How to Delete specific template specialization with keyword delete in C++

I am trying to understand some use cases of the keyword delete in C++11.

So I tried to delete a specific class template specialization by deleting its constructor in the main method.

Here is my code :

using namespace std;

template <typename T>
class ComplexNumber
{
   T x;
   T y;    
   public:
      ComplexNumber(T a, T b) : x(a) , y(b) {}        
      void display()  {    std::cout<<x << " + i"<<y<<std::endl;   }
};

int main()
{
    ComplexNumber(char a, char b) = delete;
    ComplexNumber<int> obj1(1,2);
    ComplexNumber<double> obj2(1.0,2.0);
    ComplexNumber<char> obj3('1' , '2');
    return 0;
}

But the program execution doesn't block on "ComplexNumber obj3('1' , '2')" as expected, but on the line "ComplexNumber(char a, char b) = delete".

Here is errors' trace:

main.cpp: In function ‘int main()’:
main.cpp:28:18: error: missing template arguments before ‘(’ token
ComplexNumber(char a, char b) = delete;
              ^
main.cpp:28:19: error: expected primary-expression before ‘char’
ComplexNumber(char a, char b) = delete;
               ^~~~
main.cpp:28:27: error: expected primary-expression before ‘char’
ComplexNumber(char a, char b) = delete;
                       ^~~~
main.cpp:28:43: error: expected primary-expression before ‘;’ token
ComplexNumber(char a, char b) = delete;

Could you help to understand why we cannot delete a specific constructor "for char type" here?