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

Cd²⁺ Complexation with P(CH₂OH)₃, OP(CH₂OH)₃, and (HOCH₂)₂PO₂^–: Coordination in Solution and Coordination Polymers

The coordination of Cd²⁺ with P­(CH₂OH)₃ (THP) in methanol was followed by ³¹P and ¹¹¹Cd 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 CdCl₂ at room temperature produces coordination polymer ³_∞[Cd₃Cl₆(OP­(CH₂OH)₃)₂] (<b>1</b>). The same oxidation reaction at 70 °C gives another coordination polymer, _∞[CdCl₂(OP­(CH₂OH)₃)] (<b>2</b>). Complexes <b>1</b> and <b>2</b> are the first structurally characterized complexes featuring OP­(CH₂OH)₃ as a ligand that acts as a linker between Cd atoms. The addition of NaBPh₄ to the reaction mixture gives coordination polymer _∞[Na₂CdCl₂(O₂P­(CH₂OH)₂)₂(H₂O)₃] (<b>3</b>) with (HOCH₂)₂PO₂^– as the ligand. Coordination polymers <b>1</b>–<b>3</b> have been characterized by X-ray analysis, elemental analysis, and IR spectroscopy