Design of Lead(II) Metal-Organic Frameworks Based on Covalent and Tetrel Bonding.
Three solid materials, [Pb(HL)(SCN)2 ]⋅CH3 OH (1), [Pb(HL)(SCN)2 ] (2), and [Pb(L)(SCN)]n (3), were obtained from Pb(SCN)2 and an unsymmetrical bis-pyridyl hydrazone ligand that can act both as a bridging and as a chelating ligand. In all three the lead center is hemidirectionally coordinated and is thus sterically optimal for participation in tetrel bonding. In the crystal structures of all three compounds, the lead atoms participate in short contacts with thiocyanate sulfur or nitrogen atoms. These contacts are shorter than the sums of the van der Waals radii (3.04-3.47 Å for Pb⋅⋅⋅S and 3.54 Å for Pb⋅⋅⋅N) and interconnect the covalently bonded units (monomers, dimers, and 2D polymers) into supramolecular assemblies (chains and 3D structures). DFT calculations showed these contacts to be tetrel bonds of considerable energy (6.5-10.5 kcal mol(-1) for Pb⋅⋅⋅S and 16.5 kcal mol(-1) for Pb⋅⋅⋅N). A survey of structures in the CSD showed that similar contacts often appear in crystals of Pb(II) complexes with regular geometries, which leads to the conclusion that tetrel bonding plays a significant role in the supramolecular chemistry of Pb(II) .
Young Researchers and Elite Club, Tabriz Branch, Islamic Azad University, Tabriz (Iran).
Masoumeh
M
Servati Gargari
Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a Zagreb (Croatia). vstilinovic@chem.pmf.hr.
Vladimir
V
Stilinović
Departament de Química, Universitat de les Illes Balears, Crta de Valldemossa km 7.5, 07122 Palma de Mallorca (Baleares) (Spain).
Antonio
A
Bauzá
Departament de Química, Universitat de les Illes Balears, Crta de Valldemossa km 7.5, 07122 Palma de Mallorca (Baleares) (Spain).
Antonio
A
Frontera
School of Chemistry, NUI, Galway (Ireland).
Patrick
P
McArdle
Department of Chemistry, Clemson University, Clemson, SC 29634-0973 (USA).
Donald
D
Van Derveer
Department of Chemistry, University of Malaya, 50603 Kuala Lumpur (Malaysia).
Seik Weng
SW
Ng
Department of Chemistry, Faculty of Science, University of Maragheh, P.O. Box 55181-83111, Maragheh (Iran). mahmoudi_ghodrat@yahoo.co.uk.
Ghodrat
G
Mahmoudi
crystal engineering; lead; metal-organic frameworks; noncovalent interactions; supramolecular chemistry