Introducing Stereogenic Centers to Group XIV Metallatranes

Extending Chirality in Group XIV Metallatranes

The syntheses of the racemic amino alcohol rac-N(CH₂CMe₂OH)(CMe₂CH₂OH)(CH₂CHMeOH) (L^22'1*H₃, 2) and its representative N(CH₂CMe₂OH)(CMe₂CH₂OH)(CH₂C(R)HMeOH) (L^22'1RH₃, 3) with the stereogenic carbon center being R-configured are reported. Also reported are the stannatranes L^22'1*SnOt-Bu (4) L^22'1RSnOt-Bu (6) and germatranes L^22'1*GeOEt (5) and L^22'1RGeOEt (7) as well as the trinuclear tin oxocluster [(μ₃-O)(μ₃-O-t-Bu){SnL^22'1R}₃] (8). NMR and IR spectroscopy, electrospray ionization mass spectrometry (ESI MS), and single crystal X-ray diffraction analysis characterize these compounds. Computational studies accompany the experimental work and help understand the diastereoselectivity observed in the course of the metallatrane syntheses.

Mononuclear Pseudostannatranes Possessing Unsymmetrical [4.4.3.01,5]Tridecane Cage: Experimental and Theoretical Aspects of Reverse Kocheshkov Reaction in Phenyl Pseudostannatrane

The synthetic protocols, structural aspects, and spectroscopic aspects of mononuclear pseudostannatranes possessing a [4.4.3.0^1,5]tridecane cage have been reported. A tripodal ligand N(CH₂CH₂OH){CH₂(2-t-Bu-4-Me-C₆H₂OH)}₂ (H₃L) having unsymmetrical arms was reacted with n-butyltrichlorostannane, phenyltrichlorostannane, and tin tetrachloride under different solvent systems to obtain pseudostannatranes (1-3). The reaction of n-butyltrichlorostannane and the ligand in CH₃OH/Na/THF yielded an aqua complex of pseudostannatrane [LSnBu(H₂O)] (1_a), which was crystallized as its acetone solvate (i.e 1_a·Me₂CO). However, the same reactants yielded methanol complex [LSnBu(CH₃OH)] (1_b) when the reaction was carried out in the NaOCH₃/C₂H₅OH system. Similarly, the reaction of phenyltrichlorostannane and the ligand under these solvent systems yielded pseudostannatranes, i.e., an aqua complex [LSnPh(H₂O)] (2_a) and a methanol complex [LSnPh(CH₃OH)] (2_b) (where 2_a was crystallized as 2_a·Me₂CO). The reaction of tin tetrachloride and the ligand in the Et₃N/THF system resulted in the formation of pseudostannatrane [LHSnCl₂] (3). A similar product was isolated as its triethylamine solvate (3·NEt₃) due to the disproportion reaction when PhSnCl₃ was reacted with the ligand in the Et₃N/C₆H₅CH₃ system, which demonstrates the first report on the reverse Kocheshkov reaction in pseudostannatranes. The experimental findings on the formation of 3·NEt₃ due to the reverse Kocheshkov reaction have been corroborated with ¹¹⁹Sn NMR spectroscopy and density functional calculations that provide insightful information about the underlying details of the reaction route.

Tricyclic tin(iv) cages: synthetic aspects and intriguing features of stannatranes and pseudostannatranes

This perspective summarizes various synthetic routes of stannatranes and pseudostannatranes along with their interesting features, such as appearance of satellites in their NMR spectra, cluster formation upon hydrolysis and exchange reactions.

Control of Λ- and Δ-Isomerization of the Atrane Cages in Group XIV Metallatranes by Chiral Axial Substituents

The syntheses of the novel stannatranes N(CH₂CMe₂O)₃Sn-(1 S)-(-)-OC(O)C(OMe)(CF₃)(C₆H₅), 1( S, Δ), and N(CH₂CMe₂O)₃Sn-(1 R)-(+)-OC(O)C(OMe)(CF₃)(C₆H₅), 2( R, Λ), and germatranes N(CH₂CMe₂O)₃Ge-(1 S)-(-)-OC(O)C(OMe)(CF₃)(C₆H₅), 3( S, Δ), and N(CH₂CMe₂O)₃Ge-(1 R)-(+)-OC(O)C(OMe)(CF₃)(C₆H₅), 4( R, Λ) (with 1, S, Δ-configured/2, R, Λ-configured and 3, S, Δ-configured/4, R, Λ-configured being pairs of enantiomers) are reported. The compounds were characterized by NMR and IR spectroscopy, electrospray ionization mass spectrometry, and single crystal X-ray diffraction analysis. The epimerization via Λ ⇌ Δ ring flip of the enantiomeric stannatrane pair 1( S, Δ)/2( R, Λ) was investigated by NMR experiments at variable temperatures and density functional theory (DFT) calculations.

The sodium chloride complex catena-poly[[{μ3-2-[bis(2-hydroxyethyl)amino]ethan-1-ol}sodium] chloride], N(CH2CH2OH)3·NaCl

The reaction of sodium chloride with 2-[bis(2-hydroxyethyl)amino]ethan-1-ol results in the formation of the title salt {[Na{N(CH2CH2OH)3}]Cl} n . The polymeric structure is characterized by a sodium cation coordinated by one nitrogen and five oxygen atoms in a distorted octahedral environment. The resulting one-dimensional {—O—Na—O—Na—O}— coordination polymer extends parallel to [010] and is connected through the chloride counter-anion via O—H...Cl hydrogen bonding, giving rise to a two-dimensional supramolecular structure parallel to (001).

The amino alcohol MeN(CH2CMe2OH)2

The crystal structure, including a graph-set analysis, of 1-[(2-hydroxy-2-methylpropyl)methylamino]-2-methylpropan-2-ol, C9H21NO2, is reported. The structure is characterized by unsymmetrical intra- and intermolecular O—H...O hydrogen bridges, giving rise to the formation of an infinite polymer consisting of eight-membered rings arranged in zigzag chains running along theaaxis.