The effect of prostaglandins A2,E1,E2,15 methyl E2, 16, 16 dimethyl E2 and F2α on erythropoiesis

Prostaglandins A₂, E₁, E₂, methylated E₂s and F₂α affected erythropoiesis and/or erythropoietin (Ep) production. This action is indicated in the exhypoxic, polycythemic mouse where radioiron incorporations into RBC increased after administration of these compounds. The kidney and liver have been indicated through previous studies, to actively participate in Ep production. By the removal of one of these active sites in a murine system treated with prostaglandins it is shown that a response is reflected in Ep levels. Interference of the action of prostaglandins (PG) is altered by the removal of one of these target sites of Ep production. The erythropoietic responses elicited by PGA₂, E₁, and perhaps the methylated PGE₂s act through the liver whereas PGE₂ may operate through a renal pathway for its response. PGF_2α reveals no effect on erythropoietic activity and is no different than that observed for vehicle-treated controls. The prostaglandins tested appear to act primarily through the kidney or liver but the possibility exists that some yet undetermined organ site may also be involved.     

Molecular structure of tetranuclear [{Mo2O(S2CNEt2)(η-O2CCF3)(μ-N-o-tol)2}2(μ-O)(μ-O2CCF3)2] formed upon addition of trifluoroacetic acid to syn-[MoO(μ-N-o-tol)(S2CNEt2)]2

Addition of trifluoroacetic acid to syn-[MoO(μ-N-o-tol)(S₂CNEt₂)]₂ in chloroform affords tetranuclear [{Mo₂O(S₂CNEt₂)(η¹-O₂CCF₃)(μ-N-o-tol)₂}₂(μ-O)(μ-O₂CCF₃)₂] which has been crystallographically characterised. It consists of four molybdenum(V) centres linked via bridging imido, trifluoroacetate and oxo ligands and results from replacement of a dithiocarbamate by two trifluoroacetate ligands.     

A versatile entry into aqueous niobium chemistry: isolation and structure of the intermediate Nb4(μ2-O)2(μ2-OC2H5)4Cl4(OC2H5)4(HOC2H5)4

The reduction of ethanolic solutions of niobium pentachloride with zinc, followed by treatment with aqueous acids serves as a versatile entry into the aqueous solution chemistry of niobium. From the zinc-reduced solution, the major intermediate, Nb₄(μ₂-O)₂(μ₂-OC₂H₅)₄Cl₄(OC₂H₅)₄(HOC₂H₅)₄, was isolated and the crystal structure determined by X-ray crystallography. The complex crystallizes in the orthorhombic space group Pccn, with Z=4, a=21.0105(9), b=11.0387(5), c=19.1389(8), V=4438.9(3) ų, M_r=1090.19,R₁=0.0327 and wR₂=0.0876. The structure revealed a centrosymmetric tetrameric Nb(IV) complex, consisting of a pair of edge-sharing bi-octahedral Nb₂(μ₂-OC₂H₅)₄Cl₂(OC₂H₅)₂(HOC₂H₅)₂ units that are joined by two axial oxo ligands. The Nb-Nb distance of 2.7458(3) Å is consistent with a single metal-metal bond.     

Synthesis and structural characterization of the molecular loop [cis-Mo2(N,N-di-p-anisylformamidinate)2]2(O2C-CHCCH-CO2)2

A new molecular loop composed of two quadruply bonded Mo₂(DAniF)₂ units (DAniF=N,N^′-di-p-anisylformamidinate) linked by two chiral allene-1,3-dicarboxylate anions has been prepared from the reaction of [cis-Mo₂(DAniF)₂(MeCN)₄](BF₄)₂ with the bis(tetraethylammonium) salt of allene-1,3-dicarboxylic acid. This compound, [cis-Mo₂(DAniF)₂]₂(O₂C-CHCCH-CO₂)₂ (1), has been characterized by X-ray crystallography and by ¹H NMR and UV-Vis spectroscopy. The molecule possesses a center of inversion and hence is meso. There is only weak electronic coupling between the two Mo₂ ⁴⁺ units as revealed by electrochemical measurements.     

Thallium(III) complexes of the metalloligands [Pt2(μ-S)2(PPh3)4] and [Pt2(μ-Se)2(PPh3)4]

Reactions of [Pt₂(μ-S)₂(PPh₃)₄] with the diarylthallium(III) bromides Ar₂TlBr [Ar = Ph and p-ClC₆H₄] in methanol gave good yields of the thallium(III) adducts [Pt₂(μ-S)₂(PPh₃)₄TlAr₂]⁺, isolated as their salts. The corresponding selenide complex [Pt₂(μ-Se)₂(PPh₃)₄TlPh₂]BPh₄ was similarly synthesised from [Pt₂(μ-Se)₂(PPh₃)₄], Ph₂TlBr and NaBPh₄. The reaction of [Pt₂(μ-S)₂(PPh₃)₄] with PhTlBr₂ gave [Pt₂(μ-S)₂(PPh₃)₄TlBrPh]⁺, while reaction with TlBr₃ gave the dibromothallium(III) adduct [Pt₂(μ-S)₂(PPh₃)₄TlBr₂]⁺[TlBr₄]⁻. The latter complex is a rare example of a thallium(III) dihalide complex stabilised solely by sulfur donor ligands. X-ray crystal structure determinations on the complexes [Pt₂(μ-S)₂(PPh₃)₄TlPh₂]BPh₄, [Pt₂(μ-S)₂(PPh₃)₄TlBrPh]BPh₄ and [Pt₂(μ-S)₂(PPh₃)₄TlBr₂][TlBr₄] reveal a greater interaction between the thallium(III) centre and the two sulfide ligands on stepwise replacement of Ph by Br, as indicated by shorter Tl-S and Pt?Tl distances, and an increasing S-Tl-S bond angle. Investigations of the ESI MS fragmentation behaviour of the thallium(III) complexes are reported.     

The arylation of [Pt2(μ-S)2(PPh3)4]

Routes to the synthesis of the mixed sulfide-phenylthiolate complex [Pt₂(μ-S)(μ-SPh)(PPh₃)₄]⁺ have been explored; reaction of [Pt₂(μ-S)₂(PPh₃)₄] with excess Ph₂IBr proceeds readily to selectively produce this complex, which was structurally characterised as its PF₆⁻ salt. Reactions of [Pt₂(μ-S)₂(PPh₃)₄] with other potent arylating reagents (1-chloro-2,4-dinitrobenzene and 1,5-difluoro-2,4-dinitrobenzene) also produce the corresponding nitroaryl-thiolate complexes [Pt₂(μ-S){μ-SC₆H₂(NO₂)₂X}(PPh₃)₄]⁺ (X = H, F). The complex [Pt₂(μ-S)(μ-SPh)(PPh₃)₄]⁺ reacts with Me₂SO₄ to produce the mixed alkyl/aryl bis-thiolate complex [Pt₂(μ-SMe)(μ-SPh)(PPh₃)₄]²⁺, but corresponding reactions with the nitroaryl-thiolate complexes are plagued by elimination of the nitroaryl group and formation of [Pt₂(μ-SMe)₂(PPh₃)₄]²⁺. [Pt₂(μ-S)(μ-SPh)(PPh₃)₄]⁺ also reacts with Ph₃PAuCl to give [Pt₂(μ-SAuPPh₃)(μ-SPh)(PPh₃)₄]²⁺.     

Omega chain methylated analogs of PGF2α and PGE2

Our previously published prostaglandin (PG) synthesis route, in which the ω-chain is added in the penultimate step, provides facile access to a wide variety of ω-chain variant PG analogs. Each series requires only the synthesis of the appropriate methylated acylphosphonate for the Emmons' condensation. The syntheses of analogs bearing the following methylation pattern are detailed: 15-Me; 17, 17-(Me)₂; 17, 17, 20-(Me)₃; 18, 18, 20-(Me)₃; 15, 18, 18, 20-(Me)₄; and 15-Ome-18, 18, 20-(Me)₃. The well-known 16, 16-dimethyl prostaglandins have also been prepared by this sequence. The synthesis of 16, 16-tetramethylene-PG analogs is also described.     

A cyclic osmastannyl complex, Os(κ(Sn,P)-SnMe2C6H4PPh2)(κ-S2CNMe2)(CO)(PPh3) derived from the osmastannol complex, Os(SnMe2OH)(κ-S2CNMe2)(CO)(PPh3)2

Treatment of the six-coordinate trimethylstannyl complex, Os(SnMe₃)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (1) with SnMe₂Cl₂ produces Os(SnMe₂Cl)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (2), which in turn reacts readily with hydroxide ion to give, Os(SnMe₂OH)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (3). The osmastannol complex 3 undergoes a reaction with 2 equivalents of ^tBuLi, in which one of the phenyl rings of a triphenylphosphine ligand is “ortho-stannylated”, without cleavage of the Os-Sn bond, to give the cyclic complex, Os(κ²(Sn,P)-SnMe₂C₆H₄PPh₂)(κ²-S₂CNMe₂)(CO)(PPh₃) (4). This novel cyclic complex is selectively functionalised at the tin atom by reaction with SnMe₂Cl₂ which exchanges one methyl group for chloride giving the diastereomeric mixture, Os(κ²(Sn,P)-SnMeClC₆H₄PPh₂)(κ²-S₂CNMe₂)(CO)(PPh₃) (5a/5b). Crystal structure determination reveals that both diastereomers occur in the unit cell. The mixture, 5a/5b, undergoes reaction with hydroxide ion to give the diastereomeric osmastannol complexes, Os(κ²(Sn,P)-SnMeOHC₆H₄PPh₂)(κ²-S₂CNMe₂)(CO)(PPh₃) (6a/6b) and with sodium borohydride to give the corresponding tin-hydride mixture, Os(κ²(Sn,P)-SnMeHC₆H₄PPh₂)(κ²-S₂CNMe₂)(CO)(PPh₃) (7a/7b). Crystal structure determinations for 2, 4, and 5a/5b have been obtained.     

Ru2(CO)4(OOCR)2(PPh3)2 sawhorse-type complexes containing μ2-η-carboxylato ligands derived from biologically active acids

The thermal reaction of Ru₃(CO)₁₂ with the biologically active acids acetyl salicylic acid (Aspirin), α-methyl-4-(isobutyl)phenylacetic acid (Ibuprofen) and 3α,7α,12α-trihydroxy-5β-cholanic acid (cholic acid) in refluxing tetrahydrofuran, followed by addition of triphenylphosphine, gives the dinuclear complexes Ru₂(CO)₄(OOCR)₂(PPh₃)₂ (1: R = C₆H₄-2-OCOMe, 2: R = CHMe-C₆H₄-4-Buⁱ, 3: C₂₃H₃₉O₃). The single-crystal structural analysis of 1 and 2 reveals a dinuclear Ru₂(CO)₄ sawhorse structure, the diruthenium backbone being bridged by the carboxylato ligands, while the two phosphine ligands occupy the axial positions at the ruthenium atoms. However, chiral carbon atoms in the carboxylic acid undergo racemisation during the thermal reaction.     

Syntheses and crystal structures of the first iridium complexes with m- and p-terphenyl (tp). {[Ir2(p-tp)(cod)2](BF4)2 · 2CH2Cl2}3 and [Ir(m-tp)(η-C5Me5)](BF4)2

Novel two iridium terphenyl complexes were prepared and their structures were characterized crystallographically. The reaction of [Ir(cod)₂]BF₄ with p-terphenyl (p-tp) in CH₂Cl₂ was carried out to afford dinuclear Ir(I) complex {[Ir₂(p-tp)(cod)₂](BF₄)₂ · 2CH₂Cl₂}₃ (cod=1,5-cyclooctadiene) (1 · 2CH₂Cl₂), whereas the reaction of the intermediate [Ir(η⁵-C₅Me₅)(Me₂CO)₃]³⁺ in Me₂CO with m-terphenyl (m-tp) was done to provide mononuclear Ir(III) complex [Ir(m-tp)(η⁵-C₅Me₅)](BF₄)₂ (2). In complex 1 · 2CH₂Cl₂, two Ir atoms are η⁶-coordinated to both sides of terminal benzene rings from the upper and lower sides in the p-tp ligand, while one Ir atom is η⁶-coordinated to one side of the terminal benzene ring in the m-tp ligand in complex 2. Each crystal structure describes the first coordination mode found in metal complexes with the m- and p-tp ligands.     

The reactions of 2-hydroxypyridine ligands with Re2Cl4(μ-dppm)2 (dppm=Ph2PCH2PPh2) that lead to 2-pyridonate complexes

2-Hydroxypyridine (Hhp), 2-hydroxynicotinic acid (HnicOH) and 6-hydroxypicolinic acid (HpicOH) react with Re₂Cl₄(μ-dppm)₂ (dppm=Ph₂PCH₂PPh₂) to afford the complexes Re₂(η²-hp)Cl₃(μ-dppm)₂ (1), Re₂(η²-HnicO)Cl₃(μ-dppm)₂ (2) and Re₂(μ-picO)₂(μ-dppm)₂ (3). The identities of 1 and 2 have been established by single-crystal X-ray structure determinations (Re-Re distances of 2.2602(3) and 2.2539(3) Å, respectively) and they are shown to have unsymmetrical structures with staggered rotational geometries and trans, cis coordination of the pair of μ-dppm ligands. The crystal of 2 that was used in the structure determination was found to be of composition 2Re₂(η²-HnicO)Cl₃(μ-dppm)₂ · Re₂Cl₆(μ-dppm)₂ · 2.906CH₂Cl₂. The structure of Re₂Cl₆(μ-dppm)₂ in this crystal is compared with structures reported in the literature for other crystals that contain this edge-sharing bioctahedral dirhenium(III) complex.     

Heterobimetallic platinum-bismuth aggregates derived from [Pt2(μ-S)2(PPh3)4]

The metalloligand [Pt₂(μ-S)₂(PPh₃)₄] reacts with Bi(S₂CNEt₂)₃ or Bi(S₂COEt)₃ in methanol to produce the orange cationic adducts [Pt₂(μ-S)₂(PPh₃)₄Bi(S₂CNEt₂)₂]⁺ and [Pt₂(μ-S)₂(PPh₃)₄Bi(S₂COEt)₂]⁺, respectively, isolated as their hexafluorophosphate salts. An X-ray structure determination on [Pt₂(μ-S)₂(PPh₃)₄Bi(S₂CNEt₂)₂]PF₆ reveals the presence of a six-coordinated bismuth centre with an approximately nido-pentagonal bipyramidal coordination geometry. Fragmentation pathways for both complexes have been probed using electrospray ionisation mass spectrometry; ions [Pt₂(μ-S)₂(PPh₃)₂Bi(S₂CXEt_n)₂]⁺ (X = O, n = 1, X = N, n = 2) are formed by selective loss of two PPh₃ ligands, and at higher cone voltages the species [(Ph₃P)PtS₂Bi]⁺ is observed. Ions formed by loss of CS₂ are also observed for the xanthate but not the dithiocarbamate ions.     

On the solvatochromic properties of the oxalate-bridged complexes [(BuCO2)3M2]2(μ-O2C2O2) where M = Mo or W

The room temperature electronic absorption spectra of the oxalate bridged MM quadruply bonded complexes [(^tBuCO₂)₃M₂]₂(μ-O₂C₂O₂), where M = Mo or W have been recorded in H₂O, THF:H₂O mixtures, THF, CH₂Cl₂, toluene, DMSO, aniline, toluene saturated with N,N-dimethylaniline and ethanol. The strong absorptions in the visible region of the electronic absorption spectra assignable to the metal-to-ligand (bridge) charge transfer are shown to be highly solvent dependent. Those samples prepared in H₂O, CH₂Cl₂ and toluene are shown to comprise of a suspension of microcrystalline particles ranging in size from 100 nm to 5 μm. Individual particles were found by scanning electron microscopy to have an aspect ratio of ∼10:1, all being needle shaped. The spectra in THF, EtOH, aniline, DMSO and toluene-N,N-dimethylaniline all show similar vibronic progressions and are attributed to discrete solvated molecular species. The spectra recorded in aniline are notably red-shifted which is proposed to arise from a combination of hydrogen bonding and Lewis base stabilization of the photoexcited state.     

Cu(C6H9N3O2)2Cl2对小麦的生态毒理效应

以冬小麦为实验材料,比较研究了(1)不同浓度配合物对小麦生长的影响;(2)相同浓度的CuC l2、配体C6H9N3O2和配合物Cu(C6H9N3O2)2C l2对冬小麦种子萌发、苗期生长及其保护酶活性的影响。结果表明:与对照相比,(1)不同浓度新配合物对小麦生长具有不同程度的抑制作用,随着浓度的增高抑制作用逐渐增大;(2)CuC l2、配合物Cu(C6H9N3O2)2C l2对小麦种子总淀粉酶活性、蛋白酶活性、萌发率、生长势、根长、株高、总生物量均具有显著的抑制作用,配合物Cu(C6H9N3O2)2C l2的抑制作用小于CuC l2,而配体C6H9N3O2对上述生物学参数具有促进作用;(3)CuC l2、配合物Cu(C6H9N3O2)2C l2处理引起膜脂过氧化,显著的提高了幼苗的M DA浓度,导致SOD、POD、CAT活性降低,CuC l2的抑制作用大于配合物Cu(C6H9N3O2)2C l2,而配体C6H9N3O2处理对SOD、POD、CAT活性的提高有促进作用。上述结果说明C6H9N3O2对CuC l2生理胁迫具有保护作用,结合态的Cu2 (配合物Cu(C6H9N3O2)2C l2)的毒性显著的降低。在此基础上探讨了配合物抑制小麦生长发育的生物学机制。     

添加氧化铁对水稻土中H2、CO2和CH4形成的影响

水稻土是甲烷产生的重要源地.厌氧条件下甲烷的形成与有机质厌氧降解产生的乙酸、H₂和CO₂有关.氧化铁作为电子受体可有效地竞争有机质向甲烷的转化,其抑制作用机理可能与乙酸、H₂和CO₂的有效消耗有关.通过向水稻土泥浆中添加无定形氧化铁和纤铁矿,分别测定了25℃厌氧恒温培养105d过程中的H₂、CO₂和CH₄的浓度变化.结果表明,添加无定形氧化铁及纤铁矿可导致H₂浓度显著降低;无定形氧化铁对H₂消耗的影响明显大于纤铁矿;添加不同氧化铁对CO₂浓度的影响与H₂浓度的变化有相同的趋势;添加氧化铁能显著抑制水稻土中甲烷形成,并导致有机碳的转移发生变化,使得CH₄-C显著降低,气相中CO₂-C量减少,而由土壤泥浆固定的CO₃^2--C量显著增加.     

First crystallographic determination of dichloro-bridged dinuclear rhodium Cp* complex with neutral Me2CO molecules. [Rh2(Cp*)2(μ-Cl)2(Me2CO)2](BF4)2 (Cp* = η-C5Me5)

The single crystals of dichloro-bridged dinuclear Rh-Cp* complex with neutral Me₂CO molecules, [Rh₂(Cp*)₂(μ-Cl)₂(Me₂CO)₂](BF₄)₂ (Cp* = η⁵-C₅Me₅), was isolated and the structure was in first determined crystallographically.     

Hyponitrite complexes: Crystal and molecular structure of [Ru2(CO)4(μ-PBu2)(μ-Ph2PCH2PPh2)(μ-η-ONNOMe)]

The new trans-hyponitrite derivative complex [Ru₂(CO)₄(μ-P^tBu₂)(μ-dppm)(μ-η²-ONNOMe)] (2, dppm = Ph₂PCH₂PPh₂) was prepared by deprotonation of [Ru₂(CO)₄(μ-H)(μ-P^tBu₂)(μ-dppm)(μ-η²-ONNOMe)][BF₄] (1) with the base DBU (1.8-diazabicyclo[5.4.0]undec-7-ene). The latter complex salt has been obtained in an improved synthesis starting from the trans-hyponitrite complex [Ru₂(CO)₄(μ-H)(μ-P^tBu₂)(μ-dppm)(μ-η²-ONNO)]. Compound 2 has been characterized by spectroscopic methods as well as by X-ray diffraction and represents the first neutral complex bearing a deprotonated monoester of the hyponitrous acid as the bridging ligand.     

Hydrido-derivatives of [Ir4(CO)10(diphosphine)]: X-ray analyses of [Ir4H(CO)9(μ-Ph2PH(CH3)PPh2)] and [Ir4 H(CO)9(μ-Ph2P(CH2)nPPh2)] (n = 2, 3)

Some novel hydrido-anions of general formula [Ir₄H(CO)₉(μ-L-L)]⁻ (L-L = Ph₂PCH(CH₃)PPh₂, Ph₂P(CH₂)₂PPh₂, Ph₂P(CH₂)₃PPh₂ and Ph₂AsCH₂AsPh₂) have been obtained by the reaction of [Ir₄(CO)₁₀(μ-L-L)] with the base 1,8-diazabicyclo[5.4.0]undec-7-ene in wet dichloromethane. According to IR and ¹H, ³¹P and ¹³C NMR data at low temperature, these anionic derivatives display a single conformation in solution: three edge-bridging COs around the triangular basal face and both the hydride and the bidentate ligands located in axial positions relative to this face. The structures of four compounds were established by X-ray diffraction studies, which confirmed the configuration proposed on the basis of spectroscopic data.