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Preparation of SNS Cobalt(II) Pincer Model Complexes of Liver Alcohol Dehydrogenase
Published on: March 19, 2020
Gold(I) and silver(I) complexes of diphosphacyclobutadiene cobaltate sandwich anions
Jennifer Malberg1, Thomas Wiegand, Hellmut Eckert
1Institute of Inorganic Chemistry, University of Regensburg, Universitätsstrasse 31, 93040 Regensburg, Germany.
Abstract:
The synthesis and structural characterization of the first coordination compounds of bis(diphosphacyclobutadiene) cobaltate anions [M(P(2)(2)R(2))(2)](-) is described. Reactions of the new potassium salts [K(thf)(3){Co(η(4)-P(2)C(2)tPent(2))(2)}] (1) and [K(thf)(4){Co(η(4)-P(2)C(2)Ad(2))(2)}] (2) with [AuCl(tht)] (tht = tetrahydrothiophene), [AuCl(PPh(3))] and Ag[SbF(6)] afforded the complexes [Au{Co(P(2)C(2)tPent(2))(2)}(PMe(3))(2)] (3), [Au{Co(P(2)C(2)Ad(2))(2)}](x) (4), [Ag{Co(P(2)C(2)Ad(2))(2)}](x) (5), [Au(PMe(3))(4)][Au{Co(P(2)C(2)Ad(2))(2)}(2)] (6), [K([18]crown-6)(thf)(2)][Au{Co(P(2)C(2)Ad(2))(2)}(2)] (7), and [K([18]crown-6)(thf)(2)][M{Co(P(2)C(2)Ad(2))(2)}(2)] (8: M = Au 9: M = Ag) in moderate yields. The molecular structures of 2 and 3, and 6-9 were elucidated by X-ray crystallography. Complexes 4-9 were thoroughly characterized by (31)P and (13)C solid state NMR spectroscopy. The complexes [Au{Co(P(2)C(2)Ad(2))(2)}](x) (4) and [Ag{Co(P(2)C(2)Ad(2))(2)}](x) (5) exist as coordination polymers in the solid state. The linking mode between the monomeric units in the polymers is deduced. The soluble complexes 1-3, 6, and 7 were studied by multinuclear (1)H-, (31)P{(1)H}-, and (13)C{(1)H} NMR spectroscopy in solution. Variable temperature NMR measurements of 3 and 6 in deuterated THF reveal the formation of equilibria between the ionic species [Au(PMe(3))(4)](+), [Au(PMe(3))(2)](+), [Co(P(2)C(2)R(2))(2)](-), and [Au{Co(P(2)C(2)R(2))(2)}(2)](-) (R = tPent and Ad).
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