Polymeric chain structures

The silver(I) complexes with the tetrakis(methylthio)tetrathiafulvalene ligand have been reported, the nitrate salt presents a 3D structure with an unprecedented 4.16-net porous inorganic layer of silver nitrate,1160 the triflate salt presents a two interwoven polymeric chain structure.1161 The latter behaves as a semiconductor when doped with iodine. With a similar ligand, 2,5-bis-(5,5,-bis(methylthio)-l,3,-dithiol-2 -ylidene)-l,3,4,6-tetrathiapentalene, a 3D supramolecular network is constructed via coordination bonds and S"-S contacts. The iodine-doped compound is highly conductive.1162 (Methylthio)methyl-substituted calix[4]arenes have been used as silver-selective chemically modified field effect transistors and as potential extractants for Ag1.1163,1164... 

A polymeric chain structure is frequently observed for zinc carboxylates. Basic zinc carboxylates form a common tetrameric species, and altering conditions can result in an interconversion between the basic and regular carboxylates.369 Mass spectrometry studies have been carried out... 

Most network structures involving crown ethers are simple hydrogen bonded chains where the crown forms second sphere coordination interactions with a complex ion. These are known for [18]crown-6, [15]crown-5 and [12]crown-4 hosts with a variety of metal complexes [17-25]. For instance when combined with the small [12] crown-4, the perchlorate salts of Mn(II), Ni(II) and Zn(II) form polymeric chain structures with alternating crown ethers and [M(H20)6]2+ cations [19]. Similarly the larger [18]crown-6 forms simple linear chains with metal complexes and cations such as fra s-[Pt(NH3)2Cl2] [20], [Cu(NH3)4(H20)]2+ (Fig.2) [21],and [Mg(H20)5(N03)] + [22],... 

The extended polymeric chain structure of [rl c2Clfi] ", reported in Ref. 534, also contains such metal-metal triple bonds. Triple order Tc—Tc bonds were also found at the a and (3 forms of Tc2Cl4(dppe)2 [535], The a isomer 1001 has an eclipsed conformation and a Tc—Tc distance of 2.15(1)A, while the (5 isomer 1002 has a twist angle of 35(2)° and a Tc — Tc distance of 2.117(1) A. These last two isomers were prepared by refluxing Tc2C14(PR3)4 (R3 = Et3, Me2Ph) in toluene with and without an excess of dppe, respectively ... 

Similar to the structure of compound 142, trigonal-bipyramidal tin centres with weak sulphoxide oxygen-tin interactions were observed in the polymeric chain structures of compounds 143-146307,308. The Sn—O lengths were reported to be in the range of 2.82 to 3.14 A. 

Such type of bonds occurs in other circumstances, e.g., BeH2, which has a polymeric chain structures with H atoms in the bridging positions. 

But few n = 1 compounds have been described. They probably have a polymeric chain structure like (13). There is also a series of tetrahedra [R4N][MnX3L] (where X = Cl, Br and L = 1-Me, 1-Et, 1-Pr, 1-vinyl and 4-Me-imidazole). 

Among the organotin thiophosphinate derivatives known so far, polymeric chain structures were reported for [Ph3Sn(OSPPh2)]n, [Me3Sn(OSPMc2)]n and... 

Hi. Coordination polymers with coordinative tin-phosphorus bonding. Coordination polymers with coordinative tin-phosphorus bonds are rare. An intermolecular P—Sn coordination was previously suggested to occur in Me2ClSnCH2CH2PPh2 which was based on NMR and Sn Mossbauer spectroscopic data. Recently, X-ray crystal structure analyses confirmed the previous assumption and showed a linear polymer with pentacoordinated tin atoms . The phosphorus and the chlorine atoms are located in axial positions. The Sn—P distance in 169 amounts to 3.065(1) A, which is comparable to the Sn—P distance of 3.078(2) A in the monomeric, intramolecularly coordinated Me2ClSnCH2CH2CH2PPhBu-f" iA The bromo-substituted analogue of 169, Me2BrSnCH2CH2PPh2, was also suggested to adopt a polymeric chain structure similar to that established for 169 . 

Figure 3.8). The DIPP wingtip group is evidently too bulky or the tether too short to allow more than a monomeric structure, whereas with a Mes substituent, the molecule has a choice between a dimeric structure with Cu-Cu interactions (CH Cyether) and a polymeric chain structure (CDClj).

Electronic band structures were calculated for several polymeric chains structurally analogous to polyacetylene (-CH-CH) and carbyne (-CbC). Ihe present calculations use the Extended Huckel molecular orbital theory within the tight binding approximation, and values of the calculated band gaps E and band widths BW were used to assess the potential applic ilitf of these materials as electrical semiconductors. Substitution of F or Cl atoms for H atoms in polyacetylene tended to decrease both the E and BW values (relative to that for polyacetylene). Rotation about rhe backbone bonds in the chains away from the planar conformations led to sharp increases in E and decreases in BW. Substitution of -SiH or -Si(CH,) groups for H in polyacetylene invaribly led to an increase in E and a decrease in BW, as was generally the case for insertion of Y ... 

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