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Selectivity for An(iii) vs. Ln(iii) binding and extraction using dipicolinamide analogs containing the C[double bond, length as m-dash]O vs. C[double bond, length as m-dash]S groups was investigated in solution and the gas-phase, and by DFT calculations. The results show higher selectivity for complex formation and extraction for Am(iii) vs. Eu(iii) for the softer dithioamide vs. the diamide ligand, while in CH3CN the diamide binds more strongly than the thioamide to several Ln(iii), forming 1 : 1 complexes.

A fluorescent sensor for NH4+ based on 1,3,5-triethylbenzene shows remarkable binding and sensing selectivity for NH4+vs. K+. Fluorescence and NMR titrations reveal surprising differences in the sensing properties and binding constants of tris-(3,5-dimethyl)pyrazole 1vs. tris(3,5-diphenyl)pyrazole 2. The roles of ion pairing and solvation are revealed by X-ray and DFT studies.

The structure of N,N′-diphenyl-1,3-benzenedisulfonamide (1) was determined by single crystal X-ray diffraction. It crystallizes in P21/n with cell dimensions: a = 11.8390(6) A, b = 12.3950(10) A, c = 12.1184(10) A, β = 94.388(6)°, and V = 1773.1(2) A3. Its di-t-butyl derivative, N,N′-bis(4-t-butylphenyl)-1,3-benzenedisulfonamide (2), was prepared and structurally characterized as two solvated structures. Both crystallize in P\(\overline 1\) with cell dimensions: 2 ⋅ CF3CH2OH, a = 9.469(2) A, b = 10.0039(18) A, c = 16.385(3) A, α = 85.561(16)°, β = 83.035(18)°, γ = 72.459(16), and V = 1467.7(5) A3; 2 ⋅ ClCH2CH2Cl, a = 9.559(2) A, b = 9.8125(12) A, c = 17.100(6) A, α = 82.495(19)°, β = 83.47(2)°, γ = 70.100(15), and V = 1491.1(6) A3. The structures exhibit hydrogen-bonding, and are evaluated in terms of preorganization for anion binding.

We report here the synthesis of the new hydride complexes (C5H4CH(CH2CH2)2NMe)- RuH(PPh3)2 (1) and [(C5H4CH(CH2CH2)2NHMe)-RuH(PPh3)2](BF4) (2), the X-ray crystal structures of 1 and 2, and an unprecedented observation of extremely short relaxation times in a monohydride complex as well as in the reaction of CpRuH(PPh3)2 with a variety of acidic proton donors. The relaxation is much faster than expected for a dipole-dipole process involving the two dihydrogen-bonded protons, but no origin for the effect could be suggested.

Hydrogen bonding (Re–H···H–N) is estimated in solution between ReH5(PPh3)2L (L=pyridine, 4-picoline, 4-dimethylaminopyridine, and 4-carbomethoxypyridine), as hydrogen bond acceptor, and indole, as hydrogen bond donor. Re–H···base hydrogen bonding between [Re(PPh3)2(MeCN)4H][BF4]2 as hydrogen bond donor and various amines as hydrogen bond acceptors is much weaker. The binding strengths are estimated by UV-VIS spectroscopy.

The (bis)dansylated sulfonamide 1,2-C6H4(NHSO2C10H6-5-N(CH3)2)2 (1) extracted Pb(II) selectively from water into 1,2-dichloroethane via an ion-exchange mechanism and showed fluorescence quenching upon Pb(II) extraction. The distribution ratios for metal extraction (determined by ICP-MS) for Pb(II) were 133-1410 times higher than those for other metal cations [Co(II), Ni(II), Cu(II), Zn(II), and Cd(II)] under identical conditions. Fluorescence quenching was observed upon Pb(II) extraction, which was dependent on Pb(II) concentration. The monodansylated control, C6H5NHSO2C10H6-5-N(CH3)2 (2), showed neither extraction nor quenching, indicating that the fluorescence effects are a direct result of Pb coordination to 1. The observed selectivity for Pb(II) is ascribed to the formation of a low-coordinate binary Pb(II)-Sulfonamido complex in the organic phase.

A calix-crown/disulfonamide dual-host combination in 1,2-dichloroethane exhibits markedly enhanced ion-pair extraction of caesium salts, with the observed synergism following an anti-Hofmeister order.

The N atoms of the title compound, C18H16N2O4S2, are not preorganized for metal cation binding. The N—H groups form hydrogen bonds with symmetry-equivalent sulfonamide groups.

The readily available benzene-1,3,5-tricarboxamide 1 enhances CsNO3 extraction by tetrabenzo-24-crown-8 via hydrogen bonding to the nitrate anion, as demonstrated by NMR and electrospray ionization mass spectrometry.

The disulfonamide receptor 1 catalyzes imine formation from aldehyde and amine, apparently by binding the transition state for the rate-determining nucleophilic attack of amine on the aldehyde.