  The mass, coupling and width of the newly observed charged resonance $
Z_{c}^{-}(4100)$ are calculated by treating it as a scalar four-quark system
with a diquark-antidiquark structure. The mass and coupling of the state $
Z_{c}^{-}(4100)$ are calculated using the QCD two-point sum rules. In these
calculations we take into account contributions of the quark, gluon and mixed
condensates up to dimension ten. The spectroscopic parameters of $
Z_{c}^{-}(4100)$ obtained by this way are employed to study its $S$-wave decays
to $\eta_c(1S)\pi^{-}$, $\eta_c(2S)\pi^{-}$, $D^{0}D^{-}$, and $ J/\psi \rho
^{-}$ final states. To this end, we evaluate the strong coupling constants
corresponding to the vertices $Z_{c}\eta_c(1S)\pi^{-}$, $
Z_{c}\eta_c(2S)\pi^{-}$, $Z_{c}D^{0}D^{-}$, and $Z_{c}J/\psi \rho^{-}$
respectively. The couplings $g_{Z_c\eta_{c1} \pi}$, $g_{Z_{c}\eta_{c2} \pi}$ ,
and $g_{Z_{c}DD}$ are computed by means of the QCD three-point sum rule method,
whereas $g_{Z_{c}J/\psi \rho }$ is obtained from the QCD light-cone sum rule
approach and soft-meson approximation. Our results for the mass $ m=(4080 \pm
150)~\mathrm{MeV}$ and total width $\Gamma =(147 \pm 19)~\mathrm{ MeV}$ of the
resonance $Z_{c}^{-}(4100)$ are in excellent agreement with the existing LHCb
data.
