Nickel selenocyanates

The complex formation is thus described in terms of mononuclear complexes 

Np + wSeCN Ni(SeCN) - and Table V-64 lists the equilibrium constants reported. 

Extrapolation of the data from 1 M NaC104 to standard conditions by SIT and Ae from [97BAH/PAR] in Appendix A resulted in the selected values  

In the data material, the Ni(SeCN)3 complex never amounted to more than a few per cent of the total nickel(ll) concentration and the value of the corresponding 

Method Ionic medium G°C) logio Pi login Pi login P . Reference 

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Cyclizations by formation of carbon—selenium bonds represent a modern method with a high synthetic potential in the chemistry of cyclophanes. Selenocyanates such as 16 are accessible usually in excellent yields through the reaction of bromides with KSeCN [27], The reaction with benzylic bromides under reductive conditions using the dilution principle results in good to excellent yields of [3.3]di-selenacyclophanes which can be deselenized photochemically, pyrolytically (without previous oxidation), or by reaction with arynes, Stevens rearrangement and subsequent reaction with Raney nickel. [2.2]Metacyclophane (18), for example, is accessible in 47% total yield by using this sequence of reactions starting with... 

KETONES Bis(phenylthio)methane. Chlorothexylborane. Grignard reagents. Nickel chloride-Zinc. o-Nitrophenyl selenocyanate. Organomagnesium(II) iodides. PhcnylthiophenyKtrimethyl-silyDmcthanc. 

Kullberg, L., Thermodynamics of metal complex formation in aqueous solution. VII. Equilibrium and enthalpy measurements on the nickel(II)-selenocyanate system, Acta Chem. Scand, A 28, (1974), 897-902. Cited on pages 297, 315, 316. 

A standard condition has been optimized for this reaction, in which the aryl amine is diazotized in 10 times its amount of acetic acid, followed by the addition of one equivalent of cuprous halide in hydrohalic acid. Under these conditions, the acetate salt of aryl amine is relatively soluble, and less froth and tarry material are formed during diazo transformation. In addition, chlorination, bromination, and iodonation of p-haloaniline to dihalobenzenes under such standard conditions give almost comparable average yields. Other modifications of this reaction include the formation of phenyl selenocyanate by the reaction with potassium selenocyanate, and aryl nitrile by the reaction with nickel cyanide. Moreover, this reaction has been extended to the preparation of phenyl thiocyanate, phenyl isothiocyanate and aromatic sulfonyl chloride. ... 

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