Crystal Structure, Electronic Structure, and Temperature-Dependent Raman Spectra of Tl[Ag(CN)₂]:  Evidence for Ligand-Unsupported Argentophilic Interactions

Abstract

The structure of thallium dicyanoargentate(I) has been determined crystallographically. The crystal structure shows an Ag-Ag distance of 3.11 Å. This is the shortest Ag-Ag distance reported for any silver dicyanide salt whose crystal structure has been determined. Raman spectra of the compound show four nu(C)(-)(N) peaks that are well-resolved in the 10-80 K temperature range. This result agrees well with group theory analysis. Extended Hückel calculations using relativistic wave functions have been carried out for two models which describe the interactions between the Ag(CN)(2)(-) ions within the crystal structure of Tl[Ag(CN)(2)]. The results of these calculations indicate the formation of potential wells at short Ag-Ag distances. The data in this study suggest the significance of ligand-unsupported silver-silver interactions (argentophilicity) in Tl[Ag(CN)(2)]. Tl-Ag interactions are determined to be insignificant in the compound. Tl[Ag(CN)(2)] crystallizes in the monoclinic space group P2(1)/c (No. 14), with a = 7.798(1) Å, b = 14.685(3) Å, c = 8.566(2) Å, beta = 91.66(2) degrees, Z = 8, R = 0.0643, and R(w) = 0.0899.

Novel Cyanide Coordination Models in Layer-Type Hydrated Double Salts of AgCN and AgF

“…), but significantly lower than those found in Tl[Ag(CN) 2 ] (2107, 2250 cm À1 ) [10] and other silver cyano complexes. [13] Generally, n Ä(CN) of a terminal MÀCN group shifts to a higher frequency if it forms a bridge of the MÀCNÀM' type derived from s coordination of the weakly antibonding nitrogen lone pair to a second metal center M'.…”

“…We then used a zirconium catalyst in asymmetric Strecker reactions. In the presence of a zirconium catalyst (10 mol %) that was prepared from Zr(OtBu) 4 , (R)-6,6'-dibromo-1,1'-bi-2-naphthol ((R)-6-Br-BINOL, 2 equiv), [9] and N-methylimidazole (NMI, 3 equiv), aldimine 1 a was treated with Bu 3 SnCN [10] in dichloromethane at À 45 8C. The reaction proceeded smoothly to afford the corresponding aaminonitrile in 70 % yield with 55 % ee.…”

“…[4] Hitherto the shortest Ag ± Ag distance reported for any silver dicyanide salt of known crystal structure is 3.11 , which was found in Tl[Ag (CN) 2 ]. [10] In the intertwined double (ÀAgÀSRÀ) n -strand chain structure of crystalline (3-methylpentane-3-thiolato)silver, the closest contact between strands is AgÀAg 2.886(4) , which is interpreted as nonbonding. [11] In contrast, the much shorter AgÀAg distances of 2.748 ± 2.811 in 1 and 2 provide supporting evidence for the significance of argentophilicity in polynuclear compounds of silver(i), [10] which is a complementary logical extension of the well-established concept of aurophilicity for gold(i) complexes.…”

“…[10] In the intertwined double (ÀAgÀSRÀ) n -strand chain structure of crystalline (3-methylpentane-3-thiolato)silver, the closest contact between strands is AgÀAg 2.886(4) , which is interpreted as nonbonding. [11] In contrast, the much shorter AgÀAg distances of 2.748 ± 2.811 in 1 and 2 provide supporting evidence for the significance of argentophilicity in polynuclear compounds of silver(i), [10] which is a complementary logical extension of the well-established concept of aurophilicity for gold(i) complexes. [12] It is worthy of note that the Raman spectra of 1 and 2 exhibit strong cyano stretching absorptions at 2078 and 2080 cm…”

Crystal structure of aqua-bis(4-nitrobenzoato)disilver(I),Ag2(C7H4No4)2(H2O)

“…Silver is by far the less investigated coinage metal in coordination chemistry, which can possibly be attributed to the poor solubility of silver(I) compounds in common solvents and the sensitivity toward photodecomposition [1]. On the other hand, it has been found that many factors such as the nature of the ligands, solvents, counter-anions, etc., appear to modulate the stereochemistry of silver complexes [2].…”