Crown ether alkali metal TCNQ complexes revisited – the impact of smaller cation complexes on their solid-state architecture and properties (original) (raw)
Related papers
Crown ether complexes of transition metals
Polyhedron, 1982
When hydrated nickel (II) chloride reacts with l&crown-6, two products are yielded: NiZC12(H20)s Clz. 18 C6 (compound I) and 2 NiClr. 2HrO. 18C6 (compound II). These complexes were separately isolated and characterized by infrared spectroscopy. The crystal structure of compound I is described. It crystallizes in the triclinic system with a = 8$28 (4) b = 9,693 (4). c = 10,616 (4) A, (I =55,74 (3), fi =6i,47 (3), ~=63,62 (3), V= 648,l A', space group Pl. This structure shows an unusual conformation of the 18 crown 6 polyether (all the atoms of the crown are divided into two parallel planes separated by 1.1 A) and a Ni2C12(H20)s unit containing the nickel atoms in the form of a bridged dinuclear unit. The cohesion of the structure is given by hydrogen bonds between the crown ether and the water molecules surrounding the dinickel unit. In a previously reported structure involving crown ether the hexa-aquo metal ions were present as monometallic units.
The structure and binding energies of 12-crown-4 and benzo-12-crown-4 complexes with Li + , Na + , K + , Zn 2+ , Cd 2+ , and Hg 2+ were investigated with ab initio calculations using Hartree-Fock approximation and second-order perturbation theory. The basis set used in this study is lanl2mb. The structure optimization of cation-crown ether complexes was evaluated at HF/lanl2mb level of theory and interaction energy of the corresponding complexes was calculated at MP2/lanl2mb level of theory (MP2/lanl2mb//HF/lanl2mb). Interactions of the crown et hers and the cations were discussed in term of the structure parameter of crown ether. The binding energies of the complexes show that all complex formed from transition metal cations is more stable than the complexes formed from alkali metal cations.
Anion-induced structural diversity in 12-crown-4 complexes of transition metal salts
2001
The synthesis and X-ray crystal structures of eight transition metal complexes of 12-crown-4 are reported. These are: [Mn(H 2 O) 6 ][Mn(12-crown-4) 2 ] 2 (ClO 4 ) 6 ·6H 2 O (1), [Ni(H 2 O) 6 ](ClO 4 ) 2 ·12-crown-4 (2), [Zn(12-crown-4) 2 ] 2 [Zn(H 2 O) 6 ](ClO 4 ) 6 ·(12crown-4) 2 ·(H 2 O) 2 (3), [Mn(12-crown-4) 2 ][MnCl 4 ]·H 2 O (4), [Co(12-crown-4)Cl(H 2 O)] 2 (ClO 4 )·H 2 O (5), [Zn(12-crown-4) 2 ][ZnCl 3 (H 2 O)] 2 , [Cu(Br) 2 (12-crown-4)] (7) and [Cd(12-crown-4)(NO 3 ) 2 ] (8). Depending on the identity of the counter anion, the structures fall into three groups: (1) hydrogen bonded polymers; (2) sandwich M(12-crown-4) 2 cations alternating with transition metal containing anions; and (3) neutral molecular species incorporating 12-crown-4. : S 0 2 7 7 -5 3 8 7 ( 0 1 ) 0 0 9 0 7 -X
Zeitschrift für Naturforschung B, 1999
The thallium(I) dimethyl-N-trichloroacetylamidophosphate complex with a 18-crown-6 of the composition Tl(18-crown-6){L} (L = {Cl3CC(O)NP(O)(OCH3)2} -) has been prepared and characterized by means of IR spectroscopy and X-ray diffraction (orthorhombic, space group P212121 with a = 8.660( 1), b = 11.557(2), c =26.296(3) Å, Z = 4, V = 2631.8(6) Å3; R1 = 0.0285 and wR2 = 0.0558 for 4314 unique reflections). It was shown that (L-) is coordinated to the central atom in a bidentate manner via oxygen atoms of phosphoryl [Tl-O(l) 2.678(4) Å] and carbonyl groups [Tl-O(2) 3.012(6) Å.The Tl( 18-crown-6)+ moiety adopts a typical “sunrise” coordination with the metal atom laying 1.134(2) Å above the mean plane of the oxygen atoms of the macrocycle. This deviation is the highest value of the structurally examined Tl( 18- crown-6 )+ complexes. The Tl-O (etheric) separations are in the range 2.913(4) - 3.198(5) Å (av. 3.030(6) Å).
Complexation of the cations of six alkalides and an electride by mixed crown ethers
Journal of the American Chemical Society, 1993
It is well-known that crown ethers form sandwich complexes with the cations of many metals, but to date, the same crown ether formed both halves of the sandwich. Six new alkalides and an electride have now been synthesized that contain mixed sandwich complexes of alkali metal cations with 18-crown-6 (18C6), 15-crown-5 (15C5), and 12-crown-4 (12C4). The properties of Cs+(18C6)(15C5)Na-and Cs+(18C6)(15C5)e-demonstrate the existence of these stoichiometric compounds, but single-crystal X-ray diffraction studies yielded only the crystal systems and cell parameters. The crystal structures of K+(18C6)(12C4)Na-, K+(18C6)(12C4)K-, K+(18C6)(12C4)K-18C6, Rb+(18C6)(12C4)Na-, and Rb+(18C6)(12C4)Rb-were determined, thus verifying the thermodynamic stability of the mixed sandwich compounds relative to the 'parent" compounds that contain only one type of complexant.
American Journal of Research …, 2013
In this account 12-crown-4 (12c4), 15-crown-5 (15c5) and 18-crown-6 (18c6), their cluster complexes with Li+, Na+, K+ with general chemical formula as [M(crown ether)]+ and the water solvated complexes of Li+, Na+, K+ are theoretically studied. The chemical properties of crown ether complexes of Li, Na and K cations are compared with those of water-solvated complexes of these species. The B3LYP/6-31+G(d,p) level of calculation has been used for obtaining equilibrium geometries and Rho(r) functions (electron density distributions). By the aid of fundamental physical theorems implemented in the Quantum Theory of Atoms in Molecules (QTAIM), the structures and the physical nature of the chemical bonds have been determined for the abovementioned species at the B3LYP/6-31+G(d,p)computational level. These results establish the Metal-oxygen in all complexes in this work as ionic. Also Li+, Na+ and K+ have coordination number of 4 with 12c4 and possess the coordination number of 5 with 15c5. But the Li+ shows the coordination number of 3 with 18c6 crown ether and Na+ and K+ exhibits the coordination number of 6.
Conformational Study of the Structure of 12-crown-4−Alkali Metal Cation Complexes
The Journal of Physical Chemistry A, 2005
A conformational search was performed for the 12-crown-4 (12c4)-alkali metal cation complexes using two different methods, one of them is the CONFLEX method, whereby eight conformations were predicted. Computations were performed for the eight predicted conformations at the HF/6-31+G*, MP2/6-31+G*// HF/6-31+G*, B3LYP/6-31+G*, MP2/6-31+G*//B3LYP/6-31+G*, and MP2/6-31+G* levels. The calculated energies predict a C 4 conformation for the 12c4-Na + , -K + , -Rb + , and -Cs + complexes and a C s conformation for the 12c4-Li + complex to be the lowest energy conformations. For most of the conformations considered, the relative energies, with respect to the C 4 conformation, at the MP2/6-31+G*//B3LYP/6-31+G* are overestimated, compared to those at the MP2/6-31+G* level, the highest level of theory considerd in this report, by 0.2 kcal/mol. Larger relative energy differences are attributed to larger differences between the B3LYP and MP2 optimized geomtries. Binding enthalpies (BEs) were calculated at the above-mentioned levels for the eight conformations. The agreement between the calculated and experimental BEs is discussed.