this question has been asked in this link: Forked arrows with chemfig It is very helpful for me. I would like to thank Gonzalo Medina for his solution. However, I have two questions that I cannot find any solution anywhere.
1) How to make \chemfig work properly inside tikzpicture?
I want to have a chemical structure (which is drawn by chemfig) above and below the arrow. However when I use \chemfig{...}
all the bonds turn to arrow. I think it is because this command stays inside the \draw
command.
2) How can I change the length of only the arrow part (the line still the same) to fit the content of the node above/ below the arrow.
Here is the scheme I want to make:
Thanks a ton!
Here is my tex file:
\documentclass[class=minimal,border=0pt,10pt]{standalone}%[a4paper]
\usepackage{chemfig,chemmacros}
\usepackage{tikz}
\usetikzlibrary{arrows,positioning,calc}
\begin{document}
\begin{tikzpicture}[node distance=0cm and 2cm]
%\tikzset{myarrow/.style={->, >=latex', shorten >=1pt, thick},mylabel/.style={text width=7em, text centered} }
\setcrambond{4pt}{}{}
%\setarrowoffset{10pt}
\node (A)
{\chemfig{-[:-15,0.5,,,dash pattern = on 2pt off 2pt]O-[:15,0.5]?[A]<[:-60](-[:165,0.6]HO)-[:15,,,,line width = 4pt](-[:-60,0.6]OH)>[:-15](-[:15,0.5]O-[:-15,0.5,,,dash pattern=on 2pt off 2pt])-[:120]O-[:-165]?[A]}};
%===================================
\node [above right= of A](B)
{\hspace{2cm}\chemfig{-[:-15,0.5,,,dash pattern = on 2pt off 2pt]O-[:15,0.5]?[A]<[:-60](-[:165,0.6]RO)-[:15,,,,line width = 4pt](-[:-60,0.6]O(-[:-90,0.5]-[:-130,0.5](-[:-80,0.6]\chemabove{O}{\hspace{4mm}\scriptstyle\ominus})=[:160,0.6]O))>[:-15](-[:15,0.5]O-[:-15,0.5,,,dash pattern=on 2pt off 2pt])-[:120]O-[:-165]?[A]}};
%===================================
\node[below=of B, align=left](B1){R=H or \ch{CH2COONa} \\depending on DS}; %align=left to use \\ inside node
%===================================
\node[below=0.5 of B1](C)
{\hspace{2cm}\chemfig{-[:-15,0.5,,,dash pattern = on 2pt off 2pt]O-[:15,0.5]?[A]<[:-60](-[:165,0.6]RO)-[:15,,,,line width = 4pt](-[:-60,0.6]O(-[:-120,0.5]-[:-60,0.5](-[,0.4]OR)-[:-120,0.5]-[:-60,0.6]\chemabove{N}{\hspace{-5mm}\scriptstyle\oplus}{(}CH_3{)}_3\chemabove{Cl}{\hspace{4mm}\scriptstyle\ominus}))>[:-15](-[:15,0.5]O-[:-15,0.5,,,dash pattern=on 2pt off 2pt])-[:120]O-[:-165]?[A]}}; %{(} or {)} for sth like N(CH3)3Cl inside chemfig
%===================================
\node[below=of C, align=left](C1)
{\hspace{1cm} R=H, \chemfig{-[:30,0.5](-[:90,0.4]OR)-[:-30,0.5]-[:30,0.6]\chemabove{N}{\hspace{-5mm}\scriptstyle\oplus}{(}CH_3{)}_3\chemabove{Cl}{\hspace{5mm}\scriptstyle\ominus}}\\ \hspace{1.1cm}depending on MS};
%===================================
\node[below=0.5 of C1](D)
{\hspace{2cm}\chemfig{-[:-15,0.5,,,dash pattern = on 2pt off 2pt]O-[:15,0.5]?[A]<[:-60](-[:165,0.6]RO)-[:15,,,,line width = 4pt](-[:-60,0.6]O(-[:-30,0.6]SO_3Na))>[:-15](-[:15,0.5]O-[:-15,0.5,,,dash pattern=on 2pt off 2pt])-[:120]O-[:-165]?[A]}};
%===================================
\node[below=of D](D1)
{R=H, \ch{SO3Na}};
%===================================
\node[below=0.5 of D1](E)
{\hspace{3cm}\chemfig{-[:-15,0.5,,,dash pattern = on 2pt off 2pt]O-[:15,0.5]?[A]<[:-60](-[:165,0.6]RO)-[:15,,,,line width = 4pt](-[:-60,0.6]O(-[:-30,0.5]-[:30,0.5]-[:-30,0.5]-[:30,0.5]-[:-30,0.6]\chemabove{N}{\hspace{-5mm}\scriptstyle\oplus}{(}CH_3{)}_3\chemabove{Cl}{\hspace{5mm}\scriptstyle\ominus}))>[:-15](-[:15,0.5]O-[:-15,0.5,,,dash pattern=on 2pt off 2pt])-[:120]O-[:-165]?[A]}};
%===================================
\node[below=of E](E1)
{R=H, \chemfig{(=[:90,0.4]O)-[:-30,0.5]-[:30,0.5]-[:-30,0.5]-[:30,0.6]\chemabove{N}{\hspace{-5mm}\scriptstyle\oplus}{(}CH_3{)}_3\chemabove{Cl}{\hspace{5mm}\scriptstyle\ominus}}};
%\draw[myarrow] (A.east) -- ++(0.5,0) -- ++(0,1) |-(B.west);
%===================================
\draw[-stealth](A) --($(A.0)!0.5!(B.west|-A.0)$) |- (B.west) node[above]{\ch{ClCH2COONa}}node[below,align=left]{aq. \ch{NaOH}\\slurry medium};
%===================================
\draw[-stealth](A) -- ($(A.0)!0.5!(C.west|-A.0)$) |- (C.west) node[above]{\chemfig{?-[:90,0.5]O-[:-30,0.5]?-[:-30,0.5]-[:30,0.6]\chemabove{N}{\hspace{-5mm}\scriptstyle\oplus}{(}CH_3{)}_3\chemabove{Cl}{\hspace{5mm}\scriptstyle\ominus}}} node[below,align=left]{aq. \ch{NaOH}\\slurry medium};
%===================================
\draw[-stealth](A) -- ($(A.0)!0.5!(D.west|-A.0)$) |- (D.west) node[above,align=left]{(i) \ch{SO3}.DMF or \ch{SO3}.pyridine\\(DMF/LiCl) 50 \si{\degreeCelsius})}node[below,align=left]{(ii) \ch{NaOH}};
%===================================
\draw[-stealth](A) -- ($(A.0)!0.5!(E.west|-A.0)$) |- (E.west) node[above,align=left]{\chemfig{HO-[:30,0.5](=[:90,0.4]O)-[:-30,0.5]-[:30,0.5]-[:-30,0.5]-[:30,0.6]\chemabove{N}{\hspace{-5mm}\scriptstyle\oplus}{(}CH_3{)}_3\chemabove{Cl}{\hspace{5mm}\scriptstyle\ominus}}}node[below,align=left]{DMSO, CDI \\ 20 h, 70 \si{\degreeCelsius}};
\end{tikzpicture}
\end{document}