Synthesis and stereochemistry of mono-, bi-, and tetranuclear manganese thiolates

Abstract

The first systematic investigation of Mn-thiolate complexes is described. Anaerobic reaction of MnCl2 with 2.5 equiv of NaSPh in methanol affords [Mn4(SPh)10]1 2". The compound (Me4N)2[Mn4(SPh)10] crystallizes in triclinic space group PI with a = 13.184 (3) A, b = 23.743 (4) A, c = 12.930 (3) A, a = 91.63 (2)°, ß = 113.76 (1)°, y = 79.53 (2)°, and Z = 2. The structure was refined to R (Pw) = 4.5% (4.8%) with use of 5787 unique data (I > 3 (/)). The anion contains an adamantane-like 4(µ-8)6 cage composed of a nearly regular Mn4 tetrahedron and an irregularly distorted S6 octahedron and exhibits terminal and bridging Mn-S mean distances of 2.376 (7) and 2.46 (2) Á, respectively. Selected structural features are compared with those of five other 4(µ-8)6 cages. Anaerobic reaction of MnCl2 with 2 equiv of Na2(l,2-S2C2H4) in methanol forms extremely oxygen-sensitive [Mn(S2C2H4)2]2~. The compound (Me4N)2[Mn(S2C2H4)2]-MeCN crystallizes in monoclinic space group P2\/n with a = 9.833 (5) A, b = 17.325 (7) A, c = 13.819 (6) A, ß = 93.43 (2)°, and Z = 4. The structure was refined to R (Pw) = 4.4% (4.5%) with use of 1893 unique data (I > 3 (/)). The anion is tetrahedral with mean dimensions Mn-S = 2.432 (7) Á, chelate ring zS-Mn-S = 91.5°, and a 92.3°dihedral angle between MnS2 planes. Exposure of a solution of [Mn(S2C2H4)2]2~t o air results in the immediate formation of a dark green color and thereafter isolation of salts of [Mn2(S2C2H4)4]2'. (Et4N)2[Mn2(S2C2H4)4] crystallizes in monoclinic space group P2Jn with a = 12.039 (4) A, b = 10.699 (2) A, c = 15.012 (3) X, ß = 110.89 (2)°, and Z = 2. The structure was refined to R (R") = 4.4% (4.9%) with use of 2175 unique data (/ > 3 (/)). The centrosymmetric anion exhibits the lateral dimer structure in which bis chelate monomers are joined by two Mn-S bonds of length 2.632 (2) Á. The two Mn-Ss coordination units approach a trigonal-bipyramidal arrangement and are separated by a Mn-Mn distance of 3.596 (3) Á. [Mn2(S2C2H4)4]2™ is the first characterized Mn(III) thiolate. A compilation of the limited set of all known Mn-S bond distances is provided.[Mn(S2C2H4)2]2-and [Mn4(SPh)10]2" contain tetrahedral Mn(II) sites; [Mn(S2C2H4)2]2" remains tetrahedral and high spin in acetonitrile and DMF solutions. Magnetic and spectral properties of solutions prepared from [Mn2(S2C2H4)4]2ĩ ndicate that the dimer partially (acetonitrile) or completely (Me2SO, DMF) dissociates in solution to form monomeric [Mn(S2C2H4)2(solv)2]_. Cyclic voltammetry of these species are in accord with an E¡C¡ mechanism, in which the initial reduction product, [Mn(S2C2H4)2(solv)2]2~, rapidly and irreversibly converts to [Mn(S2C2H4)2]2~. This species is irreversibly oxidized to [Mn(S2C2H4)2(solv)2]~a t less cathodic potentials. The large £ values (0.52 V (acetonitrile), 0.76 V (DMF)) are consistent with different electroactive orbitals of [Mn(S2C2H4)2]2~a nd [Mn(S2C2H4)2(solv)2]~required by tetrahedral and six-coordinate structures, respectively. Spectral evidence is presented for Mn(III) species of the type [Mn(S2C2H...

Sulfur K-edge extended X-ray absorption fine structure spectroscopy of homoleptic thiolato complexes with Zn(II) and Cd(II)

“…The M 4 X 10 complexes containing adamantane-like cages have been reported for many metal ions and ligands. For example, the structures of [(l-SPh) 6 (MSPh) 4 ] 2À (M = Mn(II), Fe(II), and Co(II)) have been determined [32][33][34][35][36]. For Zn(II) and Cd(II) ions, the structures of [(l-SPh) 6 (MSPh) 4 ] 2À type complexes have been studied well as good structural models of metallothionein [37][38][39], including [M 4 (o-SC 6 H 4 CH 3 ) 10 ] 2À (M = Zn(II) and Cd(II)) [40], and [Zn 4 (SePh) 10 ] 2À [41].…”

Metal-selenolate chemistry: stereochemistry of adamantane-type clusters of formula [(μ-SePh)6(MSePh)4]2− (M = Zn and Cd)

“…Before use, solvents were dried over 3 A Molec-20 such compounds have been characterized by X-ray ular Sieves and sparged with Ar(g). The salt (Me4N),[Cd4(SePh),o], structure analyses (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). By contrast, the structural chem-3, was synthesized as reported earlier (22), istry of analogous metal-selenolates is essentially undeveloped.…”

Synthesis, Structure and Magnetic Behaviour of Manganese(II) Selenolate Complexes ∞1[Mn(SePh)2], [Mn(SePh)2(bipy)2] and [Mn(SePh)2(phen)2] (bipy = bipyridyl, phen = phenanthroline)

“…[6,7] Manganese, for example, plays a role as a dopant for 12-16 semiconductor films and nanocrystals, referred to as dilute magnetic semiconductors (DMS), [8,9] as well as in some manganese-oxido cluster complexes such as [Mn 12 O 12 (O 2 CCH 3 ) 16 ] [10] and [Mn 84 O 72 (O 2 CMe) 78 -(OMe) 24 (MeOH) 12 (H 2 O) 42 (OH) 6 ], [11] which are known as single-molecule magnets (SMMs). With respect to manganese chalcogenolato complexes, two synthetic approaches have been widely used.…”

“…With respect to manganese chalcogenolato complexes, two synthetic approaches have been widely used. The reaction of a manganese(II) halide with NaEPh (E = S, Se, Te) in the presence of quarternary ammonium or phosphonium salts yields anionic monomeric and oligomeric complexes {for example, [Mn(EPh) 4 ] 2-(E = S, Se, Te), [12,13] [Mn 2 (SPh) 6 ] 2- [14] and [Mn 4 (SPh) 10 ] 2- [12] }. In contrast, a few neutral complexes containing bulky organic groups, such as [Mn{N(SiMe 3 ) 2 }-(µ-SeC 6 H 2 -2,4,6-iPr 3 )(THF)], [15] [Mn(SeMes*) 2 C 4 H 8 O] (Mes* = C 6 H 2 -2,4,6-tBu 3 ), [Mn(SeC 6 H 3 -2,6-Mes 2 ) 2 ] (Mes = C 6 H 2 -2,4,6-Me 3 ) [16] and ϱ 1 [Mn(SeC 6 H 2 -2,4,6-CH 3 ) 2 ], [17] have been synthesised by reaction of [Mn{N(SiMe 3 ) 2 } 2 ] with the corresponding selenol RSeH (R = organic group).…”