Bifurcated Halogen Bonding Involving Two Rhodium(I) Centers as an Integrated σ-Hole Acceptor

Abstract

The complexes [RhX(COD)] 2 (X = Cl, Br; COD = 1,5-cyclooctadiene) form cocrystals with σ-hole iodine donors. X-ray diffraction studies and extensive theoretical considerations indicate that the d z 2 -orbitals of two positively charged rhodium(I) centers provide sufficient nucleophilicity to form a three-center halogen bond (XB) with the σ-hole donors. The two metal centers function as an integrated XB acceptor, providing assembly via a metal-involving XB.

The Isocyanide Complexes cis-[MCl2(CNC6H4-4-X)2] (M = Pd, Pt; X = Cl, Br) as Tectons in Crystal Engineering Involving Halogen Bonds

“…Pursuing our interest in crystal engineering involving halogen bonding and their effect on properties and reactivity (for our recent works on HaBs see references [16,[50][51][52][53][54][55] and references therein), in the current study we undertook a joint synthetic and theoretical study concerning cis-bisisocyanide complexes cis-[PdCl 2 (CNC 6 H 4 -4-X) 2 ] (X = Cl 1, Br 2) and cis-[PtCl 2 (CNC 6 H 4 -4-Br) 2 ] (3), in which we explored the potential of these organometallics as useful 2σhD/2σhA systems for HaB-involving crystal engineering.…”

Metal Centers as Nucleophiles: Oxymoron of Halogen Bond‐Involving Crystal Engineering

“…However, recently the QTAIM approach has been combined with other approaches, such as the NCIPlot analysis. [46,49] Predominantly, XRD structure coordinates were employed for subsequent theoretical studies, [46,48,50] while in some instances the theoretical approaches used only model complexes, for example, I•••Co(I) and I•••Au(À 1). [51][52][53] In the following subsections, we inspected the appropriate geometrical parameters and computationally analyzed the XRD structures involving structure-directing σ-hole•••d[M] interactions for the occurrence of HaBs and highlighted applications of these interactions for HaB-involving crystal engineering.…”

“…Moreover, the dimerization energy is À 4.5 kcal/mol that is in the range of recent reports on σhole•••d z 2 [M] HaBs. [46] The value of MEP at Ni indicates that this interaction has a predominant HaB nature. This was further supported by a recent study, [67] which has evidenced that the σhole at the I-atom in FIB embraces a large region and can be involved in HaBs with CÀ I•••:A angles up to 105°.…”

On the Importance of Halogen Bonding Interactions in Two X-ray Structures Containing All Four (F, Cl, Br, I) Halogen Atoms

“…We used the equation E = 0.556*V r to estimate the association energy of each HaB. This equation has been successfully used before in a variety of halogen bonding interactions [41][42][43][44][45][46][47][48][49]. As a result, the association energy of HaB "a" is −1.67 kcal/mol, HaB "b" is −0.78, and HaB "c" is −0.88 kcal/mol.…”