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2,2′‐Azobispyridine in Phosphorus Coordination Chemistry: A New Approach to 1,2,4,3‐Triazaphosphole Derivatives
Author(s) -
Panova Yulia S.,
Sheyanova Alexandra V.,
Zolotareva Nataliya V.,
Sushev Vyacheslav V.,
Arapova Alla V.,
Novikov Alexander S.,
Baranov Evgenii V.,
Fukin Georgy K.,
Kornev Alexander N.
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201800831
Subject(s) - chemistry , triethylamine , intramolecular force , yield (engineering) , adduct , ligand (biochemistry) , medicinal chemistry , hydrazine (antidepressant) , derivative (finance) , stereochemistry , organic chemistry , biochemistry , materials science , receptor , chromatography , economics , financial economics , metallurgy
Oxidative addition of 2,2′‐azobispyridine ( abpy ) to PCl 3 in CH 2 Cl 2 or THF gave the 1:1 addition product, containing phosphorus in high oxidation state (+5) and a reduced form of the ligand. 2,2′‐Hydrazobispyridine ( hbpy ) was prepared by reduction of abpy with hydrazine‐hydrate in 63 % yield. Interaction of hbpy with PCl 3 in the presence of triethylamine gave ( abpy ) 2– PCl ( 2 ) in 25 % preparative yield. A similar reaction of hbby with (Et 2 N) 2 PCl afforded ( abpy ) 2– PNEt 2 ( 4 ) in 89 % yield. Compound 4 after work‐up with PCl 3 or PBr 3 gave 2 and ( abpy ) 2– PBr ( 6 ) respectively in high yields. Diethylamino‐derivative 4 formed (κ 2 ‐ N , N ) adduct with SiCl 4 7 (coordination by Py and azo‐functions), while the chloro‐derivative 2 did not. Reaction of 2 with PCl 5 is accompanied with liberation of PCl 3 and formation of spirocyclic ate complex [( abpy ) 2– 2 P] + PCl 6 – . All structurally characterized compounds demonstrated short distances between pyridyl nitrogen and the phosphorus atom. However, the QTAIM analysis did not reveal the presence of appropriate bond critical points (3, –1) for the intramolecular noncovalent interactions N ··· P in 2 , 4 , and 6 . We theoretically estimated values of the rotation barriers for the pyridyl and Et 2 N moieties in 4 using the relaxed potential energy surface scan at the B3LYP/6‐31G(d) level of theory. The values of rotation barriers are very close to each other, viz. 13.2 (pyridyl) and 13.0 (Et 2 N) kcal/mol.