Nuclear quadrupole resonance of charge transfer complexes. Part 3.—A14N and35Cl n.q.r. study of the 1:1 complex of 3,5-dichloropyridine with iodine monochloride

1976 ◽  
Vol 72 (0) ◽  
pp. 1964-1969 ◽  
Author(s):  
Graham A. Bowmaker
Keyword(s):  
Charge Transfer ◽  
Nuclear Quadrupole Resonance ◽  
Charge Transfer Complexes ◽  
Iodine Monochloride ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

Nuclear quadrupole resonance of charge-transfer complexes. II. The aminehalogen complexes

1969 ◽  
Vol 22 (10) ◽  
pp. 2047 ◽  
Author(s):  
GA Bowmaker ◽  
S Hacobian
Keyword(s):  
Charge Transfer ◽  
Nuclear Quadrupole Resonance ◽  
Charge Transfer Complexes ◽  
Iodine Monochloride ◽  
Bonding Theory ◽  
Resonance Frequencies ◽  
Quadrupole Resonance ◽  
Iodine Monobromide ◽  
Nuclear Quadrupole ◽  
Electronic Ground

Nuclear quadrupole resonance frequencies have been measured for some of the halogen nuclei in a number of crystalline charge-transfer complexes of amines with bromide, iodine, iodine monobromide, and iodine monochloride. From these measurements it has been possible to calculate approximate charge distributions for the bromine, iodine monobromide, and iodine monochloride complexes of 3,5-di-bromopyridine. The results correlate well with a three-centre delocalized LCAO-MO bonding theory. The correlation of this MO description with Mulliken's charge-transfer bonding scheme for n-σ complexes is discussed. This approach indicates the importance of considering an ?ionic? structure (which does not involve transfer of charge from the donor to the acceptor) in the electronic ground state of these complexes.

Nuclear quadrupole resonance of charge transfer complexes. I. The trihalide ions

1968 ◽  
Vol 21 (3) ◽  
pp. 551 ◽  
Author(s):  
GA Bowmaker ◽  
S Hacobian
Keyword(s):  
Charge Transfer ◽  
Nuclear Quadrupole Resonance ◽  
Charge Distribution ◽  
Crystal Field ◽  
Charge Transfer Complexes ◽  
Halogen Atoms ◽  
Charge Distributions ◽  
Resonance Frequencies ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

The nuclear quadrupole resonance frequencies of the halogen atoms in the trihalide ions 13 and Ibr2 in some of their crystalline salts have been measured. The results have been correlated with a simple LOAD-MO bonding description and the charge distributions in the ions have been calculated. These ions can be regarded as charge-transfer complexes as described by Mulliken. The effect of the crystal field on the charge distribution in the I3 ion has been investigated.

On the Correlation of 35Cl Nuclear Quadrupole Coupling Constants with π→γ3 and π→γ5 Optical Electron Transfer Bands of Transition Metal Complexes and its Significance in Pi-Bonding

1969 ◽  
Vol 24 (2) ◽  
pp. 193-199 ◽  
Author(s):  
Paul Machmer
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Transition Metal ◽  
Metal Ions ◽  
Nuclear Quadrupole Resonance ◽  
Coupling Constants ◽  
Resonance Frequencies ◽  
Quadrupole Coupling ◽  
Quadrupole Resonance ◽  
Nuclear Quadrupole

From a consideration of odd-even intramolecular electron transfer processes in octahedrally co-ordinated transition metal complexes, two relationships have been derived. The first correlation describes π → γ3 optical electron transfer bands of the complexes K2OsCl6, K2IrCl6, K2PtCl6, K2PtCl4 as a function of the respective 35Cl nuclear quadrupole coupling constants. The second relationship correlates π → γ5 optical charge transfer transitions of the substances K2ReCl6, K2OsCl6, K2IrCl6 with the 35Cl nuclear quadrupole coupling constants of these compounds. By using this charge transfer model, a linear relationship has been verified between the optical electronegativity values of the quadrivalent transition metal ions W4⨁, Re4⊖, Os4⨁, Ir4⨁, Pt4⨁ and the 35Cl nuclear quadrupole coupling constants of their hexachloro complexes. The empirically established equation χMen+ = 0.537 which describes the 35Cl n.q.r. frequencies of the hexachloro complexes of Re4⨁, Os4⨁, Ir4⨁, Pt4⨁ and Pd4⨁ as a function of the optical electronegativity values χ of these metal ions, has been used to estimate 35Cl nuclear quadrupole resonance frequencies of chloro complexes as yet not probed by nuclear quadrupole resonance spectroscopy, e.g. Zeise's salt (KPtCl3C2H4), K3IrCl6, K2RuCl6, K3RhCl6 and K3MoCl6. Conversely, by the same procedure the optical electronegativity χ of W4⨁ and Au3⨁ has been estimated from the 35Cl quadrupole resonance frequency of K2WCl6 and KAuCl4 (χ W4⨁= 1.71 and χ Au3⨁=2.80). In the case of analogous bromo complexes, the equation χ Men+ = 0.19 mol accounts for the dependence of the 79Br nuclear quadrupole resonance frequencies upon the optical electronegativity of the metal ions. The assignment of electron transfer bands in other chloro complexes is discussed in the light of this “nuclear quadrupole resonance criterion“ of optical charge transfer bands.

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