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1.
Angew Chem Int Ed Engl ; 57(16): 4130-4142, 2018 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-29543368

RESUMO

The elephant is in the room-a metaphorical idiom for an obvious problem or risk that nobody wants to discuss. This abstract is not intended to be a summary, to reveal major findings, or unveil conclusions. On the contrary, it is aimed to provoke curiosity as to the question of corporate survival. Is there any recipe to be followed for companies to achieve this? The answer comes neither from the modest and traditional study rooms of philosophers nor the recent fact-based studies from the offices (and well-paid opinions) of business consultants. The Archimedean point from which we can objectively explore the subject of corporate survival does not exist. Instead we offer seven analogies (or metaphors) as intellectual platforms where new perspectives can be considered. Innovation obviously plays a major role in corporate survival-yet, by its nature all innovation is messy. In order to reduce entropy, this abstract reveals some keywords in alphabetical order starting from A, such as ambidexterity, architecture, and ant colonies, moving on to B, such as, (mental) boxes and biodiversity. For obvious reasons, C plays a major role-sufficiently that we have already revealed curiosity as one part of the answer-treading over to D (Darwin, DNA, and discontinuity), followed by E (earthquakes and evolution). As a final warning signal in order to manage the expectation: It is not the intention of this article to give a comprehensive overview about the rich and complex history of Merck KGaA, Darmstadt, Germany. Indeed, only the final chapter will provide reference to this company: Before the curtains will finally close, an epilogue will start in which one of the protagonists of the 350-year journey of the company-Emanuel Merck-will appear on the stage and "let history speak for itself". Still curious?

3.
Inorg Chem ; 35(5): 1132-1135, 1996 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-11666300

RESUMO

The synthesis of the novel asymmetric ligand 1-[bis(2-pyridylmethyl)amino]-3-[2-(2-pyridyl)ethoxy]-2-hydroxypropane (ppepOH) is reported. The ligand is suitable to form asymmetric dinuclear complexes with various transition metal ions. As an example, the synthesis and X-ray structure analysis of the dinickel(II) complex [Ni(2)(ppepO)(C(6)H(5)COO)(2)(CH(3)COOH)]ClO(4).C(4)H(10)O are described. The complex crystallizes in the monoclinic space group P2(1)/n with the following unit cell parameters: a = 13.704(10) Å, b = 14.849(10) Å, c = 22.697(14) Å, beta = 96.80(5) degrees, Z = 4. The nickel(II) ions are bridged by the alkoxy donor of the ligand and two benzoate anions. The hexadentate ligand leaves a free coordination site at one of the nickel(II) ions, which is occupied by a monodentate coordinated acetic acid molecule. The coordination of the neutral acetic acid molecule is selectively stabilized by a strong intramolecular hydrogen bond of the acidic proton to the &mgr;-alkoxo bridge of the dinuclear complex. The asymmetric complex was prepared in order to mimic the substrate uptake in the dinuclear active site of ureases. The magnetic and spectroscopic properties of the complex were determined and related to those of the urease enzymes.

4.
Inorg Chem ; 35(13): 3792-3803, 1996 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-11666566

RESUMO

Dinuclear nickel(II) complexes of the ligands 2,6-bis[bis((2-benzimidazolylmethyl)amino)methyl]-p-cresol (bbapOH), N,N,N',N'-tetrakis(2-benzimidazolylmethyl)-2-hydroxy-1,3-diaminopropane (tbpOH), N-methyl-N,N',N'-tris(2-benzimidazolylmethyl)-2-hydroxy-1,3-diaminopropane (m-tbpOH) and 1-[N,N-bis(2-benzimidazolylmethyl)amino]-3-[2-(3,5-dimethyl-1H-pyrazol-1-yl)ethoxy]-2-hydroxypropane (bpepOH) were prepared in order to model the active site of urease. The novel asymmetric structures of the dinuclear complexes were characterized by X-ray structure analysis. The complex [Ni(2)(bbapO)(ClO(4))(H(2)O)(MeOH)](ClO(4))(2).Et(2)O, 1, crystallizes in the monoclinic space group P2(1)/c, with a = 10.258(2) Å, b = 19.876(3) Å, c = 25.592(4) Å, and beta = 97.12(2) degrees. The nickel ions in 1 are bridged by the phenoxy donor of the ligand and a perchlorate anion. The complexes [Ni(2)(tbpO)(MeCOO)(H(2)O)](ClO(4))(2).H(2)O.Et(2)O, 2, [Ni(2)(m-tbpO)(PhCOO)(EtOH)(2)](ClO(4))(2).EtOH, 3, and [Ni(2)(bpepO)(MeCOO)(H(2)O)(2)](ClO(4))(2).H(2)O.Et(2)O.2EtOH, 4, also crystallize in the monoclinic crystal system with the following unit cell parameters: 2, C2/c, a = 35.360(13) Å, b = 10.958(3) Å, c = 24.821(10) Å, beta = 103.55(3) degrees; 3, Cc, a = 14.663(5) Å, b = 32.630(13) Å, c = 9.839(3) Å, beta = 92.49(2) degrees; 4, C2/c, a = 27.689(13) Å, b = 12.187(5) Å, c = 31.513(14) Å, beta = 115.01(3) degrees. The dinuclear centers of all these complexes are bridged by the alkoxy donor of the ligand and a carboxylate function. Compounds 2 and 3 have one of the nickel ions in a five-coordinated, trigonal bipyramidal coordination environment and thus show a high structural similarity to the dinuclear active site of urease from Klebsiella aerogenes. Furthermore, their magnetic and spectroscopic properties were determined and related to those of the urease enzymes. Activity toward hydrolysis of test substrates (4-nitrophenyl)urea, 4-nitroacetanilide, 4-nitrophenyl phosphate or bis(4-nitrophenyl) phosphate by the dinuclear complexes were examined by UV spectroscopic measurements.

5.
Inorg Chem ; 35(8): 2360-2368, 1996 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-11666436

RESUMO

Novel Fe(III)Fe(III) and Fe(II)Fe(III) complexes [Fe(2)(BBPMP)(&mgr;-OAc)(&mgr;-X)](n)() (1, X = OAc(-), n = 1+; 2, X = OH(-), n = 1+; 3, X = OAc(-), n = 0; 4, X = OH(-), n = 0), where BBPMP(3)(-) is the anion of 2,6-bis[(2-hydroxybenzyl)(2-pyridylmethyl)aminomethyl]-4-methylphenol, and OAc(-) is acetate, were prepared in order to provide models for the active site of purple acid phosphatases (PAPs). Complex 1 was obtained by the reaction of H(3)BBPMP with Fe(ClO(4))(2).6H(2)O in methanol and sodium acetate trihydrate under ambient conditions, while complex 3 was synthesized as described for 1, under an argon atmosphere with low levels of dioxygen. 2 was isolated from 1in acetonitrile by a substitution of the bridging acetate group by hydroxide, while 4 was generated in solution during a spectropotentiostatic experiment on 2, under argon. Complex 1, [Fe(III)(2)(BBPMP)(&mgr;-OAc)(2)]ClO(4).H(2)O, has been characterized by X-ray crystallography. Crystal data: monoclinic, space group P2(1)/n, a = 14.863(5) Å, b = 12.315(3) Å, c = 20.872(8) Å, beta = 90.83(3) degrees, Z = 4. IR, Mössbauer, magnetic, electronic absorption, and electrochemical properties of 1-3 have been investigated, and some of these properties represent a contribution to the understanding of the dinuclear iron center of PAPs. Complexes 2, [Fe(III)(2)(BBPMP)(&mgr;-OAc)(&mgr;-OH)]ClO(4) (lambda(max) = 568 nm/epsilon = 4760 M(-)(1) cm(-)(1)), and 4 [Fe(II)Fe(III)(BBPMP)(&mgr;-OAc)(&mgr;-OH)] (lambda(max) = 516 nm/epsilon = 4560 M(-)(1) cm(-)(1)), constitute good synthetic analogues for the chromophoric site for the oxidized and reduced forms, respectively, of the enzyme.

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