  We report the observation of superconductivity in the CuIr2Se4 spinel induced
by partial substitution of Pt for Ir. The optimal doping level for
superconductivity in Cu(Ir1-xPtx)2Se4 is x = 0.2, where Tc is 1.76 K. A
superconducting Tc vs. composition dome is established between the metallic,
normal conductor CuIr2Se4 and semiconducting CuIrPtSe4. Electronic structure
calculations show that the optimal Tc occurs near the electron count of a large
peak in the calculated electronic density of states and that CuIrPtSe4 is a
band-filled insulator. Characterization of the superconducting state in this
heavy metal spinel through determination of {\Delta}C/{\gamma}Tc, indicates
that it is BCS-like. The relatively high upper critical field at the optimal
superconducting composition (Hc2(0) = 3.2 T) is much larger than that reported
for analogous rhodium spinels and is comparable to or exceeds the Pauli field
(mu0Hp), suggesting that strong spin orbit coupling may influence the
superconducting state. Further, comparison to doped CuIr2S4 suggests that
superconductivity in iridium spinels is not necessarily associated with the
destabilization of a charge-ordered spin-paired state through doping.
