Teshome B. Yisgedu

Structures of Mn(II) complexes of bis(2-pyridylmethyl)amine (bpa) and (2-pyridylmethyl)(6-methyl-2-pyridylmethyl)amine (Mebpa): geometric isomerism in the solid state

The crystal structures of [Mn(bpa)2](ClO4)2 (1), [bpau2009=u2009bis(2-pyridylmethyl)amine], and Mn(6-Mebpa)2(ClO4)2 (2), [6-Mebpau2009=u2009(6-methyl-2-pyridylmethyl)(2-pyridylmethyl)amine] have been determined. In 1, two facial [Mn(bpa)2]2+ isomers are observed in the same unit cell, one with C i (1a) and the other with C2 (1b) symmetries. In 2, only the isomer with C2 symmetry is observed. The structure of [Mn(bpa)2]2+ with only C2 symmetry has been reported previously (Inorg. Chem., 31, 4611 (1992)). The bond length order Mn–Namineu2009>u2009Mn–Npyridyl, observed in the C2 and the C i isomers in the crystals of 1, is the reverse of the order observed in the structure of [Mn(bpa)2](ClO4)2 which contains only the C2 isomer in the unit cell. The structure of 2 in which only the C2 isomer is found, also shows the bond length order Mn–Npyridylu2009>u2009Mn–Namine. In cyclic voltammetric experiments in acetonitrile solutions, 1 and 2 show irreversible anodic peaks at E pu2009=u20091.60 and 1.90u2009V respectively, (vs. Ag/AgCl), assigned to the oxidation of Mn(II) to Mn(III). The substantially higher oxidation potential of 2 is attributable to a higher rearrangement energy in complex 2 due to the steric effect of the methyl substituent.

[2,2'-(2,6,9,13-Tetra-azatetra-decane-1,14-di-yl)diphenolato]iron(III) iodide.

The title FeIII complex, [Fe(C22H32N4O2)]I, contains a six-coordinate FeN4O2 cation in which the ligand is a reduced Schiff base resulting from the NaBH4 reduction of the condensation product between salicylaldehyde and 1,5,8,12-tetraazadodecane. In spite of the increased flexibility of the saturated backbone of the ligand compared to the Schiff base from which it was synthesized, the complex adopts a cis-FeN4O2 conformation for the phenolic O-atom donors, which contrasts with the trans conformation adopted by the analogous ClO4 − salt [Yisgedu et al. (2009 ▶). J. Chem. Crystallogr. 39, 315–319]. In addition to extensive N—H⋯I hydrogen bonding between the amine H atoms and the anion there is a weak C—H⋯I interaction.

Bis[μ-2-(2-pyridylmethyl­amino­meth­yl)phenolato]-κ4 N,N′,O:O;κ4 O:N,N′,O-bis­[(thio­cyanato-κN)copper(II)]

The centrosymmetric binuclear complex, [Cu2(C13H13N2O)2(NCS)2], formed via phenolate oxygen bridges, involves the CuII atoms in a distorted square-pyramidal coordination [τ = 0.197u2005(1)]. A Cu⋯Cu separation of 3.2281u2005(3)u2005Å is observed. The in-plane Cu—Ophenolate distance [1.9342u2005(8)u2005Å] is shorter than the axial distance [2.252u2005(8)u2005Å]. The Cu—Namine and Cu—Npy distances are similar [2.0095u2005(10) and 2.0192u2005(10)u2005Å, respectively]. The Cu—Nthiocyanate distance [1.9678u2005(11)u2005Å] is in the range found for Cu—N distances in previously determined structures containing coordinated thiocyanate anions. There is an intermolecular hydrogen bond between the amine H atom and the S atom of a coordinated thiocyanate anion.

Di-μ-perchlorato-bis-{μ-2-[(2-pyrid-yl)methyl-amino-meth-yl]phenolato)dicopper(II) acetonitrile disolvate.

In the crystal of the dinuclear title compound, [Cu2(C13H13N2O)2(ClO4)2]·2CH3CN, the two bridging perchlorate ions chelate to the two CuII atoms in a μ-O:O′ fashion on opposite sides of the equatorial plane. The CuII ions display a distorted octahedral coordination geometry (in the usual 4 + 2 Jahn–Teller arrangement), each being coordinated by two O atoms from the two perchlorate ligands, and two N and O atoms from the reduced Schiff base ligand. The asymmetric unit contains two acetonitrile solvent molecules. In the crystal structure, in addition to N—H⋯O hydrogen bonds, there are weak C—H⋯O interactions between the perchlorate O atoms and the reduced Schiff base ligand. C—H⋯N interactions are also present.

Bis[(2-methyl-benz-yl)bis-(pyridin-2-ylmethyl-κN)amine-κN]manganese(II) bis-(perchlorate).

In the title complex, [Mn(C20H21N3)2](ClO4)2, two tridentate (2-methylbenzyl)bis(pyridin-2-ylmethyl)amine (L) ligands form the MnII complex [MnL 2](ClO4)2. The MnII ion lies on a twofold axis and the complex cation is significantly distorted from regular octahedral geometry. The packing is stabilized by weak C—H⋯O interactions between the cations and anions, which link them into a zigzag ribbon along [101]. The perchlorate anion is disordered and was constrained to be tetrahedral with two orientations having occupancies of 0.768u2005(4) and 0.232u2005(4). The 2-methylbenzyl moiety is also disordered over two sets of sites, with occupancies of 0.508u2005(15) and 0.492u2005(15).

2-[2-(2-Pyrid-yl)eth-yl]isoindolinium perchlorate.

In the title salt, C15H17N2 +·ClO4 −, the isoindoline N atom is protonated and an intramolecular N—H⋯N hydrogen bond occurs. In the crystal, N—H⋯O and numerous weak C—H⋯O interactions occur between the cation and anion. The O atoms of the perchlorate anion are disordered over four sets of sites with occupancies of 0.438u2005(4), 0.270u2005(9), 0.155u2005(8) and 0.138u2005(5).

[(6-Methyl-2-pyridylmeth-yl)(2-pyridylmeth-yl)amine][(2-pyridylmeth-yl)amine]copper(II) bis-(perchlorate).

The title compound, [Cu(C6H8N2)(C13H15N3)](ClO4)2, is a mixed ligand complex with the CuII atom coordinated by (6-methyl-2-pyridylmethyl)(2-pyridylmethyl)amine, acting as a tridentate ligand, and 2-(2-aminomethyl)pyridine, as a bidentate ligand, leading to an N5 square-pyramidal geometry. The amine H atoms are involved in hydrogen bonding to the perchlorate O atoms and there are extensive but weak intermolecular C—H⋯O interactions in the crystal structure. The perchlorate ions are each disordered over two positions, with site occupancies of 0.601u2005(8):0.399u2005(8) and 0.659u2005(11):0.341u2005(11).

(m-Phenyl­enedimethyl­ene)diammonium p-nitro­phenyl­phosphate perchlorate

The title compound, C8H14N2 2+·C12H8N2O8P−·ClO4 −, was formed by the reaction of α,α-bis-m-xylenediamine and sodium bis-p-nitrophenylphosphate in the presence of Zn(ClO4)·6H2O in methanol solution. The two amine groups of the m-xylenediammonium ion are each protonated and each hydrogen-bonded to two O atoms of the phosphate anion, which acts as a 1,3-bridge. The ammonium groups are arranged matched face to face and each pair is doubly bridged by two perchlorate ions through hydrogen bonding. In addition, there are also weak C—H⋯O interactions. Both the N—H⋯O and C—H⋯O interactions are contained in a channel down the a axis. The perchlorate oxygen atoms are disordered over two positions with site occupancy factors of ca 0.7 and 0.3.

(Acetonitrile)[bis-(2-pyridylmeth-yl)amine]bis-(perchlorato)copper(II).

In the title compound, [Cu(ClO4)2(C12H13N3)(C2H3N)], the CuII atom is six-coordinate in a Jahn–Teller distorted octahedral geometry, with coordination by the tridentate chelating ligand, an acetonitrile molecule, and two axial perchlorate anions. The tridentate ligand bis(2-pyridylmethyl)amine chelates meridionally and equatorially while an acetonitrile molecule is coordinated at the fourth equatorial site. The two perchlorate anions are disordered with site occupancy factors of 0.72/0.28. The amine H is involved in intramolecular hydrogen bonding to the perchlorate O atoms and there are extensive but weak intermolecular C—H⋯O interactions.

Di-μ-bromido-bis­({bis­[2-(2-pyrid­yl)eth­yl]amine}copper(II)) bis­(perchlorate)

Each Cu atom in the dinuclear centrosymmetric title complex, [Cu2Br2(C14H17N3)2](ClO4)2, is ligated in a distorted square-pyramidal geometry (τ = 0.31) by a tridentate bis[2-(2-pyridyl)ethyl]amine ligand, and by two bridging Br atoms. In addition, the dinuclear species is stabilized by two hydrogen-bonded perchlorate anions.