Phosphine-imine and -enamido ligands for acceptorless dehydrogenation catalysis.

A highly tunable phosphine-imine ligand family is introduced. Following metallation with ruthenium, deprotonation of the ligand affords a phosphine-enamido species. Complexes with the ligand in both the imine and enamido forms are active toward acceptorless dehydrogenation reactions.

Coinage metal coordination chemistry of stable primary, secondary and tertiary ferrocenylethyl-based phosphines.

Ferrocene-based phosphines constitute an important auxiliary ligand in inorganic chemistry. Utilizing the (ferrocenylethyl)phosphines (FcCH2CH2)3-nHnP (Fc = ferrocenyl; n = 2, 1; n = 1, 2; n = 0, 3) the synthesis of a series of coordination complexes [(FcCH2CH2)3-nHnPCuCl]4 (n = 2, 1-CuCl; n = 0, 3-CuCl), [(FcCH2CH2)2HPCuCl] (2-CuCl), {[(FcCH2CH2)H2P]2AgCl}2 (1-AgCl), [(FcCH2CH2)2HPAgCl] (2-AgCl), [(FcCH2CH2)3PAgCl]4 (3-AgCl), [(FcCH2CH2)3PM(OAc)]4 (M = Cu, 3-CuOAc M = Ag, 3-AgOAc), [(FcCH2CH2)3-nHnPAuCl] (n = 1, 2-AuCl; n = 0, 3-AuCl), via the reaction between the free phosphine and MX (M = Cu, Ag and Au; X = Cl, OAc), is described. The reaction between the respective phosphine with a suspension of metal-chloride or -acetate in a 1 : 1 ratio in THF at ambient temperature affords coordinated phosphine-coinage metal complexes. Varying structural motifs are observed in the solid state, as determined via single crystal X-ray analysis of 1-CuCl, 3-CuCl, 1-AgCl, 3-AgCl, 3-CuOAc, 3-AgOAc, 2-AuCl and 3-AuCl. Complexes 1-CuCl and 3-CuCl are tetrameric Cu(i) cubane-like structures with a Cu4Cl4 core, whereas silver complexes with primary and tertiary phosphine reveal two different structural types. The structure of 1-AgCl, unlike the rest, displays the coordination of two phosphines to each silver atom and shows a quadrangle defined by two Ag and two Cl atoms. In contrast, 3-AgCl is distorted from a cubane structure via elongation of one of the ClAg distances. 3-CuOAc and 3-AgOAc are isostructural with step-like cores, while complexes 2-AuCl and 3-AuCl reveal a linear geometry of a phosphine gold(i) chloride devoid of any aurophilic interactions. All of the complexes were characterized in solution by multinuclear (1)H, (13)C{(1)H} and (31)P NMR spectroscopic techniques; the redox chemistry of the series of complexes was examined using cyclic voltammetry. This class of complexes has been found to exhibit one reversible Fe(ii)/Fe(iii) oxidation couple, suggesting the absence of electronic communication between the ferrocenyl units on individual phosphine ligands as well as between different phosphines on the polymetallic cores.

An unsupported metal hydroxide for the design of molecular µ-oxo bridged heterobimetallic complexes.

A terminal and unsupported chromium(III) hydroxide is reported. The terminal hydroxide is used to synthesize the first example of a heterobimetallic Ti-O-Cr compound containing an unsupported µ-oxo bridge. The heterobimetallic complex exhibits a new absorbance at 288 nm (4.32 eV), which is assigned to a metal-to-metal charge transfer (MMCT) transition.

Goldilocks effect in magnetic bistability: remote substituent modulation and lattice control of photoinduced valence tautomerism and light-induced thermal hysteresis.

The thermal-induced and photoinduced valence tautomerism of a series of Co(dioxolene)(2)(4-X-py)(2) complexes (dioxolene = 3,5-di-tert-butylcatecholate or 3,5-di-tert-butylsemiquinonate; 4-X-py = 4-(X)pyridine, X = H (1), OMe (2), Me (3), CN (4), Br (5), NO(2) (6)) is described. The thermal valence tautomerism (ls-Co(III)(SQ)(Cat)(4-X-py)(2) <--> hs-Co(II)(SQ)(SQ)(4-X-py)(2)) is only observed for complexes 4, 5, and 6 where each is accompanied by a hysteresis loop of ca. 5 K. When a crystalline sample of 4-6 is held at 10 K in a SQUID magnetometer and irradiated with white light (lambda = 400-850 nm), the hs-Co(II) tautomer is formed. When the light source is removed, and the sample is slowly heated, the hs-Co(II) tautomer persists until ca. 90 K, approximately 40 K higher than the thermal stability of previously reported complexes. Heating and cooling the sample while maintaining irradiation results in the appearance of a new light-induced thermal hysteresis loop below 90 K (DeltaT = ca. 25 K). Below 50 K, the hs-Co(II) tautomer displays temperature-independent relaxation to the ls-Co(III) form, and above 50 K, the relaxation is thermally activated with an activation energy E(a) > ca. 1500 cm(-1). The coordination geometry (trans-pyridines), pyridine substitution, and crystal packing forces conspire to create the comparatively thermally stable photogenerated hs-Co(II) tautomer, thus providing an excellent handle for molecular and crystal engineering studies.

Preparation of the octahedral d(6) amido complex TpRu(CO)(PPh(3))(NHPh) (Tp = Hydridotris(pyrazolyl)borate): solid-state structural characterization and reactivity.

The reaction of TpRu(CO)(PPh(3))(OTf) (2) with LiNHPh affords the amido complex TpRu(CO)(PPh(3))(NHPh) (3) in 88% isolated yield. The amido complex 3 has been characterized by (1)H NMR, (13)C NMR, (31)P NMR, elemental analysis, cyclic voltammetry, and a solid-state X-ray diffraction study. Variable temperature NMR studies have revealed a rotational barrier around the ruthenium-amido nitrogen bond of 3 of 12 kcal/mol (transformation of the major isomer to the minor isomer). The solid-state structure of 3 discloses a pyramidal amido moiety. Heating benzene solutions of the amido complex 3 and 1,4-cyclohexadiene or 9,10-dihydroanthracene results in no observable reaction. Reaction of complex 2 with excess aniline yields [TpRu(CO)(PPh(3))(NH(2)Ph)][OTf] (4).

[(Zr6B)Cl11-xI2+x] (0< or = x < or = 6): a new mixed-halide structure with zigzag cains of clusters in multiply twinned crystals.

The new [(Zr6B)Cl11-xI2+x] phase (with 0 < or = x < or = 6) is obtained from reactions of ZrI4, ZrCl4, and elemental Zr and B for 2-4 weeks in sealed Ta tubing at 800-850 degrees C. Single crystals of [(Zr6B)Cl6.44(7)I6.56] have been characterized by X-ray diffraction at room temperature (orthorhombic Pbcn, Z = 4, a = 12.365(2) A, b = 15.485(3) A, c = 13.405(2) A). This structure contains zigzag chains of boron-centered (Zr6B) octahedra that are interconnected by Cl(i-i) halides. Further three-dimensional connectivity is achieved by I(a-a-a) bridges. The noncluster interconnecting two-bonded X(i) sites are occupied statistically by a mixture of Cl and I. For each site both positions were resolved. This structure forms within a phase width of 0 < or = x < or = 6 at temperatures between 800 and 850 degrees C. Crystals of this phase appear to be always multiply twinned.

Rational synthesis of beta-substituted chlorin building blocks.

Chlorins bearing synthetic handles at specific sites about the perimeter of the macrocycle constitute valuable building blocks. We previously developed methodology for preparing meso-substituted chlorin building blocks and now present methodology for preparing several complementary beta-substituted chlorin building blocks. The chlorins bear one or two beta substituents, one meso substituent, a geminal dimethyl group to lock in the chlorin hydrogenation level, and no flanking meso and beta substituents. The synthesis involves convergent joining of an Eastern half and a Western half. New routes have been developed to two beta-substituted bromo-dipyrromethane monocarbinols (Eastern halves). A new beta-substituted Western half was prepared following the method for preparing an unsubstituted Western half (3,3-dimethyl-2,3-dihydrodipyrrin). Chlorin formation is achieved by a two-flask process of acid-catalyzed condensation followed by metal-mediated oxidative cyclization. beta-Substituted chlorins have been prepared in 18-24% yield bearing a 4-iodophenyl group at the 8-position, a 4-iodophenyl group or a 4-[2-(trimethylsilyl)ethynyl]phenyl group at the 12-position, and a 4-iodophenyl group and a 4-[2-(trimethylsilyl)ethynyl]phenyl group at diametrically opposed beta-positions (2, 12). The latter building block makes possible the stepwise construction of linear multi-chlorin architectures. The chlorins exhibit typical absorption and fluorescence spectra. A systematic shift in the absorption maximum (637-655 nm for the free base chlorins, 606-628 nm for the zinc chlorins) and intensity of the chlorin Q(y)() band (epsilon up to 79 000 M(-)(1) cm(-)(1)) is observed depending on the location of the substituents. The characteristic spectral features and location of substituents in defined positions make these chlorins well suited for a variety of applications in biomimetic and materials chemistry.

The parathyroid glands in chronic renal failure: a study of their growth and other properties made on the basis of findings in patients with hypercalcemia.

We investigated the growth of hyperplastic parathyroid glands removed at operation from 16 patients with chronic renal failure complicated by hypercalcemia, by incubating fresh tissue with tritiated thymidine. In each gland the proportion of cells synthesizing DNA was determined directly by counting labeled nuclei after autoradiography and indirectly from incorporation of label into DNA, and the mean diameter of chief cell nuclei was measured. Both DNA synthesis and mean nuclear diameter were positively correlated with plasma calcium level. Assuming the mean duration of S phase to be 12 hours, the birthrate of new cells (mean +/- SD) was 18.5% +/- 23.6% per year, significantly (p less than 0.05) greater than the 11.5% +/- 7.4% per year found in 63 parathyroid adenomas previously studied. On the basis of estimated disease duration, the minimum birthrate needed to grow glands of the observed weight was 23.4% +/- 16.5% per year. The similarity between observed and needed birthrates indicates that the glands were growing almost as fast as when renal failure began, and that parathyroid growth was no longer regulated in accordance with normal plasma calcium homeostasis. To account for this, we propose that the disordered growth is a consequence of an increase in secretory set point, which in turn is a consequence of calcitriol deficiency. Because the effectiveness of parathyroid hormone is impaired in renal failure, a large increase in total hormone secretion is needed to raise the plasma calcium level to the new set point, and the necessary increase in gland size can be achieved only by a sustained increase in the rate of cell division.

Hyperdiploidy of cultured dermal fibroblasts from patients with aerodigestive squamous carcinoma.

The incidence of hyperdiploidy in monolayer cultures of dermal fibroblasts from 88 patients with squamous carcinoma of the aerodigestive tract was compared with similar cultures from 39 normal subjects using three different techniques; 1) metaphase assay (MA), 2) flow cytometry of stationary cell cultures (FCMs), and 3) flow cytometry of proliferating dividing cell cultures (FCMd). In vitro hyperdiploidy was considered to be present (IVH+): 1) by MA if more than 4% of metaphases were altered, excluding tetraploidy; 2) by FCMs if more than 8% of cells in stationary cultures were hyperdiploid (i.e., DNA index greater than 1), and 3) by FCMd if more than 6% of cells in logarithmic cultures were hypertetraploid (i.e., DNA index greater than 2). There was excellent concordance between the three assays, which assigned cell cultures from 55 of the 88 patients with aerodigestive squamous carcinoma (62%) to the in vitro hyperdiploidy positive (IVH+) category. Cell cultures from all 39 normal individuals were hyperdiploidy negative (IVH-). These data suggest that some substantial proportion of patients with aerodigestive squamous carcinoma may have a genetic predisposition for the disease, which can be identified by these assays. The flow cytometry methods were easier to carry out and may be substituted for the metaphase analyses.

Patterns of lead excretion in patients with gout and chronic renal failure--a comparative German and Australian study.

The 6 day calcium EDTA lead excretion test was performed on German and Australian subjects with normal and impaired renal function, some of whom had gout, in order to determine if the pattern of results differed between the two countries. The German subjects lived around Heidelberg in an industrialized area where chronic lead nephropathy had not hitherto been thought to exist, while the Australian subjects were all from the State of Queensland where chronic lead nephropathy from the ingestion of lead paint during childhood continues to contribute to morbidity and mortality. Apart from the subjects with normal renal function, the German subjects consistently excreted less lead than the Queensland subjects and a strikingly consistent pattern was found: in both countries, subjects with a history of lead exposure, whether gouty or not, had greater EDTA lead excess values than subjects with gout but no lead exposure, these subjects in turn having greater EDTA lead excess values than subjects with neither gout nor lead exposure. In each country, the highest median EDTA lead excess occurred not in the group with gout and lead exposure, but in the group without gout and with lead exposure.

Evidence for genetic predisposition for some nasopharyngeal cancers by in vitro hyperdiploidy in human dermal fibroblasts.

A numerical alteration in chromosome complement in human dermal fibroblast cultures, hyperdiploidy with a normal occurrence of tetraploidy (IVH), has been reported to be associated with some hereditary single tumors including squamous carcinoma of the nasopharynx (NPC). Its incidence was compared in cultures derived from 39 NPC patients and 29 clinically normal subjects without a family cancer history by two different methods (percentage of numerically altered metaphases in chromosome preparations from nonconfluent monolayer Petri dish cultures in logarithmic growth, and by the distribution of DNA content of propidium iodide stained cells from plastic flask cultures in stationary growth phase as assayed by flow cytometry) to ascertain its usefulness in identification of such genetic predisposition. Concordance was observed between the two assays. There was a linear relationship between the percentage of hyperdiploid metaphases assayed in the chromosome preparations and the percentage of cells with a DNA index of greater than 1 as determined by flow cytometry. By metaphase assay, none of the 29 normals showed IVH. OF the 39 carcinoma of the nasopharynx patients studied, 19 had IVH and 20 did not. By flow cytometry there were significant differences in the flow cytometry DNA index (p less than 0.001) of IVH-negative (all normals and 20 carcinoma of the nasopharynx patients) and IVH-positive carcinoma of the nasopharynx patients. The percentage of cells with a DNA index of 2 and greater than 1 could be used to distinguish all IVH-negative from the IVH-positive subjects and, thus, were considered to be the parameters of choice in assaying IVH by flow cytometry. None of the subjects studied showed increased in vitro tetraploidy (IVT), which has been associated with some heritable colon cancer syndromes. Irrespective of family cancer history, approximately one-half of the NPC patients (19 of 39) had IVH, which has been reported to be associated with the in vivo expression of certain heritable tumors including carcinoma of the nasopharynx. The average age of carcinoma of the nasopharynx diagnosis was earlier (mean 52 yr) for the IVH-positive group than for the IVH-negative carcinoma of the nasopharynx group (mean 67 yr).

In vitro evidence for genetic predisposition in some human pancreatic adenocarcinoma.

A numerical alteration in chromosome complement in human dermal fibroblast cultures, hyperdiploidy with a normal occurrence of tetraploidy (IVH) has been reported to be associated with some hereditary single tumors, including pancreatic adenocarcinoma (PaCa). The incidence of IVH was compared in cultures derived from 34 PaCa patients and 39 clinically normal subjects without a family tumor history by three assay systems: (a) percentage of numerically altered metaphases in chromosome preparations (MA); (b) percentage of cells from high-density, stationary cultures with a DNA index (DI) greater than 1 (FCMs); (c) percentage of cells with a DI greater than 2 from cultures of cells undergoing division (FCMd). The last two measurements were obtained by flow cytometric measurement of propidium idodide (PI) stained cells. Concordance was observed between the three assays. There was a linear relationship between the percentage of hyperdiploid metaphases assayed in the chromosome preparation and the percentage of cells with a DI greater than 1 by FCMs and a DI greater than 2 by FCMd. IVH was considered to be present (IVH+) by the MA technique if the percentage of numerically altered metaphases was over 4% exclusive of tetraploids, by the FCMs technique if DI greater than 1 was greater than 10%, and by FCMd if DI greater than 2 was greater than 7%. The assayed group could be divided into two IVH groups on the basis of all three assays, individually or collectively.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro hyperdiploidy in dermal fibroblasts: evidence for genetic predisposition in aerodigestive tract cancer.

A numerical alteration in chromosome complement in human dermal fibroblast cultures, hyperdiploidy with a normal occurrence of tetraploidy (IVH) has been reported (Danes 1984) to be associated with some heritable single tumors including squamous carcinoma of the nasopharynx (Danes 1986). The incidence of IVH was compared in cultures derived from 65 patients with squamous carcinoma in different regions of the aerodigestive tract (ADT) and 32 clinically normal subjects without a family cancer history by 2 different assays, metaphase assay (MA) and flow cytometry (FCM). By MA, none of the 32 normals showed IVH. Of the 65 ADT patients studied, 35 had IVH and 30 did not. By FCM, there were significant differences in the FCM DNA index (p values less than 0.001) of IVH- (all normals and 30 ADT patients) and IVH+ ADT patients. The per cent of cells with a DI of 2 and greater than 1 could be used to distinguish all IVH- from the IVH+ subjects and were thus considered to be the parameters of choice in assaying IVH by FCM. None of the subjects studied showed increased in vitro tetraploidy (IVT) which has been associated with some heritable colon cancer syndromes. Irrespective of family cancer history, approximately half (35/65) of the ADT patients had IVH which has been shown to be associated with the in vivo expression of certain heritable tumors. The average age of squamous carcinoma diagnosis was earlier (mean 50 yrs) for the IVH+ group than for the IVH- ADT group (mean 72 yrs).

A standardized assay to identify colon cancer genotypes by in vitro tetraploidy in human dermal fibroblasts.

Increased tetraploidy in dermal fibroblast cultures (IVT), which is a putative biomarker for genetic predisposition to colon cancer, was assayed by two different methods: by per cent of tetraploid metaphases in chromosome preparations from non-confluent monolayer petri dish cultures in logarithmic growth (MA); by flow cytometry (FCM) distribution of DNA content of propidium iodide stained cells from plastic flask cultures in stationary growth phase. The assayed cultures were derived from split thickness skin biopsies from two clinical groups: 11 normal individuals without a family history of colon cancer and 17 clinically affected individuals with autosomal dominant polyposis coli cancer syndrome (6 with colonic adenomatosis, i.e. familial polyposis coli (FPC) and 11 also having extracolonic lesions, i.e. the Gardner syndrome, (GS). Concordance was observed between the two assays. There was a linear relationship between the per cent of tetraploid metaphases assayed in the chromosome preparations and the per cent of cells with a DNA index (DI) of precisely 2, or of all cells with a DI greater than 1 as determined by FCM. In comparisons between the clinical groups, there was significant differences in the FCM DNA index (p values less than 0.001) of IVT- (normals and IVT- FPC) and IVT+ individuals (IVT+ GS and those FPC with IVT). The per cent of cells with a DI of 2 and greater than 1 could be used to distinguish all IVT- individuals (normals and IVT- FPC) from IVT+ FPC individuals. However, only by per cent of cells with a DI greater than 1 could all the individual GS affecteds be distinguished from IVT- individuals. Thus, the per cent of cells with a DI greater than 1 is considered to be the parameter of choice to be used in assaying IVT by flow cytometry.

Chronic lead nephropathy in Queensland: alternative methods of diagnosis.

Indices of past lead absorption were measured and compared in patients with chronic renal failure from many causes, including some with chronic lead nephropathy. X-ray fluorescence (XRF) yielded finger bone lead concentrations by a new in vivo method. These correlated significantly with excess urinary lead following calcium di-sodium EDTA (ethylenediamine tetra-acetate) and erythrocyte lead concentration. Discriminant function analysis demonstrated that the patients in the study could be separated into two groups without any reference to the EDTA lead excretion test using the following variables, all of which contributed significantly to the discrimination. In order of importance, these were: a childhood history of acute lead poisoning, a history of gout, a family history of gout and detectable XRF finger bone lead. Although the XRF finger bone lead measurement is convenient and non-invasive, its lack of sensitivity (48%) limits its usefulness as a screening test for chronic lead nephropathy.

Chronic renal failure with gout: a marker of chronic lead poisoning.

EDTA (calcium disodium edetate) lead mobilization and x-ray fluorescence (XRF) finger bone lead tests were done in 42 patients with chronic renal failure and without persisting lead intoxication. Nineteen of 23 patients with gout and 8 of 19 without gout had positive EDTA lead mobilization tests. Those patients with gout excreted significantly more excess lead chelate than those without gout. In the gout group 17 patients denied any childhood or industrial exposure to lead. They had a greater number of positive tests and excreted significantly more excess lead chelate than 14 patients with neither gout nor lead exposure. These results confirm that gout in the presence of chronic renal failure is a useful marker of chronic lead poisoning. Of 27 patients with positive lead mobilization tests, only 13 had elevated XRF finger bone lead concentrations (sensitivity 48%). Three of 15 patients with negative lead mobilization tests had elevated XRF finger bone lead concentrations (specificity 80%). Although the XRF finger bone lead test is a convenient noninvasive addition to the diagnostic evaluation of patients with chronic renal failure and gout, its application is limited due to the lack of sensitivity of the method.

Major coat protein and single-stranded DNA-binding protein of filamentous virus Pf3.

The region of the Pf3 virus genome encoding its major coat protein and its single-stranded DNA-binding protein is organized somewhat like the corresponding region of the fd (M13, f1) genome. Nevertheless, the major coat protein is unique among the major coat proteins of fd and the other filamentous phages studied in that it lacks a signal sequence and appears to be a direct translation product and in that it has fewer basic amino acid residues than its equivalent of DNA phosphates in the virion. These features are relevant to considerations of both protein insertion into membranes and DNA structure in filamentous viruses. The single-stranded DNA-binding protein also has a sequence that is different from the sequences of single-stranded DNA-binding proteins from other filamentous viruses.