Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.4.1.14 (SPS)
 813 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The lithium salt of the anionic SPS pincer ligand composed of a central hypervalent lambda4-phosphinine ring bearing two ortho-positioned diphenylphosphine sulfide side arms reacts with [Mn(CO)5Br] to give fac-[Mn(SPS)(CO)3]. This isomer can be converted photochemically to mer-[Mn(SPS)(CO)3], with a very high quantum yield (0.80+/-0.05). The thermal backreaction is slow (taking ca. 8 h at room temperature), in contrast to rapid electrode-catalyzed mer-to-fac isomerization triggered by electrochemical reduction of mer-[Mn(SPS)(CO)3]. Both geometric isomers of [Mn(SPS)(CO)3] have been characterized by X-ray crystallography. Both isomers show luminescence from a low-lying 3IL (SPS-based) excited state. The light emission of fac-[Mn(SPS)(CO)3] is largely quenched by the efficient photoisomerization occurring probably from a low-lying Mn-CO dissociative excited state. Density functional theory (DFT) and time-dependent DFT calculations describe the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of fac- and mer-[Mn(CO)3(SPS)] as ligand-centered orbitals, largely localized on the phosphinine ring of the SPS pincer ligand. In line with the ligand nature of its frontier orbitals, fac-[Mn(SPS)(CO)3] is electrochemically reversibly oxidized and reduced to the corresponding radical cation and anion, respectively. The spectroscopic (electron paramagnetic resonance, IR, and UV-vis) characterization of the radical species provides other evidence for the localization of the redox steps on the SPS ligand. The smaller HOMO-LUMO energy difference in the case of mer-[Mn(CO)3(SPS)], reflected in the electronic absorption and emission spectra, corresponds with its lower oxidation potential compared to that of the fac isomer. The thermodynamic instability of mer-[Mn(CO)3(SPS)], confirmed by the DFT calculations, increases upon one-electron reduction and oxidation of the complex.
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PMID:Syntheses, X-ray structures, photochemistry, redox properties, and DFT calculations of interconvertible fac- and mer-[Mn(SPS)(CO)3] isomers containing a flexible SPS-based pincer ligand. 1632 2

Reactions of Ln(BH4)3(THF)n and [Li(Et2O)]SPS(Me)], the lithium salt of an anionic SPS pincer ligand composed of a central hypervalent lambda4-phosphinine ring bearing two ortho-positioned diphenylphosphine sulfide sidearms, led to the monosubstituted compounds [Ln(BH4)2(SPS(Me))(THF)2] [Ln = Ce (1), Nd (2)], while the homoleptic complexes [Ln(SPS(Me))3] [Ln = Ce (3), Nd (4)] were obtained by treatment of LnX3 (X = I, BH4) with [K(Et2O)][SPS(Me)]. The [UX2(SPS(Me))2] complexes [X = Cl (5), BH4 (6)] were isolated from reactions of UX4 and the lithium or potassium salt of the [SPS(Me)]- anion. The X-ray crystal structures of 1.1.5THF, 2.1.5THF, 3.2THF.2Et2O, and 5.4py reveal that the flexible tridentate [SPS(Me)]- anion is bound to the metal as a tertiary phosphine with electronic delocalization within the unsaturated parts of the ligand.
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PMID:Lanthanide and uranium complexes with an SPS-based pincer ligand. 1711 89