Question
Which of the following pairs represent linkage isomers?
A.
$$\left[ {Pd{{\left( {P\,P{h_3}} \right)}_2}{{\left( {NCS} \right)}_2}} \right]\,{\text{and}}\,\left[ {Pd{{\left( {P\,P{h_3}} \right)}_2}{{\left( {SCN} \right)}_2}} \right]$$
B.
$$\left[ {Co{{\left( {N{H_3}} \right)}_5}N{O_3}} \right]S{O_4}\,{\text{and}}\,\left[ {Co{{\left( {N{H_3}} \right)}_5}S{O_4}} \right]N{O_3}$$
C.
$$\left[ {PtC{l_2}{{\left( {N{H_3}} \right)}_4}} \right]B{r_2}\,{\text{and}}\,\left[ {Pt\,B{r_2}{{\left( {N{H_3}} \right)}_4}} \right]C{l_2}$$
D.
$$\left[ {Cu{{\left( {N{H_3}} \right)}_4}} \right]\left[ {Pt\,C{l_4}} \right]\,{\text{and}}\,\left[ {Pt{{\left( {N{H_3}} \right)}_4}} \right]\left[ {CuC{l_4}} \right]$$
Answer :
$$\left[ {Pd{{\left( {P\,P{h_3}} \right)}_2}{{\left( {NCS} \right)}_2}} \right]\,{\text{and}}\,\left[ {Pd{{\left( {P\,P{h_3}} \right)}_2}{{\left( {SCN} \right)}_2}} \right]$$
Solution :
The $$SC{N^ - }$$ ion can coordinate through $$S$$ or $$N$$ atom giving rise to linkage isomerism
$$M \leftarrow SCN$$ thiocyanato
$$M \leftarrow NCS$$ isothiocyanato.