Kirill I. Tugashov

Coordination chemistry of polymercuramacrocycles. Complexation of cyclic trimeric perfluoro-o-phenylenemercury with neutral oxygeneous Lewis bases

Cyclic trimeric perfluoro- o -phenylenemercury ( o -C 6 F 4 Hg) 3 ( I ) readily reacts with N , N -dimethylformamide and hexamethylphosphoramide to form complexes {[( o -C 6 F 4 Hg) 3 ](HCONMe 2 ) 2 } ( II ) and {[( o -C 6 F 4 Hg) 3 ][(Me 2 N) 3 PO] 2 } ( III ), respectively, which contain two amide ligands per one macrocycle molecule. An X-ray diffraction study of II and III has shown that they have bipyramidal structures wherein the molecules of an amide are located above and below the metallacycle plane and each of them is simultaneously bonded via the oxygen atom to all Hg atoms of the cycle. The reaction of I with dimethylsulfoxide affords complex {[( o -C 6 F 4 Hg) 3 ](Me 2 SO) 3 } ( VI ) containing three Lewis basic species per molecule of I . According to X-ray diffraction data, two of three dimethylsulfoxide ligands in VI are also coordinated through the oxygen atom with all mercury centres of the macrocycle, forming a bipyramidal structure, while the third sulfoxide ligand is bonded only to one Hg atom of the cycle. The complex of similar composition and structure, {[( o -C 6 F 4 Hg) 3 ](MeCOOEt) 3 } ( IV ), is produced in the interaction of I with ethyl acetate but this complex is much less stable than VI . The latter correlates with a considerably lower Lewis basicity of ethyl acetate as compared to that of dimethylsulfoxide.

Coordination chemistry of macrocyclic multidentate Lewis acids. Synthesis and structures of complexes of cyclic trimeric perfluoro-o-phenylenemercury with N,N-dimethylacetamide and n-butyronitrile

Cyclic trimeric perfluoro-o-phenylenemercury (o-C6F4Hg)3 readily reacts with N,N-dimethylacetamide and n-butyronitrile to form the complexes {[(o-C6F4Hg)3](MeCONMe2)2} and {[(o-C6F4Hg)3](PrnCN)}, respectively. According to X-ray diffraction data, the amide ligands are located above and below the plane of the macrocycle, each being coordinated to all Hg atoms of the macrocycle through the O atom. The nitrile ligand is bound to the macrocycle through the N atom, all Hg atoms being also involved in this bonding.

Binding of ferrocene by cyclic trimeric perfluoro-o-phenylenemercury. Synthesis and structure of the first double-decker sandwich complex of a sandwich

The first double-decker sandwich complex of a sandwich was synthesized and fully characterized. The complex was prepared by the reaction of cyclic trimeric perfluoro-o-phenylene-mercury (o-C6F4Hg)3 (1) with ferrocene in an ethereal solution at 20 °C and has the composition {[(o-C6F4Hg)3]2(Cp2Fe)} (2). The ferrocene sandwich in 2 is located between the planes of two mercury-containing macrocycles and is coordinated to each of them through donation of the π-electrons of the η5-Cp ligands to vacant orbitals of the mercury atoms of the adjacent molecule 1. It was concluded that all carbon atoms of the η5-Cp rings in complex 2 are involved in the bonding to the macrocycles. Complexation with 1 leads to considerable shifts of the ν(C-H) and ρ(C-H) bands of ferrocene in the IR spectrum to high frequencies. The structure of complex 2 was determined by X-ray diffraction.

Crown compounds for anions. Sandwich complex of cyclic trimeric perfluoro-o-phenylenemercury with [B12H11SCN]2– anion

The reaction of cyclic trimeric perfluoro-o-phenylenemercury (o-C6F4Hg)3 (1) with the polyhedral [B12H11SCN]2– anion in THF at 20 °C affords the {[(o-C6F4Hg)3](B12H11SCN)}2– (4) and {[(o-C6F4Hg)3]2(B12H11SCN)}2– (5) complexes. Complex 5 was isolated as the tetrabutylammonium salt. X-ray diffraction analysis showed that this complex has a bent-sandwich structure in which the [B12H11SCN]2– anion is located between the planes of two molecules 1 and is coordinated to both these molecules through B—H—Hg bridges and S—Hg bonds. The stability constants of complexes 4 and 5 in THF (20 °C), which were determined from the IR spectroscopic data, are 16 L mol–1 and 992 L2 mol–2, respectively.

Coordination chemistry of anticrowns. Synthesis and structure of a complex of cyclic trimeric perfluoro-o-phenylenemercury (o-C6F4Hg)3 with tungsten hexacarbonyl

The reaction of the three-mercury anticrown (o-C6F4Hg)3 (1) with tungsten hexacarbonyl in CH2Cl2 at 20 °C in the dark affords the complex {[(o-C6F4Hg)3]2[W(CO)6]} (2) containing two anticrown molecules per W(CO)6 molecule. According to the X-ray diffraction data, two carbonyl groups of W(CO)6 are involved in the formation of 2, each of these carbonyl groups being coordinated via the oxygen atom to a single mercury center of one of the two molecules 1. The formation of the complex is accompanied by a shift of ν(CO) bands in the IR spectrum with respect to the corresponding bands of the starting W(CO)6.