Dihalomethanes as Bent Bifunctional XB/XB‐Donating Building Blocks for Construction of Metal‐involving Halogen Bonded Hexagons

Abstract

The dihalomethanes CH₂ X₂ (X=Cl, Br, I) were co-crystallized with the isocyanide complexes trans-[MX^M ₂ (CNC₆ H₄ -4-X^C )₂ ] (M=Pd, Pt; X^M =Br, I; X^C =F, Cl, Br) to give an extended series comprising 15 X-ray structures of isostructural adducts featuring 1D metal-involving hexagon-like arrays. In these structures, CH₂ X₂ behave as bent bifunctional XB/XB-donating building blocks, whereas trans-[MX^M ₂ (CNC₆ H₄ -4-X^C )₂ ] act as a linear XB/XB acceptors. Results of DFT calculations indicate that all XCH₂ -X⋅⋅⋅X^M -M contacts are typical noncovalent interactions with estimated strengths in the range of 1.3-3.2 kcal mol^-1 . A CCDC search reveals that hexagon-like arrays are rather common but previously overlooked structural motives for adducts of trans-bis(halide) complexes and halomethanes.