Wall, molecules and drawing with tikz/chemfig

Question

I would like to get to this result:

This is the code till now:

\documentclass[10pt, a4paper]{article}
\usepackage{lipsum}
\usepackage[utf8]{inputenc}
\usepackage{chemfig,stackengine,graphicx}
\usepackage{xcolor,tikz}
\usepackage[version=3]{mhchem}

\begin{document}
\lipsum[10]
\begin{align}
\ce{HCN + H_2O \rightleftharpoons H_3O^+ + CN^-}\\
\schemestart[-45]
 \chemfig{**6(--(-CH_3)---(-)-)}
\schemestop
\end{align}
\lipsum[20]

\end{document}

Where I need your help

• making the inner circle of the benzene ring a little smaller
• turn the molecule a little, so it looks like on the image
• draw the wall (left in the picture), connected to the molecule

In the meantime, thank you so much for your attention and participation.

Answer 1

Here is a “chemfig only” idea:

\documentclass{article}
\usepackage{chemfig}

\definesubmol{wallpart}{-[:-90,.5](-[:110,.5])}
\definesubmol{wall}{!{wallpart}!{wallpart}!{wallpart}}

\begin{document}

\chemfig{
  !{wall}
  (-[:0]**6(---(-CH_3)---))
  !{wall}
}

\end{document}

As far as I know the size of the circle (relative to the size of the ring) is controlled by the parameter \CF@cycle@inraduiscoeff. Its initial value is 0.75. Defining it to some smaller value scales the circle down. Here is how the above looks with

\makeatletter
\def\CF@cycle@inraduiscoeff{0.6}
\makeatother

However, there is no official interface for this parameter so it might or might not be available in future versions…

Answer 2

I don't know how to do the chemistry part of the problem (changing the -45 seemed to have no effect, so I just rotated what was provided), but the wall can be emulated with a stack of slashes / and a \rule.

\documentclass[10pt, a4paper]{article}
\usepackage{lipsum}
\usepackage[utf8]{inputenc}
\usepackage{chemfig,stackengine,graphicx}
\usepackage{xcolor,tikz}
\usepackage[version=3]{mhchem}

\begin{document}
\lipsum[10]

{\centering\Longstack{/ / / / / /}\kern-1pt\rule[-2pt]{1pt}{6\baselineskip}\rotatebox{30}{%
\schemestart[-45]
 \chemfig{**6(--(-CH_3)---(-)-)}
\schemestop
}\par}

\lipsum[20]

\end{document}