Superconductivity in Nb$_3$Pd$_{0.75}$Se$_7$

Here, we report the discovery of superconductivity in the transition metal chalcogenide Nb$_3$Pd$_{0.75}$S$_7$ with a transition temperature $T_c = 1.9 $ K. In extremely thin, needle like single crystals we observe upper critical fields $H_{c2}^b(T \rightarrow 0$ K) $\simeq 14 $ T for fields directed along the needle axis, or the crystallographic \emph{b}-axis. This value is 4 times larger than the expected weak coupling Pauli limiting field. For fields applied along two directions perpendicular to the \emph{b}-axis, we observe considerably smaller but anisotropic upper critical fields. For fields along and perpendicular to the $b$-axis we observe a temperature-dependent anisotropy $\gamma = H_{c2}^b/H_{c2}^{\perp b}$ as large as 6 (as $T \rightarrow T_c$). This behavior suggests that this compound is a multi-band superconductor. The low symmetry of its crystallographic structure implying low electronic dimensionality, coupled to multi-band behavior and very high upper critical fields, suggests an unconventional superconducting ground-state.