Martin Curran

Manganese(II) complexes of hexanedioic and heptanedioic acids: X-ray crystal structures of [Mn(O2C(CH2)4CO2(phen)2H2O] · 7H2O and [Mn(phen)2(H2O)2][Mn(O2C(CH2)5CO2) [phen)2H2O](O2C(CH2)5CO2) · 12.5H2O

Mn(CH 3 CO 2 ) 2 ·4H 2 O reacts with ethanolic solutions of hexanedionic and heptanedioic acids ( ca 1:1 mol ratio) to produce the respective manganese(II) complexes [Mn(O 2 C(CH 2 ) 4 CO 2 )H 2 O] ( 1 ) and [Mn(O 2 C(CH 2 ) 5 CO 2 )] ( 2 ). Subsequent reaction of 1 and 2 with 1,10-phenanthroline (phen) ( ca 1:2 mol ratio) in aqueous ethanol gives [Mn(O 2 C(CH 2 ) 4 CO 2 )(phen) 2 H 2 O]·7H 2 O ( 3 ) and [Mn(phen) 2 (H 2 O) 2 ][Mn(O 2 C(CH 2 ) 5 CO 2 (phen) 2 H 2 O](O 2 C(CH 2 ) 5 CO 2 )·12.5H 2 O ( 4 ), respectively. Complexes 3 and 4 have been structurally characterised. The asymmetric unit in 3 has a manganese(II) atom coordinated to four nitrogen atoms from two chelating phenanthroline ligands, one oxygen atom from a unidentate (O 2 C(CH 2 ) 4 CO 2 ) −2 ligand and one oxygen atom from a water molecule which is in a cisoid position with respect to the diacid ligand. The asymmetric unit in 4 contains two mononuclear manganese(II) species, the dication [Mn(phen) 2 (H 2 O) 2 ] 2+ and the neutral manganese heptanedioate complex [Mn(O 2 (CH 2 ) 5 CO 2 )(phen)(H 2 O)], along with a non-coordinated (O 2 C(CH 2 ) 5 CO 2 ) 2− counter dianion. In the dication [Mn(phen) 2 (H 2 O) 2 ] 2+ the manganese atom is coordinated to four nitrogen atoms from two chelating phenanthroline ligands and two oxygen atoms from two cisoid water molecules. In the neutral fragment [Mn(O 2 C(CH 2 ) 5 CO 2 )(phen) 2 (H 2 O)] the metal atom is coordinated to four nitrogen atoms from two chelating phenanthroline ligands, one oxygen atom from a unidentate (O 2 C(CH 2 ) 5 CO 2 ) 2− ligand and one oxygen atom from a water molecule which is cis with respect to the coordinated carboxylate oxygen of the heptanedioate ligand. IR, magnetic and conductivity data for the complexes are given. All four complexes are catalysts for the disproportionation of H 2 O 2 in the presence of added imidazole.

Synthesis, X-ray crystal structure and catalytic activity of the manganese(II) complex [Mn(bdoa)(H2O)3](bdoaH2 =benzene-1,2-dioxyacetic acid)

Benzene-1,2-dioxyacetic acid (bdoaH2) reacts with Mn(CH3CO2)2·4H2O in an ethanol-water mixture to give the manganese(II) complex [Mn(bdoa)(H2O)3]. The X-ray crystal structure of the complex shows the metal to be pseudo seven-coordinate. The quadridentate bdoa2− dicar☐ylate ligand forms an essentially planar girdle around the metal, being strongly bondedtransoid by a car☐ylate oxygen atom from each of the two car☐ylate moieties (mean MnO 2.199A˚) and also weakly chelated by the two internal ether oxygen atoms (mean MnO 2.413A˚). The coordination sphere about the manganese is completed by three water molecules (mean MnO 2.146A˚) lying in a meridional plane orthogonal to that of the bdoa2− ligand. Magnetic, conductivity and voltammetry data for the complex are given, and its use as a catalyst for the disproportionisation of H2O2 is described.

Synthesis and structure of the MnII,II complex salt [Mn2(η1η1µ2-oda)(phen)4(H2O)2][Mn2][Mn2(η1η1µ2-oda)(phen)4(η1-oda)2]·4H2O (odah2= octanedioic acid): a catalyst for H2O2 disproportionation

The synthesis and X-ray crystal structure of the MnII,11 complex double salt [Mn2(η1η1µ2-oda)(phen)4(H2O)2][Mn2(η1η1µ2-oda(phen)4(η1-oda)2]·4H2O is reported, together with its catalytic activity towards the disproportionation of H2O2.

Synthesis and catalytic activity of manganese(II) complexes of pentanedioic acid; X-ray crystal structure of [Mn(phen)2(H2O)2][Mn(O2C(CH2)3CO2)(phen)2H2O]-(O2C(CH2)3CO2) · 12H2O (phen = 1,10-phenanthroline)

Abstract Reaction of manganese(II) acetate tetrahydrate with pentanendioic acid gives [Mn(O2C(CH2)3CO2)] · H2O (1). Complex 1 reach with 1,10-phenanthroline (phen) (∼ 1:3 mol ratio) in ethanol giving the mono-phenanthroline complex [Mn(O2C(CH2)3CO2)(phen)] (2). Using less phenanthroline (∼ 1 mmol of 1:2 mol phenanthroline) in an ethanol-water solvent mixture gives the bis-phenanthroline complex [Mn(phen)2(H2O)2][Mn(O2C(CH2)3CO2)(phen)2H2O](O2C(CH2)3CO2) · 12H2O (3) which was characterised using X-ray crystallography. Complex 3 contains two independent mononuclear manganese(II) species, the dication [Mn(phen)2(H2O)2]2+ and the neutral manganese pentanedioate complex [Mn(O2C(CH2)3CO2)(phen)2(H2O], along with a non-coordinated (O2C(CH2)4CO2)2 counter dianion. In the dication [Mn(phen)2(H2O2]2+ the manganese atom is coordinated to four nitrogen atoms from two chelating phenanthroline ligands and two oxygen atoms from two cisoid water molecules. In the neutral fragment [Mn(O2C(CH2)3(CO2)(phen)2(H2O)] the metal atom is coordinated to four nitrogen atoms from two chelating phenanthroline ligands, one oxygen atom from a unidentate (O2C(CH23CO2)2 ligand and one oxygen atom from a water molecule which is cis with respect to the coordinated carboxylate oxygen of the pentanedioate ligand. IR, magnetic and conductivity data for the complexes are given. All three complexes are catalysts for the disproportionation of H2O3 in the presence of added imidazole.

Syntheses, X-ray crystal structures and catalytic activities of the manganese(II) butanedioic acid complexes [Mn2(O2C(CH)2)2CO2)2(phen)2 (H2O)]·2H2O and {[Mn(O2C(CH2)2CO2)(bipy)(H2O)2]·H2O}n

Abstract Manganese(II) acetate reacts with an ethanolic solution of butanedioic acid (ca 1 : 1 mol ratio) to produce the white complex [Mn(O2C(CH2)2CO2)(H2O)2] (1) in high yield. Subsequent reaction of 1 with 1,10-phenantroline (phen) and 2,2′-bipyridine (bipy) gives the yellow crystalline products [Mn2(O2C-(CH2)2CO2)2(phen)2(H2O)4]·2H2O (2) and {[Mn(O2C(CH2)2CO2)(bipy)(H2O)2]·H2O}n (3), respectively. Complexes 2 and 3 have been structurally characterized. Complex 2 is a centrosymmetric dimeric complex in which the unique manganese(II) atom has distorted octahedral coordination geometry and is ligated by a chelating phenanthroline and two cisoid water molecules. A pair of butanedioic ligands bridge the two metals with each diacid using only one carboxylate oxygen from each end. Complex 3 consists of infinite zigzag chains of composition [Mn(O2C(CH2)2CO2)(bipy)H2O)2], in which pairs of symmetry-related manganese(II) atoms are bridged by butanedioic dianionic ligands, the carboxylate functions of which coordinate to the metals in a unidentate fashion. Each manganese atom has a distorted octahedral coordination geometry and is ligated by a chelating bipyridyl ligand, two cisoid water molecules and two cisoid carboxylate oxygen atoms from separate bridging butanedioic ligands. IR, magnetic and conductivity data for the complexes are given. Complexes 2 and 3 are significantly better catalysts than 1 for the disproportionation of H2O2 in the presence of added imidazole.

Synthesis and catalase activity of manganese(II) complexes of cis-5-norbornene-Endo-2,3-dicarboxylic acid (ndaH2): X-ray crystal structure of [Mn(η1η1-nda)(phen)2]·EtOH·H2O (phen = 1,10-phenantholine)

Abstract Manganese(II) chloride reacts with the sodium salt of cis-5-norbornene-endo-2,3-dicarboxylix acid (ndaH2) in aqueous media to give the manganese(II) complex [Mn (nda)H2O] (1). Complex 1 reacts with 1,10-phenanthroline (phen) to give the mononuclear manganese(II) adduct [Mn(η1η1-nda)(phen)2]·EtOH·H2O (2). The X-ray crystal structure of 2 shows the manganese atom at the centre of a distorted N4O2 octahedron comprising four nitrogen atoms from two chelating phen ligands, and two oxygen atoms, one from each of the two carbohylate functions of the nda−2 ligand. Spectroscopic and magnetic data for 1 and 2 are reported, together with their catalytic activity towards the disproportionation of H2O2.

Binuclear and polymeric manganese(II) salicylate complexes: synthesis, crystal structure and catalytic activity of [Mn2(Hsal)4(H2O)4] and [{Mn2(sal)2(Hsal)(H2O)-(H3O)(py)4·2py}n](H2sal = salicylic acid, py = pyridine)

The two air-stable manganese(II) salicylate complexes [Mn2(Hsal)4(H2O)4]1 and polymeric [{Mn2(sal)2(Hsal)(H2O)(H3O)(py)4·2py}n]2(H2sal = salicylic acid and py = pyridine) have been synthesised easily, and their crystal structures determined. Both contain unsymmetrically bridging salicylate ligands. In the presence of added pyridine 1 and 2 vigorously catalyse the disproportionation of H2O2.

Synthesis, X-ray crystal structure and catalytic activity of the manganese(II) E-urocanic acid (E-uroH) complex [Mn(E-uro)2(H2O)4]

Abstract Manganese(II) chloride tetrahydrate reacted with the sodium salt of E -urocanic acid ( E -uroH) in aqueous media giving the manganese(II) complex [Mn( E -uro) 2 (H 2 O) 4 ] in high yield. The X-ray crystal structure of the complex shows two distinct isomers of [Mn( E -uro) 2 (H 2 O) 4 ]. One isomer has the amine nitrogen atom of the imidazole ring lying in a cisoid orientation with respect to the carbon-carbon double bond which bears the pendant carboxylate group, whilst in the other isomer the same nitrogen atom is transoid to the double bond. Both species are centrosymmetric, so that the asymmetric unit comprises two independent half molecules. The geometry at manganese is approximately octahedral, with the metal coordinated by the imine nitrogen atoms from two urocanate anions trans to one another and also by four water molecules. Spectroscopic, magnetic and electrochemical data for the complex are given, together with its catalytic activity towards the disproportionation of H 2 O 2 .