Filamentous growth of Escherichia coli K12 elicited by dimeric,mixed-valence complexes of ruthenium

Dimeric, mixed-valence [(Ru(II), Ru(III)] compounds of ruthenium caused filament formation in growing cultures of Escherichia coli K12. Three compounds with the general formula Ru₂(NH₃)₆X₅ · H₂O (where X is a halide) were tested; in order of decreasing effectiveness (and with the concentration giving maximum effect), these were the bromo (10^-5 M), chloro (10^-4 to 10^-5 M), and iodo (10^-3 to 10^-4 M) analogues. Filamentation elicited by the bromo and chloro compounds was spontaneously reversible after 3–4 h, and tentatively attributed to oxidation of the active mixed-valence form to inactive Ru(III) complexes. Several compounds known to accelerate division of filaments formed under other conditions were ineffective in reversing the filamentation, but the presence of 0,43 M-dimethylsulphoxide totally inhibited filamentation caused by the bromo or chloro compounds and by cis-Pt(NH₃)₂Cl₂ (cisplatin), an established filamenting and antitumour agent. The ruthenium complexes bound to mammalian DNA, but were without effect on the UV spectrum or cellular content of DNA in E. coli, despite showing marked mutagenic activity in reverse mutation tests with Salmonella typhimurium. Cells remained sensitive to inhibition of division by the ruthenium complexes until immediately prior to the division event. Possibilities for the (probably complex) mode of action and the potential of related compounds for therapeutic use are discussed.Non-standard abbreviation DMSO dimethylsulphoxide     

SYNTHESIS AND BASE PAIRING PROPERTIES OF 9-DEAZAPURINE N7-NUCLEOSIDES IN OLIGONUCLEOTIDE DUPLEXES AND TRIPLEXES

The 9-deazaguanine N⁷-2′-deoxyribofuranoside (3) as well as the bromo and iodo derivatives 4a,b were synthesized and incorporated in oligonculeotide duplexes and triplexes. Their base pairing properties were investigated and compared with those of the parent purine N⁷-2′-deoxyribofuanosides.     

Synthesis and characterization of the 1:1 adducts of copper(I) halides with bidentate N,N′-bis(benzophenone)-1,2-diiminoethane Schiff base: Crystal structures of [Cu(bz2en)2][CuX2] (X = Br, I) complexes

1:1 adducts of N,N′-bis(benzophenone)-1,2-diiminoethane (bz₂en) with copper(I) chloride, bromide and iodide, [Cu(bz₂en)₂][CuX₂] (X = Cl, Br, and I), have been synthesized and the structures of the solid bromide and iodide adducts were determined by X-ray crystallography from single-crystal data. The solid-state structure reveals ionic complexes containing a cation of copper(I) ion coordinated to four nitrogen atoms of two bz₂en molecules (distorted tetrahedron) and a linear dibromocuprate(I) and a di-μ-iodo-diiododicuprate(I) anion for the bromo and iodo adducts, respectively. The bromo adduct structure contains CH?Br intermolecular hydrogen bonds. The complexes are very stable towards atmospheric oxygen in the solid state. The spectral properties of the above complexes are also discussed.     

Halogenated biphenyls as AHH inducers: Effects of different halogen substituents

4′-Iodo-, 4′-bromo-, 4′-chloro- and 4′-fluoro-2,3,4,5-tetrachlorobiphenyl were administered to immature male Wistar rats and the effects of this homologous series of 4′-halo-2,3,4,5-tetrachlorobiphenyls on the microsomal drug-metabolizing enzymes were determined. All the halogenated biphenyls increased microsomal benzo[a]pyrene hydroxylase (or aryl hydrocarbon hydroxylase, AHH), ethoxyresorufin (ER) O-deethylase and dimethylaminoantipyrine (DMAP) N-demethylase. The effects of the 4′-halo-2,3,4,5-tetrachlorobiphenyls on the microsomal enzyme activities and on the relative peak intensities and spectral shifts of the reduced cytochrome P-450:CO and ethylisocyanide (EIC) binding difference spectra were similar to those observed after coadministration of phenobarbitone (PB) and 3-methylcholanthrene (MC). The relative activities of the halogenated biphenyls were determined using two $\text{in}$$\text{vitro}$ assays; namely cytochrome P-448 associated induction in rat hepatoma H-4-II E cells in culture and competitive binding to the hepatic cytosolic $\text{Ah}$ receptor protein from male Wistar rats. Dose-response experiments for the iodo, bromo, chloro and fluoro analogs gave EC₅₀(M) values of 8.5×10^?9, 6.6×10^?8, 5.7×10^?7, and 3.3×10^?5, and 1.5×10^?6, 2.5×10^?6, 4.1×10^?6 and 2.5×10^?5 for the ER O-deethylase induction and receptor binding assays respectively. The relative potencies of the 4′-halo-2,3,4,5-tetrachlorobiphenyls followed the order I>Br>Cl>F for both assays and differences in the EC₅₀ values for the iodo and fluoro analogs were greater than three orders of magnitude for ER O-deethylase induction in rat hepatoma cells in culture. One possible explanation for these effects may be associated with differences in the polarizability of the laterally substituted halogen groups. However, other differences in the physico-chemical properties of the halogen atoms may also be important.     

Partitioning of mercury in aqueous biphasic systems and on ABEC™ resins

Poly(ethylene glycol)-based aqueous biphasic systems (PEG-ABS) can be utilized to separate and recover metal ions in environmental and hydrometallurgical applications. A concurrent study was conducted comparing the partitioning of mercury between aqueous layers in an ABS [Me-PEG-5000/(NH₄)₂SO₄] and partitioning of mercury from aqueous solutions to aqueous biphasic extraction chromatographic (ABEC-5000) resins. In ammonium sulfate solutions, mercury partitions to the salt-rich phase in ABS, but by using halide ion extractants, mercury will partition to the PEG-rich phase after formation of a chloro, bromo or iodo complex. The efficacy of the extractant increases in the order Cl⁻<Br⁻<I⁻. This behavior is also observed using the ABEC resins where halo complexes of mercury will adsorb to the resin from (NH₄)₂SO₄ solutions with retention following the same order. The onset of mercury extraction or adsorption is different for the three extractants, occurring at the lowest extractant concentration for I⁻, followed by Br⁻, and then Cl⁻. Fluoride does not extract mercury. Extraction or adsorption of mercury is improved at the lowest halide concentrations in the presence of sulfuric acid. The addition of sulfuric acid to (NH₄)₂SO₄ solution results in ABEC retention of mercury even in the absence of halide extractant.     

Iodo bridged lead(II) compounds of azoimidazoles: Single crystal X-ray structures of [di-iodo-{1-methyl-2-(p-tolylazo)imidazole}lead(II)]n and {1-methyl-3-benzyl-2-(p-tolylazo)imidazolium}m-{tri-iodoplumbate(II)}m

PbI₂ forms iodo-bridged neutral polymer upon reaction with 1-alkyl-2-(arylazo)imidazoles (RaaiR′). The reaction of PbI₂ and dialkyl imidazolium iodides [RaaiR′R″]⁺I⁻ has synthesized {1,3-dialkyl-2-(arylazo)imidazolium}_m-{tri-iodoplumbate(II)}_m. The complexes are characterized by different spectroscopic studies. Iodobridged chelated polymer, [Pb(RaaiR′)I₂]_n, has been established by single crystal X-ray diffraction measurements in one case. Tri-iodoplumbates form iodo bridged anion polymer, which connects [RaaiR′R″]⁺ by hydrogen bonding and are placed in between the pillars of [Pb(μ-I)₆]_n motif.     

Activation of the inositol trisphosphate second messenger system by cAMP in a mouse fibroblast cell line

Intracellular Ca²⁺ mobilization events were assessed in mouse L cells, which contain native prostaglandin E₁ receptors and transfected human ₂ adrenergic receptors. Both Fura2 (single cell measurements) and Quin 2, (cuvette assays) were used to determine [Ca²⁺]_i levels. Our results demonstrate that in the transfected cells there is a dose-dependent increase in [Ca²⁺]_i in response to isoproterenol (0.1 nM–100 nM), which is inhibited by the -adrenergic antagonist, propranolol, and is a result of intracellular Ca²⁺ release. [Ca²⁺]₁ in these cells was also increased by prostaglandin E₁, 8 bromo cyclic AMP, and aluminum fluoride. Both 8 bromo cAMP and isoproterenol induced a rapid increase in the levels of IP₁, IP₂, and IP₃. The data presented demonstrate that the elevation of intracellular cyclic AMP induces an increase in IP₃ production which leads to an elevation in [Ca²⁺];. We propose that this cyclic AMP dependent activation of the IP₃ generating system occurs at a post-receptor site.Abbreviations cAMP Adenosine Cyclic 3-5-Monophosphate - [Ca²⁺]_i intracellular [Ca²⁺]_i - 8 Br cAMP 8 Bromo Adenosine Cyclic 3-5-Monophosphate - DAG Diacylglycerol - EGTA] [Ethylene Bis (oxyethylenenitrilo)] Tetracetic acid - BSA Bovine Serum Albumin - HBSS-H Hanks' Balanced Salt Solution buffered with HEPES to pH 7.4 - HEPES 4-(2-Hydroxyethyl)-1-piperazineethanesulfonic acid - PIP₂ Phosphatidylinositol 4,5-bisphosphate - IP₂ Inositol 4 Phosphate - IP₂ Inositol 4,5 Bisphosphate - IP₃ Inositol Trisphosphate - PGE₁ Prostaglandin E₁ - PBS Phosphate Buffered Saline Solution     

Functional analysis of iodotyrosine deiodinase from drosophila melanogaster

The flavoprotein iodotyrosine deiodinase (IYD) was first discovered in mammals through its ability to salvage iodide from mono‐ and diiodotyrosine, the by‐products of thyroid hormone synthesis. Genomic information indicates that invertebrates contain homologous enzymes although their iodide requirements are unknown. The catalytic domain of IYD from Drosophila melanogaster has now been cloned, expressed and characterized to determine the scope of its potential catalytic function as a model for organisms that are not associated with thyroid hormone production. Little discrimination between iodo‐, bromo‐, and chlorotyrosine was detected. Their affinity for IYD ranges from 0.46 to 0.62 μM (K_d) and their efficiency of dehalogenation ranges from 2.4 – 9 x 10³ M^?1 s^?1 (k_cat/K_m). These values fall within the variations described for IYDs from other organisms for which a physiological function has been confirmed. The relative contribution of three active site residues that coordinate to the amino acid substrates was subsequently determined by mutagenesis of IYD from Drosophila to refine future annotations of genomic and meta‐genomic data for dehalogenation of halotyrosines. Substitution of the active site glutamate to glutamine was most detrimental to catalysis. Alternative substitution of an active site lysine to glutamine affected substrate affinity to the greatest extent but only moderately affected catalytic turnover. Substitution of phenylalanine for an active site tyrosine was least perturbing for binding and catalysis.     

Heterobinuclear Zn‐Ln (Ln = La,Nd, Eu,Gd, Tb,Er and Yb) complexes based on asymmetric Schiff‐base ligand: synthesis,characterization and photophysical properties

With a novel asymmetric Schiff‐base zinc complex ZnL (H₂L = N‐(3‐methoxysalicylidene)‐N′‐(5‐bromo‐3‐methoxysalicylidene)phenylene‐1,2‐diamine), obtained from phenylene‐1,2‐diamine, 3‐methoxysalicylaldehyde and 5‐bromo‐3‐methoxysalicylaldehyde, as the precursor, a series of heterobinuclear Zn‐Ln complexes [ZnLnL(NO₃)₃(CH₃CN)] (Ln = La, 1; Ln = Nd, 2; Ln = Eu, 3; Ln = Gd, 4; Ln = Tb, 5; Ln = Er, 6; Ln = Yb, 7) were synthesized by the further reaction with Ln(NO₃)₃·6H₂O, and characterized by Fourier transform‐infrared, fast atom bombardment mass spectroscopy and elemental analysis. Photophysical studies of these complexes show that the strong and characteristic near‐infrared luminescence of Nd³⁺, Yb³⁺and Er³⁺ with emissive lifetimes in the microsecond range has been sensitized from the excited state of the asymmetric Schiff‐base ligand due to effective intramolecular energy transfer; the other complexes do not show characteristic emission due to the energy gap between the chromophore and lanthanide ions. Copyright © 2012 John Wiley & Sons, Ltd.     

Nucleosides and Nucleotides. 192. Toward the Total Synthesis of Cyclic ADP-Carbocyclic-Ribose. Formation of the Intramolecular Pyrophosphate Linkage by a Conformation-Restriction Strategy in a Syn-form Using a Halogen Substitution at the 8-Position of the Adenine Ring

Abstract

The synthesis of cyclic ADP-carbocyclic-ribose (2), as a stable mimic for cyclic ADP-ribose, was investigated. Construction of the 18-membered backbone structure was successfully achieved by condensation of the two phosphate groups of 19, possibly due to restriction of the conformation of the substrate in a syn-form using an 8-chloro substituent at the adenine moiety. SN2 reactions between an optically active carbocyclic unit 8, which was constructed by a previously developed method, and 8-bromo-N ⁶-trichloroacetyl-2′,3′-O-isopropylideneadenosine 9c gave N-1-carbocyclic derivative, which was deprotected to give 5′,5′-diol derivatives 18. When 18 was treated with POCl₃ in PO(OEt)₃, the bromo group at the 8-position was replaced to give N-1-carbocyclic-8-chloroadenosine 5′,5′-diphosphate derivative 19 in 43% yield. Treatment of 19 with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride gave the desired intramolecular condensation product 20 in 10% yield. This is the first chemical construction of the 18-membered backbone structure containing an intramolecular pyrophosphate linkage of a cADPR-related compound with an adenine base.     

Synthesis and an angiolytic role of novel piperazine–benzothiazole analogues on neovascularization,a chief tumoral parameter in neoplastic development

A novel series of benzoic acid N′-[2-(4-benzothiazol-2-yl-piperazin-1-yl)-acetyl]-hydrazides 6a–j were synthesized and characterized by IR, ¹H, ¹³C NMR, elemental and mass spectral analyses. The in-vitro cytotoxicity and cell viability assay of the synthesized compounds 6a–j were evaluated against Dalton’s lymphoma ascites (DLA) cells. Our results showed that compound 6c with a bromo group on phenyl ring has showed promising antiproliferative efficacy. Further investigation of compound 6c on in-vivo treatment model depicts the increased tumor suppression through inhibition of angiogenesis.     

Affinities of methylphenidate derivatives for dopamine,norepinephrine and serotonin transporters

We have synthesized several derivatives of dl-threo-methylphenidate (Ritalin) bearing substituents on the phenyl ring. IC₅₀ values for binding of these compounds to rat brain monoamine transporters were assessed using [³H]WIN 35,428 (striatal membranes, dopamine transporters, DAT), [³H]nisoxetine (frontal cortex membranes, norepinephrine transporters, NET) and [³H]paroxetine (brain stem membranes, 5HT transporters, 5HTT). Affinities (1/Ki) decreased in the order: DAT > NET ⪢ 5HTT. Substitution at the para position of dl-threo-methylphenidate generally led to retained or increased affinity for the dopamine transporter (bromo > iodo > methoxy > hydroxy). Substitution at the meta position also increased affinity for the DAT (m-bromo > methylphenidate; m-iodo-p-hydroxy > p-hydroxy). Substitution at the ortho position with bromine considerably decreased affinity. Similar IC₅₀ values for binding of o-bromomethylphenidate to the dopamine transporter were measured at 0, 22 and 37 degrees. N-Methylation of the piperidine ring of methylphenidate also considerably reduced affinity. The dl-erythro isomer of obromomethylphenidate did not bind to the DAT (IC₅₀ > 50,000 nM). Affinities at the dopamine and norepinephrine transporters for substituted methylphenidate derivatives were well correlated (r² = 0.90). Abilities of several methylphenidate derivatives to inhibit [³H]dopamine uptake in striatal synaptosomes corresponded well with inhibition of [³H]WIN 35, 428 binding. None of the compounds examined exhibited significant affinity to dopamine D1 or D2 receptors (IC₅₀ > 500 or 5,000 nM, respectively), as assessed by inhibition of binding of [³H]SCH 23390 or [¹²³I]epidepride, respectively, to striatal membranes.     

Synthesis, reactivity, and structures of dialuminum complexes containing linked ketiminate ligands

Linked bis(ketimine) (1) can be prepared with the reaction of excess 2,4-pentanedione and 4,4′-methylene-bis(2,6-diisopropylaniline) in methanol in the presence of catalytic amount of formic acid. The dialuminum alkyl complexes containing the linked bis(ketiminate) dianionic ligands, [OC(Me)CHC(Me)N(2,6-ⁱPr₂C₆H₂-4)AlR₂]₂CH₂ (2, R = Me; 3, R = Et), were prepared by a reaction of 2 equiv AlR₃ with [OC(Me)CHC(Me)NH(2,6-ⁱPr₂C₆H₂-4)]₂CH₂ in methylene chloride. Reactions of 2 with 2 and 4 equiv of I₂ gave corresponding aluminum iodo complexes 4 and 5, respectively. Treatment of 5 with 2 equiv of AgBF₄, however, gave a diboron complex, [OC(Me)CHC(Me)N(2,6-ⁱPr₂C₆H₂-4)BF₂]₂CH₂ (6), in 18% isolated yield. All new complexes have been characterized by ¹H and ¹³C NMR spectroscopy and complexes 2, 3, and 6 are also confirmed by X-ray diffraction.     

Synthesis and base pairing properties of 9-deazapurine N7-nucleosides in oligonucleotide duplexes and triplexes

The 9-deazaguanine N7-2'-deoxyribofuranoside (3) as well as the bromo and iodo derivatives 4a,b were synthesized and incorporated in oligonucleotide duplexes and triplexes. Their base pairing properties were investigated and compared with those of the parent purine N7-2'-deoxyribofuanosides.     

Tin-119 NMR studies on diorganoyltin(IV)dihalides and triorganoyltin(IV)halides; Formation and stereochemistry of adducts

The reactions of R₂SnX₂ (R = Ph, Me; X = Cl, Br) with excess halide, tributylphosphine, tricyclohexylphosphine and tributylphosphine oxide have been investigated in dichloromethane solution by tin-119 and phosphorus-31 NMR techniques. R₂SnX₂ form five coordinate 1:1 adducts with halide and phosphine (phos) ligands whilst both 1:1 and 1:2 adducts are formed with tributylphosphine oxide (L). Tin-119 spectra imply that Ph₂SnX₂(phos) has the phosphine in the equatorial position of a trigonal bipyramid. At low temperature there is evidence for a slow intramolecular twist mechanism between octahedral isomers of Ph₂SnCl₂L₂. The stereochemistry of the complexes Ph₂SnX₂L₂ differ between chloro and bromo compounds and no mixed halide complex is observed. In the case of the bromo system only, the 1:3 adduct [Ph₂SnBrL₃]⁺Br⁻ is formed. Ph₃SnCl does not react with phosphines but it does give 1:1 adducts with Cl⁻, L and pyridine. All the adducts have similar tin-119 chemical shifts which is consistent with the phenyl groups being equatorial in the five coordinate trigonal bipyramidal adducts. Ph₄Sn does not form adducts with X⁻, L or phosphine.     

Retardation of leaf senescence by urea cytokinins in Raphanus sativus

Approximately 500 urea derivatives and related compounds were tested for ability to retard leaf senescence as measured by chlorophyll retention in radish (Raphanus sativus) leaf discs. Of the 90 compounds found to be active, some had activity at 10^?6 M of the same order as kinetin. There was a high correlation between ability to promote chlorophyll retention and initiation of cell division. Highly active compounds had a planar ring and a HNCONH bridge; substitution with a HNCSNH bridge reduced activity and all other tested arrangements of the bridge gave inactive compounds. Substitution of both amino hydrogen atoms on one or both sides of the bridge reduced or removed activity. Some N′-substituted phenyl ureas were highly active. Introduction of a N-phenyl ring to a N-phenyl urea increased activity except where one ring was substituted in the para position with chloro, bromo or iodo. The activities of symmetrical disubstituted ureas were generally less than the corresponding N-monosubstituted derivative. The results suggest that the receptor site for cytokinin activity is the same for senescence retadation and cell division initiation.     

Surface coordination chemistry of noble-metal electrocatalysts: Oxidative addition and reductive elimination of iodide at iridium,platinum and gold in aqueous solutions

The oxidative addition and reductive elimination of the iodo ligand has been compared at smooth polycrystalline gold, platinum and iridium surfaces in aqueous solutions. On these three metals, the iodo species undergoes spontaneous oxidative chemisorption to form a close-packed monolayer of zero-valent iodine, the saturation coverage of which is limited by the van der Waals radius of the iodine atom; this oxidative addition process is further manifested by evolution of hydrogen gas from proton reduction. Elimination of iodine from these surfaces can be achieved by its reduction back to the anion either by application of sufficiently negative potentials or by exposure to ample amounts of hydrogen gas. On Pt and Ir, the reductive desorption of iodine is coupled with reductive chemisorption of hydrogen; consequently, the reaction is a two-electron, pH-dependent process. A plot of E_1/2, the potential at which the iodine coverage is decreased to half its maximum value, against pH yields information concerning the redox potential of the I_(ads)/I⁻_(ads) couple in the surface-coordinated state. On Au, where dissociative chemisorption of hydrogen does not occur, the iodine-stripping process is a pH-independent, one-electron reaction. The difference in the redox potentials [E^o_I(ads) -E^o_I(aq] for the I_(ads) and I_2(aq)/I⁻_(aq) redox couples was found to be −0.90 V on Au, − 0.76 V on Pt, and −0.72 V on Ir. These values imply that the ratio of the formation constants for surface coordination of the iodine and iodide species (K_f,I/K_f,I−) is 2 × 10²⁸ on Au, 1 × 10²⁶ on Pt, and 2 × 10²⁵ on Ir.     

A mixed NCP pincer palladacycle as catalyst precursor for the coupling of aryl halides with aryl boronic acids

The reaction of phosphinite Me₂NCH₂CC(CH₂)₂OP(i-Pr)₂ (2) with Li₂PdCl₄ in methanol at room temperature affords the air and water stable mixed pincer palladacycle (Me₂NCH₂(Cl)CC(CH₂)₂OP(i-Pr)₂-κNκCκP)PdCl (3) whose structure has been ascertained by means of an X-ray diffraction study. This pincer palladacycle is a highly efficient catalyst precursor for the coupling of aryl boronic acids and aryl chlorides. Both electron-rich and -poor aryl chlorides are efficiently coupled in the presence of 3 to furnish the corresponding cross-coupled products in excellent yields, and a wide variety of functional groups are tolerated in both aryl chloride and aryl boronic acid. The experimental protocol has also been extended for the coupling of iodo and bromo arenes with aryl boronic acids for the generation of hindered biphenyls. The coupling process afforded very good yields of biphenyl products containing two ortho substituents. Steric hindrance is more sensitive for ortho substituents in the aryl boronic acid and is more pronounced when the coupling reaction involves three ortho substituents.     

Regulatory flexibility of methylotrophic yeasts in chemostat cultures: Simultaneous assimilation of glucose and methanol at a fixed dilution rate

The influence of the composition of methanol/glucose-mixtures as only sources of carbon and energy on growth and regulation of the synthesis of enzymes involved in methanol-dissimilation was studied under chemostat conditions at a fixed dilution rate with the methylotrophic yeasts Hansenula polymorpha and Kloeckera sp. 2201. Both carbon sources were found to be utilized completely independently of the composition of the C₁/C₆ mixture. Using mixtures of ¹⁴C-labelled methanol and glucose the growth yield for glucose was found to be constant for all C₁/C₆-mixtures tested and both yeasts. The growth yield for methanol, however, was reduced by up to 25% when the proportion of methanol in the inflowing medium was lower than 20% (w/w with respect to glucose) for H. polymorpha and 50% (w/w with respect to glucose) for Kloeckera sp. 2201 respectively. During growth with C₁/C₆-mixtures containing higher C₁-proportions of methanol regular growth yields for methanol were recorded which corresponded to the growth yields found with methanol as the only carbon source.The regulation of the synthesis of the enzymes of the dissimilatory pathway for methanol was found to be under multiple control. Although glucose was present in the medium methanol had a positive effect on the synthesis of these enzymes. Thus, in addition to derepression induction by methanol was also observed. This inductive effect was found to increase with increasing proportions of methanol in the mixture. Depending on the enzyme, 10–40% methanol in the mixture resulted in a maximal induction with enzyme specific activities equal to those found in cells grown with methanol as the only carbon source. No further enhancements in enzyme specific activities were observed during growth on mixtures containing more than 40% methanol.Abbreviations and terms C₁ Methanol - C₆ glucose - C₁/C₆ mixture compositions are given in % (w/w) - C₀ concentration of ¹⁴C in the inflowing medium (DPM ml^-1) - C(t) concentration of ¹⁴C incorporated in cells as a function of time t (DPM ml^-1) - d dilution rate (h^-1) - DPM disintegrations per minute - q _s q _C1 and q _C6 are specific rates of consumption of substrate, methanol and glucose respectively [g (g cell dry weight)^-1 h^-1] - q _O2 and q _CO2 are the specific rates of oxygen consumption and carbon dioxide release [mmol (g cell dry weight)^-1 h^-1] - RQ respiration quotient (q _CO2 q _O2 ^-1) - s _C1 and s _C6 are the residual concentrations of methanol and glucose in the culture liquid (g l^-1) - s _O/C1 and s _O/C6 are the concentrations of methanol and glucose in the inflowing medium (g l^-1) - Sp.A. enzyme specific activity - x cell dry weight concentration (g l^-1) - Y _X/C1 and Y _X/C6 are growth yields on methanol and glucose respectively (g cell dry weight (g substrate)^-1 - Y _C/C1 growth yield with methanol with respect to carbon (g carbon assimilated (g carbon supplied)^-1 - _m maximum specific growth rate (h^-1)     

Synthesis and structural studies of dimolybdenum(V), palladium(II) and dicopper(I) complexes that contain mixed pyridyl-iso-propylphosphine ligands

The reaction of Mo₂(μ-O₂CCH₃)₄ with 2-pyridyl(diisopropylphosphino)methane (NP) affords the dimolybdenum(V) complex Mo₂(μ-O)₂O₂Cl₂(η²-NP)₂ (1). Complexes of the related 2-pyridylbis(diisopropylphosphino)methane ligand (NP²) have been isolated, namely, a mixed bromo/chloro complex of composition PdBr_1.09Cl_0.91(η²-NP²) (2) and the dicopper(I) complex [Cu₂(μ-η³-NP²)₂](BF₄)₂ (3). The structures of 1, 2 and 3 have been established by X-ray crystallography.