David R. Armstrong

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In the chlorophyll (Chl) biosynthesis pathway the formation of protochlorophyllide is catalyzed by Mg-protoporphyrin IX methyl ester (MgPME) cyclase. The Ycf54 protein was recently shown to form a complex with another component of the oxidative cyclase, Sll1214 (CycI), and partial inactivation of the ycf54 gene leads to Chl deficiency in cyanobacteria and(More)
The Protein Data Bank in Europe (http://pdbe.org) accepts and annotates depositions of macromolecular structure data in the PDB and EMDB archives and enriches, integrates and disseminates structural information in a variety of ways. The PDBe website has been redesigned based on an analysis of user requirements, and now offers intuitive access to improved(More)
The chemisorption of the soft scorpionate Li[PhTm(Me)] onto silver and gold surfaces is reported. Surface enhanced Raman spectroscopy in combination with the Raman analysis of suitable structural models, namely, [Cu(kappa(3)-S,S,S-PhTm(Me))(PCy(3))], [Ag(kappa(3)-S,S,S-PhTm(Me))(PCy(3))], [Ag(kappa(2)-S,S-PhTm(Me))(PEt(3))], and(More)
Previously we reported that direct zincation of N,N-dimethylaniline by the mixed-metal zincate reagent 1 ((TMEDA)Na(TMP)(t-Bu)Zn(t-Bu)) surprisingly led to meta-metallation (zincation) of the aniline, as manifested in the crystalline complex 2 ((TMEDA)Na(TMP)(m-C(6)H(4)-NMe(2))Zn(t-Bu)), and that iodination of these isolated crystals produced the(More)
Studied extensively in solution and in the solid state, Li(TMP) (TMP=2,2,6,6-tetramethylpiperidide) is an important utility reagent popular as a strongly basic, weakly nucleophilic tool for C-H metallation. Recently, there has been a surge in interest in mixed metal derivatives containing the bulky TMP anion. Herein, we start to develop hetero (alkali(More)
The reaction of the multidentate Schiff base species TrenSal, TrenBrSal, and TEtSal with copper acetate is reported. The heptadentate ligands generate a tetrametallic L(2)Cu(4)OH motif that contains an internalized hydroxide anion. In contrast, the hexadentate TEtSal ligand is found to form an open trimetallic motif. The importance of L(2)Cu(4)OH to the(More)
The often studied THF solvates of the utility alkali-metal amides lithium and sodium 2,2,6,6-tetramethylpiperidide are shown to exist in the solid state as asymmetric cyclic dimers containing a central M(2)N(2) ring and one molecule of donor per metal to give a distorted trigonal planar metal coordination. DFT studies support these structures and confirm(More)
Exploring the reactivity of sodium butylmagnesiate reagent [{Na(THF)6}(+){(Ph2Si(NAr*)2)Mg(Bu)(THF)}(-)] (1) supported by the bulky chelating silyl(bisamido) ligand {Ph2Si(NAr*)2}(2-) (Ar* = 2,6-iPr2-C6H3) towards N-methylbenzimidazole (bIm(Me)), pyrrole and 2,6-diisopropylaniline (NH2Ar*), this study provides new insights into the ability of this(More)