如何在 chemfig 上获取钩状键的名称？

Question

我不知道@{l4}为键创建名称的正确语法。我想将最后一个箭头向前置于虚线键上。

%%%%%%%%%%%% ETEP 1 %%%%%%%%%%%%%%%%%%%%%% 
\chemfig{M(
-[@{l2}2,,,,dotted]H
-[@{l1}:10]@{carb1}\charge{135:10pt=$\delta^+$}{}([2]-{})
-[:-10]@{ox1}\charge{45:5pt=$\delta^-$}{O}?[Lacid2] 
-[@{l3}:10]H?[Lbasic2])
-O-M?[Lacid2,{1,,,,dotted}]-O?[Lbasic2, {1,,,,dotted}]
} 

\schemestop
%\chemmove[⟨opt⟩]{\draw[⟨tikz opt⟩](⟨name1⟩)⟨tikz link⟩(⟨name2⟩);}
\chemmove[red, shorten <=2pt]{
\draw(ox1)..controls +(90:1cm)and+(north east:2cm)..(carb1);
\draw(l1)..controls +(270:.25cm)and+(east:2cm)..(l2);
\draw(l3)..controls +(270:.25cm)and+(west:2cm)..(l4)}

Answer 1

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc}
\usepackage{chemfig}
\begin{document}
\schemestart
\chemfig{M(
    -[@{l2}2,,,,dotted]H
    -[@{l1}:10]@{carb1}\charge{135:10pt=$\delta^+$}{}([2]-{})
    -[:-10]@{ox1}\charge{45:5pt=$\delta^-$}{O}?[Lacid2]
    -[@{l3}:10]@{h}H?[Lbasic2])
    -O-M?[Lacid2,1,dotted]-@{o}O?[Lbasic2,{-},dotted]
}
\schemestop
\chemmove[red, shorten <=2pt]{
    \coordinate (l4) at ($(o)!0.5!(h)$);
    \draw (ox1) .. controls +(90:1cm) and +(north east:2cm) .. (carb1);
    \draw (l1) .. controls +(270:.25cm) and +(east:2cm) .. (l2);
    \draw (l3) .. controls +(270:.3cm) and +(180:1cm) .. (l4);
    }
\end{document}