Nuclear quadrupole resonance and crystallographic studies of three-co-ordinated copper(I) cations with alkylpyridine ligands

Abstract

The preparation and 63,65Cu NQR resonance frequencies of fourteen three-co-ordinated complex cations of copper(I) with alkylpyridine ligands are reported. Crystal structures of seven of these have also been determined. The complexes show a wide variety of symmetries but in none does the copper atom lie on an ideal three-fold axis. In most the copper lies in an essentially trigonal-planar environment but with at least two of the pyridine ligands twisted well out of the plane containing the copper and the three nitrogen atoms. In most cases one of the N–Cu–N bond angles is significantly greater than 120° while the length of the opposing bond is significantly greater than that of the two bonds that form this angle. All the NQR frequencies at 77 K are in the neighbourhood of 45 MHz, with the exception of that of the complex with 3,5-dimethylpyridine, the only ligand without at least one alkyl substituent ortho to the nitrogen atom, where the frequency at 77 K is 40.471 MHz. This difference results from the axial co-ordination of both the PF6 anions to the copper cation

63Cu NQR Studies of Two-and Three-coordinated Complexes of Cu(I) with Siloxyl Ligands

“…The only previous measurement for an oxygen-coordinated compound of Cu(I) is that of Cu 2 0 -probably the first Cu(I) compound studied by NQR -where each copper atom is also linearly bonded to two oxygen atoms, and the resonance frequency (26.697 MHz at 87 K, [3]) is noticeably lower than those reported here. In accord with the trend that was found for the two-or three-coordinated cations with pyridine ligands [4,5] or the polyhalocuprate anions [6,7], the resonance frequencies of the three-coordinated species are significantly higher than those of the two-coordinated complexes. The observation of two resonance frequencies for Ia and a single resonance frequency for lib is in accord with their published crystal structures [2].…”

Crystal Structure and NQR of Two Copper (I) Complexes of 4,6-Dimethylpyrimidine-2-thione

“…The effect of changing the non bridging ligand to an arom atic amine can be esti mated as an increase of about 4.0 M Hz from the fact that the frequencies of three-coordinated complex cations analogous to A, where the ligand is a substi tuted pyridine molecule such as 2,6-lutidine, are in the range 4 2 -4 6 M Hz [3], The frequencies observed here are thus roughly those that would be expected.…”

“…•6CHC13 and 2, [Cu(dmpt)]6 -C 2H 4C12, that were prepared in the course of an extensive investigation of the 63Cu N Q R spectra of a variety of Cu(I) complexes [2][3][4][5][6][7].…”

Synthesis, Characterisation, Crystal Structures, Reactivity, and Electrochemistry of Ruthenium-Nitrido, Ruthenium-Cobalt-Imido and Ruthenapyrrolidone Carbonyl Clusters Containing Alkyne Ligands

“…This signal is significantly downfield relative to those of [Ru 2 Co(CO) 6 (m 3 -CO)(h 5 -C 5 Me 5 )(m 3 -NH)] [16] ( 15 N: d 131.4 (d, J( 15 N,H) 76.95 Hz)); the ªlinkedº RuCo ligand fragment is shown to be more electron withdrawing than the two carbonyl ligands. In previous studies, metallocyclic rings were formed by coupling of alkynes, [35±37] dialkynes [38,39] and ynamines, [40] whereas the Ru (3) (8) ). The ªlinkedº RuCo-ligand fragment takes the place of two radial CO ligands with respect to the known complex [Ru 2 Co(CO) 6 (m 3 -CO)(h 5 -C 5 Me 5 )(m 3 -NH)], [16] bonding through the p interaction of carbon atoms of the phenyl group (the ipso-C atom is not involved).…”