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

The dihalomethanes CH2X2 (X=Cl, Br, I) were co-crystallized with the isocyanide complexes trans-[MX2M(CNC6H4-4-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, CH2X2 behave as bent bifunctional XB/XB-donating building blocks, whereas trans-[MX2M(CNC6H4-4-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.