\newcommand{\disk}[1]{%
   \begin{tikzpicture}\draw[fill=#1,overlay,#1](0,0)circle(2pt);\end{tikzpicture} 
}
\newcommand{\ddisk}[2]{%
\begin{tikzpicture}\draw[fill=#1,overlay,#1] (0,#2pt) circle (#2pt);\end{tikzpicture} 
}
  \newcommand{\gua}[2]{%
     \setatomsep{2.0em}\setcrambond{0.2em}{}{}%
     \chemfig{%
         -[:#2]\disk{blue}*5(-=@{n7#1}\disk{blue}-(*6(-(=@{o#1}\disk{red})-\disk{blue}(-@{n#1}\disk{gray})-(%
         -\disk{blue}(-[::60]\disk{gray})(-[::-60]@{n2#1}\disk{gray}))=\disk{blue}-))=-)%     
  }}

