Cascade complexes of an octaaza cryptand: co-ordinated azide with linear M–NNN–M geometry

Abstract

The octaamino cryptand, L2, obtained by tetrahydroborate reduction of the [2+3] condensation product of tris(2-ethy1amino)amine with terephthalaldehyde, acts as a host for pairs of protons or first-series transition-metal cations. An X-ray crystallographic structure determination of [ H,L2I4+ reveals a pair of protons held at opposite ends of the molecule by strong intramolecular hydrogen bonding of each proton to two of the amino nitrogen atoms. Pairs of transition-metal cations co-ordinated to the amino N-donors accommodate mono-and tri-atomic bridging ligands, such as OHor imidazolate, generating weak to moderate antiferromagnetic interaction. Dicopper( 11) p-azido complexes have been prepared where the combination of a large zero-field splitting in t h e ESR spectrum and a near Curie-law dependence of -3.84 (t) 360 183 7.&7.5 (m) 8.40 (s) -3.84 (br s) 183 6.67 (s) 3.53 (br s) 1.55 (br s) 2.53 (br s) L2 CD,CI, 360 298 6.89 (s, 4 H) 3.67 (s, 4 H) 2.0 (br s, 2 H) 2.65 (t, 4 H) CH4L21CCF3S031, (CD,),SO 400 298 7.45 (s, 4 H) 2.80 (s, 4 H) 8.65 (br s) 4.22 (s, 4 H) [Ag,LZ][CF,S03]2 CD3CN 500 298 7.12 (s, 4 H) 2.78 (4 H) 2.9 (br) 3.78' (4 H) 338 7.12 (s, 4 H) 2.80 (4 H) 2.92 3.78' (4 H) [Cu2LZ][CF3S03], CD3CN 500 338 6.89 (4 H) 2.80 2.90 3.90, 3.65 Chemical shifts 6 relative to SiMe,. Overlapped. Assigned on the basis of comparison with the copper(1) spectrum. 323 7.22 (s) 2.90(br s) --3.97 (s) 298 2.80 (s) 2.85 (m) 3.95 (d), 3.53 (1) H E 2.83 (br s) 3.4, 2.1 (br) 2.65 (br s) 2.81 (t, 4 H) 2.61 (t, 4 H) 2.71 (t) 2.95 3.00 (4 H) 3.28, 2.95 3.35 (br t), 2.95 (d) Table 2 Torsion angles (")in [H,L2][CF,S0,], C( 3 1 )-C( 30)-N( 1 )-C( 10) 128.9 C(3O)-N( 1)-C( 10)-C( 11) C( 3 1 )-C( 30)-N( 1 j C ( 23 *) -58.4 -99.2 C(30)-N( 1 )-C(23*)-C(22*) 167.0 C(ll)--C(lO)-N(l)-C(23*) 175.0 C( 10)-N( l)-C(23*)-C(22*) -66.5 N( 1 )-C( 10)-C( 1 1)-N( 12) C( 1 0)-C( 1 1 )-N( 12)-C( 1 3) C( 1 1 )-N( 12)-C( 13)-C( 14) N(12)-C(13)-C(14)-C(15) C( 13)-C( 14)-C( 15)-C( 16) C( 16)-C( 17)-C(20)-N(2 1) C( 20)-N( 2 1 )-C( 22)-C(23) C( 17)-C(20)-N(21)-C(22) N(21)4'(22)-C(23)-N(l*) N(l)-C(3O)-C(31)-N(32) C( 30)-C(3 1 )-N(32)-C(3 3) C(3 1 )-N(32)-C(33)-C(34) N(32)-C(33)-C(34)-C(35) * Symmetry operation +x , y , 1z.-50.1 -167.3 -172.9 115.7 173.4 -112.4 178.4 -153.2 -66.9 -76.9 178.6 106.9 -49.6 L1 *6H,O 70.2 -118.1 -178.6 2.6 -177.1

(η5-Cyclopentadienyl)(thiocyanato-N)bis(triphenylphosphine)ruthenium dichloromethane solvate

“…In the complex bis[(2,2'-bipyridyl-N,N')thiocyanato-N]ruthenium the Ru--N bond length is 2.055 (5) A, the angle at the ligand N atom is 168.2 (5) °, and the angle N--C--S is 177.5 (6) °. The angles are consistent with the Ru centre in this complex and in the title compound being a good rr donor (Drew, bin-Othman & Nelson, 1976).…”

Ferromagnetic Interaction in μ1,3‐Cyanamido‐Derived Copper(II) Cryptates

“…As before the shortest CuÀN distances are those involving the 1,3-cyanamido bridge (Cu1ÀN4, 1.947(7); Cu2ÀN5, 2.040(6) ), which again shows localised bonding: one short [a]Symmetry transformations used to generate equivalent atoms: #1: Magnetic susceptibility and EPR measurements: The magnetic susceptibility of the hydrogencyanamido-bridged cryptate 1 was studied at a field of 1 T over the temperature range 2-250 K. The c M T versus T plot (Figure 3) shows the c M T values to increase with decreasing temperature to a maximum value of 1.029 cm 3 K mol À1 at 7 K and subsequently to decrease to a value of 0.997 cm 3 K mol À1 at 2 K. The experimental values can be fitted to a modified BleaneyBowers expression [22] for the magnetic susceptibility of isotropically coupled S = ). [23,24] The moderately strong antiferromagnetic interaction in the bis(1,3-m-HNCN)dicopper(ii) complex reported earlier [7a] (bridge angles Cu-N-C % 121-1268 and 144-1478), implied by the 298 K moments of 1.35 m B (298 K) and 0.66 m B (98 K), respectively, is comparable with the level of antiferromagnetic interaction mediated by similarly bent azido bridges.…”

Synthesis, Spectroscopic and Electrochemical Studies of Mononuclear Fe(II) and Ni(II) Complexes Containing a Macrocyclic Ligand Derived from Pyridine-2,6-dicarboxaldehyde and 1,2-Bis(2-aminoethoxy) Ethane

“…The structure [12] is shown in Fig.1. In this paper R = H and the compound 1 is considered as a new one.…”

“…In Pb 2 L 1 (SCN) 4 two strong bands appeared at 2013 and 813cm -1 is due to SCN --centered absorption [10]. The strong bands at 1620-1660 and 1580-1600 cm -1 are assigned to ν( C=N) and the highest-energy pyridine ring vibration, respectively [11,12]. ) of the complexes.…”