New highly ordered hydrophobic siloxane-based coordination polymers

Racleş, Carmen; Shova, Sergiu; Cazacu, Maria; Ţîmpu, Daniel

doi:10.1016/j.polymer.2013.09.001

Cited by 21 publications

(12 citation statements)

References 55 publications

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“…However, highly ordered, crystalline polymeric covalent structures, where siloxane motifs alternate with coordinated metal blocks, were obtained with carboxylic ligands, 1,3-bis(carboxypropyl)tetramethyldisiloxane (H 2 CX) prepared for the first time in 1999 [ 15 ], bis(p-carboxyphenyl)diphenylsilane (H 2 L 1 ), and bis(3,4-dicarboxyphenyl)dimethylsilane (H 4 L 2 ) were prepared later [ 126 ] ( Figure 9 a). They were used alone to directly coordinate the metal ions [ 127 , 128 , 129 ] or complexes of the latter with vacancies [ 55 , 99 , 130 , 131 ] or in combination with ancillary organic ligands (imidazole [ 132 , 133 ], 4,4′-bipyridyl [ 134 ], 4,4′-azopyridine [ 56 , 132 , 135 ], 1,2-di(4-pyridyl)ethylene [ 134 ], 1,10-phenanthroline [ 126 ], etc.) ( Figure 9 b) and metal ions or clusters, which allow highly directional intermolecular interactions (metal-ligand, hydrogen bonds and π-π stacking interactions).…”

Section: Highly Ordered Coordination Polymers Containing Silicon or Silicone Motifmentioning

confidence: 99%

From Amorphous Silicones to Si-Containing Highly Ordered Polymers: Some Romanian Contributions in the Field

Cazacu¹,

Racleş²,

Zaltariov³

et al. 2021

Polymers

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Polydimethylsiloxane (PDMS), in spite of its well-defined helical structure, is an amorphous fluid even at extremely high molecular weights. The cause of this behavior is the high flexibility of the siloxane backbone and the lack of intermolecular interactions attributed to the presence of methyl groups. These make PDMS incompatible with almost any organic or inorganic component leading to phase separation in siloxane-siloxane copolymers containing blocks with polar organic groups and in siloxane-organic copolymers, where dimethylsiloxane segments co-exist with organic ones. Self-assembly at the micro- or nanometric scale is common in certain mixed structures, including micelles, vesicles, et cetera, manifesting reversibly in response to an external stimulus. Polymers with a very high degree of ordering in the form of high-quality crystals were obtained when siloxane/silane segments co-exist with coordinated metal blocks in the polymer chain. While in the case of coordination of secondary building units (SBUs) with siloxane ligands 1D chains are formed; when coordination is achieved in the presence of a mixture of ligands, siloxane and organic, 2D structures are formed in most cases. The Romanian research group’s results regarding these aspects are reviewed: from the synthesis of classic, amorphous silicone products, to their adaptation for use in emerging fields and to new self-assembled or highly ordered structures with properties that create perspectives for the use of silicones in hitherto unexpected areas.

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Section: Highly Ordered Coordination Polymers Containing Silicon or Silicone Motifmentioning

confidence: 99%

From Amorphous Silicones to Si-Containing Highly Ordered Polymers: Some Romanian Contributions in the Field

Cazacu¹,

Racleş²,

Zaltariov³

et al. 2021

Polymers

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“…A search of the Cambridge Structural Database (CSD, version 5.40, last update February 2019; Groom et al, 2016) indicated that seven compounds formed by 1,3-bis(3-carboxypropyl)tetramethyldisiloxane itself or its anions have been characterized structurally. Two of them are co-crystals of the acid with organic bases derived from pyridine [refcodes NERTOV (Vlad et al, 2013a) and VIPZUR (Racles et al, 2013)]. Other complexes represent one-or two-dimensional coordination polymers formed by Cu II (YIGXOD; Vlad et al, 2013b), Co II (NERTIP; Vlad et al, 2013a), Zn II [NERTUB (Vlad et al, 2013a), GIWSAI (Vlad et al, 2014) and GAPKOA (Zaltariov et al, 2016)].…”

Section: Database Surveymentioning

confidence: 99%

Syntheses and crystal structures of the one-dimensional coordination polymers formed by [Ni(cyclam)]²⁺ cations and 1,3-bis(3-carboxypropyl)tetramethyldisiloxane anions in different degrees of deprotonation

Gavrish¹,

Shova²,

Cazacu³

et al. 2020

Acta Cryst E

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The asymmetric units of the title compounds, namely, catena-poly[[(1,4,8,11-tetraazacyclotetradecane-κ4 N 1,N 4,N 8,N 11)nickel(II)]-μ-1,3-bis(3-carboxylatopropyl)tetramethyldisiloxane-κ2 O:O′], [Ni(C10H24O5Si2)(C12H24N4)] n (I), and catena-poly[[[(1,4,8,11-tetraazacyclotetradecane-κ4 N 1,N 4,N 8,N 11)nickel(II)]-μ-4-({[(3-carboxypropyl)dimethylsilyl]oxy}dimethylsilyl)butanoato-κ2 O:O′] perchlorate], {[Ni(C10H25O5Si2)(C12H24N4)]ClO4} n (II), consist of one (in I) or two crystallographically non-equivalent (in II) centrosymmetric macrocyclic cations and one centrosymmetric dianion (in I) or two centrosymmetric monoanions (in II). In each compound, the metal ion is coordinated by the four secondary N atoms of the macrocyclic ligand, which adopts the most energetically stable trans-III conformation, and the mutually trans O atoms of the carboxylate in a slightly tetragonally distorted trans-NiN4O2 octahedral coordination geometry. The crystals of both types of compounds are composed of parallel polymeric chains of the macrocyclic cations linked by the anions of the acid running along the [101] and [110] directions in I and II, respectively. In I, each polymeric chain is linked to four neighbouring ones by hydrogen bonding between the NH groups of the macrocycle and the carboxylate O atoms, thus forming a three-dimensional supramolecular network. In II, each polymeric chain contacts with only two neighbours, forming hydrogen bonds between the partially protonated carboxylic groups of the bridging ligand. As a result, a lamellar structure is formed with the layers oriented parallel to the (1\overline{1}1) plane.

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“…While Davies et al . synthesized and used as ligands hexa(4‐carboxyphenyl)disiloxane molecules, we tried to use a longer and more flexible dicarboxylic acid, 1,3‐bis(carboxypropyl)tetramethyldisiloxane, as a ligand for metals or for the construction of more complex structures …”

Section: Introductionmentioning

confidence: 99%

Hydrophobic, amorphous metal–organic network readily prepared by complexing the aluminum ion with a siloxane spaced dicarboxylic acid in aqueous medium

Cazacu¹,

Turcan-Trofin²,

Vlad³

et al. 2018

J of Applied Polymer Sci

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A less common dicarboxylic acid with siloxane spacer, 1,3-bis(carboxypropyl)tetramethyldisiloxane, whose structure is for the first time determined crystallographically, is used to coordinate aluminum through an environment-friendly preparation process, resulting in a polymeric structure of amorphous metal-organic framework (aMOF) type. The high flexibility of the spacer induced by the siloxane bond gives the polymeric product a glass transition slightly below room temperature, while the long length of the former creates the premises for collapse of the network and consequently reduced porosity. At the same time, the high hydrophobicity of the tetramethyldisiloxane fragment and its low surface energy, which causes it to migrate to the air interface, gives the network low moisture sorption capacity guaranteeing the stability of its properties in a wet environment. The particulate complex, of the order of 1-200 nm, as generated by the synthesis, proves to be suitable as filler for silicone with outstanding reinforcement effect, without significantly affecting their transparency. The presence of the dimethylsiloxane units in the structure of both the matrix and the filler ensures good incorporation of the latter without the need for special compatibility treatments.

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New highly ordered hydrophobic siloxane-based coordination polymers

Cited by 21 publications

References 55 publications

From Amorphous Silicones to Si-Containing Highly Ordered Polymers: Some Romanian Contributions in the Field

From Amorphous Silicones to Si-Containing Highly Ordered Polymers: Some Romanian Contributions in the Field

Syntheses and crystal structures of the one-dimensional coordination polymers formed by [Ni(cyclam)]²⁺ cations and 1,3-bis(3-carboxypropyl)tetramethyldisiloxane anions in different degrees of deprotonation

Hydrophobic, amorphous metal–organic network readily prepared by complexing the aluminum ion with a siloxane spaced dicarboxylic acid in aqueous medium

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New highly ordered hydrophobic siloxane-based coordination polymers

Cited by 21 publications

References 55 publications

From Amorphous Silicones to Si-Containing Highly Ordered Polymers: Some Romanian Contributions in the Field

From Amorphous Silicones to Si-Containing Highly Ordered Polymers: Some Romanian Contributions in the Field

Syntheses and crystal structures of the one-dimensional coordination polymers formed by [Ni(cyclam)]2+ cations and 1,3-bis(3-carboxypropyl)tetramethyldisiloxane anions in different degrees of deprotonation

Hydrophobic, amorphous metal–organic network readily prepared by complexing the aluminum ion with a siloxane spaced dicarboxylic acid in aqueous medium

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Syntheses and crystal structures of the one-dimensional coordination polymers formed by [Ni(cyclam)]²⁺ cations and 1,3-bis(3-carboxypropyl)tetramethyldisiloxane anions in different degrees of deprotonation