Square Planar Pt(II) Ion as Electron Donor in Pnictogen Bonding Interactions

Abstract

It has been proposed that late transition metals with low coordination numbers (square planar or linear) can act as nucleophiles and participate in σ-hole interactions as electron donors. This is due to the existence, in this type of metal complexes, of a pair of electrons located at high energy d-orbitals (dz2 or dx2-y2), which are adequate for interacting with antibonding σ-orbitals [σ*(X–Y)] where Y is usually an electron withdrawing element and X an element of the p-block. This type of d[M]→σ*(X–Y) interaction has been reported for metals of groups 9–11 in oxidation states +1 and +2 (d8 and d10) as electron donors and σ-holes located in halogen and chalcogen atoms as electron acceptors. To our knowledge, it has not been described for σ-holes located in pnictogen atoms. In this manuscript, evidence for the existence of pnictogen bonding involving the square planar Pt(II) metal as the electron donor and Sb as the electron acceptor is provided by using an X-ray structure retrieved from the Cambridge Structural Database (CSD) and theoretical calculations. In particular, the quantum theory of atoms in molecules (QTAIM), the noncovalent interaction plot (NCIPlot) and molecular electrostatic potential (MEP) methods were used. Moreover, to further confirm the nature of the Sb···Pt(II) contact, a recently developed method was used where the electron density (ED) and electrostatic potential (ESP) distribution were compared along the Sb···Pt(II) bond path.

Metal-involved C⋯dz2-PtIItetrel bonding as a principal component of the stacking interaction between arenes and the platinum(ii) square-plane

“…This bonding was considered along with other interactions between carbon and metals (found on the Cambridge Structural Database search) and the identified type of noncovalent interaction was formulated as a metal-involved tetrel bonding. Its recognition expands a set of the previously reported types of metal-involving noncovalent interactions, which so far include halogen, 48 chalcogen, 22 and pnictogen 49 bondings. We hope this study will stimulate other works focused on metal-involved interactions and the construction of supramolecular architectures based on these noncovalent forces.…”

Pd and Pt metal atoms as electron donors in σ-hole bonded complexes

“…A study by Burguera et al indicated that Sb also can act as an electron donor in the square planar Pt(II)-complexes creating a metal-assisted pnicogen bond scheme. 57 The NBO results for square planar complexes revealed a small orbital contribution (E2 = 1.07 kcal mol À1 ) due to a donation from the Pt d z 2 orbital to s*(Sb-Cl). The QTAIM and NCI analyses confirmed the existence of a PtÁ Á ÁSb interaction that is comparable to our complexes with platinum.…”

Group-10 π-hole⋯dz2[MII] interactions: a theoretical study of model systems inspired by CSD structures

“…8,9 For instance, Ni II , 10 Rh I , 11 Pd II , 12,13 Pt II , 14,15 and Au I , [16][17][18][19] are able to behave as halogen, [10][11][12][13][14][15][16][17][18][19] chalcogen 20 and pnictogen bond acceptors. 21 A common feature in those interactions is the participation of a lone pair located at the d z 2 or d x 2 −y 2 atomic orbital of the metal centre.…”

“…Interaction energies (E, kcal mol −1 ), D3 dispersion contribution (E disp . kcal mol −1 ) and equilibrium distances (d, Å) from the metal to the ring centroid for complexes[11][12][13][14][15][16][17][18][19][20][21][22] …”