Synthesis and structural studies of early transition metalloporphyrin complexes .1. X-ray structures of meso-5,10,15,20 tetratolyl hafnium(IV) mu-dioxo dimer complex and meso-5,10,15,20 tetratolyl porphyrin vanadium(IV) oxo complex

(TTP) hafnium dichloride, 1, where TTP = meso-5,10,15,20 tetratolyl porphyrin dianion, has been synthesized and spectroscopically characterized as a precursor to 2. Hydrolysis of 1 gives (TTP) hafnium p-dioxo dimer, 2. (TTP) vanadium oxo complex, 3, can be obtained by hydrolysis of the corresponding chloro complex. Compound 2 has been characterized by spectroscopic and single crystal X-ray diffraction analyses. [(TTP)HfO](2) . toluene crystalizes in the space group C2/c, a = 31.906(6) Angstrom, b = 16.864(3) Angstrom, c = 19.180(4) Angstrom, beta = 117.52(3)degrees, V = 9152(3) Angstrom(3), d(calcd) = 1.369 g/cm(3), Z = 8, 6029 unique observed reflections, final R = 0.077. The Hf atom is 1.02 Angstrom from the plane of the porphyrin ring; Hf-O bond lengths are 2.1 Angstrom. The hafnium atoms are 3.06(1) Angstrom from each other and the average Hf-O-Hf angle is 94 degrees. The porphyrin rings are 5.4 degrees from being parallel and the distance between the centers of the porphyrin rings is similar to 5.1 Angstrom. TTPVO . mesitylene, 3, crystallizes from mesitylene in the space group <P(1)over bar>, a = 8.365(2), b = 10.320(3), c = 14.380(5) Angstrom, alpha = 91.91(3), beta = 91.44(3), gamma = 108.26(2)degrees, V = 1177.2(6) Angstrom(3), d(calcd) = 1.27 g/cm(3), Z = 1, 1851 observed unique reflections, final R = 0.069. The average V - N distance = 2.016 Angstrom. The coordination geometry around the vanadium is distorted C-4v. The V = O group is disordered about the center of inversion. The vanadium atom resides 0.57 Angstrom above the plane of the nitrogens. The (ring center) -V = O angle is 165.9 degrees while the V = O vector is essentially colinear with the vector normal to the plane of nitrogens.