Hydrogen bonding in proton-transfer compounds of 5-sulfosalicylic acid with a series of aliphatic nitrogen Lewis bases

The crystal structures of the proton-transfer compounds of 5-sulfosalicylic acid (3-carboxy-4-hydroxybenzenesulfonic acid) with the aliphatic nitrogen Lewis bases, hydroxylamine, triethylamine, pyrrolidine, morpholine, N-methylmorpholine and piperazine, viz. hydroxyammonium 3-carboxy-4-hydroxybenzenesulfonate (1), triethylaminium 3-carboxy-4-hydroxybenzenesulfonate (2), pyrrolidinium 3-carboxy-4-hydroxybenzenesulfonate monohydrate (3), morpholinium 3-carboxy-4-hydroxybenzenesulfonate monohydrate (4), N-methylmorpholinium 3-carboxy-4-hydroxybenzenesulfonate monohydrate (5) and piperazine-1,4-diium bis(3-carboxy-4-hydroxybenzenesulfonate) hexahydrate (6) have been determined and their comparative structural features and hydrogen-bonding patterns described. Crystals of 4 are triclinic, space group P-1 while the remainder are monoclinic with space group either P21/c (1 - 3) or P21/n (5, 6). Unit cell dimensions and contents are: for 1, a = 5.0156(3), b = 10.5738(6), c = 18.4785(9) Å, β = 96.412(5)o, Z = 4; for 2, a = 8.4998(4), b = 12.3832(6), c = 15.4875(9) Å, β = 102.411(5)o, Z = 4; for 3, a = 6.8755(2), b = 15.5217(4), c = 12.8335(3) Å, β = 92.074(2)o, Z = 4; for 4, a = 6.8397(2), b = 12.9756(5), c = 15.8216(6) Å, α = 90.833(3), β = 95.949(3), γ = 92.505(3)o, Z = 4; for 5, a = 7.0529(3), b = 13.8487(7), c = 15.6448(6) Å, β = 90.190(6)o, Z = 4; for 6, a = 7.0561(2), b = 15.9311(4), c = 12.2102(3) Å, β = 100.858(3)o, Z = 2. The hydrogen bonding generates structures which are either two-dimensional (2 and 5) or three-dimensional (1, 3, 4 and 6). Compound 6 represents the third reported structure of a salt of 5-sulfosalicylic acid having a dicationic piperazine species. \u

Structures of the silver (I) complexes with maleic and fumaric acids: Silver(I) hydrogen maleate, silver(I) maleate and silver (I) fumarate

A series of silver (I) complexes with the unsatu- rated isomeric dicarboxylic acids, maleic and fumaric, has been prepared and the structures of three of these, silver(I) hydrogen maleate, (1), silver(I) maleate, (2) and silver(I) fumarate, (3), were determined by X-ray diffraction. All three structures are polymeric, with (1) and (2) based on bis(carboxylato-0, 0‘) dimers. With (1), a strong intramolecular hydrogen bond is found [O. O, 2.494(2) A], involving the acidic proton and the cis-related carboxylate group. In this respect it is similar to maleic acid and other hydrogen maleates. With (2), a unique feature is the presence of an ethylene-Ag π-bond to one of the independent silver ions [Ag —C, 2.448(5) A] giving angle distortion about the dimer unit. The polymeric structure of (3) is based on an unusual cyclic, open figure-eight Ag4 complex unit involving four different carboxy-lato-(0, 0‘) interactions. This results in three separate Ag. Ag contacts [2.924(1) A, 2.925(1) A, 3.090(1) A]