125330-38-3Relevant academic research and scientific papers
Monomeric and dimeric vanadium(IV) and -(V) complexes of N-(hydroxyalkyl)salicylideneamines: Structures, magnetochemistry, and reactivity
Carrano, Carl J.,Nunn, Christine M.,Quan, Roger,Bonadies, Joseph A.,Pecoraro, Vincent L.
, p. 944 - 951 (2008/10/08)
The N-(hydroxyalkyl)salicylideneamine ligands (H2SALAHE = 2-(salicylideneamino)-1-hydroxyethane; H2SALAHP = 3-(salicylideneamino)-1-hydroxypropane; H2SALAMHP = 2-(salicylideneamino)-2-methyl-1-hydroxypropane; H2SALAMHE = 2-(salicylideneamino)-2-metnyl-1-hydroxyethane [or 2-(salicylideneamino)-1-hydroxypropane]; H2SALATHM = tris(hydroxymethyl)(salicylideneamino)methane) form monomeric and dimeric complexes when reacted with VO2+ salts in organic solvents. When a 2:1 ligand to metal ratio is used in the synthesis, the mononuclear VO(HSALAHE)2 (1) crystallizes as a dark green solid with X-ray diffraction analysis demonstrating it to be a five-coordinate species with the ligands bound in a bidentate fashion by using the phenolate and imine nitrogen atoms. When a 1:1 ligand to metal ratio is used and the reaction maintained strictly anaerobic, a dimer of composition [VO(SALAHE)]2 (3) is recovered. X-ray crystallography demonstrates that the ligand is a tridentate dianion in this complex, which is a dialkoxy-bridged dimer with a syn orientation of vanadyl oxygen atoms. This structure is in contrast to a polymeric material of the same composition [VO(SALAHE)]n (2), which is thought to be an infinite spin ladder. Magnetic exchange in 2 (1.01 μB/V) is slightly greater than in 3 (1.52 μB/V), which probably reflects the larger extent of σ overlap between dxy orbitals of the two vanadium atoms in the planar 2 as opposed to the bent 3. These vanadium(IV) dimers can be converted to an unusual V(V) dimer of composition [VVOL]2O. An X-ray diffraction analysis of the SALAMHP derivative 4c shows that the ligands are again tridentate; however, one alkoxide acts as a weak bridge while the other is nonbridging. The strongest link between the vanadium atoms is a nonlinear oxo group that is part of the V2O34+ core. Crystallographic parameters for 1, 3, and 4c are as follows. VO(SALAHE)2 (1) (C18H20N2O5V): MW, 395.31; a, 10.301 (2) A?; b, 8.733 (3) A?; c, 20.575 (5) A?; β, 104.19 (2)°; V, 1794.4 (6) A?3; monoclinic (P21/c); Z = 4; for 2953 unique data (3 2σ(I), the structure refined to R(Fo) = 0.062. [VO(SALAHE)]2 (3) (C18H18N2O6V2): MW, 460; a, 22.530 (3) A?; 6.530 (6) A?; c, 13.115 (15) A?; β, 93.04 (10)°; V, 1927 (4) A?3; monoclinic (P21/c); Z = 4; for 2510 unique data (0 2σ(I), the structure refined to R(Fo) = 0.077. [VO(SALAMHP)]2O (4c) (C22H26N2O7V2): MW, 532.4; a, 33.929 (6) A?; b, 7.203 (2) A?; c, 19.618 (5) A?; β, 98.97 (2)°; V, 4736.1 (8) A?3; monoclinic (C2/c); Z = 8; for 4248 unique data (3 3σ(I), the structure refined to R(Fo) = 0.052.
