Table 3.
Selected Bond Lengths (Å), Bond Angles (deg), and Vibrational Stretching Frequencies (cm−1) Calculated for Six-Coordinate (ImH)FeIII(NO), (ImH)FeIII(NO)···(ImH) and (ImH)FeIII(NO)···(H2O) Adducts.a
| Complex | Fe–NO | N–O | ∠FeNO | Fe–NImp | NNO···NImd | ONO···NImd | ν(Fe–NO) | ν(N–O) |
|---|---|---|---|---|---|---|---|---|
| (ImH)–FeIII–NO, Cs symmetry | ||||||||
| FeP(NH2)8 | 1.630 | 1.138 | 178.4 | 2.027 | – | – | 666 | 2057 |
| FeP(CH3)8 | 1.632 | 1.137 | 179.7 | 2.025 | – | – | 666 | 2063 |
| FeP | 1.636 | 1.136 | 179.8 | 2.020 | – | – | 660 | 2070 |
| FePF8 | 1.642 | 1.134 | 179.8 | 2.019 | – | – | 649 | 2077 |
| FePCl8 | 1.643 | 1.133 | 179.8 | 2.014 | – | – | 647 | 2079 |
| FeP(NO2)8 | 1.656 | 1.130 | 179.9 | 2.005 | – | – | 629 | 2092 |
| (ImH)–FeIII–NO←:N(ImH), Cs symmetry | ||||||||
| FeP(NH2)8 | 1.642 | 1.132 | 175.4 | 2.026 | 3.454 | 2.855 | 650 | 2084 |
| FeP(CH3)8 | 1.645 | 1.131 | 175.3 | 2.023 | 3.426 | 2.832 | 647 | 2088 |
| FeP | 1.650 | 1.130 | 175.8 | 2.020 | 3.401 | 2.777 | 639 | 2096 |
| FePF8 | 1.657 | 1.128 | 177.3 | 2.019 | 3.353 | 2.706 | 626 | 2103 |
| FePCl8 | 1.660 | 1.127 | 177.2 | 2.014 | 3.346 | 2.685 | 623 | 2104 |
| FeP(NO2)8 | 1.683 | 1.126 | 178.5 | 2.005 | 3.264 | 2.535 | 575 | 2101 |
| (ImH)–FeIII–NO←:N(ImH), C1 symmetry | ||||||||
| FeP(NH2)8 | 1.638 | 1.133 | 176.1 | 2.028 | 3.351 | 2.966 | 656 | 2080 |
| FeP(CH3)8 | 1.642 | 1.132 | 174.5 | 2.025 | 3.238 | 2.929 | 650 | 2085 |
| FeP | 1.648 | 1.131 | 172.2 | 2.021 | 3.118 | 2.920 | 641 | 2089 |
| FePF4 | 1.654 | 1.130 | 169.4 | 2.019 | 3.010 | 2.921 | 627 | 2088 |
| FePF8 | 1.662 | 1.130 | 166.8 | 2.016 | 2.922 | 2.917 | 609 | 2083 |
| FePCl8 | 1.672 | 1.130 | 163.4 | 2.010 | 2.794 | 2.897 | 587 | 2072 |
| FeP(NO2)8 | 1.713 | 1.131 | 156.0 | 2.003 | 2.529 | 2.797 | 519 | 2041 |
| (ImH)–FeIII–NO←(:OH2), C1 symmetry | ||||||||
| FeP | 1.647 | 1.131 | 173.4 | 2.020 | 2.949 | 2.807 | 644 | 2092 |
| (ImH)–FeIII–NO←(:OH2)2, C1 symmetry | ||||||||
| FeP | 1.655 | 1.126 | 174.6 | 2.022 | 2.97/3.12 | 2.74/2.78 | 635 | 2117 |
| (ImH)–FeIIIPH–NO, constrained ∠FeIIINO, Cs symmetry | ||||||||
| FeP | 1.755 | 1.146 | 140° | 1.981 | – | – | 440 | 1938 |
| FeP | 1.701 | 1.141 | 150° | 1.989 | – | – | 505 | 1993 |
| FeP | 1.664 | 1.138 | 160° | 2.002 | – | – | 594 | 2036 |
| FeP | 1.643 | 1.136 | 170° | 2.014 | – | – | 645 | 2062 |
| FeP | 1.641 | 1.136 | 172° | 2.017 | – | – | 649 | 2065 |
| FeP | 1.639 | 1.136 | 174° | 2.018 | – | – | 657 | 2067 |
a
NImp and NImd are the nitrogen atoms of proximal and distal imidazoles, respectively (see Figure 9).