Influences of approaching tropical cyclones on water vapor and aerosols in the atmospheric boundary layer of Guangdong-Hong Kong-Macau Greater Bay Area of China

The outer circulation of tropical cyclones (TCs) on the western North Pacific has been reported to substantially influence the atmospheric environment over the Guangdong-Hong Kong-Macau Greater Bay Area (GBA) of China, whereas dynamic evolution and redistribution of water vapor and aerosol in the atmospheric boundary layer (ABL) responding to moving TCs have yet to be understood. This study aims to answer three key research questions related to the influences of the approaching TCs: (1) how do water vapor and aerosol particles over the GBA change during the TC approaching stage? (2) how does the ABL in terms of vertical wind structure respond to the approaching TCs? and (3) how does turbulence influence the vertical profile of aerosol during the approaching stage? Based on an intensive analysis of three-year reanalysis and Doppler LiDAR data, this study identified a dry-polluted time over the GBA when a TC was located at ~1000 km away on South China Sea. Before that, horizontal wind has consistently come from the northeast, creating a favorable condition for weak transboundary air pollution to the GBA. During the dry-polluted time, the highest surface PM_2.5 concentration was resulted from the enhanced downdraft and early-stage wind shear, i.e., stronger wind started occurring at upper-level ABL, while the further turbulent mixing induced by wind shear enhancement and updrafts recovery pumped surface pollution upward to the upper level when TCs became closer. Our findings are expected to improve both weather and PM_2.5 forecasts under the impacts of approaching TCs.

Assessment of SARS-CoV-2 Immunity in Convalescent Children and Adolescents

Persistence of protective immunity for SARS-CoV-2 is important against reinfection. Knowledge on SARS-CoV-2 immunity in pediatric patients is currently lacking. We opted to assess the SARS-CoV-2 adaptive immunity in recovered children and adolescents, addressing the pediatrics specific immunity towards COVID-19. Two independent assays were performed to investigate humoral and cellular immunological memory in pediatric convalescent COVID-19 patients. Specifically, RBD IgG, CD4+, and CD8+ T cell responses were identified and quantified in recovered children and adolescents. SARS-CoV-2-specific RBD IgG detected in recovered patients had a half-life of 121.6 days and estimated duration of 7.9 months compared with baseline levels in controls. The specific T cell response was shown to be independent of days after diagnosis. Both CD4+ and CD8+ T cells showed robust responses not only to spike (S) peptides (a main target of vaccine platforms) but were also similarly activated when stimulated by membrane (M) and nuclear (N) peptides. Importantly, we found the differences in the adaptive responses were correlated with the age of the recovered patients. The CD4+ T cell response to SARS-CoV-2 S peptide in children aged <12 years correlated with higher SARS-CoV-2 RBD IgG levels, suggesting the importance of a T cell-dependent humoral response in younger children under 12 years. Both cellular and humoral immunity against SARS-CoV-2 infections can be induced in pediatric patients. Our important findings provide fundamental knowledge on the immune memory responses to SARS-CoV-2 in recovered pediatric patients.

Synthesis, structure and reactivity of iridium complexes containing a bis-cyclometalated tridentate C^N^C ligand

In an effort to synthesize cyclometalated iridium complexes containing a tridentate C^N^C ligand, transmetallation of [Hg(HC^N^C)Cl] (1) (H2C^N^C = 2,6-bis(4-tert-butylphenyl)pyridine) with various organoiridium starting materials has been studied. The treatment of 1 with [Ir(cod)Cl]2 (cod = 1,5-cyclooctadiene) in acetonitrile at room temperature afforded a hexanuclear Ir4Hg2 complex, [Cl(κ2C,N-HC^N^C)(cod)IrHgIr(cod)Cl2]2 (2), which features Ir-Hg-Ir and Ir-Cl-Ir bridges. Refluxing 2 with sodium acetate in tetrahydrofuran (thf) resulted in cyclometalation of the bidentate HC^N^C ligand and formation of trinuclear [(C^N^C)(cod)IrHgIr(cod)Cl2] (3). On the other hand, refluxing [Ir(cod)Cl]2 with 1 and sodium acetate in thf yielded [Ir(C^N^C)(cod)(HgCl)] (4). Chlorination of 4 with PhICl2 gave [Ir(C^N^C)(cod)Cl]·HgCl2 (5·HgCl2) that reacted with tricyclohexylphosphine to yield Hg-free [Ir(C^N^C)(cod)Cl] (5). Chloride abstraction of 5 with silver(i) triflate (AgOTf) gave [Ir(C^N^C)(cod)(H2O)](OTf) (6) that can catalyze the cyclopropanation of styrene with ethyl diazoacetate. Reaction of 1 and [Ir(CO)2Cl(py)] (py = pyridine) with sodium acetate in refluxing thf afforded [Ir(C^N^C)(HgCl)(py)(CO)] (7), in which the carbonyl ligand is coplanar with the C^N^C ligand. On the other hand, refluxing 1 with (PPh4)[Ir(CO)2Cl2] and sodium acetate in acetonitrile gave [Ir(C^N^C)(κ2C,N-HC^N^C)(CO)] (8), the carbonyl ligand of which is trans to the pyridyl ring of the bidentate HC^N^C ligand. Upon irradiation with UV light 8 in thf was isomerized to 8', in which the carbonyl is trans to a phenyl group of the bidentate HC^N^C ligand. The isomer pair 8 and 8' exhibited emission at 548 and 514 nm in EtOH/MeOH at 77 K with lifetime of 84.0 and 64.6 μs, respectively. Protonation of 8 with p-toluenesulfonic acid (TsOH) afforded the bis(bidentate) tosylate complex [Ir(κ2C,N-HC^N^C)2(CO)(OTs)] (9) that could be reconverted to 8 upon treatment with sodium acetate. The electrochemistry of the Ir(C^N^C) complexes has been studied using cyclic voltammetry. Reaction of [Ir(PPh3)3Cl] with 1 and sodium acetate in refluxing thf led to isolation of the previously reported compound [Ir(κ2P,C-C6H4PPh2)2(PPh3)Cl] (10). The crystal structures of 2-5, 8, 8', 9 and 10 have been determined.

Oxidizing Cerium(IV) Alkoxide Complexes Supported by the Kläui Ligand [Co(η5-C5H5){P(O)(OEt)2}3]-: Synthesis, Structure, and Redox Reactivity

Tetravalent cerium alkoxide complexes supported by the Kläui tripodal ligand [Co(η⁵-C₅H₅){P(O)(OEt)₂}₃]^- (L_OEt^-) have been synthesized, and their nucleophilic and redox reactivity have been studied. Treatment of the Ce(IV) oxo complex [Ce^IV(L_OEt)₂(O)(H₂O)]·MeCONH₂ (1) with ⁱPrOH or reaction of [Ce^IV(L_OEt)₂Cl₂] (2) with Ag₂O in ⁱPrOH afforded the Ce(IV) dialkoxide complex [Ce^IV(L_OEt)₂(OⁱPr)₂] (3-iPr). The methoxide and ethoxide analogues [Ce^IV(L_OEt)₂(OR)₂] (R = Me (3-Me), Et (3-Et)) have been prepared similarly from 2 and Ag₂O in ROH. Reaction of 3-iPr with an equimolar amount of 2 yielded a new Ce(IV) complex that was formulated as the chloro-alkoxide complex [Ce^IV(L_OEt)₂(OⁱPr)Cl] (4). Treatment of 3-iPr with HX and methyl triflate (MeOTf) afforded [Ce(L_OEt)₂X₂] (X^- = Cl^-, NO₃^-, PhO^-) and [Ce^IV(L_OEt)₂(OTf)₂], respectively, whereas treatment with excess CO₂ in hexane led to isolation of the Ce(IV) carbonate [Ce^IV(L_OEt)₂(CO₃)]. 3-iPr reacted with water in hexane to give a Ce(III) complex and a Ce(IV) species, presumably the reported tetranuclear oxo cluster [Ce^IV₄(L_OEt)₄(O)₅(OH)₂]. The Ce(IV) alkoxide complexes are capable of oxidizing substituted phenols, possibly via a proton-coupled electron transfer pathway. Treatment of 3-iPr with ArOH afforded the Ce(III) aryloxide complexes [Ce^III(L_OEt)₂(OAr)] (Ar = 2,4,6-tri-tert-butylphenyl (5), 2,6-diphenylphenyl (6)). On the other hand, a Ce(III) complex containing a monodeprotonated 2,2'-biphenol ligand, [Ce^III(L_OEt)₂(^tBu₄C₁₂H₄O₂H)] (7) (^tBu₄C₁₂H₄O₂H₂ = 4,4',6,6'-tetra-tert-butyl-2,2'-biphenol), was isolated from the reaction of 3-iPr with 2,4-di-tert-butylphenol. The crystal structures of complexes 3-iPr, 3-Me, 3-Et, and 5-7 have been determined.

4-Coordinated, 14-electron ruthenium(ii) chalcogenolate complexes: synthesis, electronic structure and reactions with PhICl2 and organic azides

The 4-coordinated Ru^II chalcogenolate complexes [Ru(STipp)₂(PPh₃)₂] (Tipp = 2,4,6-triisopropylphenyl, 1) and [Ru(SeMes)₂(PPh₃)₂] (Mes = 2,4,6-trimethylphenyl, 2) have been synthesized, and their reactions with PhICl₂ and organic azides have been studied. Complex 2 synthesized from [Ru^II(PPh₃)₃Cl₂] and NaSeMes displays a seesaw structure with P-Ru-P and Se-Ru-Se bond angles of 103.43(13) and 145.26(6)°, respectively. Natural bond order analyses revealed that in each of 1 and 2, there are two n →σ* (donor-acceptor) π interactions between the chalcogen lone pairs and the Ru-P antibonding molecular orbitals. The calculated second-order perturbation interaction energies of the two interactions for 1 (20.5 and 18.3 kcal mol^-1) are stronger than those of 2 (13.6 and 11.0 kcal mol^-1), suggesting the thiolate ligand (TippS^-) is a stronger π-donor than the selenolate ligand (MesSe^-) with respect to Ru^II. Chlorination of 1 with PhICl₂ afforded the dichloride complex [Ru(STipp)₂Cl₂(PPh₃)] (3), which was hydrolyzed to the hydroxo complex [Ru(STipp)₂(OH)Cl(PPh₃)] (4) after column chromatography on silica in air. Treatment of 4 with HCl and methyl triflate gave 3 and [Ru(STipp)₂(OH)(OTf)(PPh₃)] (OTf = triflate, 5), respectively. Reactions of 1 and 2 with p-tolyl azide (p-tolN₃) afforded the tetrazene complexes [Ru{N₄(p-tol)₂}(ER)₂(PPh₃)] (ER = STipp (6), SeMes (7)), whereas that with tosyl azide (TsN₃) gave the imido complexes [Ru(κ²-NTs)(STipp)₂(PPh₃)] (ER = STipp (8), SeMes (10)). The short Ru-N_imido distances in 8 [1.883(3) Å] and 10 [1.892(2) Å] are indicative of multiple bond character. Treatment of 8 with TsN₃ afforded the tetrazene complex [Ru(N₄Ts₂)(STipp)₂(PPh₃)] (9), but no cycloaddition was found between 10 and TsN₃. Nucleophilic attack of the imido ligand in 10 with methyl triflate yielded the amido complex [Ru(κ²-NMeTs)(SeMes)₂(PPh₃)](OTf) (11). The crystal structures of 2, 4, 6, and 8-11 have been determined.

A Combined Experimental and Theoretical Study of the Versatile Reactivity of an Oxocerium(IV) Complex: Concerted Versus Reductive Addition

A combined experimental and theoretical investigation on the cerium(IV) oxo complex [(L_OEt )₂ Ce(=O)(H₂ O)]⋅MeC(O)NH₂ (1; L_OEt ^- =[Co(η⁵ -C₅ H₅ ){P(O)(OEt)₂ }₃ ]^- ) demonstrates that the intermediate spin-state nature of the ground state of the cerium complex is responsible for the versatility of its reactivity towards small molecules such as CO, CO₂ , SO₂ , and NO. CASSCF calculations together with magnetic susceptibility measurements indicate that the ground state of the cerium complex is of multiconfigurational character and comprised of 74 % of Ce^IV and 26 % of Ce^III . The latter is found to be responsible for its reductive addition behavior towards CO, SO₂ , and NO. This is the first report to date on the influence of the multiconfigurational ground state on the reactivity of a metal-oxo complex.

Molecular Structure and Optical Nonlinearity of 1,8-Bis(Ferrocenyl)-3-t-Butyl-Oct-3-Ene-1,5,7-Triyne

Interaction of 1,8-bis(ferrocenyl)-octatetrayne 1 with one equiv. of t-butyl lithium followed by treatment with water gave 1,8-bis(ferrocenyl)-3- t-butyl-oct-3-ene-1,5,7-triyne 2. The solid-state structure of 2, containing a bent carbon chain between two ferrocenes, has been determined. The nonlinear optical properties of 2 were also investigated.

Iridium porphyrin complexes with μ-nitrido, hydroxo, hydrosulfido and alkynyl ligands

Iridium porphyrin complexes containing μ-nitrido, hydroxo, hydrosulfido, and alkynyl ligands have been synthesized and structurally characterized, and their oxidation has been studied. The alkyl-IrIII porphyrin complex [Ir(tpp)R] (tpp2- = 5,10,15,20-tetraphenylporphyrin dianion; R = C8H13; 1) was synthesized by reaction of [Ir(cod)Cl]2 (cod = 1,5-cyclooctadiene) with H2tpp in refluxing monoethylene glycol. Treatment of 1 with PPh3 and [(LOEt)Ru(N)Cl2] (LOEt- = [(η5-C5H5)Co{P(O)(OEt)2}3]-) gave [Ir(tpp)(R)(PPh3)] (2) and the μ-nitrido complex [R(tpp)Ir(μ-N)RuCl2(LOEt)] (3), respectively. The cyclic voltammogram of 3 exhibited a reversible oxidation couple at 0.44 V versus Fc+/0 (Fc = ferrocene). The oxidation of 3 with [(4-BrC6H4)3N](SbCl6) resulted in Ir-C bond homolysis and formation of the chloride complex [Cl(tpp)Ir(μ-N)RuCl2(LOEt)] (4). The short Ir-N(nitrido) bond distances in 3 [1.944(3) Å] and 4 [1.831(4) Å] are indicative of multiple bond character and thus these two μ-nitrido complexes can be described by the two resonance forms: IrIII-N[triple bond, length as m-dash]RuVI and IrV[double bond, length as m-dash]N[double bond, length as m-dash]RuIV. Similarly, the oxidation of 2 with [(4-BrC6H4)3N](SbCl6) yielded [Ir(tpp)Cl(PPh3)] (5). Chloride abstraction of 5 with TlPF6 in tetrahydrofuran (thf) afforded [Ir(tpp)(PPh3)(thf)](PF6) (6) that reacted with CsOH·H2O and Li2S to give the hydroxo [Ir(tpp)(OH)(PPh3)] (7) and hydrosulfido [Ir(tpp)(PPh3)(SH)] (8) complexes, respectively. Treatment of 6 with phenylacetylene in the presence of CuI and Et3N yielded the bimetallic complex [Ir(tpp)(PPh3)(μ-η1:η2-C[triple bond, length as m-dash]CPh)(CuI)] (9), whereas the transmetallation of 6 with LiC[triple bond, length as m-dash]CPh afforded the mononuclear alkynyl complex [Ir(tpp)(PPh3)(C[triple bond, length as m-dash]CPh)] (10). The electrochemistry of the Ir porphyrin complexes has been studied using cyclic voltammetry. On the basis of the measured redox potentials of [Ir(tpp)(PPh3)X], the ability of X- to stabilize the IrIV state is ranked in the order: R- > PhC[triple bond, length as m-dash]C- > Cl- ∼ OH-. Oxidation of 8 and 9 with [(4-BrC6H4)3N](SbCl6) led to isolation of 5 and [Ir(tpp)(PPh3)(H2O)]+, respectively. The crystal structures of complexes 3, 4, and 7-10 have been determined.

Reactions of cerium complexes with transition metal nitrides: synthesis and structure of heterometallic cerium complexes containing bridging catecholate ligands

Heterometallic cerium complexes containing bridging catecholate ligands have been synthesized from cerium complexes with Kläui's tripodal ligand and metal catecholates.

A Nitrido-bridged Heterometallic Ruthenium(IV)/Iron(IV) Phthalocyanine Complex Supported by A Tripodal Oxygen Ligand, [Co(η5-C5H5){P(O)(OEt)2}3]-: Synthesis, Structure, and Its Oxidation to Give Phthalocyanine Cation Radical and Hydroxyphthalocyanine Complexes

Dinuclear iron nitrido phthalocyanine complexes are of interest owing to their applications in catalytic oxidation of hydrocarbons. While nitrido-bridged diiron phthalocyanine complexes are well documented, the oxidation chemistry of heterodinuclear iron(IV) phthalocyanine nitrides has not been well explored. In this paper we report on the synthesis of a heterometallic Fe^IV/Ru^IV phthalocyanine nitride and its oxidation to yield phthalocyanine cation radical and hydroxyphthalocyanine complexes. Treatment of [Fe^II(Pc)] (Pc^2- = phthalocyanine dianion) with [Ru^VI(L_OEt)(N)Cl₂] (L_OEt^- = [Co(η⁵-C₅H₅){P(O)(OEt)₂}₃]^-) (1) afforded the heterometallic μ-nitrido complex [Cl₂(L_OEt)Ru^IV(μ-N)Fe^IV(Pc)(H₂O)] (2) that contains an Ru^IV=N = Fe^IV linkage with the Ru-N and Fe-N distances of 1.689(6) and 1.677(6) Å, respectively, and Ru-N-Fe angle of 176.0(4)°. Substitution of 2 with 4- tert-butylpyridine (Bupy) gave [Cl₂(L_OEt)Ru^IV(μ-N)Fe^IV(Pc)(Bupy)]. The cyclic voltammogram of 2 displayed a reversible Pc-centered oxidation couple at +0.18 V versus Fc^+/0 (Fc = ferrocene). The oxidation of 2 with [N(4-BrC₆H₄)₃]SbCl₆ led to isolation of the cationic complex [Cl₂(L_OEt)Ru^IV(μ-N)Fe^IV(Pc^·+)(H₂O)][SbCl₆]_0.85[SbCl₅(OH)]_0.15 (2[SbCl₆]_0.85[SbCl₅(OH)]_0.15), whereas that with PhICl₂ yielded the chloride complex [Cl₂(L_OEt)Ru^IV(μ-N)Fe^IV(Pc^·+)Cl] (3). Complexes 2[SbCl₆]_0.85[SbCl₅(OH)]_0.15 and 3 have been characterized by X-ray crystallography. The UV/visible spectra of 2⁺ (λ_max = 515 and 747 nm) and 3 (λ_max = 506 and 748 nm) displayed absorption bands that are characteristic of Pc cation radical. The EPR spectrum of 3 showed a signal with the g value of 2.0012 (width = 5 G) that is consistent with an organic radical. The spectroscopic data support the formulation of 2⁺ and 3 as Ru^IV-Fe^IV Pc cation radical complexes. The reaction of 2 with PhI(CF₃CO₂)₂ in dried CH₂Cl₂ afforded a mixture of [Cl₂(L_OEt)Ru^IV(μ-N)Fe^IV(Pc^·+)(CF₃CO₂)] (4) and a hydroxyphthalocyanine complex, [Cl₂(L_OEt)Ru^IV(μ-N)Fe^IV(Pc-OH)(H₂O)](CF₃CO₂) (5), whereas that in wet CH₂Cl₂ (containing ca. 0.5% water) led to isolation of 5 as the sole product. Complex 4 was independently prepared by salt metathesis of 3 with AgCF₃CO₂.

Nuclear accident consequence assessment in Hong Kong using JRODOS

The JRODOS (Java-based Real-time Online DecisiOn Support) is a decision support system for off-site emergency management for releases of radioactive material into the environment. This paper documents the application of JRODOS by the Hong Kong Observatory in accident consequence assessment and emergency preparedness studies. For operational considerations, the most computational efficient dispersion model in JRODOS, ATSTEP, is adopted. Verification studies for JRODOS's ATSTEP model have been conducted. Comparison with tracer experiment results showed that under neutral atmospheric conditions and distances up to 50 km, the JRODOS simulation outputs were in general of the same order of magnitude with the tracer data. To further evaluate the capability of JRODOS in short-range simulation, a case study on the Fukushima nuclear power plant accident was also carried out. JRODOS was able to produce realistic simulation results which were comparable to the actual airborne monitoring data of the Cs-137 ground deposition from the Fukushima accident. Furthermore, the results of a comprehensive study to assess the potential consequences of accidents at a nearby nuclear power station are presented. Simulation using the French S3 source term for the Guangdong Nuclear Power Station at Daya Bay showed that the projected effective doses within Hong Kong remain far below the IAEA generic criteria of projected dose for urgent protective actions in sheltering/evacuation, while the projected equivalent dose in thyroid may meet the IAEA generic criteria for use of thyroid blocking agent at some areas in the northeastern part of Hong Kong, at distances of up to about 40 km from Daya Bay depending on the prevailing weather conditions in different seasons.

Heterobimetallic Nitrido Complexes of Group 8 Metalloporphyrins

Heterobimetallic nitrido porphyrin complexes with the [(L)(por)M-N-M'(L_OEt)Cl₂] formula {por^2- = 5,10,15,20-tetraphenylporphyrin (TPP^2-) or 5,10,15,20-tetra(p-tolyl)porphyrin (TTP^2-) dianion; L_OEt^- = [Co(η⁵-C₅H₅){P(O)(OEt)₂}₃]^-; M = Fe, Ru, or Os; M' = Ru or Os; L = H₂O or pyridine} have been synthesized, and their electrochemistry has been studied. Treatment of trans-[Fe(TPP)(py)₂] (py = pyridine) with Ru(VI) nitride [Ru(L_OEt)(N)Cl₂] (1) afforded Fe/Ru μ-nitrido complex [(py)(TPP)Fe(μ-N)Ru(L_OEt)Cl₂] (2). Similarly, Fe/Os analogue [(py)(TPP)Fe(μ-N)Os(L_OEt)Cl₂] (3) was obtained from trans-[Fe(TPP)(py)₂] and [Os(L_OEt)(N)Cl₂]. However, no reaction was found between trans-[Fe(TPP)(py)₂] and [Re(L_OEt)(N)Cl(PPh₃)]. Treatment of trans-[M(TPP)(CO)(EtOH)] with 1 afforded μ-nitrido complexes [(H₂O)(TPP)M(μ-N)Ru(L_OEt)Cl₂] [M = Ru (4a) or Os (5)]. TTP analogue [(H₂O)(TTP)Ru(μ-N)Ru(L_OEt)Cl₂] (4b) was prepared similarly from trans-[Ru(TTP)(CO)(EtOH)] and 1. Reaction of [(H₂O)(por)M(μ-N)M(L_OEt)Cl₂] with pyridine gave adducts [(py)(por)M(μ-N)Ru(L_OEt)Cl₂] [por = TTP, and M = Ru (6); por = TPP, and M = Os (7)]. The diamagnetism and short (por)M-N(nitride) distances in 2 [Fe-N, 1.683(3) Å] and 4b [Ru-N, 1.743(3) Å] are indicative of the M^IV═N═M'^IV bonding description. The cyclic voltammograms of the Fe/Ru (2) and Ru/Ru (4b) complexes in CH₂Cl₂ displayed oxidation couples at approximately +0.29 and +0.35 V versus Fc^+/0 (Fc = ferrocene) that are tentatively ascribed to the oxidation of the {L_OEtRu} and {Ru(TTP)} moieties, respectively, whereas the Fe/Os (3) and Os/Ru (5) complexes exhibited Os-centered oxidation at approximately -0.06 and +0.05 V versus Fc^+/0, respectively. The crystal structures of 2 and 4b have been determined.

Iodosylbenzene and iodylbenzene adducts of cerium(IV) complexes bearing chelating oxygen ligands

Reactions of [Ce(IV)(LOEt)2Cl2] (LOEt(-) = [Co(η(5)-C5H5){P(O)(OEt)2}3](-)) and [Ce(μ-O){N(Pr(i)2PO)2}4Cl2] with PhIO afford the λ3-iodane complexes [Ce(IV)(LOEt)2{OI(Cl)Ph}2] and [Ce{N(Pr(i)2PO)2}3{OI(Cl)Ph}], respectively, whereas that between [Ce(IV)(LOEt)2Cl2] and PhIO2 or excess PhIO yields the λ5-iodane adduct [Ce(IV)(LOEt)2{OI(O)ClPh}2]. The crystal structures of the Ce(IV)λ3- and λ5-iodane complexes have been determined and their oxo transfer reactivities have been investigated.

Heterobimetallic cerium(iv) oxo clusters supported by a tripodal oxygen ligand

Heterometallic Ce^IV/M (M = Mo^VI, Re^VII, V^V) oxo clusters supported by the Kläui tripodal oxygen ligand [(η⁵-C₅H₅)Co{P(O)(OEt)₂}₃]⁻ (L_OEt⁻) have been synthesized and the catalytic activity of the Ce^IV/V^V oxo cluster in the oxidation of thioanisoles has been studied.

Tetravalent cerium pseudohalide complexes supported by the Kläui tripodal ligand [Co(η5-C5H5){P(O)(OEt)2}3]−

Cerium(iv) pseudohalide complexes supported by the Kläui tripodal ligand [Co(η⁵-C₅H₅){P(O)(OEt)₂}₃]⁻ (L_OEt⁻) have been synthesized and structurally characterized.

Ruthenium chalcogenonitrosyl and bridged nitrido complexes containing chelating sulfur and oxygen ligands

Ruthenium thio- and seleno-nitrosyl complexes containing chelating sulfur and oxygen ligands have been synthesised and their de-chalcogenation reactions have been studied. The reaction of mer-[Ru(N)Cl3(AsPh3)2] with elemental sulfur and selenium in tetrahydrofuran at reflux afforded the chalcogenonitrosyl complexes mer-[Ru(NX)Cl3(AsPh3)2] [X = S (1), Se (2)]. Treatment of 1 with KN(R2PS)2 afforded trans-[Ru(NS)Cl{N(R2PS)2}2] [R = Ph (3), Pr(i) (4), Bu(t) (5)]. Alternatively, the thionitrosyl complex 5 was obtained from [Bu(n)4N][Ru(N)Cl4] and KN(Bu(t)2PS)2, presumably via sulfur atom transfer from [N(Bu(t)2PS)2](-) to the nitride. Reactions of 1 and 2 with NaLOEt (LOEt(-) = [Co(η(5)-C5H5){P(O)(LOEt)2}3](-)) gave [Ru(NX)LOEtCl2] (X = S (8), Se (9)). Treatment of [Bu(n)4N][Ru(N)Cl4] with KN(R2PS)2 produced Ru(IV)-Ru(IV)μ-nitrido complexes [Ru2(μ-N){N(R2PS)2}4Cl] [R = Ph (6), Pr(i) (7)]. Reactions of 3 and 9 with PPh3 afforded 6 and [Ru(NPPh3)LOEtCl2], respectively. The desulfurisation of 5 with [Ni(cod)2] (cod = 1,5-cyclooctadiene) gave the mixed valance Ru(III)-Ru(IV)μ-nitrido complex [Ru2(μ-N){N(Bu(t)2PS)2}4] (10) that was oxidised by [Cp2Fe](PF6) to give the Ru(IV)-Ru(IV) complex [Ru2(μ-N){N(Bu(t)2PS)2}4](PF6) ([10]PF6). The crystal structures of 1, 2, 3, 7, 9 and 10 have been determined.

Heterobimetallic rhenium nitrido complexes containing the Kläui tripodal ligand [Co(η5-C5H5){P(O)(OEt)2}3]−

Heterometallic rhenium/iridium and rhenium/rhodium complexes containing the Kläui tripodal ligand have been synthesized and characterized.

Synthesis, Structure and Electrochemistry of [Ru2(S2CNMe2)3(μ3-S2CNMe2)2]2[Mo6O19] · 2CH3COCH3

Reaction of MoO2(S2CNMe2)2 with RuCl3 ・χH2O in acetone at reflux afforded [Ru2(S2CNMe2)3- (μ3-S2CNMe2)2]2[Mo6O19]・2CH3COCH3 (1・2CH3COCH3) which was characterized by singlecrystal X-ray diffraction to show a dinuclear ruthenium-dithiocarbamate species as cation and hexamolybdate as counter anion. The [Ru2(S2CNMe2)3(μ3-S2CNMe2)2]+ cation may be considered as a combination of [Ru(S2CNMe2)3] with a cis-[Ru(S2CNMe2)2]+ species, and the Lindqvist anion [Mo6O19]2− is located on an inversion center between two cations. Spectroscopic properties along with the electrochemistry of compound 1・2CH3COCH3 are reported.

A revised definition for cure of childhood acute lymphoblastic leukemia

With improved contemporary therapy, we re-assess long-term outcome in patients completing treatment for childhood acute lymphoblastic leukemia to determine when cure can be declared with a high degree of confidence. In 6 successive clinical trials between 1984 and 2007, 1291(84.5%) patients completed all therapy in continuous complete remission. The post-therapy cumulative risk of relapse or development of a second neoplasm and the event-free survival rate and overall survival were analyzed according to the presenting features and the three treatment periods defined by relative outcome. Over the three treatment periods, there has been progressive increase in the rate of event-free survival (65.2% vs. 74.8% vs. 85.1% [P<0.001]) and overall survival (76.5% vs. 81.1% vs. 91.7% [P<0.001]) at 10 years. The most important predictor of outcome after completion of therapy was the type of treatment. In the most recent treatment period, which omitted the use of prophylactic cranial irradiation, the post-treatment cumulative risk of relapse was 6.4%, death in remission 1.5%, and development of a second neoplasm 2.3% at 10 years, with all relapses except one occurring within 4 years off therapy. None of the 106 patients with the t(9;22)/BCR-ABL1, t(1;19)/TCF3-PBX1 or t(4;11)/MLL-AFF1 had relapsed after 2 years from completion of therapy. These findings demonstrate that with contemporary effective therapy that excludes cranial irradiation, approximately 6% of children with acute lymphoblastic leukemia may relapse after completion of treatment, and those who remain in remission at 4 years post-treatment may be considered cured (i.e., less than 1 % chance of relapse).

A tetravalent cerium complex containing a Ce=O bond

Whereas terminal oxo complexes of transition and actinide elements are well documented, analogous lanthanide complexes have not been reported to date. Herein, we report the synthesis and structure of a cerium(IV) oxo complex, [CeO(LOEt )2 (H2 O)]⋅MeC(O)NH2 (1; LOEt (-) =[Co(η(5) -C5 H5 ){P(O)(OEt)2 }3 ](-) ), featuring a short CeO bond (1.857(3) Å). DFT calculations indicate that the hydrogen bond to cocrystallized acetamide plays a key role in stabilizing the CeO moiety of 1 in the solid state. Complex 1 exhibits oxidizing and nucleophilic reactivity.