Michael T. Casey

Syntheses and X-ray crystal structures of cis-[Mn(bipy)2Cl2] · 2H2O · EtOH and cis-[Mn(phen)2Cl2] (bipy = 2,2′-bipyridine; phen = 1,10-phenanthroline); catalysts for the disproportionation of hydrogen peroxide

Abstract MnCl 2 ·4H 2 O reacts with 2,2′-bipyridine (bipy) to give cis -[Mn(bipy) 2 Cl 2 ] ( 1 ), and recrystallisation of 1 from ethanol gives cis -[Mn(bipy) 2 Cl 2 ]·2H 2 O·EtOH ( 2 ). MnCl 2 ·4H 2 O and 1,10-phenanthroline (phen react to form cis -[Mn(phen) 2 Cl 2 ] ( 3 ). In each case, the X-ray crystal structures of 2 and 3 show the manganese(II) atom to have a similar distorted octahedral geometry, and in both cases there is extended π-π stacking of the conjugated ring systems. Compared with MnCl 2 ·4H 2 O, 1 and 3 are much more efficient catalysts for the disproportionation of hydrogen peroxide. The catalytically active species are believed to be [Mn(bipy) 2 (H 2 O) 2 ] 2+ and [Mn(phen) 2 (H 2 O) 2 ] 2+ , respectively.

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 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.

PREPARATION AND CATALASE-TYPE ACTIVITY OF MANGANESE(II) AMINO ACID COMPLEXES

Abstract Manganese(II) complexes of the amino acids l -leucine, glycine, l -valine, l -glutamine, l -threonine, l -tryptophan, l -phenylalanine, l -methionine, l -aspartic acid and l -glutamic acid have been prepared. The complexes have metal: acid ratios of 1:2. Spectroscopic, magnetic and physical data for the complexes are presented. All of the manganese complexes catalytically disproportionate hydrogen peroxide in the presence of imidazole.

Reaction of 1,1′-diacetylferrocene with hydrazine hydrate: Synthesis and X-ray crystal structures of bis(hydrazine)bis(hydrazinecarboxylato-N′,O)iron(II), [Fe(N2H4)2(O2CNHNH2)2], and the cyclic biferrocene diazine, [N(Me)CC5H4FeC5H4C(Me)N]2

1,1′-Diacetylferrocene reacts with neat hydrate over a period of 72 h at 20°C to give the dihydrazone [H2NN(Me)CC5H4FeC5H4C(Me)NNH2] (6) in almost quantitative yield. Either prolonging the reaction time or reacting 6 with fresh hydrazine causes the iron to be stripped from the metallocene and bis(hydrazine)bis(hydrazinecarboxylato-N′,O) iron(II), [Fe(N2H4)2(OOCNHNH2)2] (11), crystallizes. In the presence of Ba2+ or Mo2+ ions two molecules of complex 6 react to give the cyclic diazine [N(Me)CC5H4FeC5H4C (Me)N]2 (7) in high yield. Hydrazine is liberated in this reaction. Complexes 6 and 11 have been characterized crystallographically. The cyclic voltammograms of complexes 6 and 7 contain essentially non-reversible oxidation peaks.

Manganese(II) complexes of 3,6,9-trioxaundecanedioic acid (3,6,9-tddaH2): X-ray crystal structures of [Mn(3,6,9-tdda) (H2O)2]·2H2O and {[Mn(3,6,9-tdda)(phen)2·3H2O]·EtOH}n

Abstract 3,6,9-trioxaundecanedioic acid (3,6,9-tddaH2) reacts with Mn(CH3CO2)2·4H2O in ethanol to give [Mn(3,6,9-tdda)]·H2O (1). Recrystallization of 1 from methanol gives crystals of [Mn(3,6,9-tdda) (H2O)2]·2H2O (2). Complex 1 reacts with an ethanolic solution of 1,10-phenanthroline (phen) to give {[Mn(3,6,9-tdda)(phen)2]·3H2O·EtOH}n (3). All of the complexes are extremely water soluble. Complexes 2 and 3 were structurally characterised. The manganese(II) ion in 2 is seven coordinate, with an approximately pentagonal bipyramidal O7 coordination sphere. The axial donors are water molecules and the pentagonal plane is occupied by the diacid, acting as a pentadentate ligand through the three ethereal oxygens and one oxygen atom from each of the carboxylate functions. In complex 3 the manganese(II) ion is six-coordinate, being bound to two bidentate phenanthroline ligands and to the carboxylate oxygen atoms from two symmetry related diacids which are coordinated in a cis fashion. The structure consists of polymeric chains, with diacid ligands bridging the manganese ions. There is π-π stacking of pairs of phenanthroline ligands on adjacent chains, running along both the z and y directions.