Pairwise Assembly of Organopalladium(II) Units with Cyanurato(3−) and Trithiocyanurato(3−) Ligands: Formation of Chiral Pd12, Pd10, and Pd9 Cage-Molecules

The o-palladated, chloro-bridged dimers [Pd{2-phenylpyridine(-H)}-μ-Cl]2 and [Pd{N,N-dimethylbenzylamine(-H)}-μ-Cl]2 react with cyanuric acid in the presence of base to afford closed, chiral cage-molecules in which 12 organo-Pd(II) centers, located in pairs at the vertices of an octahedron, are linked by four tetrahedrally arranged cyanurato(3−) ligands. Incomplete (Pd10) cages, having structures derived from the corresponding Pd12 cages by replacing one pair of organopalladium centers with two protons, have also been isolated. Reaction of [Pd{2-phenylpyridine(-H)}-μ-Cl]2 with trithiocyanuric acid gives an entirely different and more open type of cage-complex, comprising only nine organopalladium centers and three thiocyanurato(3−) ligands: cage-closure in this latter system appears to be inhibited by steric crowding of the thiocarbonyl groups.

1 H and 13 C NMR spectra of complex 1 S5 2D 1 H/ 1 H and 1 H/ 13 C NMR spectra of complex 1 S6 Effect of a chiral shift reagent on the 1 H NMR spectrum of complex 1 S7 1 H and 13 C NMR spectra of complex 3 S8 2D 1 H/ 13 C NMR and HR mass spectra of complex 3 S9 1 H and 13 C NMR spectra of complex 4 S10 2D 1 H/ 13 C NMR spectra of complex 4 S11 Effects of a chiral shift reagent on the 1 H NMR spectrum of complex 4 S12 and S13 1 H and 2D 1 H/ 13 C NMR spectra of complex 5 S14 High resolution mass spectrum of the Pd 10 complex 4 and energy-minimised model for the disodium adduct [4 2 +2Na] 2+ S15 Space-filling representation of the structure of 1 and an energyminimised model of its hypothetical trithiocyanurato(3-) analogue S16 Analogies between the Pd 12 /Pd 10 structures reported here and closo/nido C 2 B 10 and C 2 B 9 carborane structures S17

S2
Crystallographic analyses of complexes 1, 2, 3 and 5 Crystals of 1 were grown by vapour diffusion of methanol into a solution of 1 in dichloromethane and acetone over some 2 weeks, yielding yellow single crystals. Single crystal X-ray diffraction data were collected on an Agilent Technologies Gemini Ultra S CCD diffractometer, using Cu-Kα radiation, equipped with an Oxford Cryosystems low-temperature device operating at 150 K. Crystals of 2 were grown by vapour diffusion of benzene into a solution of 2 in 1:1 v/v dichloromethane/chloroform over a period of 1 month, yielding yellow single crystals. Crystals were very thin and weakly diffracting, so they were studied using synchrotron radiation on beamline 11.3.1 (λ = 0.77490 Å) at the Advanced Light Source, Berkeley, USA, using an Agilent Cryojet low-temperature device operating at 100 K. by full-matrix least squares against F 2 using all data. Though most H atoms could be distinguished in the difference Fourier map, the H-atoms were included at geometrically idealized positions and refined in riding-model approximation.[S 5 ] Shift limiting restraints were used throughout the refinement. The anisotropic displacement factors of one of the 2-phenylpyridine ligands in the asymmetric unit were split over two sites. These were refined using PARTs, with similarity (SIMU), rigid bond (DELU) and SAME restraints. Benzene solvent molecules were located in the structure and refined isotropically, with suitable restraints. All other full-weight non-H atoms were modelled with anisotropic displacement parameters. However, there were further regions of highly disordered solvent electron density that could not be modelled. These were described by implementing the SQUEEZE routine in PLATON.[S 6 ] CCDC 929577.
Crystals of 3 were grown by vapour diffusion of methanol into a solution of 3 in chloroform over some 2 weeks, yielding yellow single crystals. Single crystal X-ray diffraction data were collected on an Agilent Technologies Gemini Ultra S CCD diffractometer, using Mo-Kα radiation, equipped with an Oxford Cryosystems low-temperature device operating at 150 K. Crystals of 5 were grown by vapour diffusion of benzene into a solution of 5 in dichloromethane over ca. 1 month, yielding yellow single crystals. Crystals were studied using synchrotron radiation on beamline I19[S 8 ] (λ = 0.6889 Å) at Diamond Light Source, Harwell, UK, using an Oxford Cryosystems "Cryostream Plus" low-temperature device operating at 100 K.
Crystal data for 5: C 108 H 72 N 18 Pd 9 S 9 , Mr = 2868.08, monoclinic, P2 1 /c, a = 23.4882 (9) Shift limiting restraints and planarity restraints on the 2-phenylpyridine ligands were used throughout the refinement to maintain sensible values. The anisotropic displacement factors of three of the 2-phenylpyridine ligands were split over two sites. These were refined using PARTs, with similarity (SIMU), rigid bond (DELU) and SAME restraints. All full-weight non-H atoms were modelled with anisotropic displacement parameters. The H-atoms were included at geometrically idealized positions and refined in riding-model approximation. Solvent in the central cavity and around the molecule could not be assigned to any of the reagents involved in the synthesis of the crystals, and so the SQUEEZE[S 6 ] routine in PLATON was implemented in order to model this solvent disorder. CCDC 929576.

Middle:
Corresponding 1 H NMR spectrum of the Pd 10 complex 4. 700 MHz, CDCl 3 . Note that three doublets associated with the five different environments of the o-metallated ligand are resolved, with the remaining two resonances coinciding to produce the doublet at 4.08 ppm.