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. Author manuscript; available in PMC: 2011 May 3.
Published in final edited form as: Inorg Chem. 2010 May 3;49(9):4133–4148. doi: 10.1021/ic902181e

Table 2.

Geometric and vibrational properties of [Fe(P*)(NO)] complexes (P* = substituted porphyrin2− or porphine2− ligand; cf. Scheme 1) a

Molecule Geometric Parameters [Å] Vibrational Frequencies [cm−1]
Fe-N N-O ∠Fe-N-O Fe-NP Ref. ν(N-O) ν(Fe-NO) δip(Fe-N-O) c Ref. Condition
[FeII(OEP)(NO)]  (1)
Monoclinic (form I)
Triclinic (form II)
1.722
1.731
1.167
1.168
144
143
2.004
2.010		 14 1671 522 e 388 e d KBr (N-O),
solid
[FeII(OEP)(15N18O)] 1597 508 e 381 e
[FeII(TPP)(NO)] b  (2) 1.72 1.12 149 2.00 47 1697 532 371 9b KBr
[FeII(TPP)(15N18O)] 1625 515 365
[FeII(TPP)(NO)] 1678 524 15b benzene
[FeII(TPP)(NO)] 538 16a solid
[FeII(DPDME)(NO)] 1.723 1.187 143 2.005 48 1651 48 KBr
[FeII(PPDME)(NO)] 1655 49 KBr
1673 toluene
[FeII(OEP)(NO)], struct. E f
Calc: B3LYP/LanL2DZ		 1.742 1.215 143 2.020 d 1615 503 403 d -
[FeII(OEP)(NO)], struct. N f
Calc: B3LYP/LanL2DZ		 1.742 1.215 143 2.020 d 1616 499/504 408 d -
[FeII(OEP)(NO)], struct. E f
Calc: BP86/LanL2DZ*		 1.687 1.190 144 2.023 d 1713 620 406 d -
[FeII(OEP)(NO)], struct. N f
Calc: BP86/LanL2DZ*		 1.687 1.190 144 2.022 d 1712 620 416 d -
[FeII(P)(NO)]
Calc: BP86/TZVP		 1.705 1.179 146 2.019 9a 1703 595 427 9a -
[FeII(P)(NO)]
Calc: BP86/6-311G*		 1.695 1.181 144 2.012 d 1712 624 439 d -
[FeII(P)(NO)]
Calc: BP86/6-31G*		 1.686 1.192 144 2.008 d 1725 632 439 d -
[FeII(P)(NO)]
Calc: BP86/LanL2DZ*		 1.688 1.188 144 2.021 d 1726 619 428 d -
[FeII(P)(NO)]
Calc: B3LYP/TZVP		 1.718 1.161 142 2.021 d 1790 585 444 d -
[FeII(P)(NO)]
Calc: B3LYP/LanL2DZ*		 1.712 1.169 141 2.020 d 1825 538 435 d -
[FeII(P)(NO)]
Calc: B3LYP/LanL2DZ		 1.742 1.212 143 2.019 9b 1637 507 425 9b -
[FeII(TPP)(MI)(NO)] 1.750 1.182 138 2.008 50 1630 437 e 563 e 9b,c KBr (N-O),
solid
[FeII(TPP)(MI)(15N18O)] 1556 429 e 551 e
[FeII(To-F2PP)(MI)(NO)] 1.752 1.202 138 2.012 9b 1624 9b KBr
[FeII(P)(MI)(NO)]
Calc: BP86/TZVP		 1.734 1.186 140 2.022 9a 1662 609 482 9a -
[FeII(P)(MI)(NO)]
Calc: B3LYP/LanL2DZ		 1.810 1.215 142 2.030 9b 1611 505 430 9b -
a

DPDME = deuteroporphyrin IX dimethylester2−; PPDME = protoporphyrin IX dimethylester2−; MI = 1-methylimidazole; P = Porphine2− ligand used for calculations; values for Fe-NP distances are averaged; the Fe-N-O angle (∠Fe-N-O) is given in degrees.

b

Highly disordered structure.

c

The δ(Fe-N-O) in-plane (ip) bending vibration.

d

This work.

e

Determined from NRVS using 57Fe. Compared to natural abundance isotopes (n.a.i.) Fe, the modes ν(Fe-NO) and δip(Fe-N-O) appear about 1 – 2 cm−1 shifted to lower energy.

f

Conformer E corresponds to the monoclinic form I whereas conformer N corresponds to the triclinic form II from crystallography (cf. Scheme 2).