Stable Silver(I) Hydride Complexes Supported by Diselenophosphate Ligands

Abstract

The first stable structure of silver(I) cluster cations [Ag(8)(mu(4)-H){Se(2)P(OR)(2)}(6)](+) [R = (i)Pr, 1; Et, 2] containing Ag(I)-hydride bridges (Ag-mu-H-Ag) in T symmetry was reported. The clusters having an interstitial hydride were composed of an octanuclear silver core in tetracapped tetrahedral geometry, which was inscribed within a Se(12) icosahedron represented by six dialkyl diselenophosphate ligands in a tetrametallic-tetraconnective (mu(2), mu(2)) bonding mode. The presence of hydride was unequivocally corroborated by both (1)H and (109)Ag NMR spectroscopies of which a nonet in the (1)H NMR spectrum for the hydride resonance coupled with a doublet peak observed in the (109)Ag NMR spectrum clearly suggests that eight silver nuclei are equivalent in the NMR time scale and a fast exchange of the positions between the vertex and capping silver atoms in solution must occur. The hypothesis was also supported by a density functional theory (DFT) investigation on a simplified model [Ag(8)(H)(Se(2)PH(2))(6)](+), which confirmed that the Ag(8)H cubic core of T(h) symmetry may not be formed as it is energetically highly unfavorable (0.67 eV less stable than the T structure).

Eight‐Electron Silver and Mixed Gold/Silver Nanoclusters Stabilized by Selenium Donor Ligands

“…[11] To elucidate the effects of surface functionalization of nanoparticle induced by ligand variations,i ti sn ecessary to isolate silver NCs having both sulfur and selenium surface ligands,w ith well-defined chemical compositions in order to compare their structures and physiochemical properties.In our search for silver NCs,w eh ave been able to synthesize acouple of mixed-valent silver species such as Ag 20 and Ag 21 protected by dithiophosphate (dtp) ligands, [9] but so far we could only isolate as eries of hydride/chalcogenide/ halide-centered silver(I) cluster compounds containing selenium as surface ligands.Notable examples are [Ag 7 (H){Se 2 P-(O i Pr) 2 } 6 ], [Ag 8 (X){Se 2 P(O i Pr) 2 } 6 ] + (X = H, Cl, Br), [Ag 9 (Se)-{Se 2 P(OEt) 2 } 8 ] À ,[ Ag 10 (Se){Se 2 P(O i Pr) 2 } 8 ], [Ag 11 (m 9 -I)(m 3 -I) 3 -{Se 2 P(O i Pr) 2 } 6 ] + ,a nd [Ag 12 (m 5 -X) 2 {Se 2 P(OEt) 2 } 10 ]( X = Br, I). [12,13] Thel ack of Ag n (dsep) m (dsep = diselenophosphate) molecular structures precludes ad eep understanding of the physicochemical properties of such silver NCs,a nd fundamental questions on the dsep-capped Ag 20 and Ag 21 clusters await to be resolved:1 )Have both silver NCs with Sa nd Se protecting ligands identical geometric structure or not;a nd 2) How do the ligands affect the optical and chemical properties of these NCs?T hese questions are important for understanding the properties of ligand-protected silver NCs.As diselenophosphates are easily oxidized under aerobic conditions and decompose rapidly via PÀSe bond cleavages in the presence of excess amount of reducing reagents, [14] the direct synthetic procedure adopted for the preparation of Ag 20 (dtp) 12 cannot be used. Therefore we focused on the ligand exchange reactions.H erein, we report the synthesis, characterization, and first crystal structure of silver NCs [Ag 20 {Se 2 P(O i Pr) 2 } 12 ], (3), and [Ag 21 {Se 2 P(OEt) 2 } 12 ] + ,( 4), stabilized by dsep ligands,w hich can only be made via…”

Eight‐Electron Silver and Mixed Gold/Silver Nanoclusters Stabilized by Selenium Donor Ligands

“…In our search for silver NCs,w eh ave been able to synthesize acouple of mixed-valent silver species such as Ag 20 and Ag 21 protected by dithiophosphate (dtp) ligands, [9] but so far we could only isolate as eries of hydride/chalcogenide/ halide-centered silver(I) cluster compounds containing sele- [12,13] Thel ack of Ag n (dsep) m (dsep = diselenophosphate) molecular structures precludes ad eep understanding of the physicochemical properties of such silver NCs,a nd fundamental questions on the dsep-capped Ag 20 and Ag 21 clusters await to be resolved:1 )Have both silver NCs with Sa nd Se protecting ligands identical geometric structure or not;a nd 2) How do the ligands affect the optical and chemical properties of these NCs?T hese questions are important for understanding the properties of ligand-protected silver NCs.…”

“…As diselenophosphates are easily oxidized under aerobic conditions and decompose rapidly via PÀSe bond cleavages in the presence of excess amount of reducing reagents, [14] the direct synthetic procedure adopted for the preparation of Ag 20 (dtp) 12 2 ]w ith an isolated yield of 86 %( Scheme 1). Both 3 and 4 were fully characterized by abroad spectrum of standard chemical characterization methods,including multinuclear NMR spectroscopy,E SI mass spectrometry,a nd Xray photoelectron spectroscopy (XPS).…”

Synthesis, Characterization, and Reactivity of the Group 11 Hydrido Clusters [Ag6H4(dppm)4(OAc)2] and [Cu3H(dppm)3(OAc)2]

“…Consequently, Ag I -H complexes have proven to be relatively rare. 21,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] Moreover, the examples isolated thus far are either homometallic monohydrides, e.g., [ 10 ] 2+ ). 39 Herein, we report the synthesis and characterization of the first structurally characterized homometallic silver polyhydrido cluster, [Ag 6 H 4 (dppm) 4 (OAc) 2 ].…”