A complex of the following Formula I: M, in which A. M is a metal atom selected from copper and silver; L is a cyclic alkyl amino carbene (CAAC) ligand having a saturated cyclic structure in which the atoms of the ring which includes the carbene site consist of carbon atoms and one nitrogen atom; and X is a monoanionic ligand; or B. M is a gold atom; L is a cyclic alkyl amino carbene (CAAC) ligand having a saturated cyclic structure in which the atoms of the ring which includes the carbene site consist of carbon atoms and one nitrogen atom; and X is a monoanionic amide ligand having the formula R'-N-R" or N in which R' and R" are selected from hydrogen and organic groups, which when both organic groups may be the same or different; and represents a cyclic organic group which may contain one or more rings; excluding the compound Ad L-Au-NTf 2 in which Ad L is and Tf is CF 3 -SO 2 -; and excluding the compound Ad L-Ag-Cl in which Ad L has the same meaning; and excluding the compounds wherein Dipp is 2,6-diisopropylphenyl; and excluding the compounds wherein R is i Pr and Ar is 2,6- i Pr 2 C 6 H 3 and excluding the compounds A. M is a metal atom selected from copper and silver; L is a cyclic alkyl amino carbene (CAAC) ligand having a saturated cyclic structure in which the atoms of the ring which includes the carbene site consist of carbon atoms and one nitrogen atom; and X is a monoanionic ligand; or M is a metal atom selected from copper and silver; L is a cyclic alkyl amino carbene (CAAC) ligand having a saturated cyclic structure in which the atoms of the ring which includes the carbene site consist of carbon atoms and one nitrogen atom; and X is a monoanionic ligand; or B. M is a gold atom; L is a cyclic alkyl amino carbene (CAAC) ligand having a saturated cyclic structure in which the atoms of the ring which includes the carbene site consist of carbon atoms and one nitrogen atom; and X is a monoanionic amide ligand having the formula R'-N-R" or N in which R' and R" are selected from hydrogen and organic groups, which when both organic groups may be the same or different; and represents a cyclic organic group which may contain one or more rings; excluding the compound Ad L-Au-NTf 2 in which Ad L is and Tf is CF 3 -SO 2 -; and excluding the compound Ad L-Ag-Cl in which Ad L has the same meaning; and excluding the compounds wherein Dipp is 2,6-diisopropylphenyl; and excluding the compounds wherein R is i Pr and Ar is 2,6- i Pr 2 C 6 H 3 and excluding the compounds M is a gold atom; L is a cyclic alkyl amino carbene (CAAC) ligand having a saturated cyclic structure in which the atoms of the ring which includes the carbene site consist of carbon atoms and one nitrogen atom; and X is a monoanionic amide ligand having the formula R'-N-R" or N in which R' and R" are selected from hydrogen and organic groups, which when both organic groups may be the same or different; and represents a cyclic organic group which may contain one or more rings; excluding the compound Ad L-Au-NTf 2 in which Ad L is and Tf is CF 3 -SO 2 -; and excluding the compound Ad L-Ag-Cl in which Ad L has the same meaning; and excluding the compounds wherein Dipp is 2,6-diisopropylphenyl; and excluding the compounds wherein R is i Pr and Ar is 2,6- i Pr 2 C 6 H 3 and excluding the compounds