Discrete and Polymeric Cu(II) Complexes Derived from in Situ Generated Pyridyl-Functionalized Bis(amido)phosphate Ligands, [PO₂(NHPy)₂]⁻

New examples of Cu­(II) complexes containing in situ generated bis­(amido)­phosphate ligands, [PO₂(NHPy)₂]⁻, have been synthesized [(L¹)⁻, where Py = 2-pyridyl, and (L²)⁻, where Py = 4-pyridyl). These anionic ligands were obtained by the P–N bond hydrolysis reaction of the corresponding phosphonium salts or phosphoric triamides in the presence of Lewis acidic Cu­(II) ions in polar solvents. A discrete mononuclear complex {Cu­[PO₂(NH²Py)₂]₂} (<b>3</b>) was obtained for the in situ ligand featuring 2-pyridyl substituents, whereas a 1D coordination polymer {[Cu­(PO₂(NH⁴Py)₂)₂(H₂O)₂]·2DMF·2H₂O}_∞ (<b>4</b>) was obtained for the ligand containing 4-pyridyl functionalities. The structural analyses show that in <b>3</b> the ligand (L¹)⁻ is bonded to the metal ion in a chelating tridentate N,N,O coordination and the coordinated P–O group is oriented in a syn fashion with respect to the pyridylamino groups. However, in <b>4</b> the ligand (L²)⁻ is bonded in a bridging fashion to two Cu­(II) ions via its pyridyl nitrogen donors. The two phosphorus-bound oxygen atoms in (L²)⁻ are anti-oriented and are involved in intermolecular H-bonding interactions with the metal-bound water hydrogen atoms to yield a 3D network. Topology analysis of the H-bonded assembly in <b>4</b> shows the presence of a (4-c)₂, 8-c binodal <b>scu</b> net as represented by the Schläfli symbol of (4⁴·6²)₂(4¹⁶·6¹²) [4⁴·6² for the (L²)⁻ ligand and 4¹⁶·6¹² for the Cu atoms]. An interesting 2D Cu­(I) coordination polymer {[Cu­(PO­(NH⁴Py)₃)­(PO₂(NH⁴Py)₂)]·DMF·2H₂O}_∞ (<b>5</b>) in uninodal <b>hcb</b> topology was obtained as a minor product along with <b>4</b>. Formation of the 2D assembly in <b>5</b> is mediated by the tridentate coordination of the phosphoric triamide ligand [PO­(NH⁴Py)₃]. The role of the anionic (L²)⁻ ligand in <b>5</b> is to merely restore the charge balance in the assembly and provide the fourth coordination to the tetrahedral Cu­(I) ion. Solvent uptake studies on the activated sample of <b>4b</b> shows a preferential adsorption of water vapors over aliphatic alcohols

Anion Driven [Cu^IIL₂]_<i>n</i> Frameworks: Crystal Structures, Guest-Encapsulation, Dielectric, and Possible Ferroelectric Properties

Employing a flexible phosphoramide ligand L, PhPO­(NH³Py)₂ (³Py = 3-pyridyl), four new Cu­(II) cationic coordination assemblies <b>1</b>, <b>1a</b>, <b>2</b>, and <b>3</b> of composition {[Cu₂L₄(H₂O)₂]·(ClO₄)₄·(H₂O)₅·(CH₃OH)}_∞, {[Cu₃L₆(H₂O)₃]·(ClO₄)₅·(NO₃)·(H₂O)₁₁}_∞, {[Cu₄L₈(H₂O)₅]·(NO₃)₈·L·(H₂O)₉}, and {[Cu₃L₆]·(NO₃)₆·(H₂O)₈·(CH₃OH)₂}, respectively, were synthesized. The compounds <b>1</b> and <b>1a</b> having perchlorate and mixed perchlorate-nitrate anions, respectively, were obtained as noncentrosymmetric 1D-helical assemblies. However, <b>2</b> and <b>3</b> were obtained as discrete centrosymmetric assemblies of composition M₄L₈ and M₃L₆, respectively. Interestingly, <b>2</b> can encapsulate the hydrated potassium cation [K­(H₂O)₈]⁺ in its intrinsic cavity. The ferroelectric measurements of <b>1</b> and <b>1a</b> gave a well saturated ferroelectric hysteresis loop giving saturation polarization (<i>P</i>_s) values of 1.8 and 0.55 μC/cm², respectively. This indicates that the presence of nitrate anion in the packing structure has an effect in altering the asymmetry of the system, which causes a change of polarization in <b>1a</b> in comparison with that of <b>1</b>. Furthermore, the room temperature dielectric constant values of 118.7, 27.4, and 39.2 for <b>1</b>, <b>1a</b>, and <b>2</b>, respectively, suggest that they are potential candidates for high-technique applications