AgI Centers Research Articles

Anion Control in Bipyridylsilver(I) Networks: A Helical Polymeric Array

A helical staircase structure is observed for the layers made from chains of alternating AgI centers and pytz ligands in [Ag(pytz)(NO3)]∞ (pytz = 3,6-di-(4-pyridyl)-1,2,4,5-tetrazine). Decisive for the formation of this array—a view of the structure along the helical axis is shown on the right—is the anionic ligand NO, as shown by the comparison with the analogous PF and BF compounds. These two show parallel chains of alternating AgI ions and pytz ligands held in pairs through weak AgAg contacts and π–π interactions between adjacent pytz ligands.

Silver(I) Sandwich Complexes of Oxa‐Crowned Derivatives of Dithiomaleonitrile

AbstractThe coordination chemistry of the four oxa‐crowned derivatives of dithiomaleonitrile mn‐12S2O2, mn‐15S2O3, mn‐18S2O4, and mn‐21S2O5 as well as of the acyclic bis(methylthio)maleonitrile mn‐S2 with AgI was investigated by X ray structural and spectroscopic methods. The 2:1 complexes (ligand/AgI) [Ag(mn‐12S2O2)2]PF6, [1]PF6, [Ag(mn‐15S2O3)2]PF6, [2]PF6, and [Ag(mn‐S2)2]PF6, [6]PF6, and the 1:1 complexes [Ag(mn‐15S2O3)]ClO4, [3]ClO4, [Ag(mn‐18S2O4)]PF6, [4]PF6, and [Ag(mn‐21S2O5)]PF6 [5]PF6, were obtained with AgPF6 or AgClO4 in MeOH. The stoichiometry of the macrocyclic AgI complexes and the coordination mode of mn‐S2On+1 coronands (n = 1–4) is determined by the length of the macrocyclic oligoethylene chain. – The mn‐crown dithioethers mn‐12S2O2 and mn‐15S2O3 form with AgPF6 the new sandwich complexes [Ag(mn‐12S2O2)2]PF6, [1]PF6, and [Ag(mn‐15S2O3)2]PF6, [2]PF6. [1]PF6 crystallises in the triclinic space group P1. In the centrosymmetric cation [1]+ each mn‐12S2O2 ligand is coordinated to the AgI centre in an endo manner via both S atoms and one O atom. The distance of the second O atom of mn‐12S2O2 to AgI is somewhat longer than a normal Ag–Oether bond. The overall environment around AgI in [1]+ is that of a distorted cubic S4O4 set of donors. [2]PF6 crystallises in the monoclinic space group C2/c. In the centrosymmetric cation [2]+ silver(I) is planar‐coordinated by the four S atoms of both mn‐15S2O3 molecules. The six O atoms of both mn‐15S2O3 ligands show only long‐range interactions to the AgI ion. They surround AgI almost vertically to the planar S4 set of donors in a crown‐like manner. – The crystal structures of the 1:1 complexes [Ag(mn‐18S2O4)]PF6, [4]PF6, and [Ag(mn‐21S2O5)]PF6, [5]PF6, consist of linear chain polymers. [5]PF6 forms an N‐bridged chain polymer of endocyclic [Ag(mn‐21S2O5)]+ units with S1O4NNitrile coordination at the AgI centre. In the 2:1 complex [Ag(mn‐S2)2]PF6, [6]PF6, each mn‐S2 acts as a monodentate NNitrile donor. – 13C‐NMR studies in nitromethane solution confirm that the AgI ions in the complexes of the mn‐crown dithioethers remain coordinated. However, the AgI ion in complex of mn‐S2 is decoordinated.

Unique structural features in silver(I) dithioether complexes: the single-crystal structures of [Agn(PhSCH2CH2CH2SPh)2n](BF4)n·0.5nH2O and [Agn(MeSCH2CH2CH2SMe)n](BF4)n

The X-ray structure of [Agn(PhSCH2CH2CH2SPh)2n]n+ shows an infinite array of tetrahedral AgI atoms coordinated via one S-donor of four distinct PhSCH2CH2CH2SPh ligands, whereas [Agn(MeSCH2CH2CH2SMe)n]n+ is a chain polymer involving trigonal (µ2-S)2, S ligation with one S-donor bridging two adjacent AgI centres while the other S-donor of the dithioether ligand is non-bridging.

Silver macrocyclic complexes: synthesis, crystal structures and redox properties of [Ag([18]aneN2S4)]PF6and [Ag(Me2[18]aneN2S4)]BPh4([18]aneN2S4= 1,4,10,13-tetrathia-7,16-diazacyclooctadecane, Me2[18]aneN2S4= 7,16-dimethyl-1,4,10,13-tetrathia-7,16-diazacyclooctadecane)

Reaction of AgNO3 with one molar equivalent of [18]aneN2S4(1,4,10,13-tetrathia-7,16-diazacyclooctadecane) or Me2[18]aneN2S4(7,16-dimethyl analogue) in refluxing MeOH–H2O affords the complex cations [Ag([18]aneN2S4)]+ and [Ag(Me2[18]aneN2S4)]+ respectively. [Ag([18]aneN2S4)]PF6 crystallises in the orthorhombic space group Pcab with a= 16.7327(25), b= 17.5023(11), c= 14.7031(6)Å and Z= 8. The metal ion is bound to a highly distorted octahedral arrangement of the six macrocyclic donor atoms [Ag–S 2.630(4), 2.664(4), 2.719(4), 2.774(4)Å; Ag–N 2.533(10), 2.817(15)Å]. The complex cation adopts a rac configuration in which the two S–N–S linkages are bound meridionally to the metal ion. [Ag(Me2[18]aneN2S4)]BPh4 crystallises in the monoclinic space group P21/n with a= 10.7529(15), b= 19.0571(28), c= 18.9360(22)Å, β= 106.035(10)° and Z= 4. The cation is disordered and shows two different configurations. The major [70.8(8)%] component shows an unusual kite-based pyramidal geometry with AgI bound via a periplanar arrangement of four S-donor atoms [Ag–S(1) 2.583(4), Ag–S(4), Ag–S(4) 2.819(3), Ag–S(10) 2.663(4), Ag–S(13) 2.673(4)Å] and one apical N-donor atom [Ag–N(7) 2.517(11)Å]. The second N-donor atom does not interact with the metal centre [Ag ⋯ N(16) 3.684(11)Å]. In view of the asymmetric bond length distribution, the overall stereochemistry may alternatively be described as tetrahedral through S(1), N(7), S(10) and S(13), with S(4) interacting more weakly at long range. Although this complex is severely distorted, it is clear that unlike in [Ag([18]aneN2S4)]+, the S(4)–N(7)–S(10) linkage in [Ag(Me2[18]aneN2S4)]+ binds facilally to the AgI centre to give a distorted meso isomer. The minor [29.2(8)%] component differs only in the orientation of the S(1), N(16′) and S(13) linkage. Although the C–C and C–S bond lengths in this region were constrained, it is clear that N(16′) is directed towards, and is co-ordinated to the Ag1 centre [Ag–N(16′) 2.778(10)Å], giving an octahedral complex in a genuine meso configuration. [Ag([18]aneN2S4)]+ shows a reversible AgI–AgII couple at E½=+0.65 V and a quasi-reversible AgI–Ag0 couple at E½=–0.74 V while [Ag(Me2[18]aneN2S4)]+ shows an irreversible AgI–AgII couple at Epa=+0.78 V and an irreversible AgI–Ag0 couple at Epc=–0.78 V (all potentials vs. ferrocene–ferrocenium).