Biimidazole and Bis(amide)bipyridine Molybdenum Carbonyl Complexes as Anions Receptors

Abstract

Compounds [Mo(CO)4(N-N)] (N-N = 4,4'-bis((4-methylphenyl)carbamoyl)-2,2'-bipyridine, bipy', 1; or 2,2'-biimidazole, H2biim, 2), [MoCl(eta3-methallyl)(CO)2(N-N)] (N-N = bipy', 3; H2biim, 4), and [Mo(eta3-methallyl)(CNtBu)(CO2)(N-N)]BAr'4 (Ar' = 3,5-bis(trifluoromethyl)phenyl; N-N= bipy', 5; H2biim, 6) were synthesized and characterized, and their behavior toward anions was investigated in solution (IR and 1H NMR) and in solid state (X-ray diffraction).

Imidazole to NHC Rearrangements at Molybdenum Centers: An Experimental and Theoretical Study

“…The IR spectra in the carbonyl region show two intense bands for the cis-{Mo(CO) 2 } moiety, at 1951, 1867 cm À1 (1) and 1954, 1869 cm À1 (2), in accordance with their formulation as cationic complexes of the {MoA C H T U N G T R E N N U N G (h 3 -allyl)A C H T U N G T R E N N U N G (bipy)(CO) 2 } fragment. [11] The 1 H and 13 C NMR spectra of compounds 1 and 2 show the presence of a molecular mirror plane, and the incorporation of one N-alkylimidazole ligand per metal fragment (see the Experimental Section). The addition of the equimolar amount of a strong base to a solution of compound 1 in tetrahydrofuran caused the deprotonation of the C2 À H group of the N-methylimidazole ligand, affording the imidazol-2-yl complex 3 (Scheme 3).…”

Artificial Receptors for the Recognition of Phosphorylated Molecules

“…630 A specific combination of amide functionality and molybdenum metal-carbonyl fragments was used to produce receptors 581 . These systems are of interest because they might allow anion binding to be monitored via IR spectroscopy.…”

Anion receptor coordination tripods capped by [9]ane-S3

“…contribution from a 2:1 host:guest species was also included, 21 = 6.5(3) to model the data however the fit remained unsatisfactory. Overall, the complexes show significantly higher affinity than related metal complexes with only a single pyridyl ligand, 23 which are found to bind only very weakly. This is likely to be a The presence of a 1:2 host:guest species in many cases may indicate the possibility of anions either binding separately to different pyridyl ligands or nestling within the CH binding pocket of the [9]ane-S 3 in a similar way to the X-ray crystal structure of 1 and the related [9]ane-S 3 capped palladium complex.…”

“…14, 15, [21][22][23][24][25] Square planar palladium(II) and platinum(II) species have been used to form dipodal and tetrapodal molecular tweezers, 14,[26][27][28] and other more labile ion such as silver(I) have also been investigated.…”