Bond lengths dinitrogen complexes

Because the N2 molecule in the complex is still expected to have partial multiple bond character, the d-type functions could be needed. Therefore, d-type function have been added to nitrogen atoms (using a Gaussian exponent of 0.8) of the dinitrogen molecule. Our preliminary test of the effect of phosphorus atom d-type functions on the calculated Zr-PH3 bond lengths of model complexes A1 and A7 showed that the influence of d-type functions on the P atom is insignificant. Therefore, here we will not include d-type of functions for P-atoms. 

The coordination of the dinitrogen ligand is maintained when traTO-[Re(N2)Cl(dppe)2] is exposed to NaX salts (X = NCS, NCO , Ns ) in THF/MeOH solutions. The isothiocyanato and azido complexes of type (276) have been studied by X-ray structural analysis.A Re— N2 bond length of 1.951 A is observed for the NCS compound which is somewhat shorter than that in the starting material and indicates a considerable degree of double bond character. 

The very labile dinitrogen complex [Mo(CO)(N2)(Ph2PCH2-CH2PPh2)2] has been described in detail. Its immediate precursor, [Mo(CO)(Ph2PCH2CH2PPh2)2], is obtained by the reaction of [Mo(N2)2-(Ph2PCH2CH2PPh2)2] with, for example, benzyl propionate under carefully controlled conditions (283, 322). This precursor is square pyramidal in the solid state, with carbon monoxide at the apex and an essentially vacant coordination position trans to it. The CO bond length is 1.192(12) A, and v(CO) = 1690 cm 1, and the nearest ap-... 

There has been a report of bridged dinitrogen complexes of iron(III) and chromium(lll) complexes, formed by reaction of the metallo(IlI)porphyrinate triftate with [Re(N2)(PMe2Ph)4Cl] to make the Fe-N-N-Re or Cr-N-N-Re bridged complexes. The Fe complex has a magnetic moment of about 4.4 /u-b at room temperature, consistent with a S = 312,512 admixed spin state for the iron(lll), and a pyrrole-H shift of -3.23 ppm, consistent with the expected weak-fteld nature of the N2 ligand. The stracture shows a linear Fe-N-N-Re unit (Fe-Nl-N2 = 170°, Nl-N2-Re = 177°) with Fe-N bond length of 1.93 similar to that of the TPPFe -azide complex (1.953 A). 

A representative example of how initially unrecognized disorder between pairs of structurally dissimilar groups resulted in incorrect bond length determinations is provided by the observation that the dinitrogen complex rra 5 -Cr(dmpe)2(N2)2 was reported to have an unusually short N-N bond length of 0.985(4) however,... 

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