= Solution
Both complexes contain <cobalt>(III), hence a $d^6$ metal ion. The approximately <octahedral molecular geometry>, relatively high metal <oxidation state> and five <ammonia> donors make the <octahedral splitting> large enough that pairing is favorable. Their low-spin configuration is
$$
\boxed{t_{2g}^{6}e_g^{0},\qquad S=0.}
$$
All six metal $d$ <electrons> are paired, and the <ligands in coordination chemistry> have closed shells, so neither complex has a permanent spin <magnetic moment>: both exhibit <diamagnetism>. The difference between N and O attachment is insufficient to change this low-spin assignment.
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