Fluorinated Arylarsonate-Containing Polyoxomolybdates: pH-Dependent Formation of Mo vs Mo Species and Their Solution Properties.

We report on the synthesis and structural characterization of six novel arylarsonate-containing polyoxomolybdates with fluorinated-functionalities in the position of the phenyl ring. The reaction of the various arylarsonic acids, RAsOH [ = 4-F-CH (H), 4-FC-CH (H), 4-FCO-CH (H)] with NaMoO·2HO in aqueous pH 3 solution resulted in the heteropoly-6-molybdates [{(4-F-CH)As}MoO(HO)] (), [{(4-FC-CH)As}MoO] () and [{(4-FCO-CH)As}MoO(HO)] (), which were isolated as guanidinium salts. When the reaction was performed in aqueous pH 1 solution the inverted-Keggin type heteropoly-12-molydates [{(4-F-CH)As}MoO] (), [{(4-FC-CH)As}MoO] () and [{(4-FCO-CH)As}MoO] (), were obtained and isolated as sodium salts.

C-H bond activation at antimony(III): synthesis and reactivity of Sb(III)-oxyaryl species.

We report on the synthesis, structure and reactivity of [{NCN}Sb(CH-Bu-3,5-O-4)] (3), an organoantimony(III)-oxyaryl species obtained upon C-H bond activation in a phenolate ligand and stabilised by the monoanionic pincer {NCN}. The mechanism leading to the formation of 3 is highly sensitive to steric considerations. It was probed experimentally and by DFT calculations, and a number of intermediates and related complexes were identified.

Metal Complexes Containing Homoleptic Diorganoselenium(II) Ligands: Synthesis, Characterization and Investigation of Optical Properties.

[()-2'-{-CH-(4)-oxazol-5-one}CHCH]Se (, L) and [()-4'-{2-CH-(4)-oxazol-5-one}CHCH]Se (, L) were prepared, structurally characterized and used as ligands to obtain new metal complexes of types [MX(L)] [L: M = Ag, X = OTf (); M = Au, X = Cl (); L: M = Ag, X = OTf (); M = Au, X = Cl ()], [(MX)(L)] [M = Ag, X = OTf, L (); L ()], [ZnCl(L)] [L (); L ()] and [Ag(L)][PF] [L (); L ()]. The silver complexes and were ionic species (1:1 electrolytes) in a MeCN solution, while in the solid state, the triflate fragments were bonded to the silver cations. Similarly, the 2:1 complexes and were found to behave as 1:2 electrolytes in a MeCN solution, but single-crystal X-ray diffraction demonstrated that compound showed the formation of a dimer in the solid state: a tetranuclear [Ag(OTf)] built through bridging triflate ligands was coordinated by two bridging organoselenium ligands through the nitrogen from the oxazolone ring and the selenium atoms in a 1κN:2κSe fashion.

Mixed noble metal-oxo clusters: platinum(IV)-gold(III) oxoanion [PtAuO((CH)AsO)].

The first discrete mixed platinum(IV)-gold(III) oxoanion [PtAuO((CH)AsO)] (1) was synthesized by reaction of HPt(OH) with H[AuCl] in a simple one-pot procedure in aqueous solution at pH 7 and comprises two equivalent PtO(As(CH)) units which are linked by three square-planar AuO units. Polyanion 1 could be isolated as a potassium or sodium salt in good yield, which were structurally characterized in the solid state by single-crystal XRD and TGA, and in solution by multinuclear (H, C, Pt) NMR, indicating that polyanion 1 is stable in solution, which was confirmed by ESI-MS studies. The sodium salt of 1 undergoes a clean single-crystal-to-single-crystal (SCSC) structural transformation upon rehydration and dehydration.

Synthesis of Bis(amino acids) Containing the Styryl-cyclobutane Core by Photosensitized [2+2]-Cross-cycloaddition of Allylidene-5(4)-oxazolones.

The irradiation of 2-aryl-4-(-3'-aryl-allylidene)-5(4)-oxazolones with blue light (456 nm) in the presence of [Ru(bpy)](BF) (bpy = 2,2'-bipyridine, 5% mol) gives the unstable cyclobutane-bis(oxazolones) by [2+2]-photocycloaddition of two oxazolones . Each oxazolone contributes to the formation of with a different C=C bond, one of them reacting through the exocyclic C=C bond, while the other does so through the styryl group. Treatment of unstable cyclobutanes with NaOMe/MeOH produces the oxazolone ring opening reaction, affording stable styryl-cyclobutane bis(amino acids) .

Organopnictogen(III) bis(arylthiolates) containing NCN-aryl pincer ligands: from synthesis and characterization to reactivity.

Salt elimination reactions between organopnictogen(III) dichlorides, RPnCl [R = 2,6-(MeNCH)CH, Pn = Sb (1), Bi (2); R = 2,6-{MeN(CHCH)NCH}CH, Pn = Sb (3), Bi (4); R = 2,6-{O(CHCH)NCH}CH, Pn = Sb (5), Bi (6)] and 2 equivalents of KSCHMe-2,6 afforded the isolation of a series of new NCN-chelated monoorganopnictogen(III) bis(arylthiolates), RPn(SCHMe-2,6) [R, Pn = Sb (7), Bi (8); R, Pn = Sb (9), Bi (10); R, Pn = Sb (11), Bi (12)]. Compounds 7 and 8 are unstable upon exposure to a dry O atmosphere and their aerobic decomposition yields the monoorganopnictogen(III) oxides, -[2,6-(MeNCH)CHPn(μ-O)] [Pn = Sb (13), Bi (14)] with concomitant formation of the corresponding disulfide, ArS-SAr (Ar = CHMe-2,6). The oxidative addition of elemental sulfur or selenium to 7 undergoes a similar reaction path and gives stable heterocyclic species -[2,6-(MeNCH)CHSb(μ-E)] [E = S (15), Se (16)].

Stereoselective, Ruthenium-Photocatalyzed Synthesis of 1,2-Diaminotruxinic Bis-amino Acids from 4-Arylidene-5(4)-oxazolones.

The irradiation of ()-2-phenyl-4-aryliden-5(4)-oxazolones in deoxygenated CHCl at 25 °C with blue light (465 nm) in the presence of [Ru(bpy)](BF) (5% mole ratio) as a triplet photocatalyst promotes the [2+2] photocycloaddition of the C═C bonds of the 4-arylidene moiety, thus allowing the completely regio- and stereoselective formation of cyclobutane-bis(oxazolone)s as single stereoisomers. Cyclobutanes have been unambiguously characterized as the μ-isomers and contain two -oxazolones coupled in an -head-to-head form. The use of continuous-flow techniques in microreactors allows the synthesis of cyclobutanes in only 60 min, compared with the 24-48 h required in batch mode.

Reactivity of ()-4-Aryliden-5(4)-thiazolones: [2 + 2]-Photocycloaddition, Ring-Opening Reactions, and Influence of the Lewis Acid BF.

The irradiation of ()-2-phenyl-4-aryliden-5(4)-thiazolones with blue light (465 nm) in CHCl solution promotes [2 + 2]-photocycloaddition of the exocyclic C═C bonds and the formation of the dispirocyclobutanes . This reaction takes place with high stereoselectivity, given that the ε-isomer (1,3 head-to-tail syn coupling) is formed in more than 90% yield in most of the cases. However, irradiation of 5(4)-thiazolones with blue light (456 nm) in dry MeOH in the presence of BF·OEt leads to the monospirocyclobutanes with full stereoselectivity, also affording the ε-isomer.

Pd-Oxazolone complexes conjugated to an engineered enzyme: improving fluorescence and catalytic properties.

Different Pd-complexes containing orthometallated push-pull oxazolones were inserted by supramolecular Pd-amino acid coordination on two genetically engineered modified variants of the thermoalkalophilic Geobacillus thermocatenolatus lipase (GTL). Pd-lipase conjugation was performed on the solid phase in the previously immobilized form of GTL under mild conditions, and soluble conjugated Pd-GTL complexes were obtained by simply desorbing by washing with an acetonitrile aqueous solution. Three different Pd complexes were incorporated into two different genetically modified enzyme variants, one containing all the natural cysteine residues changed to serine residues, and another variant including an additional Cys mutation directly in the catalytic serine (Ser114Cys).

Fluorescent Orthopalladated Complexes of 4-Aryliden-5(4)-oxazolones from the Kaede Protein: Synthesis and Characterization.

The goal of the work reported here was to amplify the fluorescent properties of 4-aryliden-5(4)-oxazolones by suppression of the hula-twist non-radiative deactivation pathway. This aim was achieved by simultaneous bonding of a Pd center to the N atom of the heterocycle and the carbon of the arylidene ring. Two different 4-(()-arylidene)-2-(()-styryl)-5(4)-oxazolones, the structures of which are closely related to the chromophore of the Kaede protein and substituted at the 2- and 4-positions of the arylidene ring ( OMe; F), were used as starting materials.

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore.

The stereoselective synthesis of truxillic bis-amino esters from polyfunctional oxazolones is reported. The reaction of 4-(()-arylidene)-2-()-styryl-5(4)-oxazolones with Pd(OAc) resulted in -palladation and the formation of a dinuclear open-book complexes with carboxylate bridges, where the Pd atom is C^N bonded to the oxazolone. In the two exocyclic C=C bonds of the oxazolone are in a face-to-face arrangement, which is optimal for their [2 + 2] photocycloaddition.

Evaluation of bismuth-based dispersion energy donors - synthesis, structure and theoretical study of 2-biphenylbismuth(iii) derivatives.

A series of 2-biphenyl bismuth(iii) compounds of the type (2-PhCH)BiX [n = 0 (1); n = 1, X = Cl (2), Br (3), I (4), Me (5); n = 2, X = Cl (6), Br (7), I (8)] has been synthesized and analyzed with focus on intramolecular London dispersion interactions. The library of the compounds was set up in order to investigate the Biπ arene interaction by systematic variation of X. The structural analysis in the solid state revealed that the triarylbismuth(iii) compound 1 shows an encapsulation of the metal atom but the distances between the bismuth atom and the phenyl centroids amount to values close to or larger than 4.

Tetra-(-tolyl)antimony(III)-Containing Heteropolytungstates, [{(-tolyl)Sb}(-α-XWO)] (X = P, As, or Ge): Synthesis, Structure, and Study of Antibacterial and Antitumor Activity.

We have synthesized and structurally characterized three tetra-(-tolyl)antimony(III)-containing heteropolytungstates, [{(-tolyl)Sb}(-α-XWO)] [X = P (), As (), or Ge ()], in aqueous solution using conventional, one-pot procedures. The polyanions , , and were fully characterized in the solid state and in solution and were shown to be soluble and stable in aqueous medium at pH 7. Biological studies demonstrated that all three polyanions possess significant antibacterial and antitumor activities.

Lead(II) Siloxides.

Although Pb -siloxides have been known until now to decompose to oxoclusters, here [{RO }PbOSi(SiMe ) ] (RO =fluoroalkoxide) and, most importantly, [Pb {OSi(SiMe ) }{μ -OSi(SiMe ) } ], are presented. The unusual bonding pattern in the latter thermally stable dinuclear complex was investigated by crystallographic and computational methods. Its stability is much higher than that of the simple, yet elusive "[Pb(OSiPh ) ]", for which decomposition pathways towards [Pb (μ -O)(μ -OSiPh ) ] have been clearly established.

Aminofluoroalkoxide amido and boryloxo lead(ii) complexes.

We report here on the utilisation of a readily available bidentate aminofluoroalkoxide in lead(ii) chemistry. Stable heteroleptic three-coordinate complexes can be produced in high yields, including a convenient amido synthetic precursor and a rare case of Pb-boryloxide.

Novel mono- and bimetallic organotin(iv) compounds as potential linkers for coordination polymers.

The reaction of [2-(O[double bond, length as m-dash]CH)C6H4]Me2SnCl (2), obtained by the hydrolysis of [2-{(CH2O)2CH}C6H4]Me2SnCl (1), with the appropriate diamine, in a 2 : 1 molar ratio, in the absence of a solvent or catalyst, resulted in the bimetallic species ClSnMe2[2-C6H4(4-CH[double bond, length as m-dash]N-1,1'-C6H4C6H4-4'-N[double bond, length as m-dash]CH)-2'-C6H4]Me2SnCl (4) and ClSnMe2[2-C6H4(CH[double bond, length as m-dash]NCH2CH2N[double bond, length as m-dash]CH)-2'-C6H4]Me2SnCl (5). The reaction of 2 and 5 with KSCN gave the corresponding isothiocyanates [2-(O[double bond, length as m-dash]CH)C6H4]Me2Sn(NCS) (3) and (SCN)SnMe2[2-C6H4(CH[double bond, length as m-dash]NCH2CH2N[double bond, length as m-dash]CH)-2'-C6H4]Me2Sn(NCS) (6). Treating 3 with H2NCH2CH2NH2 also resulted in the corresponding bimetallic compound 6.

Stable lead(ii) boroxides.

The first examples of lead(ii) boroxides, [Pb(OB{CH(SiMe3)2}2)2] (1) and [{N^C}PbOB{CH(SiMe3)2}2] (5; N^C = 2-Me2NCH2C6H4), were prepared via simple protocols. These structurally characterised compounds are stable and, unlike lead(ii) alkoxides and siloxides, do not trigger uncontrolled formation of lead(ii) oxoclusters.

Triphenylbismuth(v) di[(iso)nicotinates] - transmetallation agents or divergent organometalloligands? First organobismuth(v)-based silver(i) coordination polymers.

The reaction of PhBiCl with alkali salts of isonicotinic and nicotinic acids afforded PhBi[O(O)CCHN-4] (1) and PhBi[O(O)CCHN-3] (2), respectively, which were characterized by multinuclear NMR spectroscopy in solution, mass spectrometry and IR spectroscopy in the solid state. Their molecular structures were established by single-crystal X-ray diffraction. For both 1 and 2 the molecules contain a trigonal bipyramidal CBiO core, with the phenyl groups in equatorial positions.

Tetra-Antimony(III)-Bridged 18-Tungsto-2-Arsenates(V), [(LSb(III))4(A-α-As(V)W9O34)2](10-) (L = Ph, OH): Turning Bioactivity On and Off by Ligand Substitution.

Two tetra-antimony(III)-bridged, sandwich-type 18-tungsto-2-arsenates(V), [(LSb(III))4(A-α-As(V)W9O34)2](10-) (L = Ph (1), OH (2)), were prepared and fully characterized in the solid state and in solution. Both polyanions are stable in aqueous physiological medium for at least 24 h (at concentrations ≥2.5 × 10(-6) M).

Mixed triorganobismuthines RAr2Bi [Ar = C6F5, 2,4,6-(C6F5)3C6H2] and hypervalent racemic Bi-chiral diorganobismuth(iii) bromides RArBiBr (Ar = C6F5, Mes, Ph) with the ligand R = 2-(Me2NCH2)C6H4. Influences of the organic substituent.

Triorganobismuthines R(C6F5)2Bi (1) and R[2,4,6-(C6F5)3C6H2]2Bi (2) [R = 2-(Me2NCH2)C6H4] were synthesized by reaction of RBiBr2 with C6F5MgBr and 2,4,6-(C6F5)3C6H2Li, respectively, in a 1 : 2 molar ratio. The Bi-chiral bromides R(C6F5)BiBr (3), R(Mes)BiBr (4), and R(Ph)BiBr (5) were obtained from RBiBr2 and C6F5MgBr, MesMgBr or PhMgBr, or from PhBiBr2 and RLi, in a 1 : 1 molar ratio. The molecular structures of 1-5 were determined by single-crystal X-ray diffraction and are discussed taking into account the chirality of the species.

19-Tungstodiarsenate(III) Functionalized by Organoantimony(III) Groups: Tuning the Structure-Bioactivity Relationship.

A family of three discrete organoantimony(III)-functionalized heteropolyanions-[Na{2-(Me2HN(+)CH2)C6H4Sb(III)}As(III)2W19O67(H2O)](10-) (1), [{2-(Me2HN(+)CH2)C6H4Sb(III)}2As(III)2W19O67(H2O)](8-) (2), and [{2-(Me2HN(+)CH2)C6H4Sb(III)}{WO2(H2O)}{WO(H2O)}2(B-β-As(III)W8O30)(B-α-As(III)W9O33)2](14-) (3)-have been prepared by one-pot reactions of the 19-tungstodiarsenate(III) precursor [As(III)2W19O67(H2O)](14-) with 2-(Me2NCH2)C6H4SbCl2. The three novel polyanions crystallized as the hydrated mixed-alkali salts Cs3KNa6[Na{2-(Me2HN(+)CH2)C6H4Sb(III)}As(III)2W19O67(H2O)]·43H2O (CsKNa-1), Rb2.5K5.

Ti2-Containing 18-Tungsto-2-Arsenate(III) Monolacunary Host and the Incorporation of a Phenylantimony(III) Guest.

The novel Ti2-containing, sandwich-type 18-tungsto-2-arsenate(III) [(Ti(IV)O)2(α-As(III)W9O33)2](14-) (1) was successfully synthesized by the reaction of [TiO](2+) species with [α-As(III)W9O33](9-). The monolacunary polyanion 1 is solution-stable, and a further reaction with 1 equiv of phenylantimony(III) dichloride resulted in [C6H5Sb(III)(Ti(IV)O)2(α-As(III)W9O33)2](12-) (2). Both polyanions 1 and 2 were structurally characterized in the solid state and solution.

Organoantimony(III)-Containing Tungstoarsenates(III): From Controlled Assembly to Biological Activity.

A family of three sandwich-type, phenylantimony(III)-containing tungstoarsenates(III), [(PhSb(III) ){Na(H2 O)}As(III) 2 W19 O67 (H2 O)](11-) (1), [(PhSb(III) )2 As(III) 2 W19 O67 (H2 O)](10-) (2), and [(PhSb(III) )3 (B-α-As(III) W9 O33 )2 ](12-) (3), have been synthesized by one-pot procedures and isolated as hydrated alkali metal salts, Cs3 K3.5 Na4.5 [(PhSb(III) ){Na(H2 O)}As(III) 2 W19 O67 (H2 O)]⋅41H2 O (CsKNa-1), Cs4.

A general route to monoorganopnicogen(III) (M = Sb, Bi) compounds with a pincer (N,C,N) group and oxo ligands.

The reaction of RMCl2 [R = 2,6-[MeN(CH2CH2)2NCH2]2C6H3; M = Sb (1), Bi (2)] with KOH affords the isolation of the oxides cyclo-R2M2O2 [M = Sb (3), Bi (4)]. Treatment of 3 with trifluoroacetic acid produced an ionic species (5) with a dinuclear cation that contains organic ligands protonated partially at one of the pendant arms. The cyclic oxides 3 and 4 are able to trap gaseous CO2 to give “RMCO3” [M = Sb (6), Bi (7)], the degree of these organometallic carbonates’ oligomerization being under investigation.

Organoselenium(II) halides containing the pincer 2,6-(Me2NCH2)2C6H3 ligand--an experimental and theoretical investigation.

New organoselenium(II) halides of the type [RSe](+)X(-) [R = 2,6-(Me2NCH2)2C6H3; X = Cl (2), Br (3), I (4)] were prepared by cleavage of the Se-Se bond in R2Se2 (1) with SO2Cl2 followed by halogen exchange when organoselenium chloride was treated with NaBr or KI. The reaction between 2 and R'2MCln resulted in new ionic [RSe](+)[R'2MCl(n+1)](-) [R' = 2-(Me2NCH2)C6H4, n = 1, M = Sb (5), Bi (6); R' = Ph, M = Sb, n = 1 (7) or n = 3 (8)] species. All new compounds were investigated in solution by multinuclear NMR spectroscopy ((1)H, (13)C, (77)Se, 2D experiments) and mass spectrometry.