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.     

Central cardiovascular activity of prostaglandin E2, prostagladin F2∝ and prostacyclin

Prostacyclin (PGI₂), prostaglandin E₂ (PGE₂) and prostaglandin F_2∝ (PGF_2∝) were tested here in unanesthetized male Sprague-Dawley rats for their effects on the cardiovascular system as mediated by the Central nervous system. Cannulae were chronically implanted into the third cerebral ventricle, femoral arteries and femoral veins of rats. Both PGE₂ and PGF_2∝ induced increased arterial blood pressure and tachycardia by an action on the central nervous system. The changes seen with PGE₂ were larger than those observed with PGF_2∝. Only transient depressor effects were seen with PGI₂ and these changes appeared to be due to the leakage of the substance into the peripheral vascular system.     

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.     

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.     

Comparison of the effects of prostaglandins D2, F2α and E1 on spontaneous contractions of rabbit oviduct

The effects of PGD₂, PGF_2α and PGE₁ were studied on the circular muscle of post-ovulatory rabbit oviducts $\text{in vitro}$. PGE₁ inhibited spontaneous contractile activity. Lower concentrations of PGD₂ and PGF_2α were stimulatory and higher concentrations were inhibitory. Since PGD₂ may be produced in the oviduct, any hypothesis concerning the role of prostaglandins in the control of oviductal motility and ovum transport should include PGD₂ as well as PGFs and PGEs.     

Chalcogenolato-bridged cyclometallated binuclear palladium complexes: Synthesis, spectroscopy, structures of [Pd2(μ-Cl)(μ-SMes)(C10H6NMe2-C,N)2] and [Pd2(μ-SePh)2(C10H6NMe2-C,N)2]

Reactions of orthometallated binuclear palladium complexes with NaER, obtained by NaBH₄ reduction of R₂E₂ in methanol, gave complexes, [Pd₂(μ-ER)₂(C^∩Y)₂] (HC^∩Y = N,N-dimethylbenzylamine (C₆H₅CH₂NMe₂), N,N-dimethylnaphthylamine (C₁₀H₇NMe₂), tri-o-tolylphosphine {P(tol-o)₃}; ER=SePh, SeMes, TePh, TeMes (Mes = 2,4,6-Me₃C₆H₂). Similar reactions of [Pd₂(μ-Cl)₂(C₁₀H₆NMe₂-C,N)₂] with Pb(SMes)₂ or MesSH in the presence of NaHCO₃ gave chloro/thiolato-bridged complex [Pd₂(μ-Cl)(μ-SMes)(C₁₀H₆NMe₂-C,N)₂]. The newly synthesized complexes were characterized by elemental analysis, UV-Vis, IR, NMR (¹H, ¹³C, ³¹P, ⁷⁷Se, ¹²⁵Te) spectroscopy. These complexes crystallized out preferentially in sym-cis configuration. A low energy charge transfer transition has been identified from chalcogenolate centers to an emptyπ^∗ orbital of cyclometallated ligand in absorption spectroscopy in these complexes. The structures of [Pd₂(μ-Cl)(μ-SMes)(C₁₀H₆NMe₂-C,N)₂] (1) and [Pd₂(μ-SePh)₂(C₁₀H₆NMe₂-C,N) ₂] (3) have been established by single crystal X-ray diffraction analyses. In the former, the two palladium atoms are held together by chloro and thiolato bridges whereas in the latter, the two phenylselenolato ligands bridge two palladium atoms. The pyrolysis of [Pd(μ-TeMes)(C₁₀H₆NMe₂-C,N)]₂ (10) in a furnace gave Pd₇Te₃ whereas thermolysis in TOPO afforded primarily PdTe₂.     

The oxidation of ferrocytochrome c by Br−2, (SCN)−2, N3 and OH radicals studied by pulsed-electron and γ-ray radiolysis

The reactions of ferrocytochrome c with Br^?₂, (SCN)^?₂, N₃ and OH radicals were followed by measuring the change in the optical spectra of cytochrome c on γ-irradiation as well as the rate of change of absorbance upon pulse irradiation.Ferrocytochrome c is oxidized to ferricytochrome c by Br^?₂, (SCN)^?₂ or N₃ radical with an efficiency of about 100% through a second-order process in which no intermediates were observed. The rate constants in neutral solutions at I = 0.073 are 9.7 · 10⁸ M^?1 · s^?1, 7.9 · 10⁸ M^?1 · s^?1, 1.3 · 10⁹ M^?1 · s^?1 for the oxidation by Br^?₂, (SCN)^?₂ and N₃ radicals, respectively. The rate constants do not vary appreciably in alkaline solutions (pH 8.9). The ionic strength dependence was observed for the rate constants of the oxidation by Br^?₂ and (SCN)^?₂. Those rate constants estimated on the assumption that the radicals react only with the amino acid residues with the characteristic steric correction factors were less than one-tenth of the observed ones. These results suggest that the partially exposed region of the heme is the probable site of electron transfer from ferrocytochrome c to the radical.Hydroxyl radicals also oxidize ferrocytochrome c with a high rate constant (k > 1 · 10¹⁰ M^?1 · s^?1), but with a very small efficiency (5%).     

Dithiolate and diselenolate complexes [Pt2(μ-ECH2CHCHCH2E)(PPh3)4] (E = S, Se): Synthesis, characterisation and mass spectrometric formation of the dichalcogenide species [Pt2(μ-E2)(PPh3)4]

The reactions of [Pt₂(μ-E)₂(PPh₃)₄] (E = S, Se) with cis-1,4-dichlorobut-2-ene (cis-ClCH₂CHCHCH₂Cl) give the dichalcogenolate complexes [Pt₂(μ-ECH₂CHCHCH₂E)(PPh₃)₄]²⁺; an X-ray structure determination on the thiolate complex was carried out. The complexes give the expected dications in ESI mass spectra recorded at very low cone voltages, but at moderate cone voltages undergo facile fragmentation via a retro-Diels-Alder reaction and loss of 1,3-butadiene, giving the dichalcogenide species [Pt₂(μ-E₂)(PPh₃)₄]²⁺. Analogous species containing bidentate phosphine or arsine ligands have been previously generated electrochemically, and studied theoretically.     

1,3-Bis(α-aminoisopropyl)benzene, meta-C6H4(CMe2NH2)2: An N,N-bridging and N,C,N-cyclometalating ligand

Saponification of the bis(carbamic acid ester) 1,3-C₆H₄(CMe₂NHCO₂Me)₂ (1), made by the addition of methanol to commercial 1,3-C₆H₄(CMe₂NCO)₂, yielded the meta-phenylene-based bis(tertiary carbinamine) 1,3-C₆H₄(CMe₂NH₂)₂ (2). Dinuclear [{(η⁴-1,5-C₈H₁₂)RhCl}₂{μ-1,3-C₆H₄(CMe₂NH₂)₂}] (3) resulted from the action of 2 on [{(η⁴-1,5-C₈H₁₂)Rh(μ-Cl)}₂] in toluene. Combination of 2 with PdCl₂ or K₂[PdCl₄] gave the dipalladium macrocycle trans,trans-[{μ-1,3-C₆H₄(CMe₂NH₂)₂}₂(PdCl₂)₂] (4) along with cyclometalated [{2,6-C₆H₃(CMe₂NH₂)₂-κN,κC¹,κN′}PdCl] (5). Substitution of PEt₃ for the labile chlorido ligand of 5 afforded [{2,6-C₆H₃(CMe₂NH₂)₂-κN,κC¹, κN′}Pd(PEt₃)]Cl (6). The crystal structures of the following compounds were determined: bis(carbamic acid ester) 1, ligand 2 as its bis(trifluoroacetate) salt [1,3-C₆H₄(CMe₂NH₃)₂](O₂CCF₃)₂, 2 · (HAc_f)₂, complexes 3 and 6, as well as 1,3-C₆H₄(CMe₂OH)₂ (the diol analogue of 2).     

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.     

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.     

Ab initio double-ζ (D95) valence bond calculations for the ground states of NO2, O3, and ClO2

The results of some double-ζ D95 valence-bond (VB) calculations are reported for the ground states of nitrogen dioxide, NO₂ (17 valence electrons), ozone, O₃ (18 valence electrons), and chlorine dioxide, ClO₂ (19 valence electrons). The Mulliken, Löwdin and Hiberty structural weights are reported for nine (NO₂), six (O₃), and three (ClO₂) Lewis structures that differ in the locations of the π electrons. The most important Lewis structures for NO₂ are the uncharged spin-paired diradical structure VII and the two equivalent structures that carry no formal charges (II and V). For O₃ and ClO₂, the primary Lewis structures are, respectively, the uncharged singlet diradical structure III, and I with the odd electron located in the chlorine 3pπ atomic orbital.For ClO₂, the results of some STO-6G calculations, with 16 canonical Lewis type structures included, give a much smaller value for the chlorine odd-electron charge than does the D95 vb2000 calculation with a Hartree-Fock core. However, the structural weights obtained from the STO-6G calculations do reflect the expectation that small atomic formal charge separations, together with some Cl-O covalent σ-bonding, are associated with large structural weights.     

Novel Rh-Mn mixed-metal carbonyl cluster containing μ3 and μ-bridging carbyne ligands, [(μ3-CC6H5)(μ-CC6H5)Rh2Mn2Cp2(μ-CO)3(CO)3]: structure, electrochemistry and catalytic properties

The cationic carbyne complex [Cp(CO)₂MnCC₆H₅]BBr₄ (1) reacts with PPN[Rh(CO)₄] (2) to give the title cluster [(μ₃-CC₆H₅)(μ-CC₆H₅) Rh₂Mn₂Cp₂(μ-CO)₃(CO)₃] (3) whose structure has been determined by X-ray diffraction. The electrochemical properties of 3 have been investigated using cyclic voltammetric method. At 60 °C and 2.0 MPa of initial total CO/H₂ (1:1) pressure, the catalytic activity of 3 towards hydroformylation of styrene has also been checked.     

The effects of prostaglandins E2 and F2α on synaptosomal accumulation and release of 3H-norepinephrine

Prostaglandins (PG) of both the E and F series may serve as modulators of norepinephrine (NE) release from peripheral sympathetic neurons. We have studied the effects of PGE₂ and PGF_2α on the accumulation and release of ³H-NE in the CNS using synaptosomes isolated from rat hypothalami.The release of ³H-NE from synaptosomes superfused with Krebs-Ringer bicarbonate buffer was multiphasic with an initial fast release phase followed by a slower release. Raising KC1 concentration of the superfusion medium to 56mM during the slow release phase is known to stimulate ³H-NE release. PGE₂ (1 × 10^?6M) attenuated ³H-NE release during the fast phase and reduced the amount of ³H-NE released due to KC1 stimulation. At lower concentrations of PGE₂ there was no change in the release profile. PGF_2α was without effect on ³H-NE release at all concentrations tested.The accumulation of ³H-NE was significantly diminished by PGE₂ at a concentration of 1 × 10^?6M, while a lower concentration (1 × 10^?7M) was ineffective. PGF_2α had no effect on ³H-NE accumulation at all concentrations investigated.     

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.     

Effect of mifepristone and antiestrogens on uterine PGF2α and PGE2 concentrations in ovariectomized and pregnant rats

Four antiestrogens (anordiol, tamoxifen, RU 39411, ICI 182780) and the antiprogestin, mifepristone (RU 486), were administered to the following three animal models: (1) ovariectomized rats, (2) mated rats treated post-coitally; and (3) pregnant rats treated post-implantation. The antiestrogens were administered alone or in combination with mifepristone at doses effective in preventing and/or terminating pregnancy in rats. The objective of the study was to determine whether these drugs influenced uterine concentrations of prostaglandins (PGF_2α and PGE₂).Antiestrogens administered alone to ovariectomized rats did not effect uterine PGE₂ or PGF_2α concentrations; whereas the combination of anordiol/mifepristone increased uterine PGF_2α concentration, resulting in an increase in the PGF_2α/PGE₂ ratio.Mated rats were treated post-coitally for three consecutive days with anordiol, tamoxifen, estradiol and mifepristone alone and with the combination of anordiol/mifepristone and tamoxifen/mifepristone. An increase in uterine PGF_2α concentrations and in the PGF_2α/PGE₂ ratio occurred only in anordiol/mifepristone treated group. A decrease in uterine PGE₂ concentrations occurred in animals treated with anordiol, tamoxifen and estradiol, resulting in an increase in the PGF_2α/PGE₂ ratio.Anordiol (5.0 mg/kg/day) and mifepristone (4.0 mg/kg/day) alone and the combination of anordiol/mifepristone (2.5/1.0 mg/kg/day) administered to pregnant rats on days 7, 8 and 9 of pregnancy induced an increase in PGF_2α levels without affecting uterine PGE₂ concentration. The changes in uterine PGF_2α concentrations induced by anordiol and the combination of anordiol/mifepristone resulted in an increase in the PGF_2α/PGE₂ ratio.The antiestrogens tested except for ICI 182780 possessed agonist activity when assayed by measuring their capacity to increase the uterine weights in ovariectomized rats. Also, ICI 182789 was the only antiestrogen that did not influence uterine PG concentrations. It can be concluded that ICI 182780 is the only “pure” antiestrogen among those tested.The present results show that antiestrogens and the combination of mifepristone plus anordiol at doses preventing implantation and terminating pregnancy increase uterine PGF_2α and/or decrease PGE₂ concentrations, resulting in an alteration of PGF_2α/PGE₂ ratio. These findings suggest that there exists a critical balance of PGF_2α to PGE₂ concentrations in the uterus required for the normal passage of fertilized ova through the oviduct, initiating implantation of the blastocysts, development of embryos, and maintenance of pregnancy.     

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.     

Critical evaluation of electron transfer kinetics in P700–FA/FB, P700–FX, and P700–A1 Photosystem I core complexes in liquid and in trehalose glass

This work aims to fully elucidate the effects of a trehalose glassy matrix on electron transfer reactions in cyanobacterial Photosystem I (PS I). Forward and backward electron transfer rates from A_1A^? and A_1B^? to F_X, and charge recombination rates from A₀^?, A_1B^?, A_1A^?, F_X^?, and [F_A/F_B]^? to P₇₀₀⁺ were measured in P₇₀₀–F_A/F_B complexes, P₇₀₀–F_X cores, and P₇₀₀–A₁ cores, both in liquid and in a trehalose glassy matrix at 11% humidity. By comparing CONTIN-resolved kinetic events over 6 orders of time in increasingly simplified versions of PS I at 480?nm, a wavelength that reports primarily A_1A^?/A_1B^? oxidation, and over 9 orders of time at 830?nm, a wavelength that reports P₇₀₀⁺ reduction and A₀^? oxidation, assignments could be made for nearly all of the resolved kinetic phases. Trehalose-embedded PS I samples demonstrated partially arrested forward electron transfer. The fractions of complexes in which electron transfer did not proceed beyond A₀, A₁ and F_X were 53%, 16% and 22%, respectively, with only 10% of electrons reaching the terminal F_A/F_B clusters. The ~10?μs and ~150?μs components in both liquid and trehalose-embedded PS I were assigned to recombination between A_1B^? and P₇₀₀⁺ and between A_1A^? and P₇₀₀⁺, respectively. The kinetics and amplitudes of these resolved kinetic phases in liquid and trehalose-embedded PS I samples could be well-fitted by a kinetic model that allowed us to calculate the asymmetrical contribution of the A_1A^? and A_1B^? quinones to the electrochromic signal at 480?nm. Possible reasons for these effects are discussed.     

A novel tetranuclear hydrogenphosphate-bridged Cu(II) cluster. Synthesis, structure, spectroscopy and magnetism of [Cu4(dpyam)4(μ4,η-HPO4)2(μ-X)2]X2(H2O)6 (X = Cl, Br)

Two novel tetranuclear compounds with an unprecedented mode of a hydrogenphosphato bridge, [Cu₄(dpyam)₄(μ₄,η³-HPO₄)₂(μ-X)₂]²⁺ (in which dpyam = di-2-pyridylamine and X = Cl (1), Br (2)) have been synthesised and characterised structurally and magnetically. The Cu(II) ions in the structures each display a square-pyramidal geometry, with two tridentate hydrogenphosphato groups bridging four copper atoms in a μ₄,η³ coordination mode which is rarely found in hydrogenphosphate metal compounds. Each (different) pair of Cu(II) ions is additionally bridged by halide ions, with relatively long Cu-X distances (2.551(3)-2.604(3) Å for 1 and 2.707(1)-2.766(2) Å for 2) and subsequently also a small Cu-X-Cu angle (65.7(1)° and 65.1(1)° for 1 and 61.6(1)° and 62.4(1) for 2) and a large Cu-X-Cu angle (95.5(1)° and 96.5(1)° for 1 and 91.1(1)° and 92.6(1)° for 2). Cu?Cu distances in the tetranuclear units varies from 2.802(3) to 5.232(3) Å for 1 and from 2.834(1) to5.233(1) Å in 2. The lattice structures are stabilised by extensive intermolecular hydrogen bonds. The magnetic susceptibility measurements down to 5 K revealed a weak ferromagnetic interaction between the outer pairs of Cu(II) ions which vary from 22 to 46 cm⁻¹ in 1 and 12 to 33 cm⁻¹ in 2 and a moderately strong antiferromagnetic interaction between the inner Cu(II) ions of −79 cm⁻¹ in 1 and −83 cm⁻¹ in 2, via the Cu-O-P-O-Cu pathway.     

Synthesis and characterisation of adducts of [Pt2(μ-S)2(PPh3)4] with organo-palladium and platinum-hydride substrates

The reactions of [Pt₂(μ-S)₂(PPh₃)₄] towards a range of palladium(II) complexes containing organometallic ligands (cyclopalladated N-donor ligands, η³-allyl, phenyl) have been explored, leading to the formation of a series of cationic, trinuclear sulfido-bridged aggregates containing {Pt₂PdS₂} cores. [Pt₂(μ-S)₂(PPh₃)₄] also reacts with the platinum(II) hydride complex trans-[PtHCl(PPh₃)₂] giving the adduct [Pt₂(μ-S)₂(PPh₃)₄PtH(PPh₃)]⁺. X-ray crystal structure determinations on the complexes [Pt₂(μ-S)₂(PPh₃)₄PdPh(PPh₃)]PF₆ and [Pt₂(μ-S)₂(PPh₃)₄PtH(PPh₃)]PF₆ are reported, and show the expected bis μ₃-sulfido aggregates with three square-planar metal centres.