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Isomorphous rare-earth bis[bis(2,6-diisopropyl-phenyl)phosphate] complexes and their selfassembly into two-dimensional frameworks by intramolecular hydrogen bonds
The crystal structures of rare-earth diaryl- or dialkylphosphate derivatives are poorly explored. Crystals of bis[bis(2,6-diisopropylphenyl) phosphato-kappa O] chloridotetrakis( methanol-kappa O) neodymium methanol disolvate, [Nd(C24H34O4P)Cl( CH4O)(4)]center dot 2CH(3)OH, (1), and of the lutetium, [Lu(C24H34O4P) Cl(CH4O)(4)]center dot-2CH(3)OH, (2), and yttrium, [Y(C24H34O4P) Cl(CH4O)(4)]center dot 2CH(3)OH,(3), analogues have been obtained by reactions between lithium bis(2,6-diisopropylphenyl)-phosphate and LnCl(3)(H2O)(6) (in a 2:1 ratio) in methanol. Compounds (1)-(3) crystallize in the C2/c space group. Their crystal structures are isomorphous. The molecule possesses C-2 symmetry with a twofold crystallographic axis passing through the Ln and Cl atoms. The bis(2,6-diisopropylphenyl) phosphate ligands all display a kappa O-1-monodentate coordination mode. The coordination polyhedron for the metal atom [coordination number (CN) = 7] is a distorted pentagonal bipyramid. Each [Ln{O2P(O-2,6-(Pr2C6H3)-Pr-i)(2)}(2)Cl(CH3OH)(4)] molecular unit exhibits two intramolecular O-H center dot center dot center dot O hydrogen bonds, forming six-membered rings, and two intramolecular O-H center dot center dot center dot Cl interactions, forming four-membered rings. Intermolecular O-H . . . O hydrogen bonds connect each unit via four noncoordinating methanol molecules with four other units, forming a two-dimensional hydrogen-bond network. Crystals of bis[bis(2,6-diisopropylphenyl) phosphato-kappa O] tetrakis(methanol-kappa O)(nitrato-kappa(2) O, O ') neodymium methanol disolvate, [Nd(C24H34O4P)(NO3)(CH4O)(4)]center dot 2CH(3)OH, (4), have been obtained in an analogous manner from NdCl3(H2O)(6). Compound (4) also crystalizes in the C2/c space group. Its crystal structure is similar to those of (1)-(3). The kappa(2) O, O '-bidentate nitrate anion is disordered over a twofold axis, being located nearly on it. Half of the molecule is crystallographically unique (CNNd = 8). Unlike (1)-(3), complex (4) exhibits disorder of all three methanol molecules, one isopropyl group of the phosphate ligand and the NO3- ligand. The structure of (4) displays intra- and intermolecular O-H center dot center dot center dot O hydrogen bonds similar to those in (1)-(3). Compounds (1)-(4) represent the first reported mononuclear bis[bis(diaryl/dialkyl) phosphate] rare-earth complexes.