Isomorphous rare-earth bis[bis(2,6-diisopropylphenyl)phosphate] complexes and their self-assembly 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-κO]chloridotetrakis(methanol-κO)neodymium methanol disolvate, [Nd(CHOP)Cl(CHO)]·2CHOH, (1), and of the lutetium, [Lu(CHOP)Cl(CHO)]·2CHOH, (2), and yttrium, [Y(CHOP)Cl(CHO)]·2CHOH, (3), analogues have been obtained by reactions between lithium bis(2,6-diisopropylphenyl)phosphate and LnCl(HO) (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 symmetry with a twofold crystallographic axis passing through the Ln and Cl atoms. The bis(2,6-diisopropylphenyl)phosphate ligands all display a κO-monodentate coordination mode. The coordination polyhedron for the metal atom [coordination number (CN) = 7] is a distorted pentagonal bipyramid. Each [Ln{OP(O-2,6-PrCH)}Cl(CHOH)] molecular unit exhibits two intramolecular O-H...O hydrogen bonds, forming six-membered rings, and two intramolecular O-H...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-κO]tetrakis(methanol-κO)(nitrato-κO,O')neodymium methanol disolvate, [Nd(CHOP)(NO)(CHO)]·2CHOH, (4), have been obtained in an analogous manner from NdCl(HO). Compound (4) also crystalizes in the C2/c space group. Its crystal structure is similar to those of (1)-(3). The κO,O'-bidentate nitrate anion is disordered over a twofold axis, being located nearly on it. Half of the molecule is crystallographically unique (CN = 8). Unlike (1)-(3), complex (4) exhibits disorder of all three methanol molecules, one isopropyl group of the phosphate ligand and the NO ligand. The structure of (4) displays intra- and intermolecular O-H...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.