Fundamental and second harmonic alternating current cyclic voltammetric theory and experimental results for simple electrode reactions involving solution-soluble redox couples

1976 ◽  
Vol 48 (6) ◽  
pp. 872-883 ◽  
Author(s):  
Alan M. Bond ◽  
Roger J. O'Halloran ◽  
Ivica. Ruzic ◽  
Donald E. Smith
1996 ◽  
Vol 05 (04) ◽  
pp. 653-670 ◽  
Author(s):  
CÉLINE FIORINI ◽  
JEAN-MICHEL NUNZI ◽  
FABRICE CHARRA ◽  
IFOR D.W. SAMUEL ◽  
JOSEPH ZYSS

An original poling method using purely optical means and based on a dual-frequency interference process is presented. We show that the coherent superposition of two beams at fundamental and second-harmonic frequencies results in a polar field with an irreducible rotational spectrum containing both a vector and an octupolar component. This enables the method to be applied even to molecules without a permanent dipole such as octupolar molecules. After a theoretical analysis of the process, we describe different experiments aiming at light-induced noncentrosymmetry performed respectively on one-dimensional Disperse Red 1 and octupolar Ethyl Violet molecules. Macroscopic octupolar patterning of the induced order is demonstrated in both transient and permanent regimes. Experimental results show good agreement with theory.


2009 ◽  
Vol 2009 (8) ◽  
pp. 527-532
Author(s):  
Manindranath Bera

Two new dinuclear nickel(ll) compounds of formula [Nill2(μ-L1)2](CIO4)2·MeCN (1·MeCN) and [NiII2(μ-L2)2](CIO4)2 (2) where HL1 and HL2 stand for 3-(2-(dimethylamino)ethylimino)butan-2-one oxime and 1-(2-(dimethylamino)ethyl-imino)-1-phenylpropan-2-one oxime respectively, have been synthesised. Single crystal X-ray analyses of the complexes reveal that the nickel(ll) ions are in square-planar N3O environments and form six-membered (NiNO)2 metallacycles. Cyclic voltammetric measurements of 1·MeCN and 2 in MeCN solution show quasirreversible one-electron oxidations at E1/2 = 0.566 V and 0.603 V ( vs Fc+/Fc), respectively, attributed to NiIIINiII/NiII2 redox couples. Additional reversible NiIII2/NiIIINiII redox responses were observed at relatively higher potential near E1/2 = 0.832 V and 0.850 V ( vs Fc+/Fc), respectively, for 1·MeCN and 2. Complexes 1·MeCN and 2 display intense charge-transfer bands at ∼390 and ∼345 nm in the visible region. Chemical oxidation of complex 1·MeCN by sodium hexachloroiridate(IV) hexahydrate generates red Ni2III species with characteristic new bands at ∼520 and 427 nm in the visible region as well as the characteristic EPR signals at 77 K with g⊥ > gII. Similar phenomena were observed for complex 2 upon chemical oxidation. The dinickel(ll) complexes are catalytically active for epoxidation of olefins using iodosylbenzene as the terminal oxidant.


1955 ◽  
Vol 8 (3) ◽  
pp. 322 ◽  
Author(s):  
B Breyer ◽  
HH Bauer ◽  
S Hacobian

The equation of the A.C. polarographic current for processes where the frequency of the alternating field is comparable with the rate of the electrode reaction is derived. Relative values of equilibrium rate constants of some first order electrode reactions are evaluated experimentally.


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