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SM ISO690:2012 LEHMANN, Ulrike, KLINGELE, Julia, LOZAN, Vasile, STEINFELD, Günther, KLINGELE, Marco H., KASS, Steffen, RODENSTEIN, Axel, KERSTING, Berthold. Dependence of the chemical properties of macrocyclic [NiII 2L(μ-O2CR)]+ complexes on the basicity of the carboxylato coligands (L2- = macrocyclic N6S 2 ligand). In: Inorganic Chemistry, 2010, vol. 49, pp. 11018-11029. ISSN 0020-1669. DOI: https://doi.org/10.1021/ic101574a |
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Inorganic Chemistry | ||||||
Volumul 49 / 2010 / ISSN 0020-1669 | ||||||
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DOI:https://doi.org/10.1021/ic101574a | ||||||
Pag. 11018-11029 | ||||||
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The dependence of the properties of mixed ligand [NiII 2L(μ-O2CR)]+ complexes (where L2- represents a 24-membered macrocyclic hexaamine-dithiophenolato ligand) on the basicity of the carboxylato coligands has been examined. For this purpose 19 different [NiII2L(μ-O2CR)]+ complexes (2-20) incorporating carboxylates with pKb values in the range 9 to 14 have been prepared by the reaction of [NiII 2L(μ-Cl)]+ (1) and the respective sodium or triethylammonium carboxylates. The resulting carboxylato complexes, isolated as ClO4- or BPh4- salts, have been fully characterized by elemental analyses, IR, UV/vis spectroscopy, and X-ray crystallography. The possibility of accessing the [NiII 2L(μ-O2CR)]+ complexes by carboxylate exchange reactions has also been examined. The main findings are as follows: (i) Substitution reactions between 1 and NaO2CR are not affected by the basicity or the steric hindrance of the carboxylate. (ii) Complexes 2-20 form an isostructural series of bisoctahedral [NiII2L(μ-O 2CR)]+ compounds with a N3Ni(μ-SR) 2(μ-O2CR)NiN3 core. (iii) They are readily identified by their Vas(CO) and Vs(CO) stretching vibration bands in the ranges 1684-1576 cm-1 and 1428-1348 cm -1, respectively. (iv) The spin-allowed 3A2g → 3T2g (V1) transition of the NiOS 2N3 chromophore is steadily red-shifted by about 7.5 nm per pKb unit with increasing pKb of the carboxylate ion. (v) The less basic the carboxylate ion, the more stable the complex. The stability difference across the series, estimated from the difference of the individual ligand field stabilization energies (LFSE), amounts to about 4.2 kJ/mol [ΔLFSE(2,18)]. (vi) The "second-sphere stabilization" of the nickel complexes is not reflected in the electronic absorption spectra, as these forces are aligned perpendicularly to the Ni-O bonds. (vii) Coordination of a basic carboxylate donor to the [Ni II2L]2+ fragment weakens its Ni-N and Ni-S bonds. This bond weakening is reflected in small but significant bond length changes. (viii) The [NiII2L(μ-O2CR)] + complexes are relatively inert to carboxylate exchange reactions, except for the formato complex [NiII2L(μ-O 2CH)]+ (8), which reacts with both more and less basic carboxylato ligands. |
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Cuvinte-cheie MeSH Carboxylic Acids, crystallography, X-ray, ligands, Macrocyclic Compounds, Models, Molecular, nickel, Phenols, Polyamines, Spectrum analysis, Sulfhydryl Compounds EMTREE drug terms carboxylic acid, Ligand, macrocyclic compound, nickel, phenol derivative, polyamine, thiol derivative EMTREE medical terms article, chemical structure, Chemistry, spectroscopy, X ray crystallography |
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<?xml version='1.0' encoding='utf-8'?> <resource xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xmlns='http://datacite.org/schema/kernel-3' xsi:schemaLocation='http://datacite.org/schema/kernel-3 http://schema.datacite.org/meta/kernel-3/metadata.xsd'> <identifier identifierType='DOI'>10.1021/ic101574a</identifier> <creators> <creator> <creatorName>Lehmann, U.</creatorName> <affiliation>Universitatea din Leipzig, Germania</affiliation> </creator> <creator> <creatorName>Klingele, J.</creatorName> <affiliation>University of Freiburg, Germania</affiliation> </creator> <creator> <creatorName>Lozan, V.I.</creatorName> <affiliation>Universitatea din Leipzig, Germania</affiliation> </creator> <creator> <creatorName>Steinfeld, G.</creatorName> <affiliation>University of Freiburg, Germania</affiliation> </creator> <creator> <creatorName>Klingele, M.</creatorName> <affiliation>University of Freiburg, Germania</affiliation> </creator> <creator> <creatorName>Kass, S.</creatorName> <affiliation>Universitatea din Leipzig, Germania</affiliation> </creator> <creator> <creatorName>Rodenstein, A.</creatorName> <affiliation>Universitatea din Leipzig, Germania</affiliation> </creator> <creator> <creatorName>Kersting, B.</creatorName> <affiliation>Universitatea din Leipzig, Germania</affiliation> </creator> </creators> <titles> <title xml:lang='en'>Dependence of the chemical properties of macrocyclic [NiII 2L(μ-O2CR)]+ complexes on the basicity of the carboxylato coligands (L2- = macrocyclic N6S 2 ligand)</title> </titles> <publisher>Instrumentul Bibliometric National</publisher> <publicationYear>2010</publicationYear> <relatedIdentifier relatedIdentifierType='ISSN' relationType='IsPartOf'>0020-1669</relatedIdentifier> <subjects> <subject>MeSH Carboxylic Acids</subject> <subject>crystallography</subject> <subject>X-ray</subject> <subject>ligands</subject> <subject>Macrocyclic Compounds</subject> <subject>Models</subject> <subject>Molecular</subject> <subject>nickel</subject> <subject>Phenols</subject> <subject>Polyamines</subject> <subject>Spectrum analysis</subject> <subject>Sulfhydryl Compounds EMTREE drug terms carboxylic acid</subject> <subject>Ligand</subject> <subject>macrocyclic compound</subject> <subject>nickel</subject> <subject>phenol derivative</subject> <subject>polyamine</subject> <subject>thiol derivative EMTREE medical terms article</subject> <subject>chemical structure</subject> <subject>Chemistry</subject> <subject>spectroscopy</subject> <subject>X ray crystallography</subject> </subjects> <dates> <date dateType='Issued'>2010-12-06</date> </dates> <resourceType resourceTypeGeneral='Text'>Journal article</resourceType> <descriptions> <description xml:lang='en' descriptionType='Abstract'><p>The dependence of the properties of mixed ligand [Ni<sup>II</sup> <sub>2</sub>L(μ-O<sub>2</sub>CR)]<sup>+</sup> complexes (where L<sup>2-</sup> represents a 24-membered macrocyclic hexaamine-dithiophenolato ligand) on the basicity of the carboxylato coligands has been examined. For this purpose 19 different [Ni<sup>II</sup><sub>2</sub>L(μ-O<sub>2</sub>CR)]<sup>+</sup> complexes (2-20) incorporating carboxylates with pK<sub>b</sub> values in the range 9 to 14 have been prepared by the reaction of [Ni<sup>II</sup> <sub>2</sub>L(μ-Cl)]<sup>+</sup> (1) and the respective sodium or triethylammonium carboxylates. The resulting carboxylato complexes, isolated as ClO<sub>4</sub><sup>-</sup> or BPh<sub>4</sub><sup>-</sup> salts, have been fully characterized by elemental analyses, IR, UV/vis spectroscopy, and X-ray crystallography. The possibility of accessing the [Ni<sup>II</sup> <sub>2</sub>L(μ-O<sub>2</sub>CR)]<sup>+</sup> complexes by carboxylate exchange reactions has also been examined. The main findings are as follows: (i) Substitution reactions between 1 and NaO<sub>2</sub>CR are not affected by the basicity or the steric hindrance of the carboxylate. (ii) Complexes 2-20 form an isostructural series of bisoctahedral [Ni<sup>II</sup><sub>2</sub>L(μ-O <sub>2</sub>CR)]<sup>+</sup> compounds with a N<sub>3</sub>Ni(μ-SR) <sub>2</sub>(μ-O<sub>2</sub>CR)NiN<sub>3</sub> core. (iii) They are readily identified by their V<sub>as</sub>(CO) and V<sub>s</sub>(CO) stretching vibration bands in the ranges 1684-1576 cm<sup>-1</sup> and 1428-1348 cm <sup>-1</sup>, respectively. (iv) The spin-allowed <sup>3</sup>A<sub>2g</sub> → <sup>3</sup>T<sub>2g</sub> (V<sub>1</sub>) transition of the NiOS <sub>2</sub>N<sub>3</sub> chromophore is steadily red-shifted by about 7.5 nm per pK<sub>b</sub> unit with increasing pK<sub>b</sub> of the carboxylate ion. (v) The less basic the carboxylate ion, the more stable the complex. The stability difference across the series, estimated from the difference of the individual ligand field stabilization energies (LFSE), amounts to about 4.2 kJ/mol [Δ<sub>LFSE</sub>(2,18)]. (vi) The "second-sphere stabilization" of the nickel complexes is not reflected in the electronic absorption spectra, as these forces are aligned perpendicularly to the Ni-O bonds. (vii) Coordination of a basic carboxylate donor to the [Ni <sup>II</sup><sub>2</sub>L]<sup>2+</sup> fragment weakens its Ni-N and Ni-S bonds. This bond weakening is reflected in small but significant bond length changes. (viii) The [Ni<sup>II</sup><sub>2</sub>L(μ-O<sub>2</sub>CR)] <sup>+</sup> complexes are relatively inert to carboxylate exchange reactions, except for the formato complex [Ni<sup>II</sup><sub>2</sub>L(μ-O <sub>2</sub>CH)]<sup>+</sup> (8), which reacts with both more and less basic carboxylato ligands.</p></description> </descriptions> <formats> <format>uri</format> </formats> </resource>