trans-Dichlorido(1,4,8,11-tetraazacyclotetradecane)manganese(III) tetrafluoridoborate

In the title manganese(III) complex, [MnCl2(C10H24N4)]BF4 or trans-[MnCl2(cyclam)]BF4 (cyclam is the tetradentate amine ligand 1,4,8,11-tetraazacyclotetradecane), the MnIII ions occupy the center of a distorted octahedron coordinated by all four ligand nitrogen donors in the macrobicyclic cavity and two chloride ions occupy the axial positions. Intramolecular hydrogen bonding involving the coordinated chloride ions and the hydrogen atoms of the cyclam ligand is observed. Intermolecular hydrogen bonding involving the tetrafluoridoborate anion and hydrogen atoms of the cyclam ligand leads to an infinite one-dimensional chain along the a axis. The tetrafluoridoborate and inorganic units are linked by N—H⋯F hydrogen bonds. The structure may be compared with those of analogous compounds [MnCl2(cyclam)]ClO4 and [Mn(CN)2(cyclam)]ClO4.

In the title manganese(III) complex, [MnCl 2 (C 10 H 24 N 4 )]BF 4 or trans-[MnCl 2 (cyclam)]BF 4 (cyclam is the tetradentate amine ligand 1,4,8,11-tetraazacyclotetradecane), the Mn III ions occupy the center of a distorted octahedron coordinated by all four ligand nitrogen donors in the macrobicyclic cavity and two chloride ions occupy the axial positions. Intramolecular hydrogen bonding involving the coordinated chloride ions and the hydrogen atoms of the cyclam ligand is observed. Intermolecular hydrogen bonding involving the tetrafluoridoborate anion and hydrogen atoms of the cyclam ligand leads to an infinite one-dimensional chain along the a axis. The tetrafluoridoborate and inorganic units are linked by N-HÁ Á ÁF hydrogen bonds. The structure may be compared with those of analogous compounds [MnCl 2 (cyclam)]ClO 4 and [Mn(CN) 2 (cyclam)]ClO 4 .
The substitution of two chlorine atoms in (b) by two cyano atoms in (c) appears to have the same unit cell. This is probably indicative of the same size and same charge of the two ligands.
The title compound, [Mn(cyclam)Cl 2 ].BF 4 is constructed from isolated Mn(cyclam)Cl 2 octahedra and the tetrafluoridoborate molecules (BF 4 ) (Fig 1). The manganese atom is octahedrally coordinated to four N atoms of the macrocycle in the basal position and two chlorine atoms in axial positions. The bond lengths in the title compound are shorter than those found for the corresponding bonds in the salts of [Mn(cyclam)O] 2 2 which is probably indicative of the trans-influence of oxygen in the later ion (Brewer et al. (1989)). The average Mn-N distance here (2.051 (3) Å) is slightly higher than that (2.033 Å) (  (Letumier et al. (1998)). This bond distance (Mn-Cl) is much longer than that found in the similar cation [CoCl 2 (cyclam)] + where the Co-Cl distance is 2.252 Å (Bakac et al.(1987)).
The N-Mn-N bond angles, like the bond distances and angles in the cyclam ligand, are thoroughly consistent with those in the literature (Sosa-Torres et al. (1997), Blessing (1987 and Mossin et al. (2005)).
The protonated cation and the deprotonated anion are linked through a number of intramolecular N-H···Cl and intermolecular N-H···F hydrogen bonds (Fig 2) These ligands (cyclam) provide interesting new possibilities in the field of the treatment of waste water contaminated by toxic or radioactive metals and gas purification since they can be attached to an organic or inorganic solid support via relatively simple reactions. In this respect, thermodynamic and magnetic data are complementary and most useful information which will allow rational design by the molecular engineering of more efficient chelating agents.  trans-Dichlorido (1,4,8,11-tetraazacyclotetradecane) (7)