Characterizing dusky dolphin sounds from Argentina and New Zealand

Dusky dolphin (Lagenorhynchus obscurus) acoustic sounds were characterized by analyzing narrowband recordings [0-16 kHz in New Zealand (NZ) and 0-24 kHz in Argentina], and sounds in broadband recordings (0-200 kHz) were compared to their counterparts in down-sampled narrowband recordings (0-16 kHz). The most robust similarity between sounds present in broadband recordings and their counterparts in the down-sampled narrowband recordings was inter-click interval (ICI); ICI was therefore primarily used to characterize click sounds in narrowband recordings. In NZ and Argentina, distribution of ICIs was a continuum, although the distribution of ICIs in NZ had a somewhat bimodal tendency. In NZ, sounds that had smaller mean ICIs were more likely to have constant ICIs, and less likely to have increasing or decreasing ICIs. Similar to some other delphinids, dusky dolphins may use single, short duration sounds that have a constant ICI and closely spaced clicks for communication. No whistles were documented at either study site. Temporally structured sequences of burst pulses (i.e., sounds with ICI < about 10 ms) also occurred at both study sites, and these sequences contained 2-14 burst pulses that appeared closely matched aurally and in spectrograms and waveforms.     

Synthesis, characterization, and X-ray crystal structure of di-(2,4-imidazolidinedione-5-ethyl)disulfide, C10H14N4O4S2

Di-(2,4-imidazolidinedione-5-ethyl)disulfide or homocystine hydantoin, C₁₀H₁₄N₄O₄S₂ (I), crystallizes in the non-centrosymmetric space group P2₁ (No. 4) with two molecules in the unit cell with a = 7.132(1), b = 9.282(2), c = 10.770(2) Å and = 105.68(1)°. The two imidazolidinedione rings are planar with a dihedral angle of 46.9°. The rings are joined by a diethyl disulfide bridge at chiral centers on the rings. The C-S-S-C torsion angle is –80°(–sc). The absolute stereochemistry of the chiral centers was determined to be (5S, 5S), = + 0.92 (11). Important bond distances include: S-S = 2.022(4); S-C (mean) = 1.809(8); and C=O (mean) = 1.224(7) Å. The compound is stabilized by a network of intermolecular carbonyl-to-amine hydrogen bonding and van der Waals cohesive forces.     

Spectroscopic and crystal structure analyses of methyl 1-phenyl-3,4-dioxo-2-naphthalenecarboxylate,C18H12O4

The crystal and molecular structure of methyl 1-phenyl-3,4-dioxo-2-naphthalenecarboxylate, C₁₈H₁₂O₄, has been determined from three-dimensional, single-crystal X-ray diffraction data. The compound crystallizes in the monoclinic space groupCc(No. 9, C _s ⁴ ) witha=9.837(2),b=16.397(3),c=8.706(1) Å,=94.88(1)°,Z=4,D _m =1.38(1) Mg m^–3, andD _x =1.388 Mg m^–3. The phasing model was determined by direct methods and the final full-matrix least-squares refinement yieldedR=0.0363 and R_w=0.0405 for 1374 unique reflections. Optical, infrared, NMR, and UV-VIS analyses have also been carried out. The molecules in the crystal lattice are held together by van der Waals forces.3-Carbomethoxy-4-phenyl-1,2-naphthoquinone.     

Crystal and molecular structure of chloro(tri-t-butylphosphino-C,P)triphenylarsinepalladium(II)

(SP-4-4)-chloro[2-(di-tert-butylphosphino)-2-methylpropyl-C,P] (triphenylarsine)palladium(II), C₃₀H₄₁ClPAsPd, has been characterized by single-crystal X-ray diffraction data. It crystallizes in the monoclinic space groupP2₁ witha=9.611(2),b=14.335(2),C=11.953(1) Å,=111.97(1)° andZ=2. The phasing model was determined by direct methods and the full-matrix least-squares refinement of 302 structural parameters yielded a reliability factor of 0.039 for 2269 unique reflections withI> 3(I). The square planar geometry about the Pd atom is angularly distorted due to the steric bulk of the ligands and the formation of the four-membered ring, Pd-P-C(2)-C(1), which is severely distorted. The arsine and phosphine ligands are orientedtrans across the square-planar geometry with an As-Pd-P angle of 163.5(1)°. Details of the structural content and selected bond lengths and angles are discussed. The phenyl rings are planar and in a staggered orientation. Steric bulk illustrations from ligand profile calculations (/2 vs ) about the arsine and phosphine ligands are presented.     

A host-guest optical sensor for aliphatic amines based on lipophilic cyclodextrin

A host-guest optical sensor for the determination of aliphatic amines as exemplified by octylamine is proposed. It is based on the reversible fluorescence enhancement of heptakis(2,6-di-O-isobutyl)-β-cyclodextrin(DOB-β-CD) hosting tetraphenylporphyrin (TPP) immobilized in poly(vinyl chloride) (PVC) membrane by aliphatic amine extracted from aqueous phase into membrane phase. The optimum membrane contained 1.15 wt % TPP, 6.15 wt % DOB-β-CD as sensing reagent and other membrane materials. The fluorescence enhancement of the membrane resulted from the formation of a stable three-component complex among DOB-β-CD, TPP, and aliphatic amines. With the optimum conditions described, the fluorescence response of the sensor to octylamine shows a good correlation with the theoretically derived equation in the range 1.0 × 10^–6 to 8.0 × 10^–4 mol/L. The response characteristics including reversibility, response time, reproducibility and lifetime and selectivity of this optical device are also discussed in detail. This sensor has also been applied for the determination of octylamine in water samples containing interferents with satisfactory recovery.