Metal-Involving Halogen Bonding Confirmed Using DFT Calculations with Periodic Boundary Conditions

Abstract

The cocrystallization of trans-[PtI2(NCN(CH2)5)2] and iodoform (CHI3) yields crystalline adduct trans-[PtI2(NCN(CH2)5)2]∙2CHI3, the structure of which was studied via single-crystal X-ray diffractometry (XRD). In the XRD structure of trans-[PtI2(NCN(CH2)5)2]∙2CHI3, apart from rather predictable C–H∙∙∙I hydrogen bonds (HBs) and C−I∙∙∙I halogen bonds (XBs) with the iodide ligands, we identified C–I∙∙∙Pt metal-involving XBs, where the platinum center functions as an XB acceptor (that includes a metal dz2-orbital) toward the σ-holes of I atoms of CHI3. DFT calculations (PBE-D3/jorge-TZP-DKH with plane waves in the GAPW method) were carried out in the CP2K program for isolated molecules, complex–iodoform clusters, and crystal models with periodic boundary conditions, where the noncovalent nature and the existence of the interactions were confirmed using charge analysis, Wiberg bond indexes, and QTAIM topology analysis of electron density, whereas the philicities of the noncovalent partners were proved using charge analysis, electron localization function, electron density deformation, and one-electron potential projections, as well as electron density/electrostatic potential profiles for cluster models and electrostatic potential surfaces (ρ = 0.001 a.u.) for isolated molecules.

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

“…Concerning the results reported in the current work for complexes with Pd, the ρ at BCPs varies between 0.010 and 0.050 au (see Tables S5 and S6, ESI†). The relationship between a classical C–I⋯I XB and I⋯[d z 2 -Pt II ] metal-involving XB in trans -[PtI 2 (NCN(CH 2 ) 5 ) 2 ]·2CHI 3 was discussed by Eliseeva et al 53 In this complex, the source of stabilization is the charge transfer from the metal d z 2 orbital. Therefore, the noted interactions are designated as C–I⋯[d z 2 -Pt II ] metal-involving XBs, where Pt II acts as a d z 2 -nucleophile.…”

“…51 The binding between I 2 and various d 8 metals (Pd, Ni, Co, Rh, and Ir) has also been described in van Koten's pincer complex and its 19 alterations. 52 Eliseeva et al 53 found both a classical C–I⋯I XB and metal-including C–I⋯Pt in trans -[PtI 2 (NCN(CH 2 ) 5 ) 2 ]·2CHI 3 , again using the Pt d z 2 orbital as the electron source. It was also reported by Li et al 54 that Ni or Pt metal nanoparticles are able to interact with Na cations, HF or H 2 O based on the local electrostatic contacts between positively and negatively charged areas of subunits from both groups.…”

Triel Bonds between BH3/C5H4BX and M(MDA)2 (X = H, CN, F, CH3, NH2; M = Ni, Pd, Pt, MDA = Enolated Malondialdehyde) and Group 10 Transition Metal Electron Donors

“…Subsequently, various types of TM•••I interactions were identified [40][41][42][43]. Ni and Pt metal nanoparticles can interact with Na + , HF, and H 2 O, due to the attraction between local positive and negative electrostatic potential regions on the two monomers.…”

Intermolecular Metal-Involving Pnictogen Bonding: The Case of σ-(SbIII)-Hole···dz2[PtII] Interaction

“…In the overwhelming majority of instances, studies of the “named” noncovalent interactions (i.e., named for an element or a group of elements − ) explore nonmetal atoms as coformers exhibiting Lewis basicity. However, it is also established that some positively charged metal ions can function (via their filled d-orbitals) as partners, featuring a negative potential in hydrogen, halogen, − chalcogen, , or metallophilic bonding. In contrast to the progress in understanding and the use of these noncovalent forces for supramolecular chemistry, metal-involving PnB has received very little attention.…”