Metal complex having at least one N-aminoguanidinate ligand, wherein this metal complex is of the following formula 1a or 1b wherein M is selected from the group of lanthanides, actinides, boron, gallium (Ga), indium (In), silicon (Si), germanium (Ge), tin (Sn), arsenic (As), antimony (Sb), titanium (Ti), zirconium (Zr), hafnium (Hf), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), and platinum (Pt), R 1 is hydrogen or a cyclic, linear or branched alkyl radical having up to 5 carbon atoms, NH 2, NH(CH 3), N(CH 3) 2, N(C 2 H 5) 2 or N-pyrrolidinyl, or R 1 and R 2 together with the nitrogen atom they are bonded to form a pyrrolidinyl ring; R 2 is hydrogen or a cyclic, linear or branched alkyl radical having up to 5 carbon atoms, or R 2 and R 1 together with the nitrogen atom they are bonded to form a pyrrolidinyl ring; R 3 is hydrogen or a cyclic, linear or branched alkyl radical having up to 8 carbon atoms, NH 2, NH(CH 3), N(CH 3) 2, N(C 2 H 5) 2 or N-pyrrolidinyl or a SiMe3 group, R 4 and R 5 independently of one another are hydrogen or a linear or branched alkyl radical having up to 4 carbon atoms, or R 4 and R 5 together with the nitrogen atom they are bonded to form a pyrrolidinyl ring; X is a monoanionic co-ligand selected from the hydride anion (H -), from the group of the halides, from the group of the cyclic, linear or branched alkylides having up to 8 carbon atoms, from the group of substituted or unsubstituted arylides and heteroarylides having up to 10 C atoms, from the group of alkoxylato ligands, from the group of alkylthiolato or alkylselenolato ligands or from the group of secondary amido ligands, Y is a dianionic coligand selected from the oxo group 2-, the sulfido group 2- or the imido group [NR 6] 2-, where R 6 is a cyclic, branched or linear alkyl having up to 8 carbon atoms or is a substituted or unsubstituted aryl having up to 20 carbon atoms, L is a neutral 2-electron donor ligand, a is an integer between 1 and 4 and n, m, and p each independently of one another are 0, 1, 2, 3 or 4. M is selected from the group of lanthanides, actinides, boron, gallium (Ga), indium (In), silicon (Si), germanium (Ge), tin (Sn), arsenic (As), antimony (Sb), titanium (Ti), zirconium (Zr), hafnium (Hf), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), and platinum (Pt), R 1 is hydrogen or a cyclic, linear or branched alkyl radical having up to 5 carbon atoms, NH 2, NH(CH 3), N(CH 3) 2, N(C 2 H 5) 2 or N-pyrrolidinyl, or R 1 and R 2 together with the nitrogen atom they are bonded to form a pyrrolidinyl ring; R 2 is hydrogen or a cyclic, linear or branched alkyl radical having up to 5 carbon atoms, or R 2 and R 1 together with the nitrogen atom they are bonded to form a pyrrolidinyl ring; R 3 is hydrogen or a cyclic, linear or branched alkyl radical having up to 8 carbon atoms, NH 2, NH(CH 3), N(CH 3) 2, N(C 2 H 5) 2 or N-pyrrolidinyl or a SiMe3 group, R 4 and R 5 independently of one another are hydrogen or a linear or branched alkyl radical having up to 4 carbon atoms, or R 4 and R 5 together with the nitrogen atom they are bonded to form a pyrrolidinyl ring; X is a monoanionic co-ligand selected from the hydride anion (H -), from the group of the halides, from the group of the cyclic, linear or branched alkylides having up to 8 carbon atoms, from the group of substituted or unsubstituted arylides and heteroarylides having up to 10 C atoms, from the group of alkoxylato ligands, from the group of alkylthiolato or alkylselenolato ligands or from the group of secondary amido ligands, Y is a dianionic coligand selected from the oxo group 2-, the sulfido group 2- or the imido group [NR 6] 2-, where R 6 is a cyclic, branched or linear alkyl having up to 8 carbon atoms or is a substituted or unsubstituted aryl having up to 20 carbon atoms, L is a neutral 2-electron donor ligand, a is an integer between 1 and 4 and n, m, and p each independently of one another are 0, 1, 2, 3 or 4.