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3‐(Pyridin‐4‐yl)acetylacetone: Cd II and Hg II compete for nitrogen coordination
Author(s) -
Truong Khai-Nghi,
Merkens Carina,
Englert Ulli
Publication year - 2017
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229617011408
Subject(s) - acetylacetone , chemistry , ligand (biochemistry) , bromide , octahedron , pyridine , coordination sphere , thioether , bridging ligand , coordination polymer , medicinal chemistry , crystallography , stereochemistry , crystal structure , inorganic chemistry , biochemistry , receptor
3‐(Pyridin‐4‐yl)acetylacetone (HacacPy) acts as a pyridine‐type ligand towards Cd II and Hg II halides. With CdBr 2 , the one‐dimensional polymer [Cd(μ‐Br) 2 (HacacPy)Cd(μ‐Br) 2 (HacacPy) 2 ] ∞ is obtained in which five‐ and six‐coordinated Cd II cations alternate in the chain direction. Reaction of HacacPy with HgBr 2 results in [Hg(μ‐Br)Br(HacacPy)] ∞ , a polymer in which each Hg II centre is tetracoordinated. In both compounds, each metal(II) cation is N ‐coordinated by at least one HacacPy ligand. Equimolar reaction between these Cd II and Hg II derivatives, either conducted in ethanol as solvent or via grinding in the solid state, leads to ligand redistribution and the formation of the well‐ordered bimetallic polymer catena ‐poly[[bromidomercury(II)]‐μ‐bromido‐[aquabis[4‐hydroxy‐3‐(pyridin‐4‐yl)pent‐3‐en‐2‐one]cadmium(II)]‐di‐μ‐bromido], [CdHgBr 4 (C 10 H 11 NO 2 ) 2 (H 2 O)] n or [{HgBr}(μ‐Br){(HacacPy) 2 Cd(H 2 O)}(μ‐Br) 2 ] ∞ . Hg II and Cd II cations alternate in the [100] direction. The HacacPy ligands do not bind to the Hg II cations, which are tetracoordinated by three bridging and one terminal bromide ligand. The Cd II centres adopt an only slightly distorted octahedral coordination. Three bromide ligands link them in a (2 + 1) pattern to neighbouring Hg II atoms; two HacacPy ligands in a cis configuration, acting as N‐atom donors, and a terminal aqua ligand complete the coordination sphere. Classical O—H…Br hydrogen bonds stabilize the polymeric chain. O—H…O hydrogen bonds between aqua H atoms and the uncoordinated carbonyl group of an HacacPy ligand in a neighbouring strand in the c direction link the chains into layers in the (010) plane.