Water-soluble organotin compounds

Herein, we report the syntheses of the water-soluble organotin compounds [{Me2(H)N(CH2)3}2SnX2]Y2 (1, X = Cl, Y = ClO4; 2, X = F, Y = ClO4) and {Me2(H)N(CH2)3}2SnX4 (3, X = Cl; 4, X = F). The compounds were characterized by elemental analysis, electrospray mass spectrometry, 1H, 13C, 19F, and 119Sn NMR spectroscopy, and in the case of compounds 1, 3 and 4, by single-crystal X-ray diffraction analysis. The reaction of compound 2 with fluoride anions in water was investigated by NMR spectroscopy. DFT calculations accompany the experimental work

Grafting of the 2,8-dithia-5-aza-2,6-pyridinophane macrocycle on SBA-15 mesoporous silica for the removal of Cu2+ and Cd2+ ions from aqueous solutions: synthesis, adsorption, and complex stability studies

Silica-based mesoporous materials have received growing attention in metal recovery from industrial processes, although, in general, the adsorption of metal ions by silanols is rather poor. Nevertheless, a great improvement of metal ion removal from aqueous solutions can be achieved by grafting metal-chelators on the particles’ surface. Combining the metal-chelating properties of organic ligands with the high surface area of mesoporous silica particles makes these hybrid nanostructured materials a new horizon in metal recovery, sensing and controlled storage of metal ions in industrial and mining processes. Here, the 2,8-dithia-5-aza-2,6-pyridinophane (L) macrocycle was grafted on SBA-15 mesoporous silica to obtain the SBA-L mesoporous adsorbent for the removal and controlled recovery of Cd2+ and Cu2+ ions from aqueous solution in a broad pH range (4-11). By grafting about 0.3 mmol g−1 of L on SBA-15 a maximum loading capacity of 20.9 mg g−1 and 31.8 mg g−1 was obtained for Cu2+ and Cd2+, respectively. The adsorption kinetics can be described with the pseudo-second order model, while the adsorption isotherm (298 K) followed the Langmuir model. The latter, together with potentiometric studies, suggests that the adsorption mechanism is based on metal chelation by the grafted macrocycle. In summary, SBA-L is an effective copper(ii) and cadmium(ii) chelator for possible applications where metal removal, storage and recovery are of basic importance

A Simulation Model for the Non-Electrogenic Uniport Carrier-Assisted Transport of Ions across Lipid Membranes

Impressive work has been completed in recent decades on the transmembrane anion transport capability of small synthetic transporters from many different structural classes. However, very few predicting models have been proposed for the fast screening of compound libraries before spending time and resources on the laboratory bench for their synthesis. In this work, a new approach is presented which aims at describing the transport process by taking all the steps into explicit consideration, and includes all possible experiment-derived parameters. The algorithm is able to simulate the macroscopic experiments performed with lipid vesicles to assess the ion-transport ability of the synthetic transporters following a non-electrogenic uniport mechanism. While keeping calculation time affordable, the final goal is the curve-fitting of real experimental data—so, to obtain both an analysis and a predictive tool. The role and the relative weight of the different parameters is discussed and the agreement with the literature is shown by using the simulations of a virtual benchmark case. The fitting of real experimental curves is also shown for two transporters of different structural type.This research was funded by the University of Cagliari (FIR 2020). Financial support from MIUR (PRIN 2017 project 2017EKCS35), Fondazione di Sardegna (FdS Progetti Biennali di Ateneo, annualità 2018 and 2020) is also gratefully acknowledged

Coordination chemistry of nitrile-functionalized mixed thia-aza macrocycles [9]aneN2S and [9]aneNS2 towards silver(I)

The coordination chemistry towards silver(I) of the small-ring macrocycles [9]aneN2S (1-thia-4,7-di¬aza-cyclo¬nona¬ne) and [9]aneNS2 (1,4-di¬thia-7-aza¬cyclo¬nona¬ne) incorporating nitrile-functionalized pendant arms is considered both in the presence and the absence of exogenous bridging ligands. The aim is to understand the influence of the number and length of the pendant arms on the nuclearity and dimensionality of the resulting com¬plexes. The X-ray crystal structures of the com¬plexes bis¬[4,7-bis-(cyano¬meth¬yl)-1-thia-4,7-di¬aza¬cyclo¬non¬ane-κ3N,N′,S]silver(I) tetra¬fluorido¬borate, [Ag(C10H16N4S)2]BF4 or [Ag(L1)2]BF4, [4,7-bis¬(2-cyano¬eth¬yl)-1-thia-4,7-di¬aza¬cyclo¬nonane-κ3N,N′,S](thio¬cyanato-κS)silver(I), [Ag(C12H20N4S)(NCS)] or [Ag(L2)(SCN)], and μ-thio¬cyanato-κ2S:S-bis¬{[7-(2-cyano¬eth¬yl)-1,4-di¬thia-7-aza-cyclo¬nonane-κ3N,S,S′]silver(I)} tetra¬fluor¬ido¬borate, [Ag2(C9H16N2S2)2(SCN)]BF4 or [Ag2(L3)2(μ-SCN)]BF4, are discus¬sed in relation to analogous com¬pounds in the literature

Gold Thione Complexes

The reaction of the ligand Et4todit (4,5,6,7-Tetrathiocino-[1,2-b:3,4-b']-diimidazolyl-1,3,8,10-tetraethyl-2,9-dithione) with gold complexes leads to the dinuclear gold(I) complexes [{Au(C6F5)}2(Et4todit)] and [Au(Et4todit)]2(OTf)2, which do not contain any gold-gold interactions, or to the gold(III) derivative [{Au(C6F5)3}2(Et4todit)]. The cristal structures have been established by X-ray diffraction studies and show that the gold centers coordinate to the sulfur atoms of the imidazoline-2-thione groups

Organoselenium( II ) halides containing the pincer 2,6-(Me 2 NCH 2 ) 2 C 6 H 3 ligand – an experimental and theoretical investigation

New organoselenium( II )halidesofthetype[RSe] + X − [R = 2,6-(Me 2 NCH 2 ) 2 C 6 H 3 ;X=Cl( 2 ), Br ( 3 ), I ( 4 )] were prepared by cleavage of the Se – Se bond in R 2 Se 2 ( 1 )withSO 2 Cl 2 followed by halogen exchange when organo- selenium chloride was treated with NaBr or KI. The reaction between 2 and R ’ 2 MCl n resulted in new ionic [RSe] + [R ’ 2 MCl n +1 ] − [R ’ =2-(Me 2 NCH 2 )C 6 H 4 , n =1,M=Sb( 5 ), Bi ( 6 ); R ’ =Ph,M=Sb, n =1( 7 )or n =3( 8 )] species. All new compounds were investigated in solution by multinuclear NMR spectroscopy ( 1 H, 13 C, 77 Se, 2D experiments) and mass spectrometry. The ionic nature of 2 and the antimonates species was con fi rmed by conductivity studies. The molecular structures of [{2,6-(Me 2 NCH 2 ) 2 C 6 H 3 }Se] + Cl − · n H 2 O( 2 ·H 2 Oand 2 ·2H 2 O) and [{2,6-(Me 2 NCH 2 ) 2 C 6 H 3 }Se] + [Ph 2 SbCl 4 ] − ( 8 ), respectively, were established by single-crystal X-ray di ff raction, pointing out that the ionic nature of the se compounds is also preserved in the solid state, with both nitrogen atoms strongly trans coordinated to the selenium atom of the cation. Theoretical calculations carried out at the DFT level were exploite d to investigate the nature of the bonding in compounds 2 – 4 and the free cation [RSe] + ( 2a ). A topological analysis based on the theory of Atoms-In-Molecules (AIM) and Electron Localization Function (ELF) jointly to a Natural Bond Orbital (NBO) approach was used to shed light on the e ff ect of the nature of the halogen specie s X on the bonding within the 3c-4e N – Se – Nmoiet

Chelating phosphorus–an O, C, O-coordinating pincer-type ligand coordinating PIII and PV centres

The sequence of reactions of the phosphorus-containing aryllithium compound 5-t-Bu-1,3-[(P(O)(O-i-Pr)2]2C6H2Li (ArLi) with Ph2PCl, KMnO4, elemental sulfur and elemental selenium, respectively, gave the aryldiphenylphosphane chalcogenides 5-t-Bu-1,3-[(P(O)(O-i-Pr)2]2C6H2P(E)Ph2 (1, E=O; 2, E=S; 3, E=Se). Compound 1 partially hydrolysed giving [5-t-Bu-1-{(P(O)(O-i-Pr)2}-3-{(P(O)(OH)2}C6H2]P(O)Ph2 (4). The reaction of ArLi with PhPCl2 provided the benzoxaphosphaphosphole [1(P), 3(P)-P(O)(O-i-Pr)OPPh-6-t-Bu-4-P(O)(O-i-Pr)2]C6H2P (5i) as a mixture of the two diastereomers. The oxidation of 5i with elemental sulfur gave the benzoxaphosphaphosphole sulfide [1(P), 3(P)-P(O)(O-i-Pr)OP(S)Ph-6-t-Bu-4-P(O)(O-i-Pr)2]C6H2 (5) as pair of enantiomers P1(R), P3(S)/P1(S), P3(R) of the diastereomer (RS/SR)-5 (5b). The aryldiphenylphosphane 5-t-Bu-1,3-[(P(O)(O-i-Pr)2]2C6H2PPh2 (6) was obtained from the reaction of the corresponding aryldiphenylphosphane sulfide 2 with either sodium hydride, NaH, or disodium iron tetracarbonyl, Na2Fe(CO)4. The oxidation of the aryldiphenylphosphane 6 with elemental iodine and subsequent hydrolysis yielded the aryldiphenyldioxaphosphorane 9-t-Bu-2,6-(OH)-4,4-Ph2-3,5-O2-2,6-P2-4λ5-P-[5.3.1.0]-undeca-1(10),7(11),8-triene (7). Both of its diastereomers, (RR/SS)-7 (7a) and (RS/SR)-7 (7b), were separated as their chloroform and i-propanol solvates, 7a⋅2CHCl3 and 7b⋅i-PrOH, respectively. DFT calculations accompanied the experimental work

Chelating Phosphorus-An O, C, O-Coordinating Pincer-Type Ligand Coordinating PIII and PV Centres

The sequence of reactions of the phosphorus-containing aryllithium compound 5-t-Bu-1,3-[(P(O)(O-i-Pr)(2)](2)C6H2Li (ArLi) with Ph2PCl, KMnO4, elemental sulfur and elemental selenium, respectively, gave the aryldiphenylphosphane chalcogenides 5-t-Bu-1,3-[(P(O)(O-i-Pr)(2)](2)C6H2P(E)Ph-2 (1, E=O; 2, E=S; 3, E=Se). Compound 1 partially hydrolysed giving [5-t-Bu-1-{(P(O)(O-i-Pr)(2)}-3-{(P(O)(OH)(2)}C6H2]P(O)Ph-2 (4). The reaction of ArLi with PhPCl2 provided the benzoxaphos-phaphosphole [1(P), 3(P)-P(O)(O-i-Pr)OPPh-6-t-Bu-4-P(O)(O-i-Pr)(2)]C6H2P (5i) as a mixture of the two diastereomers. The oxidation of 5i with elemental sulfur gave the benzoxaphos-phaphosphole sulfide [1(P), 3(P)-P(O)(O-i-Pr)OP(S)Ph-6-t-Bu-4-P(O)(O-i-Pr)(2)]C6H2 (5) as pair of enantiomers P1(R), P3(S)/P1(S), P3(R) of the diastereomer (RS/SR)-5 (5b). The aryldiphenylphosphane 5-t-Bu-1,3-[(P(O)(O-i-Pr)(2)](2)C6H2PPh2 (6) was obtained from the reaction of the corresponding aryldiphenylphosphane sulfide 2 with either sodium hydride, NaH, or disodium iron tetracarbonyl, Na2Fe(CO)(4). The oxidation of the aryldiphenylphosphane 6 with elemental iodine and subsequent hydrolysis yielded the aryldiphenyldioxaphosphorane 9-t-Bu-2,6-(OH)-4,4-Ph-2-3,5-O-2-2,6-P-2-4 lambda(5)-P-[5.3.1.0]-undeca-1(10),7(11),8-triene (7). Both of its diastereomers, (RR/SS)-7 (7a) and (RS/SR)-7 (7b), were separated as their chloroform and i-propanol solvates, 7a.2CHCl(3) and 7b.i-PrOH, respectively. DFT calculations accompanied the experimental work