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如何使用 chemfig 将双键的一部分加粗？

tag-icon • tag-icon tikz-pgf chemfig
如何使用 chemfig 将双键的一部分加粗？

我正在尝试获得这种化学结构的外观（参见突出显示的区域）：

在此处输入图片描述

到目前为止我可以这样做：

在此处输入图片描述

这是我的代码：

\documentclass[12pt]{standalone}
\usepackage{tikz}
\usepackage{fontspec}
\setmainfont{Times New Roman} 

\usepackage{chemfig}
\usepackage[version=3]{mhchem}
\usetikzlibrary{arrows,shadows,calc,shapes,backgrounds,intersections,positioning} 
\makeatletter
\def\CF@node@content{%
\expandafter\expandafter\expandafter
\printatom\expandafter\expandafter\expandafter
{\csname atom@\number\CF@cnt@atomnumber\endcsname}%
\ensuremath{\CF@node@strut}%
}
\makeatother
\setdoublesep{0.35700 em}  % 'Bond Spacing'
\setatomsep{1.78500 em}    % 'Fixed Length'
\setbondoffset{0.18265 em} % 'Margin Width'
\newcommand{\bondwidth}{0.06642 em} % 'Line Width'
\setbondstyle{line width = \bondwidth}
\renewcommand*{\printatom}[1]{{\sffamily\cf{#1}}}
\begin{document}
\begin{tikzpicture}[font=\small ,line width=1pt,node distance=1cm, inner sep=-0.05cm]
\node[anchor=north] at(0,0){ 
\chemname{
\chemfig{[:135]Ru?[o](-[,2.2]N*6([:80]=-=-*6(=<=>(-*6([:-120]-=(-*6(-=-(-*6(=*6(-=-=-)-=-*6(-=-=-)=-))=-=-))-=([:-80]-*6(=-=-*6(-=-[,,,,line width=2pt]=N?[o,{-}]-)=-))-N?[o,{-}]=))=)--))([:45]-[,2.2]N*6([:100]-*6(-(-*6([:-60]-N?[o,{-}]=([:-100]-*6(=*6(-N?[o,{-}]=-=-)-=<=>-))-=(-*6(=-=(-*6(-*6(-=-=-)=-=*6(-=-=-)-=))-=-))-=))=-@{tr}=-=)--=-[,,,,line width=2pt]=))}}{\textbf{\large 2}}
\chemmove{\draw[very thick,inner sep=0pt](tr)++(1cm,-.1cm)--++(0,2em)node[anchor=north west,yshift=-4mm]{$\sf \left(PF_{6}\right)_2$}--++(-2em,0);}
};
\path (0,.5)--++(2,0);
\path (0,-6.5)--++(1,0);
\end{tikzpicture}
\end{document}

如何使用 chemfig 实现我想要的外观？

答案1

我会用线宽命令绘制粗体单键-[,,,,line width=2pt]。可以通过在双键上向后（角度 = 180°）绘制粗体单键来实现粗体双键：-[::180,,,,line width=2pt]。

以下是一个例子：

\documentclass[a4paper]{scrreprt}
\usepackage[utf8]{inputenc}

\usepackage{chemfig}
\renewcommand*\printatom[1]{\small\ensuremath{\mathsf{#1}}}
\setatomsep{16.5pt}
\setbondstyle{line width=0.6pt}
\setcrambond{3pt}{0.6pt}{1.5pt}
\setdoublesep{2.6pt}
\setbondoffset{1.6pt}
\setarrowdefault{,1.0,}

\begin{document}

\chemfig{*6(=(-[::180,,,,line width=2pt])-(*6(=-=(-NH_2)-(-*6(=(-NHTs)(-[::180,,,,line width=2pt])-[,,,,line width=2pt]=(-[::180,,,,line width=2pt])-(*6(=-=-=-))--))=-))--=(-[::180,,,,line width=2pt])-[,,,,line width=2pt])}

\end{document}

具有轴手性的结构示例

答案2

我取得了不错的成果。这是我注释的代码：

\documentclass[10pt]{article}
\pagestyle{empty} % required
\usepackage{chemfig}

\renewcommand{\familydefault}{\sfdefault}
\usepackage[scaled=1]{helvet}
\usepackage[helvet]{sfmath}
\everymath={\sf}

\begin{document}
    \setchemfig{
        atom sep=15pt,
        double bond sep=2.6pt,
        bond join=true,
        cram width=3.0pt,
        cram dash width=0.75pt,
        cram dash sep=2.0pt
    }

    \chemfig{
        Ru?[Ru] % central atom (with hook)
        % 1st moiety (left)
        (-[:180,3.25,,,dash pattern=on 2pt off 2pt] % long dashed bond to pyridyl  left ring
        N*6(=( % pyridyl ring
        -[::-45] % to avoid stay too close to Ru atom
        *6(=( % 1st 8-quinolyl ring (upper left benzene ring)
        *6(-N?[Ru,,{dash pattern=on 2pt off 2pt}]=-=-) % 8-quinolyl (pyridine ring, with hook to Ru bond)
        )-=<=( % 1st 8-quinolyl ring (continuation)
        -[::0,0.1,,,draw=none]-[::180,1.2,,,line width=2pt] % bold bond as a branch
        )>)) % 1st 8-quinolyl (end)
        -=(-R_{1})-= % pyridyl (continuation)
        (-[::-75] % to avoid stay too close to Ru atom
        *6(=-=-( % 2nd 8-quinolyl ring (lower left)
        *6(- % benzene ring
        (-[::60,1.01,,,line width=2pt]-[::60,1.01,,,line width=2pt]) % bold bond as a branch
        =-=N?[Ru,,{dash pattern=on 2pt off 2pt}] % 8-quinolyl (pyridine ring, with hook to Ru bond)
        (-[::180,1.05,,,line width=2pt])-))=-)) % bold N= bond as a branch
        -)) % Ending the 1st moiety
        %
        % 2nd moiety (right, same as above)
        (-[:0.0,3.25,,,dash pattern=on 2pt off 2pt]
        N*6(=(
        -[::-45]
        *6(=(
        *6(-N?[Ru,,{dash pattern=on 2pt off 2pt}]=-=-)
        )-=<=(
        -[::0,0.1,,,draw=none]-[::180,1.2,,,line width=2pt]
        )>))
        -=(-R_{2})-=
        (-[::-75]
        *6(=-=-(
        *6(-
        (-[::60,1.01,,,line width=2pt]-[::60,1.01,,,line width=2pt])
        =-=N?[Ru,,{dash pattern=on 2pt off 2pt}]
        (-[::180,1.05,,,line width=2pt])-))=-))
        -))
    }       
\end{document}

最终结果：

在此处输入图片描述

答案3

我并不是 pgf 和 tikz 方面的专家，所以可能可以做得更好。但这是我的解决方案，我定义了一种新的键样式。

灵感来自在没有 tikzset 的情况下在 chemfig 中创建离域双键？和将参数传递给 \pgfdeclaredecoration

\documentclass[a4paper]{article}

\usepackage{chemfig}
\usetikzlibrary{decorations}

\makeatletter
\pgfdeclaredecoration{halfbold}{initial}{%
\state{initial}[width=0.5*\pgfdecoratedpathlength,next state=final]{%
\pgfsetlinewidth{5\pgflinewidth}
\pgfpathmoveto{\pgfpoint{0}{0}}
\pgfpathlineto{\pgfpoint{\pgfdecoratedpathlength}{0}}
\pgfusepathqstroke
\pgfsetlinewidth{\tikzscope@linewidth}
\pgfpathmoveto{\pgfpoint{2pt}{4pt}}
\pgfpathlineto{\pgfpoint{0.9*\pgfdecoratedpathlength}{4pt}}
\pgfusepathqstroke
}
\state{final}{%
\pgfpathmoveto{\pgfpoint{0pt}{0pt}}
\pgfpathlineto{\pgfpoint{0.5*\pgfdecoratedpathlength}{0}}}}
\makeatother

\tikzset{myrbond/.style={decorate, decoration=halfbold}}
\tikzset{mylbond/.style={decorate, decoration={halfbold, mirror}}}

\setatomsep{4em}

\begin{document}

\chemfig{[:-30]R-C-[::60]C(-[::60,,,,,mylbond]O)-[,,,,myrbond]N(-[::-60]H)-[::60]C-R}

\end{document}

您可以调整线条的粗细\pgfsetlinewidth{5\pgflinewidth}以及线条上双键之间的距离

\pgfpathmoveto{\pgfpoint{2pt}{4pt}}
\pgfpathlineto{\pgfpoint{0.9*\pgfdecoratedpathlength}{4pt}}

但我真的不确定，这是否比 @dieg0 提出的解决方案更好（或更好）

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