Structure of Cobalt(III) Complexes with (R,R)- and (R,S)-N,N,N′,N′-Tetrakis(2-aminoethyl)-2,4-pentanediamine and N,N,N′,N′-Tetrakis(2-aminoethyl)-1,3-propanediamine

Abstract

Crystal structures of the two isomeric Co(III) complexes with sexidentate ligands, (NH2CH2CH2)2NC*H(CH3)CH2C*H(CH3)N(CH2CH2NH2)2 (hereafter abbreviated as R,R- and R,S-tptn) and of the Co(III) complex with a sexidentate ligand, (NH2CH2CH2)2NCH2CH2CH2N(CH2CH2NH2)2 (abbreviated as ttn) were determined by an X-ray diffraction method. The crystal data and the final R factors are: (1) [Co(R,R-tptn)](ClO4)3·H2O, tetragonal, P42212, a=12.800(1), c=15.312(1) Å, V=2509(1) Å3, Z=4, R=0.053 for 1627 observed unique reflections, (2) [Co(R,S-tptn)]Cl3·3H2O, monoclinic, P21⁄a, a=16.778(6), b=14.296(2), c=9.478(4) Å, β=110.99(3)°, V=2123(1) Å3, Z=4, R=0.045 for 3583 reflections and (3) [Co(ttn)]Br3·H2O, trigonal, P\={3}cl, a=14.436(4), c=15.718(9) Å, V=2837(2) Å3, Z=6, R=0.096 for 1183 reflections. The equatorial preference of the methyl groups in the central six-membered chelate ring formed by Co and 2,4-pentanediamine moiety of R,R- and R,S-tptn has been recognized. In (1) the six-membered chelate ring adopts a twist boat form as in (3) with the two C–CH3 bonds in equatorial positions. In (2) the six-membered chelate ring takes a largely flattened chair form with the two C–CH3 bonds again in equatorial positions. The effect of an elongation of the Co–N bond distance on the energy of the first absorption band was discussed.

Synthesis and Reaction of α‐Dithiolactone

“…We speculated that the extrusion of nitrogen from intermediate 10 would give 4 a. This is another method for the synthesis of 4 a. Refluxing a solution of diazo-1,1,3,3-tetramethylindane (9 b) in carbon disulfide for one day afforded not 4 c but 1,1,2,3-tetramethyl-1H-indene (11) [10] in 58 % yield, suggesting that 9 b did not react with carbon disulfide, and carbene intermediate (12), [11] thus formed by nitrogen extrusion, rearranged to give 11.…”