Vanadium diaminebis(phenolate) complexes of the general formulas [LVCl(THF)] (L = Me(2)NCH(2)CH(R)N(CH(2)-2-O-3,5-C(6)H(2)(t)Bu(2))(2), where R = H, Me) and [LV(O)X] [X = Cl; R = H (2), Me (3), O(i)Pr (4), (mu-O)V(O)L (5)] are described. All compounds display octahedral geometry and trans-O(Ph) coordination. For compounds 2, 3, and 5, only one isomer, presenting the V=O ligand trans to the tripodal nitrogen, was formed, while for 4, two isomers were observed by NMR in solution. The UV-vis and circular dichroism spectra of 2 and 3 display very intense charge-transfer transition bands from the phenolate donors to the vanadium, which are in agreement with the (51)V low-field shifts observed. All vanadium(V) complexes were tested as thioanisole sulfoxidation catalysts, revealing very high selectivity when H(2)O(2) was used as the oxidant. However, no enantioselectivity was observed even when enantiopure 3 was used as the catalyst precursor. (1)H and (51)V NMR studies were conducted for the reactions of 2 with aqueous solutions of H(2)O(2) in methanol-d(4) and in acetonitrile-d(3); 2 reacts with the solvents, leading to [LV(O)OMe], by replacement of Cl by MeO in methanol, and to a new vanadium aminebis(phenolate) complex, where the dimethylamine fragment of the original ligand L was replaced by CH(3)CN. In either case, (51)V NMR spectra suggest the formation of peroxovanadium species upon the addition of a H(2)O(2) solution. The subsequent addition of thioanisole to the methanol-d(4) solution leads to regeneration of the original complex.
Objective. To describe how virtual patients are being used to simulate real-life clinical scenarios in undergraduate pharmacy education in Europe. Methods. One hundred ninety-four participants at the 2011 Congress of the European Pharmaceutical Students Association (EPSA) completed an exploratory cross-sectional survey instrument. Results. Of the 46 universities and 23 countries represented at the EPSA Congress, only 12 students from 6 universities in 6 different countries reported having experience with virtual patient technology. The students were satisfied with the virtual patient technology and considered it more useful as a teaching and learning tool than an assessment tool. Respondents who had not used virtual patient technology expressed support regarding its potential benefits in pharmacy education. French and Dutch students were significantly less interested in virtual patient technology than were their counterparts from other European countries. Conclusion. The limited use of virtual patients in pharmacy education in Europe suggests the need for initiatives to increase the use of virtual patient technology and the benefits of computer-assisted learning in pharmacy education.
Radical reactions of titanium(III) [Ti((tBu2)O2NN')Cl(S)] (S = THF, 1; S = py, 2; (tBu2)O2NN' = Me2N(CH2)2N(CH2-2-O-3,5-(t)Bu2C6H2)2) are described. Reactions with neutral electron acceptors led to metal oxidation to Ti(IV), [Ti((tBu2)O2NN')Cl(TEMPO)] (4) being formed with the TEMPO radical and [Ti((tBu2)O2NN')Cl2] (9) with PhN═NPh. [Ti((tBu2)O2NN')Cl2] was also formed when [Ti((tBu2)O2NN')Cl(S)] was oxidized by [Cp2Fe][BPh4], but the [Cp2Fe][PF6] analogue yielded [Ti((tBu2)O2NN')ClF] (8). The reactions of [Ti((tBu2)O2NN')Cl(S)] with O2 gave [Ti((tBu2)O2NN')Cl]2(μ-O) (3). The DFT calculated Gibbs energy for the above reaction showed it to be exergonic (ΔG298 = -123.6 kcal·mol(-1)). [Ti((tBu2)O2NN')(CH2Ph)(S)] (S = THF, 5; py, 6) are not stable in solution for long periods and in diethyl ether gave 1:1 cocrystals of [Ti((tBu2)O2NN')(CH2Ph)2] (7) and [Ti((tBu2)O2NN')Cl]2(μ-O) (3), most probably resulting from a disproportionation process of titanium(III) followed by oxygen abstraction by the resulting Ti(II) species. The oxidation of [Ti((tBu2)O2NN')(κ(2)-{CH2-2-(NMe2)-C6H4})] (10), which is a Ti(III) benzyl stabilized by the intramolecular coordination of the NMe2 moiety, led to a complex mixture. Recrystallization of this mixture under air led to a 1:1 cocrystal of two coordination isomers of the titanium oxo dimer (3). In one of these isomers, one metal is pentacoordinate and the dimethylamine moiety of the diamine bis(phenolate) ligand is not bonded to the metal, displaying a coordination mode of the ligand never observed before. The other titanium center is distorted octahedral with two cis-phenolate moieties. In the second unit, the coordination of the two ancillary ligands to the titanium centers reveals mutually cis-phenolate groups in one-half of the molecule and trans-coordinated in the other titanium center, keeping a distorted octahedral environment around each titanium.
This work describes reactions of heteroallenes with diamido-diamine cyclam-based Zr(iv) complexes of the general formula (Bn2Cyclam)ZrX2 (X = O(t)Bu, , O(i)Pr, , SPh, , NH(t)Bu, ) as well as the di-orthometallated species ((C6H4CH2)2Cyclam)Zr, . The reactions of isocyanates or isothiocyanates with , or resulted in the formation of N-bonded ureate or thioureate cyclam complexes upon [2 + 2] cycloaddition of the Zr-Namido bonds of the cyclam to the heteroallene (). DFT calculations showed that κ(2)-N,N'-ureate bonding is favoured over κ(2)-N,O-ureates, which in turn may be formed in reactions with bulky isocyanates as 1-naphthyl isocyanate (NpN[double bond, length as m-dash]C[double bond, length as m-dash]O). The reactions of with N,N'-cyclohexylcarbodiimide (CyN[double bond, length as m-dash]C[double bond, length as m-dash]NCy) and carbon disulfide afforded guanidinate and dithiocarbamate fragments, respectively, appended to one of the nitrogen atoms of the cyclam ligand. These reactions represent a reliable method for the synthesis of asymmetrically N-functionalized cyclams giving rise to C1 symmetry Zr(iv) species by addition of one equivalent of heteroallenes. The reaction of (Bn2Cyclam)Zr(NH(t)Bu)2, , with one equivalent of mesityl isocyanate (MesN[double bond, length as m-dash]C[double bond, length as m-dash]O) also proceeds through insertion, involving one Zr-NH(t)Bu bond. However, it was observed that the reaction of (Bn2Cyclam)Zr(NH(t)Bu)2, , with MesN[double bond, length as m-dash]C[double bond, length as m-dash]O follows a different path if the reaction is carried out at 60 °C. In this case the reaction leads to [2 + 2] addition of the Zr-Ncyclam bond to the isocyanate, with a concomitant occurrence of orthometallation of the one benzyl pending group of the cyclam ring. The reaction of (t)BuN[double bond, length as m-dash]C[double bond, length as m-dash]O with the di-orthometallated complex ((C6H4CH2)2Cyclam)Zr, , also gave a κ(2)-N,N'-ureate fragment, by isocyanate addition to the macrocycle. DFT calculations on these systems were conducted in an attempt to rationalise the reactivity patterns observed.
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