Six tris-(bipyrid-yl)iron(II) complexes with 2-substituted 1,1,3,3-tetra-cyano-propenide, perchlorate and tetra-fluorido-borate anions; order versus disorder, hydrogen bonding and C-N⋯π inter-actions.

Abderezak Addala,Takashi Matsumoto,Yukio Morimoto,Christopher Glidewell,Juan M Gutiérrez-Zorrilla,Zouaoui Setifi,Beñat Artetxe

doi:10.1107/s2056989018015426

Abstract

Structures are reported for six closely related salts of tris-(bipyrid-yl)iron(II) cations, namely tris-(2,2'-bi-pyridine)-iron(II) bis-(1,1,3,3-tetra-cyano-2-meth-oxy-propenide) 0.776-hydrate, [Fe(C10H8N2)3](C8H3N4O)2.0.776H2O, (I), tris-(2,2'-bi-pyridine)-iron(II) 1,1,3,3-tetra-cyano-2-(propyl-sulfan-yl)propenide perchlor-ate, [Fe(C10H8N2)3](C10H7N4S)(ClO4), (II), tris-(5,5'-dimethyl-2,2'-bi-pyridine)-iron(II) 1,1,3,3-tetra-cyano-2-meth-oxy-propenide tetra-fluorido-borate ethanol 0.926-solvate, [Fe(C12H12N2)3](C8H3N4O)(BF4).0.926C2H2O, (III), tris-(5,5'-dimethyl-2,2'-bi-pyridine)-iron(II) 1,1,3,3-tetra-cyano-2-eth-oxy-propenide tetra-fluorido-borate, [Fe(C12H12N2)3](C9H5N4O)(BF4), (IV), tris-(5,5'-dimethyl-2,2'-bi-pyridine)-iron(II) 1,1,3,3-tetra-cyano-2-(ethyl-sufanyl)propenide tetra-fluorido-borate, [Fe(C12H12N2)3](C9H5N4S)(BF4), (V), and tris-(5,5'-dimethyl-2,2'-bi-pyri-dine)-iron(II) 1,1,3,3-tetra-cyano-2-prop-oxypropenide tetra-fluorido-borate, [Fe(C12H12N2)3](C10H7N4O)(BF4), (VI). In compound (I), one of the anions is disordered over two sets of atomic sites with equal occupancies while, in the second anion, just one of the C(CN)2 units is disordered, again over two sets of atomic sites with equal occupancies: the anionic components are linked by multiple C-H⋯N hydrogen bonds to form a three-dimensional framework. In compound (II), the polynitrile anion is disordered over two sets of atomic sites with occupancies in the approximate ratio 3:1, while the perchlorate anion is disordered over three sets of atomic sites: there are C-N⋯π inter-actions between the cations and the polynitrile anion. The polynitrile anion in compound (III) is fully ordered, but the tetra-fluorido-borate anion is disordered over two sets of atomic sites with occupancies 0.671 (4) and 0.329 (4): the cations and the tetra-fluorido-borate anions are linked by C-H⋯F inter-actions to form an inter-rupted chain. Compounds (IV) and (V) are isostructural and all of the ionic components are fully ordered in both of them: the cations and tetra-fluorido-borate anions are linked into C 2 2(12) chains. The polynitrile anion in compound (VI) is disordered over two sets of atomic sites with approximately equal occupancies, and here the chains formed by the cations and the tetra-fluorido-borate anions are of the C 2 2(13) type.

Highlights

The polynitrile anions all have the constitution 1,1,3,3tetracyano-2-X-propenide, and it will be convenient to use abbreviations as follows: X = OMe, tcnome; X = OEt, tcnoet; X = OPr, tcnopr; X = SEt, tcnset; X = SPr, tcnspr
The polynitrile anion in compound (III) is fully ordered, but the tetrafluoridoborate anion is disordered over two sets of atomic sites with occupancies 0.671 (4) and 0.329 (4): the cations and the tetrafluoridoborate anions are linked by C—HÁ Á ÁF interactions to form an interrupted chain
As a part of our continuing study of the structural and magnetic properties of iron(II) complexes containing both polynitrile and polypyridyl units (Setifi et al, 2010; Setifi, Domasevitch et al, 2013; Setifi, Setifi et al, 2013; Setifi, Setifi, Boughzala et al, 2014; Setifi, Setifi, El Ammari et al, 2014), we report here the molecular and supramolecular structures of six tris(bipyridyl)iron(II) compounds each containing a 2-substituted-1,1,3,3-tetracyanopropenide anion as counter-ion, namely tris(2,20-bipyridine)iron(II), bis(1,1,3,3-tetracyano-2

Summary

Structural commentary

Compounds (I)–(VI) all contain a tris(bipyridine)iron(II) cation and a 2-substituted-1,1,3,3-tetracyanopropenide anion. The propenide anion of compound (III) is fully ordered, but the tetrafluoridoborate anion is disordered over two sets of atomic sites with occupancies 0.671 (4) and 0.329 (4): there is an ethanol molecule present in the structure of (III) with occupancy 0.926 (5). In none of compounds (I)–(VI) do the polynitrile units act as ligands towards the iron(II) centres, but they are always present as free anions. This is consistent with the behaviour observed in a wide range of other iron(II) complexes containing polypyridyl ligands as anions of the general type tcnX (Setifi et al, 2010; Setifi, Domasevitch et al, 2013; Setifi, Setifi et al, 2013; Setifi, Setifi, Boughzala et al, 2014). These values indicate, in each compound, the presence of low-spin FeII; in comparable high-spin complexes, the Fe—N distances are always around 2.15 A (Orpen et al, 1989)

Supramolecular features

Database survey

Synthesis and crystallization

Refinement