The synthesis and characterization of 6-hydroxymethylpyridine-2-carboxaldehyde (2-methyl-pyrimidine-4,6-diyl)bis(1-methylhydrazone) (1) is reported. Ligand 1 was designed as a ditopic pyrimidine-hydrazone molecular strand with hydroxymethyl groups attached to the terminal pyridine rings. Coordination of 1 with Cu(ClO(4))(2) x 6 H(2)O or Cu(SO(3)CF(3))(2) x 4 H(2)O in a 1:2 molar ratio resulted in the dinuclear Cu(II) complexes [Cu(2)1(CH(3)CN)(4)](ClO(4))(4) x CH(3)CN (4) and [Cu(2)1(SO(3)CF(3))(2)(CH(3)CN)(2)](SO(3)CF(3))(2) x CH(3)CN (5). X-ray crystallography and (1)H NMR NOESY experiments showed that 1 adopted a horseshoe shape with both pyrimidine-hydrazone (pym-hyz) bonds in a transoid conformation, while 4 and 5 were linear in shape, with both pym-hyz bonds in a cisoid conformation. Coordination of 1 with Cu(ClO(4))(2) x 6 H(2)O or Cu(SO(3)CF(3))(2) x 4 H(2)O in a 1:1 molar ratio resulted in three different bent complexes, [Cu(1H)(ClO(4))(2)](ClO(4)) (6), [Cu(1H)(CH(3)CN)](ClO(4))(3) x 0.5 H(2)O (7), and [Cu1(SO(3)CF(3))](2)(SO(3)CF(3))(2) x CH(3)CN (8), where the pym-hyz bond of the occupied coordination site adopted a cisoid conformation, while the pym-hyz bond of the unoccupied site retained a transoid conformation. Both 6 and 7 showed protonation of the pyridine nitrogen donor in the empty coordination site; complex 8, however, was not protonated. A variety of Cu(II) coordination geometries were seen in structures 4 to 8, including distorted octahedral, trigonal bipyramidal, and square pyramidal geometries. Coordination of the hydroxymethyl arm in the mononuclear Cu(II) complexes 6, 7, and 8 appeared to inhibit the formation of a [2 x 2] grid by blocking further access to the Cu(II) coordination sphere. In addition, the terminal hydroxymethyl groups contributed to the supramolecular structures of the complexes through coordination to the Cu(II) ions and hydrogen bonding.

Metal complexation studies were performed with the ditopic pyrimidine-hydrazone (pym-hyz) strand 6-hydroxymethylpyridine-2-carboxaldehyde (2-methyl-pyrimidine-4,6-diyl)bis(1-methylhydrazone) (1) and Pb(ClO(4))(2)·3H(2)O, Pb(SO(3)CF(3))(2)·H(2)O, Zn(SO(3)CF(3))(2), and Zn(BF(4))(2) to examine the ability of 1 to form various supramolecular architectures. X-ray crystallographic and NMR studies showed that coordination of the Pb(II) salts with 1 on a 2:1 metal/ligand ratio in CH(3)CN and CH(3)NO(2) resulted in the linear complexes [Pb(2)1(ClO(4))(4)] (2), [Pb(2)1(ClO(4))(3)(H(2)O)]ClO(4) (3), and [Pb(2)1(SO(3)CF(3))(3)(H(2)O)]SO(3)CF(3) (4). Two unusually distorted [2 × 2] grid complexes, [Pb1(ClO(4))](4)(ClO(4))(4) (5) and [Pb1(ClO(4))](4)(ClO(4))(4)·4CH(3)NO(2) (6), were formed by reacting Pb(ClO(4))(2)·6H(2)O and 1 on a 1:1 metal/ligand ratio in CH(3)CN and CH(3)NO(2). These grids formed despite coordination of the hydroxymethyl arms due to the large, flexible coordination sphere of the Pb(II) ions. A [2 × 2] grid complex was formed in solution by reacting Pb(SO(3)CF(3))(2)·H(2)O and 1 on a 1:1 metal/ligand ratio in CH(3)CN as shown by (1)H NMR, microanalysis, and ESMS. Reacting the Zn(II) salts with 1 on a 2:1 metal/ligand ratio gave the linear complexes [Zn(2)1(H(2)O)(4)](SO(3)CF(3))(4)·C(2)H(5)O (7) and [Zn(2)1(BF(4))(H(2)O)(2)(CH(3)CN)](BF(4))(3)·H(2)O (8). (1)H NMR studies showed the Zn(II) and Pb(II) ions in these linear complexes were labile undergoing metal ion exchange. All of the complexes exhibited pym-hyz linkages in their cisoid conformation and binding between the hydroxymethyl arms and the metal ions. No complexes were isolated from reacting either of the Zn(II) salts with 1 on a 1:1 metal/ligand ratio, due to the smaller size of the Zn(II) coordination sphere as compared to the much larger Pb(II) ions.

Open reduction internal fixation (ORIF) metal plates provide exceptional support for unstable bone fractures; however, they often result in debilitating soft-tissue adhesions and their rigid shape cannot be easily customized by surgeons. In this work, a surgically feasible ORIF methodology, called AdhFix, is developed by combining screws with polymer/hydroxyapatite composites, which are applied and shaped in situ before being rapidly cured on demand via high-energy visible-light-induced thiol-ene coupling chemistry. The method is developed on porcine metacarpals with transverse and multifragmented fractures, resulting in strong and stable fixations with a bending rigidity of 0.28 (0.03) N m 2 and a maximum load before break of 220 (15) N. Evaluations on human cadaver hands with proximal phalanx fractures show that AdhFix withstands the forces from finger flexing exercises, while short-and long-term in vivo rat femur fracture models show that AdhFix successfully supports bone healing without degradation, adverse effects, or soft-tissue adhesions. This procedure represents a radical new approach to fracture fixation, which grants surgeons unparalleled customizability and does not result in soft-tissue adhesions.

Metal complexation studies were performed with AgSO(3)CF(3) and AgBF(4) and the ditopic pyrimidine-hydrazone ligand 6-(hydroxymethyl)pyridine-2-carboxaldehyde (2-methylpyrimidine-4,6-diyl)bis(1-methylhydrazone) (1) in both CH(3)CN and CH(3)NO(2) in a variety of metal-to-ligand ratios. The resulting complexes were studied in solution by NMR spectroscopy and in the solid state by X-ray crystallography. Reacting either AgSO(3)CF(3) or AgBF(4) with 1 in either CH(3)CN or CH(3)NO(2) in a 1:1 metal-to-ligand ratio produced a double helicate in solution. This double helicate could be converted into a linear complex by increasing the metal-to-ligand ratio; however, the degree of conversion depended on the solvent and counteranion used. Attempts to crystallize the linear AgSO(3)CF(3) complex resulted in crystals with the dimeric structure [Ag(2)1(CH(3)CN)(2)](2)(SO(3)CF(3))(4) (2), while attempts to crystallize the AgSO(3)CF(3) double helicate from CH(3)CN resulted in crystals of another dimeric complex, [Ag(2)1(SO(3)CF(3))(CH(3)CN)(2)](2)(SO(3)CF(3))(2)·H(2)O (3). The AgSO(3)CF(3) double helicate was successfully crystallized from a mixture of CH(3)CN and CH(3)NO(2) and had the structure [Ag(2)1(2)](SO(3)CF(3))(2)·3CH(3)NO(2) (4). The linear AgBF(4) complex could not be isolated from the double helicate in solution; however, crystals grown from a solution containing both the AgBF(4) double helicate and linear complexes in CH(3)CN had the structure [Ag(2)1(CH(3)CN)(2)](BF(4))(2) (5). The AgBF(4) double helicate could only be crystallized from CH(3)NO(2) and had the structure [Ag(2)1(2)](BF(4))(2)·2CH(3)NO(2) (6).

A new ditopic pyrimidine-hydrazone ligand, 6-hydroxymethylacryloyl-2-pyridinecarboxaldehyde, 2,2'-[2,2'-(2-methyl-4,6-pyrimidinediyl)bis(1-methylhydrazone)] (L2), was synthesized with terminal acryloyl functional groups to allow incorporation into copolymer gel actuators. NMR spectroscopy was used to show that L2 adopted a horseshoe shape with transoid-transoid pym-hyz-py linkages. Metal complexation studies were performed with L2 and salts of Pb(II), Zn(II), Cu(II), and Ag(I) ions in CH3CN in a variety of metal to ligand ratios. Reacting L2 with an excess amount of any of the metal ions resulted in linear complexes where the pym-hyz-py linkages were rotated to a cisoid-cisoid conformation. NMR spectroscopy showed that the acryloyl arms of L2 did not interact with the bound metal ions in solution. Seven of the linear complexes (1-7) were crystallized and analyzed by X-ray diffraction. Most of these complexes (4-7) also showed no coordination between the acryloyl arms and the metal ions; however, complexes 1-3 showed some interactions. Both of the acryloyl arms were coordinated to Pb(II) ions in [Pb2L2(SO3CF3)4] (1), one through the carbonyl oxygen donor and the other through the alkoxy oxygen donor. One of the acryloyl arms of [Cu2L2(CH3CN)3](SO3CF3)4 (2) was coordinated to one of the Cu(II) ions through the carbonyl oxygen donor. There appeared to be a weak association between the alkoxy donors of the acryloyl arms and the Pb(II) ions of [Pb2L2(ClO4)4]·CH3CN (3). Reaction of excess AgSO3CF3 with L2 was repeated in CD3NO2, resulting in crystals of {[Ag7(L2)2(SO3CF3)6(H2O)2] SO3CF3}∞ (8), the polymeric structure of which resulted from coordination between the carbonyl donors of the acryloyl arms and the Ag(I) ions. In all cases the coordination and steric effects of the acryloyl arms did not inhibit isomerization of the pym-hyz bonds of L2 or the core shape of the linear complexes.