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Acetic Acid Mediated Synthesis of Phosphonate-Substituted Titanium Oxo Clusters.

Czakler M, Artner C, Schubert U - Eur J Inorg Chem (2014)

Bottom Line: The clusters [Ti6O4(OiPr)10(OAc)2(O3PR)2] (OAc = acetate) were obtained for a large variety of functional and non-functional groups R under a range of reaction conditions.This cluster type, which is also retained in solution, therefore appears to be very robust.Two other clusters, [Ti5O(OiPr)11(OAc)(O3PCH2CH2CH2Br)3] and [Ti5O3(OiPr)6(OAc)4(O3P-xylyl)2], were only isolated in special cases.

View Article: PubMed Central - PubMed

Affiliation: Institute of Materials Chemistry, Vienna University of Technology, Getreidemarkt 9, 1060 Wien, Austria.

ABSTRACT

New phosphonate/acetate-substituted titanium oxo/alkoxo clusters were prepared from Ti(OiPr)4 and bis(trimethylsilyl) phosphonates in the presence of acetic acid, which served to generate water in situ through ester formation. The process led to clusters with a higher degree of condensation than in previously known phosphonate-substituted titanium oxo clusters. The clusters [Ti6O4(OiPr)10(OAc)2(O3PR)2] (OAc = acetate) were obtained for a large variety of functional and non-functional groups R under a range of reaction conditions. This cluster type, which is also retained in solution, therefore appears to be very robust. Two other clusters, [Ti5O(OiPr)11(OAc)(O3PCH2CH2CH2Br)3] and [Ti5O3(OiPr)6(OAc)4(O3P-xylyl)2], were only isolated in special cases.

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Molecular structure of[Ti5(μ3-O)(μ2-OiPr)4(OiPr)7(OAc)(O3PCH2CH2CH2Br)3](8). Hydrogen atoms are omitted for clarity.
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fig03: Molecular structure of[Ti5(μ3-O)(μ2-OiPr)4(OiPr)7(OAc)(O3PCH2CH2CH2Br)3](8). Hydrogen atoms are omitted for clarity.

Mentions: Upon reaction of the aforementioned bis(trimethylsilyl) phosphonates with acetic acid andTi(OiPr)4 in a 1:1:2 ratio, in one case another cluster type wasobtained. Reaction of bis(trimethylsilyl) 3-bromopropylphosphonate at room temperature reproduciblyresulted in the cluster[Ti5(μ3-O)(μ2-OiPr)4(OiPr)7(OAc)(O3PCH2CH2CH2Br)3](8), the structure of which (Figure3) isrelated to those of previously observed clusters[Ti4(μ3-O)(μ2-OiPr)3(OiPr)5(O3PR)3L](L = neutral ligand).4,5 The latter consist of a symmetricalTi3(μ3-O)(μ2-OiPr)3(OiPr)3unit to which a Ti(OiPr)2L group is connected by means of threephosphonate ligands coordinating to two of the Ti atoms of the Ti3O triangle and thecapping Ti atom. In 8, the capping Ti(OiPr)2L group isreplaced by aTi2(μ2-OiPr)(OiPr)4(μ2-OAc)moiety. Two of the phosphonate ligands are coordinated to only one Ti atom of the Ti2unit, whereas the third bridges both of them. This phosphonate ligand has a binding mode of 4.211(w.xyz refers to the number of metal atoms to which thephosphonate ligand is coordinated [w], and the number of metal atoms to which eachoxygen is coordinated [x,y,z]10), whereas the other two phosphonate ligands, as well as those inthe cluster 1–7, have a 3.111 binding mode. TheTi2(μ2-OiPr)(OiPr)4(μ2-OAc)moiety in 8 is structurally related toTi2(OR)6(μ2-OOCR′)2.11


Acetic Acid Mediated Synthesis of Phosphonate-Substituted Titanium Oxo Clusters.

Czakler M, Artner C, Schubert U - Eur J Inorg Chem (2014)

Molecular structure of[Ti5(μ3-O)(μ2-OiPr)4(OiPr)7(OAc)(O3PCH2CH2CH2Br)3](8). Hydrogen atoms are omitted for clarity.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4362471&req=5

fig03: Molecular structure of[Ti5(μ3-O)(μ2-OiPr)4(OiPr)7(OAc)(O3PCH2CH2CH2Br)3](8). Hydrogen atoms are omitted for clarity.
Mentions: Upon reaction of the aforementioned bis(trimethylsilyl) phosphonates with acetic acid andTi(OiPr)4 in a 1:1:2 ratio, in one case another cluster type wasobtained. Reaction of bis(trimethylsilyl) 3-bromopropylphosphonate at room temperature reproduciblyresulted in the cluster[Ti5(μ3-O)(μ2-OiPr)4(OiPr)7(OAc)(O3PCH2CH2CH2Br)3](8), the structure of which (Figure3) isrelated to those of previously observed clusters[Ti4(μ3-O)(μ2-OiPr)3(OiPr)5(O3PR)3L](L = neutral ligand).4,5 The latter consist of a symmetricalTi3(μ3-O)(μ2-OiPr)3(OiPr)3unit to which a Ti(OiPr)2L group is connected by means of threephosphonate ligands coordinating to two of the Ti atoms of the Ti3O triangle and thecapping Ti atom. In 8, the capping Ti(OiPr)2L group isreplaced by aTi2(μ2-OiPr)(OiPr)4(μ2-OAc)moiety. Two of the phosphonate ligands are coordinated to only one Ti atom of the Ti2unit, whereas the third bridges both of them. This phosphonate ligand has a binding mode of 4.211(w.xyz refers to the number of metal atoms to which thephosphonate ligand is coordinated [w], and the number of metal atoms to which eachoxygen is coordinated [x,y,z]10), whereas the other two phosphonate ligands, as well as those inthe cluster 1–7, have a 3.111 binding mode. TheTi2(μ2-OiPr)(OiPr)4(μ2-OAc)moiety in 8 is structurally related toTi2(OR)6(μ2-OOCR′)2.11

Bottom Line: The clusters [Ti6O4(OiPr)10(OAc)2(O3PR)2] (OAc = acetate) were obtained for a large variety of functional and non-functional groups R under a range of reaction conditions.This cluster type, which is also retained in solution, therefore appears to be very robust.Two other clusters, [Ti5O(OiPr)11(OAc)(O3PCH2CH2CH2Br)3] and [Ti5O3(OiPr)6(OAc)4(O3P-xylyl)2], were only isolated in special cases.

View Article: PubMed Central - PubMed

Affiliation: Institute of Materials Chemistry, Vienna University of Technology, Getreidemarkt 9, 1060 Wien, Austria.

ABSTRACT

New phosphonate/acetate-substituted titanium oxo/alkoxo clusters were prepared from Ti(OiPr)4 and bis(trimethylsilyl) phosphonates in the presence of acetic acid, which served to generate water in situ through ester formation. The process led to clusters with a higher degree of condensation than in previously known phosphonate-substituted titanium oxo clusters. The clusters [Ti6O4(OiPr)10(OAc)2(O3PR)2] (OAc = acetate) were obtained for a large variety of functional and non-functional groups R under a range of reaction conditions. This cluster type, which is also retained in solution, therefore appears to be very robust. Two other clusters, [Ti5O(OiPr)11(OAc)(O3PCH2CH2CH2Br)3] and [Ti5O3(OiPr)6(OAc)4(O3P-xylyl)2], were only isolated in special cases.

No MeSH data available.


Related in: MedlinePlus