4 research outputs found
Hydroxylated phosphines as ligands for chalcogenide clusters: self assembly, transformations and stabilization
This contribution is a documentation of recent advances in the chemistry of chalcogenide polynuclear transition metal complexes coordinated with mono- and di-phosphines functionalized with hydroxo groups. A survey of complexes containing tris(hydroxymethyl)phosphine (THP) is presented. The influence of the alkyl chain in bidentate phosphines, bearing the P–(CH2)x–OH arms, is also analyzed. Finally, isolation and structure elucidation of the complexes with HP(OH)2, P(OH)3, As(OH)3, PhP(OH)2, stabilized by coordination to Ni(0) and Pd(0) centers embedded into chalcogenide clusters, is discussed
Versatile Post-functionalisation Strategy for the Formation of Modular Organic-Inorganic Polyoxometalate Hybrids
Hybrid structures incorporating different organic and inorganic constituents are emerging as a very promising class of materials since they synergistically combine the complementary and diverse properties of the individual components. Hybrid materials based on polyoxometalates (POMs) are particularly interesting due to the versatile catalytic, redox, electronic, and magnetic properties of this large family of metal-oxo clusters, yet the combination of different clusters has been scarcely reported. Hence, herein we propose a novel and general strategy for combining multiple types of metal-oxo clusters in a single hybrid molecule. Two novel hybrid POM structures (HPOMs) bis-functionalised with dipentaerythritol (R-POM1-R; R = (OCH2)3CCH2OCH2C(CH2OH)) were synthesised as building-blocks for the formation of heterometallic hybrid triads (POM2-R-POM1-R-POM2). Such a modular approach resulted in the formation of four novel heterometallic hybrids combing the Lindqvist {V6}, Anderson-Evans {XMo6} (X = Cr or Al) and trisubstituted Wells-Dawson {P2V3W15} POM structures. Their formation was confirmed by multinuclear Nuclear Magnetic Resonance (NMR), infrared (IR) and UV-Vis spectroscopy, as well as Mass Spectrometry, Diffusion Ordered Spectroscopy (DOSY) and elemental analysis. Their thermal stability was also examined by Thermogravimetric Analysis (TGA), which showed that overall the HPOM triads exhibit higher thermal stability than comparable hybrid structures containing only one type of POM. The one-pot synthesis of these novel compounds was achieved in high yields in aqueous and organic media under simple reflux conditions, without the need of any additives, and could be applied for creating other hybrid materials based on a variety of metal-oxo cluster building-blocks
Cd<sup>2+</sup> Complexation with P(CH<sub>2</sub>OH)<sub>3</sub>, OP(CH<sub>2</sub>OH)<sub>3</sub>, and (HOCH<sub>2</sub>)<sub>2</sub>PO<sub>2</sub><sup>–</sup>: Coordination in Solution and Coordination Polymers
The coordination of Cd<sup>2+</sup> with PÂ(CH<sub>2</sub>OH)<sub>3</sub> (THP) in methanol was followed by <sup>31</sup>P
and <sup>111</sup>Cd NMR techniques. A cadmium-to-phosphine coordination
ratio
of 1:3 has been established, and effective kinetic parameters have
been calculated. Air oxidation of THP in the presence of CdCl<sub>2</sub> at room temperature produces coordination polymer <sup>3</sup><sub>∞</sub>[Cd<sub>3</sub>Cl<sub>6</sub>(OPÂ(CH<sub>2</sub>OH)<sub>3</sub>)<sub>2</sub>] (<b>1</b>). The same oxidation
reaction at 70 °C gives another coordination polymer, <sub>∞</sub>[CdCl<sub>2</sub>(OPÂ(CH<sub>2</sub>OH)<sub>3</sub>)] (<b>2</b>). Complexes <b>1</b> and <b>2</b> are the first structurally
characterized complexes featuring OPÂ(CH<sub>2</sub>OH)<sub>3</sub> as a ligand that acts as a linker between Cd atoms. The addition
of NaBPh<sub>4</sub> to the reaction mixture gives coordination polymer <sub>∞</sub>[Na<sub>2</sub>CdCl<sub>2</sub>(O<sub>2</sub>PÂ(CH<sub>2</sub>OH)<sub>2</sub>)<sub>2</sub>(H<sub>2</sub>O)<sub>3</sub>]
(<b>3</b>) with (HOCH<sub>2</sub>)<sub>2</sub>PO<sub>2</sub><sup>–</sup> as the ligand. Coordination polymers <b>1</b>–<b>3</b> have been characterized by X-ray analysis,
elemental analysis, and IR spectroscopy