Wanna be an Alchemist Wanna be an Alchemist

I've been watching Full Metal Alchemist these past days and I've been wondering, It is really possible to trans-mutate matter? In the real world, I don't know if it is possible, but in the machine world, we think we "can".



Problem

Your task is, Given an input of N chemical elements (K, Mg, C, O, etc...), you are going to:


Get the first letter of the element
Convert that letter into binary
Rotate 2 bits to the right
Apply Binary Addition
If the result is more that 8 bits then get the one's complement of the result and removes the highest bit
Output the ASCII (ISO 8859-1) representation of the result




Example

Given Chemical Elements: (K, Ca, Mg)


Get the first letter of the element


K, C, M


Convert that letter into binary


K =&gt; 01001011, C =&gt; 01000011, M =&gt; 01001101


Rotate 2 bits to the right


K =&gt; 11010010, C =&gt; 11010000, M =&gt; 01010011


Sum bits

K =&gt; 11010010 +
 C =&gt; 11010000 +
 M =&gt; 01010011 = 111110101
If the result is more that 8 bits then get the one's complement and removes the highest bit


00001010


Output the ASCII representation of the result. 
Result:




Test Cases

(H, Mn, C) =&gt;  Ê

(I, H, Se) =&gt;  Ç

(K, Ca, Mg) =&gt; 




This is code golf so the shortest answer wins
Python 2, 78 bytes



e=sum(ord(e[0])/4+ord(e[0])%4*64for e in input());print chr([e,~e][e&gt;255]%256)


Try it online!

-8 bytes thanks to Jonathan Frech