Divalent Metal Complexes of 2-Formylphenoxyacetic Acid: The Crystal Structures of 2-Formylphenoxyacetic Acid, and the Isomorphous Cobalt(II) and Zinc(II) 2-Formylphenoxyacetates

The crystal structures of 2-formylphenoxyacetic acid ( ofpaH ), tetraaquabis (2-formylphenoxyacetato)-cobalt(II) (1) and tetraaquabis (2- formylphenoxyacetato )zinc(II) (2) have been determined by X-ray diffraction and refined to residuals R 0.039, 0.058 and 0.045 for 1197, 1178 and 1230 observed reflections respectively. 2-Formylphenoxyacetic acid crystallizes in a monoclinic cell, space group P21/n with a 8.066(2), b 7.375(1), c 14.206(2) Ǻ, β 98.12(1)° and Z 4. The planar molecules form unusual hydrogen-bonded chain polymers (O…O 2.694(3)Ǻ] linked through the carboxyl groups. The complexes (1) and (2) are isomorphous, the comparative cells being a 5.036(1), b 13.463(3), c 15.083(4) Ǻ, β 96.88(2)° for (1), and a 5.044(1), b 13.481(3), c 15.055(4) Ǻ, β 96.95(2)° for (2), with Z 2 and space group P21. The complexes have four waters and two trans-related carboxyl oxygens [mean M-O distances 2.129(5) and 2.117(3) Ǻ respectively] completing almost regular octahedral stereochemistries . The nickel(II) complex [Ni( ofpa )(H2O)4] is probably not isostructural with (1) and (2), and the copper(II) complex is also different, with formula [Cu( ofpa )2(H2O)2].

Spectroscopic and structural studies of some bisdithiocarbamates and cyclic thiones

The syntheses of bisdithiocarbamates from diamines and CS2 are described, and possible complications in these reactions explained. Ethylenebisdithiocarbamate was prepared from ethylenediamine and CS2 in basic solution, but the same reaction using o-phenylenediamine led to a cyclization product, o-phenyleneimidazolidine-2-thione or benzimidazolidine-2-thione. In these reactions, if slightly insufficient amounts of CS2 are used, bisdithiocarbamates will not be formed; instead, the cyclization reactions will occur, leading to the formation of thiones. Crystallographic studies were carried out for disodium ethylenebisdithiocarbamate and imidazolidine-2-thione or ethylenethiourea. The hexahydrate crystals of the former, Na2[S2CNHCH2CH2NHCS2]•6H2O, F.W. 364.42, are triclinic with a = 5.766(1), b = 7.212(1), c = 10.074(1) Å, α = 88.53(1), β = 98.41(1), γ = 105.50(1)°, V = 399.3(1) Å3, and Z = 1. The structure was determined from 2259 unique reflections, (2θ[Mo-Kα] < 65°) to an R factor of 0.022. The bisdithiocarbamate ion has a center of symmetry between the two CH2 groups, and therefore the two NCS22− groups are separated as far apart as possible. Each Na+ ion is octahedrally surrounded by five water molecules with Na … O distances ranging from 2.373 to 2.446 Å, and a sulphur atom of the thiocarbamate group with Na … S = 3.060 Å. The two C—S bonds of the CS2− group are 1.710(1) and 1.727(1) Å, and [Formula: see text]. Crystals of imidazolidine-2-thione, (CH2NH)2CS, are monoclinic, with a = 5.800(1), b = 14.516(3), c = 5.780(1) Å, β = 101.33(2)°, V = 477.2(2) Å3, and Z = 4. This structure, first determined thirty years ago, has been refined by full-matrix least-squares to R = 0.031, using 975 new Mo-Kα data.

Cyclisation during an attempted Meyer–Schuster rearrangement

The structure of a tricyclic diketone produced during Meyer–Schuster rearrangement has been established by chemical and X-ray crystallographic evidence.