Rational ligand design for metal ion recognition. Synthesis of a N-benzylated N2S3-donor macrocycle for enhanced silver(I) discrimination

Four previously documented ligand design strategies for achieving Ag(I) discrimination have been applied to the design of a new N-benzylated N2S3-donor macrocycle; the latter shows high selectivity for Ag(I) over Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) in log K and bulk membrane transport studies

Biomedical potential of unchlorinated Briarane Diterpenes from gorgonians and sea pens

[Extract] Coral reefs are generally comprised of a complex array of communities that may include many different types of coelenterates such as cnidarians (which include hard or stony corals, soft corals, sea whips and sea fans, sea pens, hydroids, zoanthids, and sea anemones) as well as ascidians (tunicates) and sponges. The corals are comprised of hexacorals (stony corals), where polyps have six or multiples of six tentacles, and octocorals, where polyps have eight tentacles. These sedentary coelenterates are generally not restricted to tropical coral reefs, and species are also found in subtropical, temperate, Arctic, and Antarctic waters

Structural diversity of lanthanum saccharinates induced by 1,10-phenanthroline: a synthetic and X-ray crystallographic study

Four new lanthanum(III) complexes of formulae [La(sac)3(phen)2(H2O)2](phen)(H2O)2 (1), [La(sac)3(phen)2(H2O)2](phen) (2), [La(sac)2(phen)(H2O)4](sac) (3) and [La(sac)2(phen)2(H2O)3] (sac)(phen)(H2O) (4) (phen = 1,10 phenanthroline, sac = saccharinate) have been synthesised and characterised by single crystal X-ray diffraction, IR, elemental analysis and thermogravimetric analysis. The binding mode of the sac anion was manipulated through the use of phen as structure inducer. In all four complexes the La(III) ion is in a nine-coordinate environment. The structures of 1 and 2 are similar, comprising of three sac anions coordinating in a monodentate fashion through the carbonyl O-atom, two bidentate phen and two water molecules coordinating directly to the same La(III) ion; a third, uncoordinated phen moiety also forms part of the unit cell. In addition, 1 is characterized by the presence of two crystallization water molecules which are absent in 2. In compound 3 the coordination sphere of La(III) is completed by a bidentate chelating sac through the N- and carbonyl O-atoms, a monodentate sac, a bidentate phen and four water ligands; a third, uncoordinated sac is also present in the crystal lattice. Compound 4 contains two bidentate phen, three water ligands and two monodentate O(carbonyl) sac ligands. The presence of three sac anions coordinating to the same lanthanide ion as well as a bidentate N–Ln–O chelating sac, confirmed by single crystal X-ray crystallography, is unprecedented for rare-earth saccharinates

Who's speaking? Predicting speaker profession from speech

International audienceVariations in speech can reveal the gender, birth place, age, and socioeconomic level of the speaker. In this paper, we show that even the profession of the speaker can be recovered from a recording. For this purpose, we design a method that combines features from both the speech signal and the transcription. For the features from the transcription, we used pretrained language models. This allows us to train a model that predicts the speaker profession from both signals. Our empirical results show that our model can narrow down the profession of the speakers considerably

Who's speaking? Predicting speaker profession from speech

International audienceVariations in speech can reveal the gender, birth place, age, and socioeconomic level of the speaker. In this paper, we show that even the profession of the speaker can be recovered from a recording. For this purpose, we design a method that combines features from both the speech signal and the transcription. For the features from the transcription, we used pretrained language models. This allows us to train a model that predicts the speaker profession from both signals. Our empirical results show that our model can narrow down the profession of the speakers considerably

WHO'S SPEAKING? PREDICTING SPEAKER PROFESSION FROM SPEECH

International audienceVariations in speech can reveal the gender, birth place, age, and socioeconomic level of the speaker. In this paper, we show that even the profession of the speaker can be recovered from a recording. For this purpose, we design a method that combines features from both the speech signal and the transcription. For the features from the transcription, we used pretrained language models. This allows us to train a model that predicts the speaker profession from both signals. Our empirical results show that our model can narrow down the profession of the speakers considerably

Metal-ion recognition. Modeling the stability constants of some mixed-donor macrocyclic metal ion complexes—a simple model

A procedure for modeling the stability constants of the Zn(II), Cd(II), Ag(I) and Pb(II) complexes of an extended series of 17-membered, mixed-donor macrocycles incorporating nitrogen, oxygen and/or sulfur donor atoms is presented. The ligands fall into two categories—those incorporating a symmetrical arrangement of their donor atom set (9 examples) and those in which the donor set has an unsymmetrical arrangement (5 examples). Metal stability constants for the former have been reported previously while corresponding data for the latter was determined as part of the present investigation. Initial computations were based on the 1:1 stability constants for the systems incorporating a symmetrical arrangement of their donor atom set. The approach employed was to assume that the overall free energy for metal complexation can be partitioned into the sum of contributions from individual metal–donor interactions. Thus for a given metal ion type, the log K data corresponding to each of these ligand systems were employed to derive parameters that are characteristic of the respective metal ion–donor bond types present. The parameterisation derived from the above (previously reported) stability data was then employed to compute log K values for the complexes of both the symmetrical and unsymmetrical ligand series. In general, quite good agreement with the experimentally determined log K values for both series of complexes was obtained. The procedure thus points the way for the prediction of metal complex stabilities for other systems that incorporate closely related ligand types

Transition and post-transition metal ion chemistry of dibenzo-substituted, mixed-donor macrocycles incorporating five donor atoms

The transition and post-transition metal ion chemistry of a wide range of potentially pentadentate dibenzo-substituted macrocyclic ligands incorporating nitrogen, oxygen and/or sulfur donors is reviewed and shown to result in a diverse range of structural types. Aspects of metal ion recognition, bulk membrane transport, systems incorporating appended chromophores, a sulfate binding system, induced Cu(I)/Cu(II) redox switching, coordination polymers, and unsymmetric macrocyclic ligand systems are all discussed

New macrocyclic ligands: XIV. synthesis and X-ray structures of potentially pentadentate ligands incorporating non-symmetrically arranged N4S-, N3OS-, N2O2S- and N2S2O-heteroatoms

The synthesis and characterization of new mixed-donor macrocyclic ligands incorporating nitrogen, sulfur and/or oxygen heteroatoms are described. The new 17- or 18-membered macrocyclic rings contain unsymmetrical arrangements of their heteroatoms in contrast to related, previously reported rings in which the donor sets are arranged symmetrically. The X-ray structures of the 17-membered rings incorporating N4O- and N4S-donor sets are presented