Influence of metal and ligand types on stacking interactions of phenyl rings with square-planar transition metal complexes

Abstract

Abstract:In order to find out whether metal type influences the stacking interactions of phenyl rings in square-planar complexes, geometrical parameters for Cu, Ni, Pd and Pt complexes, with and without chelate rings, were analyzed and compared. By searching the Cambridge Structural Database, 220 structures with Cu complexes, 211 with Ni complexes, 285 with Pd complexes, and 220 with Pt complexes were found. The results show that the chelate ring has a tendency to make the stacking interaction with the phenyl ring independent of metal type in the chelate ring. However, there are some differences among metals for complexes without a chelate ring. There are a number of structures containing Pd and Pt complexes, without chelate rings, that have short carbon-metal distances and parallel orientations of the phenyl ring with respect to the coordination plane. It was found that some of these complexes have a common fragment, CN, as a part of the ligands. This indicates that the CN supports stacking interactions of square planar complexes with the phenyl ring.

Synthesis, X-ray characterization, DFT calculations and Hirshfeld surface analysis of thiosemicarbazone complexes of Mn+ ions (n = 2, 3; M = Ni, Cd, Mn, Co and Cu)

“…The average distance between rings is 3.701(2) Å, while the average ring-metal chelate distance is 3.568(2) Å. Three metal⋯π aryl weak intermolecular interactions 28 between the copperIJII) ions and the phenyl rings of the thiosemicarbazone ligands are observed (Fig. S4c †), where the distance between the centroids of the phenyl rings and the copper atom is less than 4.0 Å and the angle defined by the vector perpendicular to the aromatic ring and the vector passing through the centroid to the copper atom is less than 40°(Table S4 †).…”

Noncovalent Interactions of π‐Systems in Crystal Structures of Transition‐Metal Complexes

“…. .π and stacking interactions of chelate rings [8,[18][19][20][21][22][23][24][25][26][27][28]. Other groups have reported CH.…”

“…shown that square-planar complexes of various metals can form these interactions and that these interactions are in fact ubiquitous [25,26].…”

“…26), shows that in most cases τ is less than 10 • or near 180 • , that is, indicating that parallel and antiparallel conformations (Figure 10.27), respectively, dominate. For interactions involving five-membered chelate rings, the number of parallel and antiparallel orientations is similar.…”

CH/π interactions in metal–porphyrin complexes with pyrrole and chelate rings as hydrogen acceptors

“…Chelate rings with a delocalized π-system can form CH/π [38][39][40][41][42][43][44] and stacking interactions [45][46][47][48][49] in a similar way to organic aromatic rings [50][51][52][53][54][55][56][57][58]. In our previous studies, structural and computational evidence has been given for a particular type of CH/π interaction where the hydrogen atom interacts with various chelate rings [38][39][40][41].…”