# Problem with mesomeric effect in chemfig

I'm trying to draw mesomeric effect for a molecule using chemfig I would like to create something like this:

From the documentation page (see chapter 11 "Representing electron movements")seems easy but I've spent the last 4 hours without any success. The first arrow is the most difficult because goes form lewis pair to the bond.

\documentclass[12pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage[left=2cm,right=2cm,top=2cm,bottom=2cm]{geometry}
\usepackage{chemfig}
\usepackage{tikz}
\setlewis{4pt}{0.8em}{black}
\begin{document}
\chemfig{*6((-H_{2}@{sb1}\lewis{26,N}{\hspace{7mm}\scriptstyle})@{dncc}=-=(-N=N-*6(=-=(-OH)-=-))-=-=)}
\chemmove{
\draw[->](sb1)..controls +(90:4mm) and +(45:4mm)..(dncc);}
\end{document}


This is the molecule without anything else:

\chemfig{*6((-H_{2}\lewis{26,N}{\hspace{7mm}\scriptstyle})=-=(-N=N-*6(=-=(-OH)-=-))-=-=)}


If possible I would like an explanation of my faults!

-

Here is how to draw the 2 first arrows:

\documentclass{article}
\usepackage{chemfig}
\begin{document}
\chemfig{*6((-[@{a1}]H_2@{a2}\Lewis{26,N})=[@{r1}]-[@{r2}]=(-N=N-*6(=-=(-OH)-=-))-=-=)}
\chemmove[-stealth,shorten <=1pt, shorten >=1pt]{%
\draw(a2)..controls +(90:5mm) and +(135:5mm)..(a1);% first arrow
\draw(r1)..controls +(225:12mm) and +(300:12mm)..(r2);% ring arrow
}
\end{document}


-
+1 thanks, so when I have to use @{a2} instead of [@{a2}]? –  G M Mar 27 at 14:26
@{<name>} to put a node in an atom and [@{<name>}] to put it in a bond. –  unbonpetit Mar 27 at 17:53
Thanks for the help! –  G M Mar 27 at 20:13