The first part of this work describes the synthesis of several bidentate and tridentate pincer ligands, based on 2,6-diaminopyridine and 2-aminopyridine, featuring phosphines, sulphides and amines as two-electron donor groups. The preparation is carried out by the reaction of 2,6-diaminopyridine and 2-aminopyridine, respectively, with chlorophosphines PR2Cl in the presence of a base. The ligands were then modified by selective oxidation of the phosphorous using elemental sulphur or hydrogen peroxide in order to modify coordination properties. Additionally, chiral precursors were used for the synthesis of chlorophosphites PR*2Cl, which lead to the formation of chiral PNP ligands. In the second and third part, several bidentate complexes were synthesized by the treatment of FeX2 with 1 or 2 equivs of PN and SN ligands, forming complexes of the overall type Fe(PNR-Ph)2X2 for the PN ligands, and, Fe(SNR-Ph)X2 for the SN ligands, respectively. The behaviour of these complexes was then investigated in solution and solid state by NMR, Mössbauer, mass and magnetic spectroscopy, and the experimental results were compared with DFT calculations. The fourth part focuses on the synthesis of tridentate PNP pincer complexes with the overall form Fe(PNPR-iPr)X2 and PNN complexes of the type Fe(PNN-iPr)X2, respectively. Reactivity with carbon monoxide was investigated, leading to the complexes cis,trans-[Fe(PNPR-iPr)(CO)X2] and trans-[Fe(PNPR-iPr)(CO)2X]+, which were characterized by NMR spectroscopy and single crystal XRD. In the fifth part, TADDOL based PNP pincer ligands were utilized to form chiral complexes of the type K2P,N-[Fe(PNP-iPr/TAD)X2] and K2P,N-[Fe(PNP-tBu/TAD)X2]. Their behaviour in solution and solid state was investigated by Mössbauer and NMR spectroscopy, showing an equilibrium between K2 and K3 coordination mode. Furthermore, the reaction with carbon monoxide leaded to the formation of the complexes K3P,N,P-[Fe(PNP-iPr/TAD)(CO)X2], which were then unsuccessfully used to form the hydride complex K3P,N,P-[Fe(PNP-iPr/TAD)(H)(CO)Br]. In the last part, PNP-BINEP ligands were treated with FeX2 to form chiral complexes Fe(PNP-iPr/BIN)X2. Finally, these complexes reacted with CO and Na[(H)BEt3)], leading to the formation of the chiral hydride Fe(PNP-iPr/BIN)(H)(CO)Br, which was then successfully used as catalyst in the homogeneous hydrogenation of ketones to alcohols.