\colorlet{mcfpusharrowcolor}{red}

\input{mp}

\colorlet{mcfpusharrowcolor}{red}
\colorlet{mcfbgcolor}{yellow}
\begin{center}
\begin{tikzpicture}[help lines, x=1cm, y=1cm]

\draw[help lines] (0,0) grid (6,3);
\node[anchor=south west, inner sep=10pt] at (1,0) {\chemfig{!{mp}}};

\mcfpush{mp12-13}{60:1.5em}{mp11-12}{60:1.5em}
\mcfpush[-4pt][4pt]{mp2-3}{105:1.5em}{mp3}{105:1.5em}

\end{tikzpicture}
\end{center}