Redox-active ligands - a viable route to reactive main group metal compounds.

Anionic redox-active ligands such as -amidophenolates, catecholates, dithiolenes, 1,2-benzendithiolates, 2-amidobenzenethiolates, reduced α-diimines, ferrocenyl and porphyrinates are capable of reversible oxidation and thus have the ability to act as sources of electrons for metal centres. These and other non-innocent ligands have been employed in coordination complexes of base transition metals to influence their redox chemistry and afford compounds with useful catalytic, optical, magnetic and conducting properties. Despite the focus in contemporary main group chemistry on designing reactive compounds with potential catalytic activity, comparatively few studies exploring the chemistry of main group metal complexes incorporating redox-active ligands have been reported.

Synthesis and crystal structure of bis-(μ-2-methyl-benzene-thiol-ato-κ:)bis-[meth-yl(2-methyl-benzene-thiol-ato-κ)indium(III)].

The dinuclear title compound, [In(CH)(CHS)] or [Me(2-MeCHS)In-μ-(2-MeCHS)InMe(2-MeCHS)], was prepared from the 1:2 reaction of MeIn and 2-MeCHSH in toluene. Its crystal structure exhibits a four-membered InS ring core bridging (2-MeCHS) groups. The dimeric units are further associated into a one-dimensional polymeric structure extending parallel to the axis inter-molecular In⋯S contacts.

Crystal structure of dimethyl-1κ(2) C-bis(μ-4-methylphenolato-1:2κ(2) O:O)(N,N,N',N'-tetramethylethylenediamine-2κ(2) N,N')indium(III)lithium(I).

The mixed bimetallic title compound, [InLi(CH3)2(C7H7O)2(C6H16N2)] or [(tmeda)Li-μ-(4-MeC6H4O)2InMe2] (tmeda is N,N,N',N'-tetra-methyl-ethylenedi-amine), exhibits a four-membered LiO2In ring core via bridging 4-methyl-phenolate groups. The Li and In atoms are in distorted tetra-hedral N2O2 and C2O2 bonding environments, respectively. The Li atom is further chelated by a tmeda group, yielding a spiro-cyclic structure.

catena-Poly[bis-[dimeth-yl(pyridine-κN)indium(III)]-μ4-benzene-1,3-diolato-bis-[di-methyl-indium(III)]-μ4-benzene-1,3-diolato].

The title compound, [In2(CH3)4(C6H4O2)(C5H5N)] or [{(CH3)2In}(1,3-O2C6H4){In(CH3)2(py)}] n , (py = pyridine) contains two crystallographically unique In(III) ions which are in distorted tetra-hedral C2O2 and distorted trigonal-bipyramidal C2O2N coordination environments. The In(III) coordination centers are bridged head-to-head via In-O bonds, yielding four-membered In2O2 rings and zigzag polymeric chains along [001].

Structural variation in ethylenediamine and -diphosphine adducts of (2,6-Me2C6H3S)2Pb: a single crystal X-ray diffraction and 207Pb solid-state NMR spectroscopy study.

Coordination complexes of (2,6-Me2C6H3S)2Pb (1) with flexible bidentate ligands have been prepared to explore new bonding environments for Pb(II) thiolates. The reaction of 1 with a series of ethylenediamine and ethylenediphosphine ligands resulted in isolation of the adducts [(2,6-Me2C6H3S)2Pb]2(tmeda) (9), [(2,6-Me2C6H3S)2Pb]3(dmpe) (10) and [(2,6-Me2C6H3S)2Pb]2(dppe) (11) [tmeda = N,N,N',N'-tetramethylethylenediamine; dmpe = bis(dimethylphosphino)ethane; dppe = bis(diphenylphosphino)ethane]. The X-ray crystal structure of 9 shows a dinuclear species in which tmeda is chelating a ψ-trigonal bipyramidal S2N2 Pb centre via axial and equatorial sites.

Bis(μ-diethyl-phosphido-κP:P)bis-[bis(2,4,6-trimethyl-phen-yl)indium(III)].

The title compound, [In(2)(C(9)H(11))(4)(C(4)H(10)P)(2)], contains a centrosymmetric In(2)P(2) core with short inter-molecular In-P bonds. This core has acute P-In-P and obtuse In-P-In bond angles compared with other [R(2)InPR'(2)](2) analogues, due to the presence of the bulky aromatic substituents on the In atom and the non-sterically demanding ethyl substituents on the P atom.

catena-Poly[[bis(pyridine)-lead(II)]bis(μ-penta-fluoro-benzene-thiol-ato)].

The title compound, [Pb(C(6)F(5)S)(2)(C(5)H(5)N)(2)](n), shows the Pb(II) atom in a ψ-trigonal bipyramidal S(2)N(2) bonding environment. Pyridine N atoms occupy axial sites, while thiol-ate S atoms and a stereochemically active lone pair occupy equatorial sites. Very long inter-molecular Pb⋯S inter-actions [3.

Rationalizing oligomerization in dimethylindium(III) chalcogenolates (Me2InER') (E = O, S, Se): a structural and computational study.

The effect on oligomerization of increased steric bulk in dimethylindium(III) chalcogenolates (Me(2)InER') (E = O, S, Se) has been examined. The facile reaction of Me(3)In with a series of phenols, thiophenols and selenophenols afforded the compounds [Me(2)InO(C(6)H(5))](2) (1), [Me(2)InO(2,6-Me(2)C(6)H(3))](2) (2), Me(2)InO(2,4,6-tBu(3)C(6)H(3)) (3), [Me(2)InS(C(6)H(5))](infinity) (4), [Me(2)InS(2,4,6-tBu(3)C(6)H(3))](infinity) (6), [Me(2)InSe(C(6)H(5))](2) (7), [Me(2)InSe(2,4,6-Me(3)C(6)H(3))](infinity) (8) and [Me(2)InSe(2,4,6-tBu(3)C(6)H(3))](infinity) (9). All compounds have been characterized by elemental analysis, melting point, FT-IR, FT-Raman, solution NMR, and X-ray crystallography.

Probing lead(II) bonding environments in 4-substituted pyridine adducts of (2,6-Me2C6H3S)2Pb: an X-ray structural and solid-state 207Pb NMR study.

The effect of subtle changes in the sigma-electron donor ability of 4-substituted pyridine ligands on the lead(II) coordination environment of (2,6-Me(2)C(6)H(3)S)(2)Pb (1) adducts has been examined. The reaction of 1 with a series of 4-substituted pyridines in toluene or dichloromethane results in the formation of 1:1 complexes [(2,6-Me(2)C(6)H(3)S)(2)Pb(pyCOH)](2) (3), [(2,6-Me(2)C(6)H(3)S)(2)Pb(pyOMe)](2) (4), and (2,6-Me(2)C(6)H(3)S)(2)Pb(pyNMe(2)) (5) (pyCOH = 4-pyridinecarboxaldehyde; pyOMe = 4-methoxypyridine; pyNMe2 = 4-dimethylaminopyridine), all of which have been structurally characterized by X-ray crystallography. The structures of 3 and 4 are dimeric and have psi-trigonal bipyramidal S(3)N bonding environments, with the 4-substituted pyridine nitrogen and bridging sulfur atoms in axial positions and two thiolate sulfur atoms in equatorial sites.

Preferred bonding motif for indium aminoethanethiolate complexes: structural characterization of (Me2NCH2CH2S)2InX/SR (X = Cl, I; R = 4-MeC6H4, 4-MeOC6H4).

The metathesis reaction of InCl3 with Me2NCH2CH2SNa or the redox reaction of indium metal with elemental iodine and the disulfide (Me2NCH2CH2S)2 yield the indium bis(thiolate) complexes (Me2NCH2CH2S)2InX [X = Cl (3) and I (4)], respectively. Compounds 3 and 4 may be further reacted with the appropriate sodium thiolate salts to afford the heteroleptic tris(thiolate) complexes (Me2NCH2CH2S)2InSR [R = 4-MeC6H4 (5), 4-MeOC6H4 (6), and Pr (7)]. Reaction of 2,6-Me2C6H3SNa with 4 affords (Me2NCH2CH2S)2InS(2,6-Me2C6H3) (8), while no reaction is observed with 3, suggesting a greater reactivity for 4.

Substituent effects on indium-phosphorus bonding in (4-RC6H4S)3In.PR'3 adducts (R = H, Me, F; R' = Et, Cy, Ph): a spectroscopic, structural, and thermal decomposition study.

The tris(arylthiolate)indium(III) complexes (4-RC(6)H(4)S)(3)In [R = H (5), Me (6), F (7)] were prepared from the 2:3 reaction of elemental indium and the corresponding aryl disulfide in methanol. Reaction of 5-7 with 2 equiv of the appropriate triorganylphosphine in benzene or toluene resulted in isolation of the indium-phosphine adduct series (4-RC(6)H(4)S)(3)In.PR'(3) [R = H, R' = Et (5a), Cy (5b), Ph (5c); R = Me, R' = Et (6a), Cy (6b), Ph (6c); R = F, R' = Et (7a), Cy (7b), Ph (7c)].

Monomeric, one- and two-dimensional networks incorporating (2,6-Me2C6H3S)2Pb building blocks.

The amine coordination of lead(II) has been examined through the preparation and structural analysis of Lewis base adducts of bis(thiolato)lead(II) complexes. Reaction of Pb(OAc)(2) with 2,6-dimethylbenzenethiol affords (2,6-Me(2)C(6)H(3)S)(2)Pb (6) in high yield. The solubility of 6 in organic solvents allows for the preparation of the 1:2 Lewis acid-base adduct [(2,6-Me(2)C(6)H(3)S)(2)Pb(py)(2)](7), and 1:1 adducts [(2,6-Me(2)C(6)H(3)S)(2)Pb(micro(2)-bipy)](infinity](8) and [(2,6-Me(2)C(6)H(3)S)(2)Pb(micro(2)-pyr)](infinity)(9)(where py = pyridine, bipy = 4,4'-bipyridyl and pyr = pyrazine) from reaction with an excess of the appropriate amine.

Identification, isolation, and characterization of cysteinate and thiolactate complexes of bismuth.

Although bismuth compounds have been used in medicine for over 200 years, chemical characterization of complexes involving biological molecules is minimal and mechanisms of bioactivity are ill-defined. The thiophilic nature of bismuth implicates sulfur centers as likely sites for interaction, and we have exploited this feature to identify, isolate, and characterize complexes of bismuth with thiolate-carboxylate bifunctional ligands including the amino acid l-cysteine. The solid-state structures of potassium dichloro(thiopropionato)bismuth (K[1d]), dimethylaminoethanethiolato(thiopropionato)bismuth (4), and dinitrato(cysteinato)bismuthphenanthroline [5(phen)] are compared with data from electrospray ionization mass spectrometry (ESI-MS).

Synthesis and structures of the first bismuth-ester complexes using heterobifunctional thiolate anchored ligands and mass spectrometric identification of ligand-bridged derivatives.

The first systematic series of bismuth complexes involving ester donors, Bi(SCH(2)C(O)OCH(2)CH(3))Cl(2), Bi(SCH(2)C(O)OCH(3))(2)Cl, and Bi(SCH(2)COOCH(3))(3), has been isolated and characterized by spectroscopic (IR, Raman) and X-ray crystallographic data. In addition, these and other species have been identified by electron-impact, electrospray, and atmospheric pressure chemical ionization mass spectometry. The generally applicable synthetic methodology involves the use of heterobifunctional ligands containing a thiolate moiety as an anchor to facilitate coordinate interactions between weak donors (carbonyls) and weak acids (bismuth).

Experimental and theoretical investigations of lithium and magnesium derivatives of bis(tert-butylamido)cyclodiphosph(III/V)- and (V/V)azane mono- and ditellurides.

Deprotonation of bis(tert-butylamido)cyclophosph(III/III)azane with organolithium or organomagnesium reagents followed by oxidation with elemental tellurium is a viable approach to the preparation of metal cyclodiphosphazane mono- and ditellurides. The reaction of the cyclodiphosph(III)azane [tBu(H)NP(mu-NtBu)2PN(H)tBu] (1) with elemental tellurium in boiling toluene affords the monotelluride [tBu(H)N(Te)P(mu-NtBu)2PN(H)tBu] (9). A similar reaction involving the magnesium salt Mg[tBuNP(mu-NtBu)2PNtBu](THF)2 (2) also yields a monotelluride Mg[tBuN(Te)P(mu-NtBu)2PNtBu]-(THF)2 (10).

Synthesis and X-ray structures of dilithium complexes of the phosphonate anions [PhP(E)(N(t)Bu)(2)](2-) (E = O, S, Se, Te) and dimethylaluminum derivatives of [PhP(E)(N(t)Bu)(NH(t)Bu)](-) (E = S, Se).

The dilithium salts of the phosphonate dianions [PhP(E)(N(t)Bu)(2)](2-) (E = O, S, Se) are generated by the lithiation of [PhP(E)(NH(t)Bu)(2)] with n-butyllithium. The formation of the corresponding telluride (E = Te) is achieved by oxidation of [Li(2)[PhP(N(t)Bu)(2)]] with tellurium. X-ray structural determinations revealed dimeric structures [Li(THF)(2)[PhP(E)(N(t)Bu)(2)]](2) in which the monomeric units are linked by Li-E bonds.

Redox chemistry of tellurium bis(tert-butylamido)cyclodiphosph(V)azane disulfide and diselenide systems: a spectroscopic and structural study.

The redox chemistry of tellurium-chalcogenide systems is examined via reactions of tellurium(IV) tetrachloride with Li[(t)()BuN(E)P(mu-N(t)Bu)(2)P(E)N(H)(t)Bu] (3a, E = S; 3b, E = Se). Reaction of TeCl(4) with 2 equiv of 3a in THF generates the tellurium(IV) species TeCl(3)[HcddS(2)][H(2)cddS(2)] 4a [cddS(2) = (t)BuN(S)P(mu-N(t)Bu)(2)P(S)N(t)Bu] at short reaction times, while reduction to the tellurium(II) complex TeCl(2)[H(2)cddS(2)](2) 5a is observed at longer reaction times. The analogous reaction of TeCl(4) and 3b yields only the tellurium(II) complex TeCl(2)[H(2)cddSe(2)](2) 5b.

The Structurally Flexible Bicyclic Bis(2-hydroxyethanethiolato)bismuth(III) Complex: A Model for Asymmetric Monoanionic Chelation of Bismuth(III).

Reaction of Bi(NO(3))(3) with 2-mercaptoethanol gives [Bi(SCH(2)CH(2)OH)(2)][NO(3)], 5(NO(3)), independent of stoichiometry. Other salts or derivatives of 5, 5(Cl) and 5(Br), are readily prepared by anion exchange reactions and can also be obtained by reaction of BiX(3) (X = Cl, Br) with 2-mercaptoethanol. Reaction of Bi(CH(3)COO)(3) with 2-mercaptoethanol gives the conjugate base of 5 which is readily protonated with glacial acetic acid to give the acetate salt 5(CH(3)COO).