Interaction of mixed-donor macrocycles containing the 1,10-phenanthroline subunit with selected transition and post-transition metal ions: metal ion recognition in competitive liquid-liquid solvent extraction of Cu(II), Zn(II), Pb(II), Cd(II), Ag(I), and Hg(II)

Two new mixed aza-thia crowns 5-aza-2,8-dithia[9]-(2,9)-1,10-phenanthrolinophane (L(4)) and 2,8-diaza-5-thia[9]-(2,9)-1,10-phenanthrolinophane (L(7)) have been synthesized and characterized. The coordination behavior of L(4) and L(7) toward the metal ions Cu(II), Zn(II), Pb(II), Cd(II), Hg(II), and Ag(I) was studied in aqueous solution by potentiometric methods, in CD3CN/D2O 4:1 (v/v) by (1)H NMR titrations and in the solid state. The data obtained were compared with those available for the coordination behavior toward the same metal ions of structurally analogous mixed donor macrocyclic ligands L(1)-L(3), L(5), L(6): all these contain a phenanthroline subunit but have only S/O/N(aromatic) donor groups in the remaining portion of the ring and are, therefore, less water-soluble than L(4) and L(7). The complexes [Cd(NO3)2(L(5))], [Pb(L(7))](ClO4)2 x 1/2MeCN, [Pb(L(4))](ClO4)2 x MeCN, and [Cu(L(7))](ClO4)2 x 3/2MeNO2 were characterized by X-ray crystallography. The efficacy of L(1)-L(7) in competitive liquid-liquid metal ion extraction of Cu(II), Zn(II), Cd(II), Pb(II), Ag(I), and Hg(II) was assessed. In the absence of Hg(II), a clear extraction selectivity for Ag(I) was observed in all systems investigated.     

GaCl3-assisted cyclization reactions in hypersilyl(trimethylsilyl)aminodichlorophosphine

Hypersilyl(trimethylsilyl)aminodichlorophosphine, (hyp)N(SiMe3)PCl2, was treated with GaCl3, which resulted in the formation of an interesting novel bicycle, composed of a four-membered SiNP2 ring and a five-membered P2Ga2Cl ring. In the presence of Me3SiN3, the same reaction provided access to a cyclo-2-phospha-4-sila-1,3-diazenium tetrachlorogallate. The free chloro-cyclo-phosphasiladiazane was obtained by the addition of nucleophilic bases.     

Boraguanidinates: synthesis, X-ray structures, and reactions of {Li2[(i)Pr2NB(NDipp)2]}2 with p-block and group 12 element halides

The new Dipp-substituted boranes (Dipp = 2,6-diisopropylphenyl) (i)Pr2NB(NHDipp)2 (5), BrB(NHDipp)2 (7b), and B(NHDipp)3 (8) have been prepared in high yields and characterized in solution by multinuclear NMR spectroscopy ((1)H, (11)B and (13)C) and in the solid state by X-ray crystallography. Reaction of 5 with 2 equiv of (n)BuLi in n-hexane produces {Li2[(i)Pr2NB(NDipp)2]}2 (6) the first example of a stable dilithiated boraguanidinate. The unsolvated complex 6 has a dimeric structure in the solid state. A survey of the reactions of 6 with p-block and Group 12 element halides revealed various types of reactivity including (a) disproportionation (InCl), (b) reduction to the metal (PbCl2, CdCl2, TeBr4, TeI4, and TlCl), and (c) simple metathesis (GeCl2, MgCl2, and ZnCl2). The metathetical products were characterized by multinuclear NMR spectra but, in contrast to the dilithiated complex 6, they readily decompose in non-coordinating solvents to form the diprotonated compound 5.     

Perturbative calculation of Franck-Condon integrals: new hints for a rational implementation

Perturbative approaches to the mode mixing effects in the calculation of Franck-Condon integrals are analyzed and discussed. The zero order multidimensional Franck-Condon integrals are factorized into products of one-dimensional ones, so that recurrence relations can be used without need of storing a huge number of data. Calculations on model systems show that at the second order of perturbation, the method gives results in very good agreement with the exact ones, even in the case of significantly large Duschinsky effect. The accuracy of the results can be substantially improved by grouping together all those modes which are strongly mixed with each other, usually a few ones, for which Franck-Condon integrals can be computed exactly, and using the perturbative approach for treating the smaller mixing between all the other modes.     

A Dual Photoredox- and Cp2TiCl2-Catalyzed Approach for the Direct Access to α-Vinyl-β-hydroxy Esters

For the first time, a dual photoredox- and titanocene-catalyzed methodology for the regioselective access to α-vinyl-β-hydroxy esters towards aldehyde allylation with 4-bromobut-2-enoate is reported. The protocol is based on the Barbier-type properties of the inexpensive and available Cp₂TiCl₂ in catalytic amount (5 mol%). The developed mild reaction conditions gave access to a library of differently functionalized α-vinyl-β-hydroxy esters in moderate diastereoselectivity, employing the commercially available ethyl 4-bromobut-2-enoate and both aromatic and aliphatic aldehydes. The reaction was realized under visible light irradiation, in the presence of an organophotocatalyst (3DPAFIPN, 2 mol%) combined with Hantzsch's ester as the sacrificial reductant. In contrast to other Barbier-type reactions employing ethyl 4-bromobut-2-enoate, the photoredox system ensures a better regioselectivity. Moreover, the use of preformed organometallic nucleophilic species (e. g., dienolborinates), and the need of metal reductants or stoichiometric amount of transition metals in low oxidation state for Barbier-type reactions, is avoided. To support the experimental evidence, a detailed photophysical study shed light on the mechanism of the reaction.     

Halogen Bonding Assembles Anion⋅⋅⋅Anion Architectures in Non-centrosymmetric Iodate and Bromate Crystals

Single crystal X-ray diffraction of iodate and bromate salts shows that the I and Br atoms in IO₃⁻ and BrO₃⁻ anions form short and linear O−I/Br ⋅⋅⋅ O contacts with the O atoms of nearby anions. Non-centrosymmetric systems are formed wherein anions are orderly aligned into supramolecular 1D and 2D networks. Theoretical evidences, namely the outcome of QTAIM and NCIplot studies, prove the attractive nature of these contacts and the ability of iodate and bromate anions to act as robust halogen bond (HaB) donors. The HaB is proposed as a general and effective assisting tool to control the architecture of acentric iodate salts.     

Structural Polymorphism and Thin Film Transistor Behavior in the Fullerene Framework Molecule 5,6;11,12‐di‐o‐Phenylenetetracene

The molecular structure of the hydrocarbon 5,6;11,12‐di‐o‐phenylenetetracene (DOPT), its material characterization and evaluation of electronic properties is reported for the first time. A single‐crystal X‐ray study reveals two different motifs of intramolecular overlap with herringbone‐type arrangement displaying either face‐to‐edge or co‐facial face‐to‐face packing depicting intensive π–π interactions. Density functional theory (DFT) calculations underpin that a favorable electronic transport mechanism occurs by a charge hopping process due to a π‐bond overlap in the DOPT polymorph with co‐facial arene orientation. The performance of polycrystalline DOPT films as active organic semiconducting layer in a state‐of‐the‐art organic field effect transistor (OFET) device was evaluated and proves to be film thickness dependent. For 40 nm layer thickness it displays a saturation hole mobility (μ_hole) of up to 0.01 cm² V^?1 s^?1 and an on/off‐ratio (I_on/I_off) of 1.5×10³.     

Excitation Dynamics in Hetero‐bichromophoric Calixarene Systems

In this work, the dynamics of electronic energy transfer (EET) in bichromophoric donor–acceptor systems, obtained by functionalizing a calix[4]arene scaffold with two dyes, was experimentally and theoretically characterized. The investigated compounds are highly versatile, due to the possibility of linking the dye molecules to the cone or partial cone structure of the calix[4]arene, which directs the two active units to the same or opposite side of the scaffold, respectively. The dynamics and efficiency of the EET process between the donor and acceptor units was investigated and discussed through a combined experimental and theoretical approach, involving ultrafast pump–probe spectroscopy and density functional theory based characterization of the energetic and spectroscopic properties of the system. Our results suggest that the external medium strongly determines the particular conformation adopted by the bichromophores, with a direct effect on the extent of excitonic coupling between the dyes and hence on the dynamics of the EET process itself.     

Weighted $${{L^p}}$$-Liouville theorems for hypoelliptic partial differential operators on Lie groups

We prove weighted \({L^p}\)-Liouville theorems for a class of second-order hypoelliptic partial differential operators \({\mathcal{L}}\) on Lie groups \({\mathbb{G}}\) whose underlying manifold is \({n}\)-dimensional space. We show that a natural weight is the right-invariant measure \(\check{H}\) of \({\mathbb{G}}\). We also prove Liouville-type theorems for \({C^{2}}\) subsolutions in \({L^{p}(\mathbb{G},\check{H})}\). We provide examples of operators to which our results apply, jointly with an application to the uniqueness for the Cauchy problem for the evolution operator \({\mathcal{L}-\partial_{t}}\).     

Bethe Ansatz and the Spectral Theory of Affine Lie Algebra-Valued Connections I. The simply-laced Case

We study the ODE/IM correspondence for ODE associated to \({\widehat{\mathfrak{g}}}\)-valued connections, for a simply-laced Lie algebra \({\mathfrak{g}}\). We prove that subdominant solutions to the ODE defined in different fundamental representations satisfy a set of quadratic equations called \({\Psi}\)-system. This allows us to show that the generalized spectral determinants satisfy the Bethe Ansatz equations.