  We report the synthesis, crystal structure, and superconductivity of
Ti$_4$Ir$_2$O. The title compound crystallizes in an $\eta$-carbide type
structure of the space group $Fd\overline{3}m$ (No. 227), with lattice
parameters $a=b=c=11.6194(1)$ \AA. The superconducting $T_c$ is found to be 5.1
$\sim$ 5.7 K. Most surprisingly, Ti$_4$Ir$_2$O hosts an upper critical field of
16.45 T, which is far beyond the Pauli paramagnetic limit. Strong coupled
superconductivity with evidences for multigap is revealed by the measurements
of heat capacity and upper critical field. First-principles calculations
suggest that the density of states near the Fermi level originates from the
hybridization of Ti-3$d$ and Ir-5$d$ orbitals, and the effect of spin-orbit
coupling on the Fermi surfaces is prominent. Large values of the Wilson ratio
($R_W$ $\sim$ 3.9), the Kadowaki-Woods ratio ($A/\gamma^2$ $\sim$ 9.0 $\times$
10$^{-6}$ $\mu\Omega$ cm/(mJ mol$^{-1}$ K$^{-1}$)$^2$), and the Sommerfeld
coefficient ($\gamma$ = 33.74 mJ mol$^{-1}$ K$^{-2}$) all suggest strong
electron correlations (similar to heavy fermion systems) in Ti$_4$Ir$_2$O. The
violation of Pauli limit is possibly due to a combination of strong-coupled
superconductivity, large spin-orbit scattering, and electron correlation. With
these intriguing behaviors, Ti$_4$Ir$_2$O serves as a candidate for
unconventional superconductor.
