculated isotope distributions it is possible to determine the elemental composition of these analytes. In this work we conduct ESI-MS investigations on M(14)E(13)Cl(2)(tmeda)(6) nanoclusters, where M is a transition metal, E represents a chalcogen, and tmeda is N,N,N',N'-tetramethyl-ethylenediamine. ESI mass spectra of these systems agree poorly with theoretical isotope distributions when data are acquired under standard conditions. This behavior is attributed to dead-time artifacts of the time-of-flight (TOF) analyzer used. It is well-known that excessively high TOF ion count rates lead to dead-time issues. Surprisingly, our data reveal that nanocluster spectra are affected by this problem even at moderate signal intensities that do not cause any problems for other types of analytes. This unexpected vulnerability is attributed to the extremely wide isotope distributions of the nanoclusters studied here. A good match between experimental and calculated nanocluster spectra is obtained only at ion count rates that are more than 1 order of magnitude below commonly used levels. Discrepancies between measured and theoretical isotope distributions have been observed in a number of previous ESI-MS nanocluster investigations. The dead-time issue identified here likely represents a contributing factor to the spectral distortions that were observed in those earlier studies. Using low-intensity ESI-MS conditions we demonstrate the feasibility of analyzing highly heterogeneous nanocluster samples that comprise subpopulations with a wide range of metal compositions.

The ligation of a N-heterocyclic carbene (NHC) to group 11 metal salts (Cu, Ag) was explored as an alternative to PR(3) ligands for the formation of copper- and silver-chalcogenolate cluster complexes. AgOAc and CuCl salts ligate with the NHC 1,3-di-isopropylbenzimidazole-2-ylidene ((i)Pr(2)-bimy) forming [Ag(OAc)((i)Pr(2)-bimy)] 1, [Ag(OAc)((i)Pr(2)-bimy)(2)] 2, [CuCl((i)Pr(2)-bimy)](2)3 and [CuCl((i)Pr(2)-bimy)(2)] 4 depending on the ratio of ligand to metal used. These have been characterized via spectroscopic and crystallographic methods. Complexes 1 and 3 were reacted with S(Ph)SiMe(3) and Se(Ph)SiMe(3) to form the polynuclear metal-chalcogenolates [Ag(4)(μ-EPh)(4)((i)Pr(2)-bimy)(4)] (5, E = S; 6, E = Se) and [Cu(3)(μ-EPh)(3)((i)Pr(2)-bimy)(3)] (7, E = S; 8, E = Se) in good yields. The structures of 5-8, as determined by single crystal X-ray crystallography, are described.

Reaction of a mixture of CuCl, PhSnCl(3) and PEt(2)Ph with S(SiMe(3))(2) in THF resulted initially in the unexpected synthesis of the ionic, mixed copper-tin sulfide cluster [Li(thf)(4)][Cu(19)S(28)(SnPh)(12)(PEt(2)Ph)(3)] in low yields. However, by adding NBu(4)Cl to the reaction solutions we were able to selectively synthesize the structurally similar cluster ion in (NBu(4))[Cu(19)S(28)(SnPh)(12)(PEt(2)Ph)(3)]. Structural characterization by single crystal X-ray analysis reveals that the cluster anions consist in principle of a copper sulfide core decorated by PhSn(3+) groups. Although additional phosphine ligands are attached to copper atoms the clusters possess an open 'Cu(3)S(3)' face mostly protected by the [Li(thf)(4)](+) and (NBu(4))(+) counterions in the crystal structure. The cluster (NBu(4))[Cu(19)S(28)(SnPh)(12)(PEt(2)Ph)(3)] displays near-infrared, temperature-dependent photoluminescence at ∼820-930 nm in the solid state, which is especially bright at temperatures below ∼100 K.

The ternary clusters (tmeda)(6)Zn(14-x)Mn(x)S(13)Cl(2) (1a-d) and (tmeda)(6)Zn(14-x)Mn(x)Se(13)Cl(2) (2a-d), (tmeda = N,N,N',N'-tetramethylethylenediamine; x ≈ 2-8) and the binary clusters (tmeda)(6)Zn(14)E(13)Cl(2) (E = S, 3; Se, 4;) have been isolated by reacting (tmeda)Zn(ESiMe(3))(2) with Mn(II) and Zn(II) salts. Single crystal X-ray analysis of the complexes confirms the presence of the six "(tmeda)ZnE(2)" units as capping ligands that stabilize the clusters, and distorted tetrahedral geometry around the metal centers. Mn(II) is incorporated into the ZnE framework by substitution of Zn(II) ions in the cluster. The polynuclear complexes (tmeda)(6)Zn(12.3)Mn(1.7)S(13)Cl(2)1a, (tmeda)(6)Zn(12.0)Mn(2.0)Se(13)Cl(2)2a, and (tmeda)(6)Zn(8.4)Mn(5.6)Se(13)Cl(2)2d represent the first examples of "Mn/ZnE" clusters with structural characterization and indications of the local chemical environment of the Mn(II) ions. The incorporation of higher amounts of Mn into 1d and 2d has been confirmed by elemental analysis. Density functional theory (DFT) calculations indicate that replacement of Zn with Mn is perfectly feasible and at least partly allows for the identification of some sites preferred by the Mn(II) metals. These calculations, combined with luminescence studies, suggest a distribution of the Mn(II) in the clusters. The room temperature emission spectra of clusters 1c-d display a significant red shift relative to the all zinc cluster 3, with a peak maximum centered at 730 nm. Clusters 2c-d display a peak maximum at 640 nm in their emission spectra.

Make way for a superlattice! A crystalline 3D superlattice of 2.3 nm molecular CdS nanoclusters was prepared from a convenient mononuclear cadmium thiophenolate precursor. HRTEM and STEM tomography show highly crystalline repetition of monodisperse frameworks. This combined with elemental and thermogravimetric analyses suggests an approximate formula [Cd(130)S(103)(SPh)(54)]., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The ferrocene-based trimethylsilyl chalcogenide reagents [FcC(O)OCH(2)CH(2)ESiMe(3)] (2, E=S, 3 E=Se, Fc=[Fe(η(5)-C(5)H(5))(η(5)-C(5)H(4))]) and [FcC(O)NHCH(2)CH(2) SSiMe(3)] (8b) have been synthesized. The reagents were reacted with solubilized transition-metal acetates to yield functionalized complexes and clusters, including the spherical nanocluster [Ag(14)S{SCH(2)CH(2)O(O)CFc)}(12)(PPh(3))(6)] (11, PPh(3) =triphenylphosphine). The complexes were characterized by NMR spectroscopy and X-ray crystallography. The electrochemical behavior of the complexes was explored by cyclic voltammetry and each displayed a single quasi-reversible redox wave with some adsorption to the electrode surface., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

New (chalcogenoethyl)ferrocenylcarboxalate functionalized silver chalcogenide nanoclusters were synthesized using a combination of silylated chalcogen reagents at low temperatures. The addition of E(SiMe(3))(2) to reaction mixtures of FcC{O}OCH(2)CH(2)ESiMe(3) (E = S, Se) and (Ph(3)P)(2)·AgOAc affords nanoclusters with approximate molecular formulas [Ag(36)S(9)(SCH(2)CH(2)O{O}CFc)(18)(PPh(3))(3)] (1), [Ag(100)Se(17)(SeCH(2)CH(2)O{O}CFc)(66)(PPh(3))(10)] (2), and [Ag(180)Se(54)(SeCH(2)CH(2)O{O}CFc)(72)(PPh(3))(14)] (3) as noncrystalline solids. Compositions were formulated on the basis of elemental analysis, high resolution transmission electron microscopy, and dynamic light scattering experiments. Solutions of these polyferrocenyl assemblies display a single quasi-reversible redox wave with some adsorption to the electrode surface as studied by cyclic voltammetry. With the smaller clusters 1, the addition of [Bu(4)N][HSO(4)] results in a shift of the reduction wave to less positive potentials than those of the complex in the absence of these oxoanions. No further shift is observed after the addition of approximately 1 equivalent of HSO(4)(-)/ferrocene branch. Cyclic voltammograms of the larger clusters 2 and 3 show the appearance of a new, irreversible wave at less positive potentials than the initial wave upon the addition of HSO(4)(-). The appearance of this new wave together with the disappearance of the reduction wave indicates a stronger interaction between the nanoclusters and the hydrogen sulfate anion.

The Co(II) and Mn(II) complexes (tmeda)Co(ESiMe(3))(2) (E = S, 1a; E = Se, 1b), (3,5-Me(2)C(5)H(3)N)(2)Co(ESiMe(3))(2) (E = S, 2a; E = Se, 2b), [Li(tmeda)](2)[(tmeda)Mn(5)(mu-ESiMe(3))(2)(ESiMe(3))(4)(mu(4)-E)(mu(3)-E)(2)] (E = S, 3a; E = Se, 3b), [Li(tmeda)](2)[Mn(SSiMe(3))(4)] (4), [Li(tmeda)]4[Mn(4)(SeSiMe(3))(4)(mu(3)-Se)(4)] (5), and [Li(tmeda)](4)[Mn(Se(4))(3)] (6) (tmeda = N,N,N',N'-tetramethylethylenediamine) have been isolated from reactions of Li[ESiMe(3)] and the chloride salts of these metals. The treatment of (tmeda)CoCl(2) with two equivalents of Li[ESiMe(3)] (E = S, Se) yields 1a and 1b, respectively, whereas similar reactions with MnCl(2) yield the polynuclear complexes 3a (E = S) and 3b (E = Se). The selective preparation of the mononuclear complex 4 is achieved by increasing the reaction ratios of Li[SSiMe(3)] to MnCl(2) to 4:1. Single crystal X-ray analysis of complexes 1-5, confirms the presence of the trimethylsilylchalcogenolate moieties and distorted tetrahedral geometry around the metal centers in each of these complexes. The structure of the tris(tetraselenide) complex [Li(tmeda)](4)[Mn(Se(4))(3)] (6), isolated in small quantities from the preparation of 5, is also described.

Silylated chalcogen reagents are proven entry points for the preparation of ligand-stabilized, nanometre-sized metal-chalcogen clusters. More recently, these reagents have been developed to incorporate specific functionalities onto the surfaces of nanoclusters. The group 11 metals Cu and Ag in particular yield a wealth of structural types, the features for which are dependent on the nature of the surface chalcogenolate ligands. The content of this review focuses on complexes that have been structurally characterized by single-crystal X-ray diffraction studies and illustrates the ease by which these frameworks can be assembled.

A series of silylated ferrocenoyl chalcogenide reagents, FcC(O)ESiMe3 (E=S, Se, Te; Fc=ferrocene), can be prepared in very good yield from FcC(O)Cl and LiESiMe3. These reagents are used in the preparation of triphenylphosphine-ligated copper and silver ferrocenoyl thiolate and selenolate complexes, [M4(E{O}CFc)4(PPh3)4], (M=Cu, Ag; E=S, Se) and [Cu2(micro-Se{O}CFc)2(PPh3)3] from solubilized copper(I) and silver(I) acetate. The structures of these complexes have been determined via single-crystal X-ray diffraction. The driving force for these reactions is the thermodynamically favorable formation and elimination of AcOSiMe3. The synthesis and characterization of both starting reagents and cluster complexes are discussed.

The synthesis and characterization of the copper and silver trimethylsilylchalcogenolates (EtPh2P)3MESiMe3 and (Et2PhP)3MESiMe3 (M = CuI, AgI) are reported. These chalcogenolate complexes can be prepared in high yield; however, they are thermally unstable. Low-temperature single-crystal X-ray analysis of (EtPh2P)3CuSSiMe3 (1b) and (Et2PhP)3CuSeSiMe3 (2a) confirms the terminal coordination of the chalcogen ligand and the tetrahedral coordination about the metal. Protonolysis of 2a with EtOH yields the terminal selenol complex (Et2PhP)3CuSeH (6). Reaction of 1b with EtPh2P-solubilized AgOAc yields the heterometallic cluster [Cu9Ag3S6(PEtPh2)8] (7) in good yield.

The silylated ferrocenyl selenium reagent 1,1'-Fe(eta5-C5H4SeSiMe3)2 has been used for the high yield formation of the phosphine-ligated copper complexes Cu2(fcSe2)(PiPr3)2 (1) and Cu4(fcSe2)2(PnPr3)4 (2) from solublilized CuOAc, as determined by single-crystal X-ray diffraction. The incorporation of a source of Se2- into the reaction scheme with the reagent Se(SiMe3)2 yields the mixed selenide/ferrocenyldiselenolate cluster [Cu20Se6(Se2fc)4(PnPr3)10] (3). Partial substitution of the PnPr3 ligand shell in 3 with the phosphinothiol Ph2P(CH2)3SH leads to an expansion of the framework and the high yield formation of the crystallographically characterized cluster Cu36(fcSe2)6Se12(PnPr3)10(Ph2P(CH2)3SH)2 (5), which contains surface alkylthiol groups on a copper-selenium core.

The binary materials ZnS, ZnSe, and ZnTe have been successfully prepared within the mesoporous framework of MCM-41 at room temperature through the use of silylated chalcogen reagents. Postsynthesis grafting of ethylenediamine facilitates the complexation of anhydrous zinc acetate to the pore surface via a ligand exchange process between monodentate 3,5-lutidine ligands and the anchored chelating moiety. Coordinated zinc acetate readily reacts with E(SiMe(3))(2) (E = S, Se, or Te), thereby encapsulating zinc chalcogenides in the mesoporous channels. ZnE-MCM-41 materials have been characterized by EDX analysis, nitrogen sorption analysis, and Raman, UV-vis, and solid-state NMR spectroscopy. The observed blue shift in the absorption maximum is in agreement with the expected quantum confinement of these materials given the nanometer dimensions of the mesoporous architecture of the silicate host.

The ternary molecular nanoclusters [Zn(x)Cd(10-x)Se4(SePh)12(PnPr3)4] (x = 1.8, 1 a; x = 2.6, 1 b) were employed as single-source precursors for the synthesis of high-quality hexagonal Zn(x)Cd(1-x)Se nanocrystals. The tellurium clusters [Zn(x)Cd(10-x)Te4(TePh)12(PnPr3)4] (x = 1.8, 2 a; x = 2.6, 2 b) are equally convenient precursors for the synthesis cubic Zn(x)Cd(1-x)E nanoparticles. The thermolysis of the cluster molecules in hexadecylamine provides an efficient system in which the inherent metal-ion stoichiometry of the clusters is retained in the nanocrystalline products, whilst also affording control of particle size within the 2-5 nm range. In all cases, the nanoparticles are monodisperse, and luminescence spectra exhibit emission energies close to the absorption edge. Analysis of the optical spectra and X-ray diffraction patterns of these materials indicates a metal-ion concentration gradient within the structures of the nanocrystals, with Zn(II) ions predominantly located near the surface of the particles.

The reaction of [(3,5-Me(2)-C(5)H(3)N)(2)Zn(ESiMe(3))(2)] (E = Se, Te) with cadmium(II) acetate in the presence of PhESiMe(3) and P(n)Pr(3) at low temperature leads to the formation of single crystals of the ternary nanoclusters [Zn(x)()Cd(10)(-)(x)()E(4)-(EPh)(12)(P(n)()Pr(3))(4)] [E = Se, x = 1.8 (2a), 2.6 (2b); Te, x = 1.8 (3a), 2.6 (3b)] in good yield. The clusters [Zn(3)Hg(7)Se(4)(SePh)(12)(P(n)()Pr(3))(4)] (4) and [Cd(3.7)Hg(6.3)Se(4)(SePh)(12)(P(n)()Pr(3))(4)] (5) can be accessed by similar reactions involving [(3,5-Me(2)-C(5)H(3)N)(2)Zn(SeSiMe(3))(2)] or [(N,N'-tmeda)Cd(SeSiMe(3))(2)] (1) and mercury(II) chloride. The metal silylchalcogenolate reagents are efficient delivery sources of {ME(2)} in cluster synthesis, and thus, the metal ion content of these clusters can be readily moderated by controlling the reaction stoichiometry. The reaction of cadmium acetate with [(3,5-Me(2)-C(5)H(3)N)(2)Zn(SSiMe(3))(2)], PhSSiMe(3), and P(n)()Pr(3) affords the larger nanocluster [Zn(2.3)Cd(14.7)S(4)(SPh)(26)(P(n)()Pr(3))(2)] (6). The incorporation of Zn(II) into {Cd(10)E} (E = Se, Te) and Zn(II) or Cd(II) into {Hg(10)Se} nanoclusters results in a significant blue shift in the energy of the first "excitonic" transition. Solid-state thermolysis of complexes 2 and 3 reveals that these clusters can be used as single-source precursors to bulk ternary Zn(x)Cd(1)(-)(x)E materials as well as larger intermediate clusters and that the metal ion ratio is retained during these reactions.

The copper-tellurolate cluster [(Cu(6)(TePh)(6)(PPh(2)Et)(5)] has been loaded into the pores of MCM-41 by solid-state impregnation techniques. It was found that the best loading conditions are 110 degrees C and 10(-)(3) Torr static vacuum. The resulting material was analyzed by powder X-ray diffraction (PXRD), nitrogen adsorption isotherms, thermogravimetric analysis (TGA), (31)P CP MAS NMR spectroscopy, and TEM. It was observed that loading is accompanied by loss of the phosphine shell, with retention of the copper-tellurium core. Condensation of the impregnated material may proceed thermally or photochemically. Thermal condensation results in the formation of Cu(2)Te nanoparticles as demonstrated by PXRD, and TEM data suggests that the process has taken place inside the pores of MCM-41. Photochemical condensation yields larger metal-chalcogen clusters in the pores as suggested by the result of UV-vis diffuse reflectance spectroscopy and TEM measurements.

Trimethylsilylselenoferrocene 1 has been prepared in good yield. The reactive silyl group on 1 is used as a driving force for the synthesis [Cl4Cd4[mu2-Se(C5H4)Fe(C5H5))6]2- 2, a Cd4Se6 adamantoid cluster with six surface ferrocenyl groups.

We report the synthesis of the complex (N,N'-tmeda)Zn(SeSiMe3)2 (1), whose pendant trimethylsilyl moieties result in a powerful reagent for the generation of ternary MM'E materials. Reaction of 1 with (PnPr3)2Cd(OAc)2 and PhSeSiMe3 has led to the formation of the ternary ZnCdSe nanocluster [(N,N-tmeda)5Zn5Cd11Se13(SePh)6(thf)2] (2). The cluster consists of a CdSe core capped by ZnSe2 units, and represents the first example of a structurally characterized II-II'-VI nanocluster. Utilization of an analogous (trimethylsilyl)tellurolate precursor leads to the formation of [(N,N-tmeda)5Zn5Cd11Te13(TePh)6(thf)] (3). The absorption spectra of 2 and 3 exhibit bands that have been assigned to "excitonic" transitions. The clusters are also luminescent at room temperature, exhibiting "band-edge" luminescence both in solution and in the solid state.

Two copper-mercury-chalcogenide clusters [Hg(15)Cu(20)E(25)(PPr(3))(18)] (1, E = S; 2, E = Se) are synthesized in good yield from the reaction of (Pr(3)P)(3)Cu-ESiMe(3) and (Pr(3)P)(2).Hg(OAc)(2) at low temperatures. Single-crystal X-ray analyses illustrate that the two ternary clusters are isomorphous and consist of a phosphine-stabilized core of mixed Hg, Cu, and E centers. Thermolysis of 1 leads to the formation of mercury metal and various forms of copper-sulfide. The copper-indium-sulfide cluster [Cu(6)In(8)S(13)Cl(4)(PEt(3))(12)] (3) is similarly prepared in 50% yield from (Et(3)P)(3)Cu-SSiMe(3), InCl(3), and S(SiMe(3))(2).

The phosphorus chemical shift (CS) tensors of several ruthenium carbonyl compounds containing a phosphido ligand, micro), bridging a Ru [bond] Ru bond were characterized by solid-state (31)P NMR spectroscopy. As well, an analogous osmium compound was examined. The structures of most of the clusters investigated have approximate local C(2v) symmetry about the phosphorus atom. Compared to the "isolated" PH(2)(-) anion, the phosphorus nucleus of a bridging phosphido ligand exhibits considerable deshielding. The phosphorus CS tensors of most of the compounds have spans ranging from 230 to 350 ppm and skews of approximately zero. Single-crystal NMR was used to investigate the orientation of the phosphorus CS tensors for two of the compounds, Ru(2)(CO)(6)(mu(2)-C [triple bond] C [bond] Ph)(mu(2)-PPh(2)) and Ru(3)(CO)(9)(mu(2)-H)(mu(2)-PPh(2)). The intermediate component of the phosphorus CS tensor, delta(22), lies along the local C(2) axis in both compounds. The least shielded component, delta(11), lies perpendicular to the Ru [bond] P [bond] Ru plane while the most shielded component, delta(33), lies perpendicular to the C [bond]P [bond] C plane. The orientation of the phosphorus CS tensor for a third compound, Ru(2)(CO)(6)(mu(2)-PPh(2))(2), was investigated by the dipolar-chemical shift NMR technique and was found to be analogous, suggesting it to be the same in all compounds. Ab initio calculations of phosphorus magnetic shielding tensors have been carried out and reproduce the orientations found experimentally. The orientation of the CS tensor has been rationalized using simple frontier MO theory. Splittings due to (99,101)Ru [bond] (31)P spin-spin coupling have been observed for several of the complexes. A rare example of (189)Os [bond] (31)P spin-spin splittings is observed in the (31)P MAS NMR spectrum of the osmium cluster, where (1)J((189)Os, (31)P) is 367 Hz. For this complex, the (189)Os nuclear quadrupolar coupling constant is on the order of several hundred megahertz.

Reactions of CuCl with Te(Ph)SiMe3 and solublizing trialkylphosphine ligands afford a series of polynuclear copper-phenyltellurolate complexes that has been structurally characterized. The formation of the complexes is found to be highly dependent on the ancillary phosphine ligand used. The synthesis and structures of [Cu2(mu-TePh)2(PMe3)4] 1, [Cu4(mu3-TePh)4(PPr(i)3)3] 2, [Cu5(mu-TePh)3(mu3-TePh)3(PEt3)3][PEt3Ph] 3, and [Cu12Te3(mu3-TePh)6(PEt3)6] 4 are described. The telluride (Te(2-)) ligands in 4 arise from the generation of TePh2 in the reaction mixtures. The subsequent co-condensation of clusters 3 and 4 leads to the generation of the nanometer sized complex [Cu29Te9(mu3-TePh)10(mu4-TePh)2(PEt3)8][PEt3Ph] 5 in good yield, in addition to small amounts of [Cu39(mu3-TePh)10(mu4-TePh)Te16(PEt3)13] 6. These complexes are formed via the photo elimination of TePh2. The cyclic voltammogram of 5 in THF solution exhibits two oxidation waves, assigned to the oxidation of the Cu(I) centers.