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The lithium and sodium phenolates of 2-[ (dimethylamino)methyl]phenol, la and 2a, 2-[(dimethylamino)methyl]-4,6-dimethylphenol, l b and 2b, and 2,6-bis[(dimethylamino)methyl]-4-methylphenol, IC and 2c, respectively, have been synthesized. The structures of these complexes in solution were studied by variable-temperature lH and l3C NMR spectroscopy and cryoscopic molecular weight measurements. The solid-state structures of complexes IC and 2c derived from 2,6-bis[ (dimethylamino)methyl]-4-methylphenol, were determined by X-ray diffraction. The complexes containing only one ortho-chelating (dimethy1amino)methyl group, i.e. la,b and 2a,b, are soluble in weakly polar solvents, like tetrahydrofuran. Complexes la and l b are tetramers in benzene. These tetramers occur in solution in two isomeric forms, Le. as aggregates with 0 2 and S 4 symmetry. The lithium "pincer-phenolate" containing two ortho-chelating (dimethy1amino)methyl groups (IC) is a trimer in apolar solvents as well as in the solid-state. It is the first example of a phenolate complex with a stable, trinuclear structure. In contrast, the sodium analog (2c) is a dimer in solution and crystallizes as a tetramer with a cubic-likeNa404 core. Crystals of Li3C3&N603, lc,aremonoclinic,spacegroupP21/n,withunit celldimensionsa= 42.381(5)A,b=8.8417(11)&~= 11.1802(10) A, fi = 90.539( 8)", and Z = 4. The structure was refined to R = 0.068 for 4106 reflections and 610 parameters.The trimeric structure contains a Li303-ring which is almost perfectly planar (within 0.05 A), and very short Li-0 and C-0 bond lengths (averages of 1.865( 9) and 1.317(6) A, respectively). As a result of intramolecular amine coordination IC is a "propeller-like" molecule with screw-type chirality. Crystals of Na4C52Hg4N8O4.C6H6, 2c, are monoclinic, space group P2/c, with a = 16.021(2) A, b = 10.275(1) A, c = 24.190(2) A, B = 130.35(1)O, 2 = 2, and final R = 0.064 for 3476 reflections and 400 parameters. This tetramer consists of a double dimer in which the NMe2 groups of one dimer do exclusively coordinate to the sodium atoms of the same dimer.

Abstract:The crystal and molecular structure and absolute configuration of 2-[ l-(S)-Me2NCH(Me)]C6H4SfnMePhBr, which is the first example of a diastereomerically pure chiral triorganotin halide, are determined by a single-crystal x-ray diffraction study. Crystals are orthorhombic, space group P212121 with Z = 4 in a unit cell of dimensions n = 9.370 (4), b = 13.361 (3), and c = 14.283 (4) A. The final R value is 0.048 for 2784 reflections. The tin atom has a distorted trigonal bipyramidal geometry with the C,N-bonded Me2NCH(Me)C6H4 group spanning one equatorial (C) and one axial (N) site. The Ph and M e groups reside in the two equatorial positions resulting in an (S)sn configuration at the tin atom (cf. Figure 1). The configuration at Sn was unambiguously determined by using anomalous diffraction effects which likewise resulted in an independent check of the configuration at the CY-C atom (S configuration). The

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Arylcopper(1) compounds containing an oxazoline substituent in the position ortho to the Cu-C bond have been synthesized from the corresponding aryllithium compounds and CuBr. Depending on the order of addition this reaction afforded either a pure arylcopper(1) compound (slow addition of CuBr to the aryllithium reagent) or a mixture of arylcopper (1) four-electron bridging bromine atoms (Cu-Br = 2.524 (3) 8, (mean); Cu-Cu = 3.023 (4) 8, (mean)). The oxazoline substituent is coordinated via the nitrogen atom (Cu-N = 1.968 (4) 8, (mean)). Ullmann biaryl coupling reactions of the new organocopper(1) compounds with 2-iodopiperonal imine were little influenced by a hetero substituent in either the arylcopper(1) compound or the aryl iodide anchoring group. Moreover, since the addition of P(OMeI3 did not influence the coupling reaction, it can be concluded that "external" ligands do not have a critical role in these reactions. The results of this study show clearly the important influence that an ortho-chelating substituent (i.e. the 2-oxazolinyl group in the present compounds) can have on both the structural features and the reactivity of the arylcopper compounds.