Robust packing in cyclopalladated primary amines: isomorphous crystal structures of four complexes with varying substitution patterns

Abstract

The crystal structures of (SP-4-4)-[rac-2-(1-aminoethyl)phenyl-kappa(2)C(1),N]chlorido(pyridine-kappaN)palladium(II), [Pd(C(8)H(10)N)Cl(C(5)H(5)N)], (I), (SP-4-4)-[rac-2-(1-aminoethyl)phenyl-kappa(2)C(1),N]bromido(pyridine-kappaN)palladium(II), [PdBr(C(8)H(10)N)(C(5)H(5)N)], (II), (SP-4-4)-[rac-2-(1-aminoethyl)-5-bromophenyl-kappa(2)C(1),N]bromido(4-methylpyridine-kappaN)palladium(II), [PdBr(C(8)H(9)BrN)(C(6)H(7)N)], (III), and (SP-4-4)-[rac-2-(1-aminoethyl)-5-bromophenyl-kappa(2)C(1),N]iodido(4-methylpyridine-kappaN)palladium(II), [Pd(C(8)H(9)BrN)I(C(6)H(7)N)], (IV), are reported. The latter is the first iodide complex in this class of compounds. All four complexes crystallize in the same space group, viz. I4(1)/a, with very similar lattice parameters a and more flexible lattice parameters c. Their packing corresponds to that of their enantiomerically pure congeners, which crystallize in the t2 subgroup I4(1).

Structures from MnX 2 and proline: isomorphous racemic compounds and a series of chiral non-isomorphous chain polymers

“…The enantiopure compounds are often found to crystallize in non-centrosymmetric translationengleiche subgroups with an asymmetric unit containing molecules related by pseudo-inversion. This has, for example, been reported for molecular structures (Whitesell et al, 1993(Whitesell et al, , 1994Calmuschi-Cula et al, 2009), salts (Kalf et al, 2008) and cocrystals (Friščić et al, 2008). None of these are compulsory rules -in the reported structures, however, the difference of the racemic to the chiral products in their general structure and with respect to their behavior upon the replacement of the anions is rather surprising.…”

Chiral Palladacycles with N-Heterocyclic Carbene Ligands as Catalysts for Asymmetric Hydrophosphination

“…Figure shows the molecular structure of the complex and the selected bond lengths and angles. At this point, it is interesting to point out that despite acetate-bridged binuclear cyclopalladate complexes with primary amines are well-known, only three X-ray examples have been described to date. ,, The molecular structure of 11 consists of two palladium centers with two cis-bridging acetate groups and two cyclometalated ( S )-[1-(1-naphthyl)ethyl]amines. The C–N orthometalated amine forms a five-membered ring in a puckered conformation, where the N atom is out of the plane by 0.48 Å.…”

One of the most complex “small molecule structures” ever reported: 16 independent molecules in the asymmetric unit for an ortho-palladated primary amine

“…[2][3][4][5][6] Ortho-palladated primary amines have been made generally accessible by Vicente et al 7 and have proven suitable building blocks for this crystal engineering purpose. 8,9 In the context of these studies, we have prepared a variety of organopalladium compounds (see ESI).w [10][11][12][13][14][15][16][17][18][19][20][21] All complexes of this kind are unspectacular with respect to their content of the asymmetric unit. Z 0 , the number of independent molecules, varies between 1 and 4.…”