Coordination Polymers with Intramolecular Fluorine-Involved Contacts in Two-Dimensional Sheet Windows

Abstract

5, and [Hg(L 2,3,4, ) 2 ] n , 6 and a discrete complex of [Hg(L 2,6-F ) 2 ], 7, in which L n-F ligands are N-(fluorinatedphenyl)-2pyrazinecarboxamides carrying fluorine atoms on the different positions of phenyl ring, have been synthesized and characterized. The crystal structures from X-ray diffraction reveal that all polymeric complexes have similar two-dimensional (2D) sheet windows. From a topological perspective, each metal atom can be viewed as 4-connected nodes and L n-F ligands can be considered as linkers in the formation of these 2D windows. Because of the flexibility of the ligand, fluorinated-phenyl rings as hanging groups in the windows are pointed toward the adjacent groups to generate different fluorine-involved intramolecular interactions. One of the common features in the crystal structures of these complexes is the presence of a strong tendency to form intramolecular F•••π interactions in 2D windows of the crystal structure of all polymeric complexes, except complex 3. These interactions are cooperating with weak C−H•••F and C−H•••O hydrogen bonds. Also, in the crystal structure of complexes 5 and 6, carrying three and four fluorine atoms on phenyl rings, type II F•••F synthons between adjacent rings have been observed in cooperation with F•••π interactions. Hirshfeld surface analysis also confirms that the F•••F/π contacts are predominant.

Fluorine‐Substituted Ligands Induce Structural Diversity of Coordination Compounds

“…The ligands have one (L 2−F , L 3−F , L 4−F ), two (L 2,5−F , L 2,6−F ), three (L 2,3,4−F ) and four (L 2,3,4,5−F ) fluorine atoms on the phenyl ring. According to previous results obtained during our research program,– N2 atom in pyrazine ring is mostly the active site of pyrazine carboxamide ligands for coordinating to Hg(II) ions. As expected, although not isostructural, the coordination mode of ligands in the current work is fixed and repeat in the all complexes as well.…”

Can Combined Electrostatic and Polarization Effects Alone Explain the F···F Negative-Negative Bonding in Simple Fluoro-Substituted Benzene Derivatives? A First-Principles Perspective

“…Such fluorine-based intermolecular interactions were extracted from the single crystal nearest neighbor dimer pairs. Khavasi and Rahimi [125] have also demonstrated the importance of F···F interactions in crystals. They noted that in coordination compounds fluorinated ligands exercise influence not only on the first coordination sphere but also on the supramolecular architecture and overall construction of the compounds [126].…”

A novel terbium–mercury compound: Preparation, structure, and properties

“…11–13 The Hg–N bond lengths are 2.110(8) and 2.20(1) Å, which is also normal and comparable with those reported previously. 14–16 The Cl–Hg–Cl bond angles are in the range of 89.29(9)°–165.8(1)°, while the N–Hg–Cl bond angles are in the range of 82.9(3)°–108.0(3)°. The N 1 (–0.5 + x , 4 – y, z )–Hg 2 –N 6 bond angle is 163.9(4)° which is close to linear.…”

“…These Tb–O bond lengths are in the normal range and comparable with those found in the literature. 17–20 The O–Tb–O bond angles locate in a very wide range of 69.0(2)°–145.6(2)°. The neighboring Tb 3+ ions are interlinked by the isonicotinic acid molecules with the number of the isonicotinic acid molecules being of -2-4-2-4- to yield a one-dimensional (1D) infinite chain running along the b direction, as shown in Figure 2.…”