@article {31305, title = {Oxidation studies on mustard gas, and the first crystal structure of a metal-mustard gas complex}, journal = {Inorganica Chimica Acta}, volume = {482}, year = {2018}, pages = {62 - 66}, abstract = {

Attempts to selectively oxidize mustard gas [(ClCH2CH2)2S, abbreviated as BCES] to the non-toxic sulfoxide using a trans-Ru(TMP)(O)2/O2 catalyst (TMP = porphyrin dianion of 5,10,15,20-tetramesitylporphyrin) have led to isolation and characterization, including an X-ray structure, of trans-Ru(TMP)(BCES)2, the first such report of a metal-mustard gas complex.

}, keywords = {Mustard Gas, Oxidations, Ruthenium porphyrins, X-ray structure}, issn = {0020-1693}, doi = {https://doi.org/10.1016/j.ica.2018.05.012}, url = {http://www.sciencedirect.com/science/article/pii/S0020169318304857}, author = {Nimal Rajapakse and Shahram Mehraban and Andrew Pacheco and Brian O. Patrick and Brian R. James} } @article {2168, title = {The complexes: RhCl(P-N)(THP), where P-N is P,N-chelated o-diphenylphosphino-N,N-dimethylaniline and THP is tris(hydroxymethyl)phosphine, and RhCl[(O)P-N][THP(O)] containing O-bonded phosphine oxides}, journal = {Inorganica Chimica Acta}, volume = {361}, number = {11}, year = {2008}, note = {ISI Document Delivery No.: 323VATimes Cited: 3Cited Reference Count: 42Lorenzini, Fabio Patrick, Brian O. James, Brian R.}, month = {Jul}, pages = {3199-3204}, type = {Article}, abstract = {{The complex RhCl(P-N)(THP) (1) is synthesized under argon from RhCl(cod)(THP) and P-N, and is structurally characterized; P-N = P, N-chelated o-diphenylphosphino-N,N-dimethylaniline}, keywords = {BEARING O-N, BIDENTATE PHOSPHINES, CATALYTIC-OXIDATION, HYDROFORMYLATION, LIGANDS, LOW-TEMPERATURE, N-DIMETHYLANILINYL SUBSTITUENTS, OXIDATION, PALLADIUM(II) COMPLEXES, phosphanes, phosphine oxides, phosphines, REACTIVITY, RHODIUM COMPLEXES, RHODIUM(I) COMPLEXES, X-ray structure}, isbn = {0020-1693}, url = {://000257475300029}, author = {Lorenzini, F. and Patrick, B. O. and James, Brian R.} } @article {828, title = {A one-pot synthesis and X-ray crystallographic and computational analyses of methyl-2,4-dimethoxysalicylate - a potential anti-tumour agent}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {82}, number = {7}, year = {2004}, note = {ISI Document Delivery No.: 861XBTimes Cited: 5Cited Reference Count: 34}, month = {Jul}, pages = {1179-1185}, type = {Article}, abstract = {The thermal decarboxylation of 2-methoxycarbonyl-5-(4{\textquoteright}-nitrophen-oxy)tetrazole (1a) with the electron-rich, aromatic compounds (anisole, N,N-dimethylaniline, 1,4-dimethoxybenzene, and 1,3,5-trimethoxybenzene), neat or in polar solvents (DMSO, DMF, and CH3CN), is investigated. The solid phase thermal decomposition of a mixture of 1a, 1,3,5-trimethoxybenzene, and a Lewis acid (AlCl3) produces methyl-2,4-dimethoxysalicylate (8) in good yield, instead of the expected 2,4,6-trimethoxybenzoic acid. The X-ray structure of 8 shows intramolecular hydrogen bonds between the carbonyl oxygen and hydrogens of Me and OH groups. A measured pK(a) value of 6.8 compares well with a value of 6.4 estimated using the [C=O...H...O] hydrogen bond distances.}, keywords = {2{\textquoteright}, 6{\textquoteright}-DIMETHOXYFLAVONE, ACID, anti-tumor, computational analysis, hydrogen bonds, HYDROGEN-BOND DATA, novel synthesis, PK(A), TETRAZOLES, X-ray structure}, isbn = {0008-4042}, url = {://000224450800007}, author = {Dabbagh, H. A. and Noroozi-Pesyan, N. and Patrick, B. O. and James, Brian R.} } @article {4998, title = {Organometallic oxides: Oxidation of the cubane [(eta-C5R5)Cr(mu(3)-O)](4) and the structures and magnetic properties of the salts {[(eta-C5R5)Cr(mu(3)-O)](4)}{tcnq} and {[(eta-C5R5)Cr(mu(3)-O)](4)}{BF4}, journal = {Organometallics}, volume = {20}, number = {9}, year = {2001}, note = {ISI Document Delivery No.: 428DKTimes Cited: 5Cited Reference Count: 41}, month = {Apr}, pages = {1840-1848}, type = {Article}, abstract = {Differential pulse and current voltammetry for the cubane-like clusters [(eta -C5R5)Cr(mu (3)-O)](4) (R = H, Me; R-5 = H4Me) showed that [(eta -C5H4Me)Cr(mu (3)-O)](4) and [(eta -C5Me5)Cr(mu (3)-O)](4) were oxidized to {[(eta -C5R5)Cr(mu (3)-O)](4)}(+) and then to {[(eta -C5R5)Cr(mu (3)-O)](4)}(2+), but [(eta -C5H5)-Cr(mu (3)-O)](4) was oxidized only to {[(eta -C5H5)Cr(mu (3)-O)](4)}(+). Oxidation of [(eta -C5Me5)Cr(mu (3)-O)](4) (1) by AgBF4 or tcnq gave {[(eta -C5Me5)Cr(mu (3)-O)](4)}{BF4} (2) {[(eta -C5Me5)Cr(mu (3)-O)](4)}{tcnq} (3). It was shown by X-ray diffraction that the average Cr-Cr, Cr-O, and Cr-Cp* distances in 2 and 3 were 0.034(2), 0.007(5), and 0.02(1) Angstrom shorter than those in 1, respectively. Compounds 1 2, and 3 were antiferromagnetic., with similar intracluster exchange coupling constants, J (-262(23), -211(34), and -266(46) cm(-1), respectively). There was coupling between unpaired electrons on {[(eta -C5Me5)Cr(mu (3)-O)](4)}(+) and {tcnq}(-) in 3 at temperatures below 110 Ii.}, keywords = {<(ETA-C5H5)CR(MU-3-O)>4, CLUSTERS, COMPLEXES, CRYSTAL-STRUCTURES, MONONUCLEAR, REACTIVITY, SINGLE-MOLECULE MAGNETS, TCNQ, X-ray structure}, isbn = {0276-7333}, url = {://000168445800017}, author = {Allen, D. P. and Bottomley, F. and Day, R. W. and Decken, A. and Sanchez, V. and Summers, D. A. and Thompson, R. C.} } @article {4842, title = {Hydrogen bonding and catalysis: A novel explanation for how a single amino acid substitution can change the pH optimum of a glycosidase}, journal = {Journal of Molecular Biology}, volume = {299}, number = {1}, year = {2000}, note = {ISI Document Delivery No.: 318NCTimes Cited: 96Cited Reference Count: 58}, month = {May}, pages = {255-279}, type = {Article}, abstract = {The pH optima of family 11 xylanases are well correlated with the nature of the residue adjacent to the acid/base catalyst. In xylanases that function optimally under acidic conditions, this residue is aspartic acid, whereas it is asparagine in those that function under more alkaline conditions. Previous studies of wild-type (WT) Bacillus circulans xylanase (BCX), with an asparagine residue at position 35, demonstrated that its pH-dependent activity follows the ionization states of the nucleophile Glu78 (pK(a) 4.6) and the acid/base catalyst Glu172 (pK(a) 6.7). As predicted from sequence comparisons, substitution of this asparagine residue with an aspartic acid residue (N35D BCX) shifts its pH optimum from 5.7 to 4.6, with an similar to 20 \% increase in activity. The bell-shaped pH-activity profile of this mutant enzyme follows apparent pK(a) values of 3.5 and 5.8. Based on C-13-NMR titrations, the predominant pK(a) values of its active-site carboxyl groups are 3.7 (Asp35), 5.7 (Glu78) and 8.4 (Glu172). Thus, in contrast to the WT enzyme, the pH-activity profile of N35D BCX appears to be set by Asp35 and Glu78. Mutational, kinetic, and structural studies of N35D BCX, both in its native and covalently modified 2-fluoro-xylobiosyl glycosyl-enzyme intermediate states, reveal that the xylanase still follows a double-displacement mechanism with Glu78 serving as the nucleophile. We therefore propose that Asp35 and Glu172 function together as the general acid/base catalyst, and that N35D BCX exhibits a "reverse protonation" mechanism in which it is catalytically active when Asp35, with the lower pK(a), is protonated, while Glu78, with the higher pK(a), is deprotonated. This implies that the mutant enzyme must have an inherent catalytic efficiency at least 100-fold higher than that of the parental WT, because only similar to 1\% of its population is in the correct ionization state for catalysis at its pH optimum. The increased efficiency of N35D BCX, and by inference all "acidic" family 11 xylanases, is attributed to the formation of a short (2.7 Angstrom) hydrogen bond between Asp35 and Glu172, observed in the crystal structure of the glycosyl-enzyme intermediate of this enzyme, that will substantially stabilize the transition state for glycosyl transfer. Such a mechanism may be much more commonly employed than is generally realized, necessitating careful analysis of the pH-dependence of enzymatic catalysis. (C) 2000 Academic Press.}, keywords = {3-DIMENSIONAL STRUCTURE, 4-BETA-XYLANASES, ACTIVE-SITE, BACILLUS-CIRCULANS XYLANASE, CYCLODEXTRIN GLYCOSYLTRANSFERASE, electrostatics, ENDO-1, GLYCOSYL-ENZYME INTERMEDIATE, ISOTOPE, MOLECULAR-WEIGHT, NMR, NUCLEAR-MAGNETIC-RESONANCE, nucleophile, PANCREATIC ALPHA-AMYLASE, pH-dependent enzyme mechanism, SHIFT, TRICHODERMA-REESEI, X-RAY CRYSTALLOGRAPHY, X-ray structure}, isbn = {0022-2836}, url = {://000087289400019}, author = {Joshi, M. D. and Sidhu, G. and Pot, I. and Brayer, G. D. and Withers, S. G. and McIntosh, L. P.} } @article {4542, title = {Reactivity studies of the zirconium alkylidene complexes [eta(5)-C5H3-1,3-(SiMe2CH2PPr2i)(2)]Zr=CHR(Cl) (R = Ph, SiMe3)}, journal = {Journal of the American Chemical Society}, volume = {121}, number = {8}, year = {1999}, note = {ISI Document Delivery No.: 174BPTimes Cited: 25Cited Reference Count: 58}, month = {Mar}, pages = {1707-1716}, type = {Article}, abstract = {{Reactivity studies of the zirconium alkylidene complexes [P2Cp]Zr=CHR(CI) (1a}, keywords = {ALPHA-OLEFINS, CARBON-MONOXIDE, CHEMISTRY, COMPLEXES, KETENE COMPLEXES, METAL KETENIMINE, tantalum, TITANOCENE, TRANSITION-METAL, X-ray structure, ZIRCONOCENE-ALKENE COMPLEXES}, isbn = {0002-7863}, url = {://000079014500011}, author = {Fryzuk,Michael D. and Duval, P. B. and Mao, Sssh and Rettig, S. J. and Zaworotko, M. J. and Macgillivray, L. R.} } @article {4013, title = {Expanded porphyrins and their heterologs}, journal = {Chemical Reviews}, volume = {97}, number = {6}, year = {1997}, note = {ISI Document Delivery No.: XZ270Times Cited: 279Cited Reference Count: 255}, month = {Sep-Oct}, pages = {2267-2340}, type = {Review}, keywords = {ACETYLENE-CUMULENE PORPHYRINOIDS, CENTERED TEMPLATE REACTIONS, COMPLEXES, DICERIUM(III) TRIS(OCTAETHYLPORPHYRINATE), ION-CONTROLLED, LOW-VALENT TITANIUM, PHOTODYNAMIC THERAPY, SCHIFF-BASE LIGANDS, TETRAPYRROLE LIGANDS, TRANSAMINATION, TRANSITION-METAL, X-ray structure}, isbn = {0009-2665}, url = {://A1997XZ27000011}, author = {Jasat, A. and Dolphin, D.} } @article {3758, title = {2,3-Pyrazinedicarboxylates of cobalt(II), nickel(II), and copper(II); Magnetic properties and crystal structures}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {74}, number = {3}, year = {1996}, note = {ISI Document Delivery No.: UF848Times Cited: 30Cited Reference Count: 28}, month = {Mar}, pages = {433-444}, type = {Article}, abstract = {{Complexes of singly and doubly deprotonated 2,3-pyrazinedicarboxylic acid (pyzdcH(2)) have been prepared and studied. Crystal data: [Ni(pyzdcH)(2)(H2O)(2)], 1, monoclinic, P2(1)/n}, keywords = {3-pyrazinedicarboxylates, ANTIFERROMAGNETISM, COMPLEXES, metal 2, SUPEREXCHANGE MECHANISM, SYNTHESIS, X-ray structure}, isbn = {0008-4042}, url = {://A1996UF84800017}, author = {Mao, L. and Rettig, S. J. and Thompson, R. C. and Trotter, J. and Xia, S. H.} } @article {3758, title = {2,3-Pyrazinedicarboxylates of cobalt(II), nickel(II), and copper(II); Magnetic properties and crystal structures}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {74}, number = {3}, year = {1996}, note = {ISI Document Delivery No.: UF848Times Cited: 30Cited Reference Count: 28}, month = {Mar}, pages = {433-444}, type = {Article}, abstract = {{Complexes of singly and doubly deprotonated 2,3-pyrazinedicarboxylic acid (pyzdcH(2)) have been prepared and studied. Crystal data: [Ni(pyzdcH)(2)(H2O)(2)], 1, monoclinic, P2(1)/n}, keywords = {3-pyrazinedicarboxylates, ANTIFERROMAGNETISM, COMPLEXES, metal 2, SUPEREXCHANGE MECHANISM, SYNTHESIS, X-ray structure}, isbn = {0008-4042}, url = {://A1996UF84800017}, author = {Mao, L. and Rettig, S. J. and Thompson, R. C. and Trotter, J. and Xia, S. H.} } @article {3241, title = {RUTHENIUM COMPLEXES CONTAINING TERTIARY PHOSPHINES AND IMIDAZOLE OR 2,2{\textquoteright}-BIPYRIDINE LIGANDS}, journal = {Inorganica Chimica Acta}, volume = {230}, number = {1-2}, year = {1995}, note = {ISI Document Delivery No.: QN719Times Cited: 26Cited Reference Count: 39}, month = {Mar}, pages = {111-117}, type = {Article}, abstract = {{Complexes RuCl3(PPh(3))L(2) (L=MeIm (1a), Im (1b)) and [RuCl2(PPh(3))(2)(bipy)]Cl . 4H(2)O (2) have been synthesized via the ruthenium(III) precursor RuCl3(PPh(3))(2) (DMA), and characterized, including an X-ray structural analysis for 1a (MeIm=N-methylimidazole}, keywords = {BIPYRIDINE COMPLEXES, CRYSTAL, crystal structures, DERIVATIVES, HYDROGEN, IMIDAZOLE COMPLEXES, ruthenium complexes, TERTIARY PHOSPHINE COMPLEXES, X-ray structure}, isbn = {0020-1693}, url = {://A1995QN71900015}, author = {Batista, A. A. and Polato, E. A. and Queiroz, S. L. and Nascimento, O. R. and James, Brian R. and Rettig, S. J.} } @article {3028, title = {A COMPARISON OF CATALYTIC ACTIVITY FOR IMINE HYDROGENATION USING RU DITERTIARY PHOSPHINE COMPLEXES, INCLUDING CHIRAL SYSTEMS}, journal = {Inorganica Chimica Acta}, volume = {222}, number = {1-2}, year = {1994}, note = {ISI Document Delivery No.: PD174Times Cited: 39Cited Reference Count: 45}, month = {Jul}, pages = {85-90}, type = {Article}, abstract = {A family of ruthenium ditertiary phosphine complexes was investigated for catalytic activity toward imine hydrogenation. The diphosphines (PP) used include chiral (chiraphos, diop, binap) and achiral (dppe, dppb) systems (chiraphos = Ph2PCH(Me)CH(Me)PPh2; diop = Ph2PCH2CHOCMe2OCHCH2PPh2; binap = 2,2{\textquoteright}-bis(diphenylphosphino)-1,1{\textquoteright}-binaphthyl; Ph2P(CH2)(n)PPh2 (n = 2, dppe; n = 4, dppb)). Activity was observed in MeOH at low catalyst concentrations (0.77 mM Ru), under moderate conditions (room temperature (r.t.), 1000 psi H2). The air-stable Ru2Cl5(PP)2 complexes were more active than the commonly used dimeric Ru2(II,II) systems to which they give rise in situ. Asymmetric induction in the prochiral ketimine PhCH2N = C(Me)Ph was consistent, though modest, within the diop and binap series of neutral complexes, implying a common catalytic intermediate within each series. A maximum e.e. of 27\% was found using Ru2Cl5(chiraphos)2 as catalyst; this represents a non-optimized figure for asymmetric induction, as no other prochiral ketimines were screened.}, keywords = {1{\textquoteright}-BINAPHTHYL, 2, 2{\textquoteright}-BIS(DIPHENYLPHOSPHINO)-1, ACIDS, ASYMMETRIC HYDROGENATION, BINAP, CATALYSIS, DIPHOSPHINE, ENANTIOSELECTIVE, HYDROGENATION, IMINE HYDROGENATION, LIGANDS, NITRILE COMPLEXES, PHOSPHINE COMPLEXES, ruthenium complexes, X-ray structure}, isbn = {0020-1693}, url = {://A1994PD17400011}, author = {Fogg, D. E. and James, Brian R. and Kilner, M.} } @article {2730, title = {INSERTIONS OF HETEROCUMULENES INTO THE M-C SIGMA-BONDS OF CP-ASTERISK-M(NO)(ARYL)2 (M=MO, W) COMPLEXES}, journal = {Organometallics}, volume = {12}, number = {10}, year = {1993}, note = {ISI Document Delivery No.: MC322Times Cited: 14Cited Reference Count: 32}, month = {Oct}, pages = {4234-4240}, type = {Note}, abstract = {{Treatment of the 16-valence-electron complexes Cp*M(NO)(aryl)2 (Cp* = eta5-C5Me5; M = Mo, W; aryl = phenyl (Ph), p-tolyl) with the heterocumulenes carbon disulfide, p-tolyl isocyanate, and carbon dioxide leads to the eta2-thiocarboxylate, eta2-amide-, and eta2-carboxylate-containing complexes, respectively, in 10-65\% isolated yields. Furthermore, Cp* W(NO) (eta2-S2C-Ph)(Ph) (1) reacts with trimethylphosphine to form Cp*W(NO)(eta2-S2C(PMe3)Ph)(Ph) (10), which contains a zwitterionic phosphonium betaine ligand. The solid-state molecular structure of 10-CH2Cl2 has been established by a single-crystal X-ray crystallographic analysis. Crystal data for Cp*W(NO)(eta2-S2C(PMe3)Ph)(Ph). CH2Cl2: monoclinic}, keywords = {ALKYL, CARBON BONDS, CO2, H-BONDS, ORGANOMETALLIC NITROSYL CHEMISTRY, REACTIVITY, TUNGSTEN, WATER, X-ray structure}, isbn = {0276-7333}, url = {://A1993MC32200074}, author = {Brouwer, E. B. and Legzdins,Peter and Rettig, S. J. and Ross, K. J.} }