Chalcogen–chalcogen secondary bonding interactions in trichalcogenaferrocenophanes

Abstract

The solid-state structures of all members in the series of trichalcogenaferrocenophanes [FeIJC 5 H 4 E) 2 E′] (E, E′ = S, Se, Te) (1-9) have been explored to understand the trends in secondary bonding interactions (SBIs) between chalcogen elements sulfur, selenium, and tellurium. To complete the series, the crystal structures of the four hitherto unknown complexes [Fe(C 5 H 4 S) 2 Te] (3), [Fe(C 5 H 4 Se) 2 S] (4), [Fe(C 5 H 4 Se) 2 Te] (6), and [Fe(C 5 H 4 Te) 2 S] (7) have been determined in this contribution. The packings of all complexes 1-9 were considered by DFT calculations at the PBE0/pob-TZVP level of theory using periodic boundary conditions. The intermolecular close contacts were considered by QTAIM and NBO analyses. The isomorphous complexes [Fe(C 5 H 4 S) 2 S] (1), [Fe(C 5 H 4 S) 2 Se] (2), and [Fe(C 5 H 4 Se) 2 Se] (5a) form dimers via weak interactions between the central chalcogen atoms of the two trichalcogena chains of adjacent complexes. In the second isomorphous series consisting of [Fe(C 5 H 4 Se) 2 S] (4) and 5b, the complexes are linked together into continuous chains by short contacts via the terminal selenium atoms. The intermolecular chalcogen-chalcogen interactions are significantly stronger in complexes [Fe(C 5 H 4 S) 2 Te] (3), [Fe(C 5 H 4 Se) 2 Te] (6), and [Fe(C 5 H 4 Te) 2 E′] (E′ = S, Se, Te) (7-9), which contain tellurium. The NBO comparison of donor-acceptor interactions in the lattices of [Fe(C 5 H 4 S) 2 S] (1), [Fe(C 5 H 4 Se) 2 Se] (5a and 5b), and [Fe(C 5 H 4 Te) 2 Te] (9) indeed shows that the n(5p Te) 2 → σ*(Te-Te) interactions in 9 are the strongest. All other interaction energies are significantly smaller even in the case of tellurium. The computed natural charges of the chalcogen atoms indicate that electrostatic effects strengthen the attractive interactions in the case of all chalcogen atoms.

Chalcogen‐Bonding Interactions in Telluroether Heterocycles [Te(CH2)m]n(n=1–4;m=3–7)

“…Figure 13 shows that, as expected, the chalcogen bonds become stronger, when moving down the periodic group, as has been concluded previously. [6,9] This trend is well in accord with that inferred earlier for the trichalcogenaferrocenophanes. [9] workers, [10c,j, 11b] have reporteds everal relatedc halcogenoethers, which contain smallm olecules insidet he tubes.…”

“…[6] As the numbero ft ellurium atoms in the macrocyclesa nd the number of Te •••Te contacts increases, the supramolecular latticesb ecome more complex. This is illustrated in Figure 8b y the solid-statel atticeso f1 ,5,9-Te 3 (CH 2 ) 9 28 shows that the coordination of each tellurium atom is expanded from two to six by four SBIs to give aq uasi-octahedral coordination sphere (see . [9] The infinite shafts in 1, 7 Table 3), which in turn suggest greater stabilization of lattices for species containing four tellurium atoms.…”

“…The orientations of the molecules also coincide with the direction [ b] The PBE0-D3/pob-TZVPb ondo rdersw erec alculated by comparison of the electron densities at BCPs to the corresponding valuesi ns ingle bonds. [9] [c] The stabilizationo ft he solid lattice was estimated by calculation of the difference of the energies in the latticep er molecule and the discrete molecules in vacuum. No thermal corrections to energies were made.…”

“…Trends in chalcogen-bond strength have been studied, for example, in as eries of trichalcogenaferrocenophanes [Fe(C 5 H 4 E) 2 E']( E, E' = S, Se, Te). [9] The complexes containing only sulfur or selenium show weaki nteractions between the chalcogen atoms, whereas in tellurium-containing complexes the chalcogenb onds betweenc halcogen atoms are significantly stronger.A ll these tellurium complexes form supramolecular networks with continuousq uasi-2D layer structures.…”

Chimeric supramolecular synthons in Ph2Te2(I2)Se

“…2). Structural studies of diorganotrichalcogenides are also scarce (Karjalainen et al, 2016;Kulcsar et al, 2007).…”