i have prepared one manganese complex from N,N-bis(picolinyldene) hydrazine and 2-pyridinealdimine. in the absence of Mn(II) they do not react to yield the ligand. for more information i attached this journal.
You said . in the absence of Mn(II) they do not react to yield the ligand. Is your problem to prepare the ligand?. Could you please, define which ligand you couldn't prepare it?
Please, find in attach, a paper on: Isolation of a Manganese Complex of a Tridentate Azo-aromatic Ligand from an Unusual Mn2(CO)10 Promoted Simultaneous Reductive Azo Cleavage and Aromatic Ring Amination Reactions
I've checked the paper you've attched. You may try to mix N,N-bis(picolinyldene) hydrazine and 2-pyridinealdimine (1:1) and fuse it without solvent under reflux for 2-4h. and leave it in refrigirator for some days and see what happen.