Co-crystallization of the dithiocarbamate complexes [MII(S2CNEt2)2] (M = Cu 1, Ni 2, Pd 3, Pt 4) and 1,3,5-triiodotrifluorobenzene (FIB) gives an isomorphic series of (1–4)∙2FIB co-crystals exhibiting the quadruple Cu/Ni/Pd/Pt...

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.

This study is the first recognition of iodopentafluorobenzene's π-hole donor ability.

By performing combined XRD and theoretical studies, we established the modes of REWGI⋯I–Pt XBs with [Pt2(μ-I)2I4]2− acting as an XB acceptor.

Cocrystallization of the nitrosoguanidinate complexes [Ni{NHC(NR 2 )NN(O)} 2 ] (R 2 = Me 2 (1), Me/Ph (2), C 5 H 10 and 2•2C 2 I 4 ; all of these solids were studied by single-crystal X-ray diffraction. Each structure exhibits the asymmetric bifurcated halogen bond μ 2 -I•••(N,O) as a characteristic feature and a structure-directing contact. DFT calculations were used to evaluate the energetic features of the bifurcated halogen bonds that range from −6.7 to −8.3 kcal/mol; in general, the I•••O contact is stronger that the I•••N contact. Molecular electrostatic potential (MEP) surfaces along with the quantum theory of "atoms in molecules" (QTAIM) and the noncovalent interaction plot index (NCIPlot) computational tools were used to characterize the bifurcated halogen bonds in the cocrystals of 1−3. Various types of bifurcated halogen bonds involving nonmetal atoms as halogen-bond-accepting centers were systematized and categorized.