Synthesis and crystallographic characterization of diphenylamide rare-earth metal complexes Ln(NPh2)3(THF)2 and [(Ph2N)2 Ln(μ-NPh2)]2

Crystallographic characterization of complexes of the smaller rare-earth elements Y, Dy, and Er with the NPh2 ligand reveals monometallic, bimetallic, and tetrametallic structures.


Database survey
A search of the Cambridge Structural Database shows 1-Yb (Yao et al., 2001) and 2-Ce (Coles et al., 2010) have been reported. Complex 1-Yb is isomorphous with 1-Er. Packing structures and contacts for 1-Y.
vdW indicates the sum of the van der Waals radii of the two atoms.  Table 5 Intermolecular contact lengths (Å ) in 1-Er.
vdW indicates the sum of the van der Waals radii of the two atoms.
vdW indicates the sum of the van der Waals radii of the two atoms.

Synthesis and crystallization
General Considerations. All manipulations and syntheses described below were conducted with rigorous exclusion of air and water using standard Schlenk line and glovebox techniques under an argon atmosphere. Solvents were sparged with UHP argon (Airgas) and dried by passage through columns containing Q-5 and molecular sieves prior to use. LnCl 3 was prepared from the previously reported literature procedure (Meyer et al., 1982). The compounds Ln[N(SiMe 3 ) 2 ] 3 were prepared from their literature procedures . HNPh 2 was purchased from commercial suppliers and used as received. NaNPh 2 and KNPh 2 were prepared by reaction of HNPh 2 with NaH or KH in THF. Synthesis and Crystallization of Y(NPh 2 ) 3 (THF) 2 , 1-Y. In a glovebox, YCl 3 (0.63 g, 3.2 mmol) was stirred for two days in THF (30 mL) in a Schlenk flask to ensure complete solvation. Under positive pressure of N 2 on a Schlenk line, a solution of KNPh 2 (1.9 g, 9.1 mmol) in THF (30 mL) was added dropwise to the YCl 3 suspension in THF at 273 K over 15 min. The reaction vessel was allowed to warm to room temperature, and after 1 h, the solvent was removed under reduced pressure to yield a colorless solid. In a glovebox, the product was extracted with toluene and evaporated to dryness. The resulting solids were washed with hexane to yield 1-Y as a colorless solid (2.2 g, 90%). The colorless solid was dissolved in diethyl ether and stored at 245 K for three days to yield colorless crystals of 1-Y.
Synthesis and Crystallization of Er(NPh 2 ) 3 (THF) 2 , 1-Er. In a glovebox, ErCl 3 (243 mg, 0.887 mmol) was stirred in THF (10 mL), which gave a pink slurry. To the stirred suspension was added NaPh 2 (500 mg, 2.62 mmol) in THF (10 mL) at 238 K dropwise over 5 min, and a color change to greenyellow and then pink was observed. After the addition, the resultant pink slurry was allowed to warm to room temperature and left to stir overnight. The volatiles were then removed under reduced pressure, which gave a pink gel. The gel was triturated with hexane several times to yield pink solids that were then dissolved in Et 2 O (17 mL) and stirred for several hours to ensure complete dissolution. Pink and colorless solids, presumably unreacted ErCl 3 and NaNPh 2 , were centrifuged, and the volatiles of the supernatant were evaporated until supersaturation. As the concentrated pink solution warmed to room temperature, large pink hexagonshaped crystals of Er(NPh 2 ) 3 (THF) 2 , 1-Er, suitable for X-ray diffraction grew within minutes (260 mg, 36%).
Synthesis and Crystallization of [(NPh 2 ) 2 Y(l-NPh 2 )] 2 , 2-Y. In a glovebox free of coordinating solvents, Y[N(SiMe 3 ) 2 ] 3 (300 mg, 0.526 mmol) was dissolved in toluene (10 mL). To the stirred solution was added HNPh 2 (272 mg, 1.61 mmol) in toluene (10 mL). The resultant colorless solution was left to stir for 48 h. The color of the solution slowly changed to yellow and a yellow precipitate was observed. The volatiles were removed under vacuum, and the resultant yellow solids were washed with hexane. The solids were stirred in benzene for 48 h, and the resultant yellow slurry was then centrifuged to remove the insoluble material. Toluene (4 mL) was added to the supernatant and the solution was concentrated to 4 mL before it was layered with hexane (15 mL). After 48 h at room temperature, yellow rectangular blocks of [(Ph 2 N) 2 Y(-NPh 2 )] 2 , 2-Y, suitable for X-ray diffraction had formed.

Figure 8
Packing structures and contacts for 3-Er.
(240 mg, 1.42 mmol) in toluene (10 mL). The resultant colorless solution was left to stir for 48 h and the color of the solution slowly turned to yellow and precipitated a yellow solid. The volatiles were removed, and the resultant yellow solids were washed with hexane. The solids were then stirred in benzene for 48 h, and the resultant yellow slurry was centrifuged to remove insoluble material. Toluene (4 mL) was added to the supernatant, and the solution was concentrated to 4 mL before it was layered with hexane (15 mL). After 48 h at room temperature, yellow rectangular blocks of [(Ph 2 N) 2 Dy(-NPh 2 )] 2 , 2-Dy, suitable for X-ray diffraction had formed.
Synthesis and Crystallization of {[(Ph 2 N)Er(l-NPh 2 )] 4 (l-O) 2 }Á(C 6 H 6 ) 2 , 3-Er. In a glovebox free of coordinating solvents, Er[N(SiMe 3 ) 2 ] 3 (300 mg, 0.463 mmol) was dissolved in toluene (10 mL). To the stirred solution was added HNPh 2 (240 mg, 1.41 mmol) in toluene (10 mL). The resultant colorless solution was left to stir for 48 h, and the solution slowly changed color to yellow. The volatiles were removed, and the resultant yellow solids were washed with hexane. The solids were then stirred in benzene for 48 h, and the resultant yellow slurry was centrifuged to remove insoluble material. Toluene (4 mL) was added to the supernatant, and the solution was concentrated to 4 mL before it was layered with hexane (15 mL). After 48 h at room temperature, yellow rectangular blocks of {[(Ph 2 N)Er(-NPh 2 )] 4 (-O) 2 }Á(C 6 H 6 ) 2 , 3-Er, suitable for X-ray diffraction had formed. Compound 3-Er is a minor product of a formal hydrolysis of 2-Er, presumably from adventitious water.

Refinement
Refinement Details. The molecules of 2-Ln and 3-Er are located about an inversion center. There were two molecules of benzene solvent present per empirical formula unit in 3-Er. Crystal data, data collection and structure refinement details are summarized in Table 8. H atoms in all five structures were placed in calculated positions and C-H bond distances were constrained to 0.95 Å for aromatic and to 0.99 Å CH 2 groups, respectively. U iso (H) values were set to 1.2U eq (C).
The two tetrahydrofuran ligands in 1-Er were modeled with disorder across two positions. For the ring of O1, two methylene groups were included in the disorder, as well as the H atoms of the remaining CH 2 groups. O-C bond distances were restrained to a target value of 1.47 (1) Å , C-C bond distances to a target value of 1.53 (1) Å . 1,3 distances between the oxygen atom and C38 and 39, and between C38B and C39B (e.g. the O-C-C angles) were restrained to be pairwise similar (with an esd of 0.02 Å ). ADPs of the disordered carbon atoms (C38, C39, C38B, C39B) were constrained to be identical. U ij components of ADPs of atoms C39 and C40 were restrained to be similar with an esd of 0.01 Å 2 and a distance cutoff of 4.0 Å . Subject to these conditions occupancies refined to 0.627 (12)/0.323 (12). For the ring involving O2, disorder was limited to one methylene C atom and the H atoms of the two adjacent CH 2 groups. No restraints were applied and occupancies refined to 0.633 (7)/0.367 (7).
The 3-Er structure was found to be multi-component and was refined as a three-component twin. The orientation matrices for the three components were identified using the program CELL_NOW (Sheldrick, 2008a). The second component is related to the first by no obvious twin law. The third component is related to the first by non-merohedry by a 180 rotation around [011]. The three components were integrated using SAINT (Bruker, 2013) and corrected for absorption using TWINABS (Sheldrick, 2012). The structure was solved using direct methods (Sheldrick 2008b) with only the non-overlapping reflections of main component 1. The structure was refined using all reflections of component 1 (including the overlapping reflections), resulting in minor component occupancies of 0.0615 (6) and 0.2010 (4).

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. Refinement. A colorless crystal of approximate dimensions 0.373 x 0.377 x 0.520 mm was mounted on a glass fiber and transferred to a Bruker SMART APEX II diffractometer. The APEX2 program package was used to determine the unitcell parameters and for data collection (15 sec/frame scan time for a sphere of diffraction data). The raw frame data was processed using SAINT and SADABS to yield the reflection data file. Subsequent calculations were carried out using the SHELXTL program. The diffraction symmetry was 2/m and the systematic absences were consistent with the monoclinic space group P21/c that was later determined to be correct. The structure was solved by direct methods and refined on F2 by full-matrix least-squares techniques. The analytical scattering factors for neutral atoms were used throughout the analysis. Hydrogen atoms were included using a riding model. Least-squares analysis yielded wR2 = 0.0812 and Goof = 1.035 for 451 variables refined against 8829 data (0.75Å), R1 = 0.0313 for those 7562 data with I > 2.0sigma(I).

Tris(diphenylamido-κN)bis(tetrahydrofuran-κO)erbium(III) (1-Er)
Crystal data [Er(C 12 Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. Refinement. A pink crystal of approximate dimensions 0.332 x 0.389 x 0.482 mm was mounted on a glass fiber and transferred to a Bruker SMART APEX II diffractometer. The APEX2 program package was used to determine the unitcell parameters and for data collection (15 sec/frame scan time for a sphere of diffraction data). The raw frame data was processed using SAINT and SADABS to yield the reflection data file. Subsequent calculations were carried out using the SHELXTL program. The diffraction symmetry was 2/m and the systematic absences were consistent with the monoclinic space group P21/n that was later determined to be correct. The structure was solved by direct methods and refined on F2 by full-matrix least-squares techniques. The analytical scattering factors for neutral atoms were used throughout the analysis. Hydrogen atoms were included using a riding model. The tetrahydrofuran ligands were disordered and were included using multiple components with partial siteoccupancy-factors. Least-squares analysis yielded wR2 = 0.0504 and Goof = 1.041 for 462 variables refined against 9687 data (0.73 Å), R1 = 0.0194 for those 8834 data with I > 2.0sigma(I).

Bis[µ-1κN:2(η 6 )-diphenylamido]bis[bis(diphenylamido-κN)dysprosium(III)] (2-Dy)
Crystal data where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.004 Δρ max = 2.65 e Å −3 Δρ min = −0.81 e Å −3 Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. Refinement. A yellow crystal of approximate dimensions 0.111 x 0.116 x 0.201 mm was mounted in a cryoloop and transferred to a Bruker SMART APEX II diffractometer. The APEX2 program package was used to determine the unitcell parameters and for data collection (20 sec/frame scan time for a sphere of diffraction data). The raw frame data was processed using SAINT and SADABS to yield the reflection data file. Subsequent calculations were carried out using the SHELXTL program. The diffraction symmetry was 2/m and the systematic absences were consistent with the monoclinic space group P21/c that was later determined to be correct. The structure was solved by direct methods and refined on F2 by full-matrix least-squares techniques. The analytical scattering factors for neutral atoms were used throughout the analysis. Hydrogen atoms were included using a riding model. The molecule was located about an inversion center. Least-squares analysis yielded wR2 = 0.0652 and Goof = 1.046 for 361 variables refined against 7264 data (0.73 Å), R1 = 0.0255 for those 6207 data with I > 2.0sigma(I).
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 ) where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 1.62 e Å −3 Δρ min = −1.10 e Å −3 Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

sup-35
Acta Cryst. (2020). E76, 1447-1453 Refinement. A yellow crystal of approximate dimensions 0.106 x 0.278 x 0.347 mm was mounted on a glass fiber and transferred to a Bruker SMART APEX II diffractometer. The APEX2 program package and the CELL_NOW were used to determine the unit-cell parameters. Data was collected using a 10 sec/frame scan time for a sphere of diffraction data. The raw frame data was processed using SAINT and TWINABS to yield the reflection data file (HKLF5 format). Subsequent calculations were carried out using the SHELXTL program. There were no systematic absences nor any diffraction symmetry other than the Friedel condition The centrosymmetric triclinic space group P-1 was assigned and later determined to be correct. The structure was solved by direct methods and refined on F2 by full-matrix least-squares techniques. The analytical scattering factors for neutral atoms were used throughout the analysis. Hydrogen atoms were included using a riding model. The molecule was located about an inversion center. There were two molecules of benzene solvent present per empirical formula-unit. At convergence, wR2 = 0.0624 and Goof = 0.96 for 552 variables refined against 10308 data (0.73Å), R1 = 0.0273 for those 9209 with I > 2.0sigma(I). The structure was refined as a three-component twin