Ag44(SR)30(4-): a silver-thiolate superatom complex.

Intensely and broadly absorbing nanoparticles (IBANs) of silver protected by arylthiolates were recently synthesized and showed unique optical properties, yet question of their dispersity and their molecular formulas remained. Here IBANs are identified as a superatom complex with a molecular formula of Ag(44)(SR)(30)(4-) and an electron count of 18. This molecular character is shared by IBANs protected by 4-fluorothiophenol or 2-naphthalenethiol. The molecular formula and purity is determined by mass spectrometry and confirmed by sedimentation velocity-analytical ultracentrifugation. The data also give preliminary indications of a unique structure and environment for Ag(44)(SR)(30)(4-).

[1]  Joseph F. Parker,et al.  Tandem mass spectrometry of thiolate-protected Au nanoparticles Na(x)Au25(SC2H4Ph)(18-y)(S(C2H4O)5CH3)(y). , 2009, Journal of the American Chemical Society.

[2]  A. Dass,et al.  AuAg alloy nanomolecules with 38 metal atoms. , 2012, Nanoscale.

[3]  C. Aikens,et al.  Origin of Discrete Optical Absorption Spectra of M25(SH)18− Nanoparticles (M = Au, Ag) , 2008 .

[4]  T. Bürgi,et al.  Preparation and Spectroscopic Properties of Monolayer-Protected Silver Nanoclusters , 2012 .

[5]  A. Allred,et al.  Electronegativity values from thermochemical data , 1961 .

[6]  Y. Negishi,et al.  Isolation and structural characterization of magic silver clusters protected by 4-(tert-butyl)benzyl mercaptan. , 2011, Chemical communications.

[7]  A. Dass.  Mass spectrometric identification of Au68(SR)34 molecular gold nanoclusters with 34-electron shell closing. , 2009, Journal of the American Chemical Society.

[8]  A. Dass,et al.  Ion mobility mass spectrometry of Au25(SCH2CH2Ph)18 nanoclusters. , 2010, ACS nano.

[9]  Robert L. Whetten,et al.  Isolation and Selected Properties of a 10.4 kDa Gold:Glutathione Cluster Compound , 1998 .

[10]  C. Aikens,et al.  Electronic Structure of Ligand-Passivated Gold and Silver Nanoclusters. , 2011, The journal of physical chemistry letters.

[11]  Thomas Bürgi,et al.  Ligand exchange reactions on Au(38) and Au(40) clusters: a combined circular dichroism and mass spectrometry study. , 2010, Journal of the American Chemical Society.

[12]  R. Murray,et al.  Poly(ethylene glycol) ligands for high-resolution nanoparticle mass spectrometry. , 2007, Journal of the American Chemical Society.

[13]  王登科,et al.  Surface-enhanced Raman scattering properties of highly ordered self-assemblies of gold nanorods with different aspect ratios , 2011 .

[14]  D. Ly,et al.  High yield, large scale synthesis of thiolate-protected Ag7 clusters. , 2009, Journal of the American Chemical Society.

[15]  R. Murray,et al.  Using Electrons Stored on Quantized Capacitors in Electron Transfer Reactions , 1999 .

[16]  R. Whetten,et al.  All-aromatic, nanometer-scale, gold-cluster thiolate complexes. , 2005, Journal of the American Chemical Society.

[17]  Stephen W. Feldberg,et al.  Quantized Capacitance Charging of Monolayer-Protected Au Clusters , 1998 .

[18]  Pablo D. Jadzinsky,et al.  Structure of a Thiol Monolayer-Protected Gold Nanoparticle at 1.1 Å Resolution , 2007, Science.

[19]  R. Whetten,et al.  On the structure of thiolate-protected Au25. , 2008, Journal of the American Chemical Society.

[20]  R. Jin,et al.  Total structure determination of thiolate-protected Au38 nanoparticles. , 2010, Journal of the American Chemical Society.

[21]  Larissa S Fenn,et al.  Surface fragmentation of complexes from thiolate protected gold nanoparticles by ion mobility-mass spectrometry. , 2010, Analytical chemistry.

[22]  R. Murray,et al.  Supporting electrolyte and solvent effects on single-electron double layer capacitance charging of hexanethiolate-coated Au140 nanoparticles. , 2005, Analytical chemistry.

[23]  R. Murray,et al.  Electrospray ionization mass spectrometry of intrinsically cationized nanoparticles, [Au(144/146)(SC(11)H(22)N(CH(2)CH(3))(3)(+))(x)(S(CH(2))(5)CH(3))(y)](x+). , 2009, Journal of the American Chemical Society.

[24]  R. Murray,et al.  Nanoparticle MALDI-TOF mass spectrometry without fragmentation: Au25(SCH2CH2Ph)18 and mixed monolayer Au25(SCH2CH2Ph)(18-x)(L)(x). , 2008, Journal of the American Chemical Society.

[25]  Borries Demeler,et al.  Sedimentation velocity analysis of highly heterogeneous systems. , 2004, Analytical biochemistry.

[26]  Y. Negishi,et al.  Ubiquitous 8 and 29 kDa gold:alkanethiolate cluster compounds: mass-spectrometric determination of molecular formulas and structural implications. , 2008, Journal of the American Chemical Society.

[27]  A. Dass,et al.  Au36(SPh)23 nanomolecules. , 2011, Journal of the American Chemical Society.

[28]  H. Häkkinen,et al.  Atomic and electronic structure of gold clusters: understanding flakes, cages and superatoms from simple concepts. , 2008, Chemical Society reviews.

[29]  Katsuyuki Nobusada,et al.  Glutathione-protected gold clusters revisited: bridging the gap between gold(I)-thiolate complexes and thiolate-protected gold nanocrystals. , 2005, Journal of the American Chemical Society.

[30]  D. A. Dougherty,et al.  The Cationminus signpi Interaction. , 1997, Chemical reviews.

[31]  R. Murray,et al.  Crystal structure of the gold nanoparticle [N(C8H17)4][Au25(SCH2CH2Ph)18]. , 2008, Journal of the American Chemical Society.

[32]  R. Jin,et al.  Quantum sized, thiolate-protected gold nanoclusters. , 2010, Nanoscale.

[33]  A. Dass.  Faradaurate nanomolecules: a superstable plasmonic 76.3 kDa cluster. , 2011, Journal of the American Chemical Society.

[34]  Hiroshi Yao,et al.  Magic-Numbered Aun Clusters Protected by Glutathione Monolayers (n = 18, 21, 25, 28, 32, 39): Isolation and Spectroscopic Characterization , 2004 .

[35]  Thomas Krick,et al.  Surfactant-free Synthesis of Ultrasmall Gold Nanoclusters , 2010 .

[36]  J. Hansen,et al.  Identification and interpretation of complexity in sedimentation velocity boundaries. , 1997, Biophysical journal.

[37]  Robert L. Whetten,et al.  Optical Absorption Spectra of Nanocrystal Gold Molecules , 1997 .

[38]  T. Pradeep,et al.  Ag(9) quantum cluster through a solid-state route. , 2010, Journal of the American Chemical Society.

[39]  A. Dass.  Nano-scaling law: geometric foundation of thiolated gold nanomolecules. , 2012, Nanoscale.

[40]  R. Whetten,et al.  Structure and Bonding in the Ubiquitous Icosahedral Metallic Gold Cluster Au144(SR)60 , 2009 .

[41]  Jin Young Kim,et al.  Determination of nanoparticle size distribution together with density or molecular weight by 2D analytical ultracentrifugation , 2011, Nature communications.

[42]  R. Jin,et al.  Synthesis and electrospray mass spectrometry determination of thiolate-protected Au55(SR)31 nanoclusters. , 2011, Chemical communications.

[43]  R. Murray,et al.  Arylthiolate-protected silver quantum dots. , 2006, Langmuir : the ACS journal of surfaces and colloids.

[44]  C. Barnes,et al.  One- and two-dimensional silver-coordination networks containing pi-sandwiched silver-silver interactions. , 2002, Inorganic chemistry.

[45]  R. Murray,et al.  Gold nanoelectrodes of varied size: transition to molecule-like charging , 1998, Science.

[46]  R. Whetten,et al.  A unified view of ligand-protected gold clusters as superatom complexes , 2008, Proceedings of the National Academy of Sciences.

[47]  R. Jin,et al.  Conversion of Anionic [Au25(SCH2CH2Ph)18]− Cluster to Charge Neutral Cluster via Air Oxidation , 2008 .

[48]  Zhi Wang,et al.  Real-space observation of prolate monolayer-protected Au(38) clusters using aberration-corrected scanning transmission electron microscopy. , 2011, Small.

[49]  J. Reimers,et al.  Chemical analysis of the superatom model for sulfur-stabilized gold nanoparticles. , 2010, Journal of the American Chemical Society.

[50]  Joseph F. Parker,et al.  Electrospray ionization mass spectrometry of uniform and mixed monolayer nanoparticles: Au25[S(CH2)2Ph]18 and Au25[S(CH2)2Ph]18-x(SR)x. , 2007, Journal of the American Chemical Society.

[51]  R. Murray,et al.  Ligand heterogeneity on monolayer-protected gold clusters. , 2005, Langmuir : the ACS journal of surfaces and colloids.

[52]  R. Whetten,et al.  Origin of magic stability of thiolated gold clusters: a case study on Au25(SC6H13)18. , 2007, Journal of the American Chemical Society.

[53]  T. Bigioni,et al.  Mass spectrometric identification of silver nanoparticles: the case of Ag32(SG)19. , 2012, Analytical chemistry.

[54]  Borries Demeler,et al.  Methods for the Design and Analysis of Sedimentation Velocity and Sedimentation Equilibrium Experiments with Proteins , 2010, Current protocols in protein science.

[55]  George M. Whitesides,et al.  Comparison of the Structures and Wetting Properties of Self-Assembled Monolayers of n- Alkanethiols on the Coinage Metal Surfaces, Cu, Ag, Au' , 1991 .

[56]  R. Whetten,et al.  Critical sizes in the growth of Au clusters , 1997 .

[57]  Borries Demeler,et al.  Monte Carlo analysis of sedimentation experiments , 2008 .

[58]  Joseph F. Parker,et al.  The story of a monodisperse gold nanoparticle: Au25L18. , 2010, Accounts of chemical research.

[59]  S. Lindeman,et al.  Silver(I) complexation of (poly)aromatic ligands. Structural criteria for depth penetration into cis-stilbenoid cavities. , 2000, Inorganic chemistry.

[60]  R. Jin,et al.  Atomically precise gold nanocrystal molecules with surface plasmon resonance , 2012, Proceedings of the National Academy of Sciences.

[61]  Joseph F. Parker,et al.  Mass Spectrometrically Detected Statistical Aspects of Ligand Populations in Mixed Monolayer Au25L18 Nanoparticles , 2008 .

[62]  P. Dugourd,et al.  Electron Emission of Gas-Phase [Au25(SG)18-6H]7− Gold Cluster and Its Action Spectroscopy , 2010 .

[63]  T. Bigioni,et al.  Glutathione-stabilized magic-number silver cluster compounds. , 2010, Journal of the American Chemical Society.

[64]  Miho Yamauchi,et al.  Stabilized gold clusters: from isolation toward controlled synthesis. , 2012, Nanoscale.

[65]  R. Gil,et al.  Probing the structure and charge state of glutathione-capped Au25(SG)18 clusters by NMR and mass spectrometry. , 2009, Journal of the American Chemical Society.

[66]  D. P. Woodruff.  The interface structure of n-alkylthiolate self-assembled monolayers on coinage metal surfaces. , 2008, Physical chemistry chemical physics : PCCP.

[67]  R. Jin,et al.  Thiolate-Protected Au24(SC2H4Ph)20 Nanoclusters: Superatoms or Not? , 2010 .

[68]  R. Murray,et al.  Mass spectrometry of small bimetal monolayer-protected clusters. , 2009, Langmuir : the ACS journal of surfaces and colloids.

[69]  Borries Demeler,et al.  A two-dimensional spectrum analysis for sedimentation velocity experiments of mixtures with heterogeneity in molecular weight and shape , 2010, European Biophysics Journal.

[70]  N. Coombs,et al.  Chiral thiol-stabilized silver nanoclusters with well-resolved optical transitions synthesized by a facile etching procedure in aqueous solutions. , 2009, Langmuir : the ACS journal of surfaces and colloids.

[71]  X. Gong,et al.  Structures of [Ag7(SR)4]- and [Ag7(DMSA)4]-. , 2010, Journal of the American Chemical Society.

[72]  J. McLean,et al.  Characterization of thiolate-protected gold nanoparticles by mass spectrometry. , 2010, The Analyst.