Mixed Dinitrogen−Organocyanamide Complexes of Molybdenum(0) and Their Protic Conversion into Hydrazide and Amidoazavinylidene Derivatives

Abstract

Organocyanamides, Ntbd1;CNR(2) (R = Me or Et), react with trans-[Mo(N(2))(2)(dppe)(2)] (1, dppe = Ph(2)PCH(2)CH(2)PPh(2)), in THF, to give the first mixed molybdenum dinitrogen-cyanamide complexes trans-[Mo(N(2))(NCNR(2))(dppe)(2)] (R = Me 2a or Et 2b) which are selectively protonated at N(2) by HBF(4) to yield the hydrazide(2-) complexes trans-[Mo(NNH(2))(NCNR(2))(dppe)(2)][BF(4)](2) (R = Me, 3a, or Et, 3b). On treatment with Ag[BF(4)], oxidation and metal fluorination occur, and the ligating cyanamide undergoes an unprecedented beta-protonation at the unsaturated C atom to form trans-[MoF(NCHNR(2))(dppe)(2)][BF(4)](2) (R = Me, 4a, or Et, 4b) compounds which present the novel amidoazavinylidene (or amidomethyleneamide) ligands. Complexes 4 are also formed from the corresponding compounds 3, with liberation of ammonia and hydrazine. The crystal structure of 2b was determined by single-crystal X-ray diffraction analysis which indicates that the N atom of the amide group has a trigonal planar geometry.

Hydrolytic Metal-Mediated Coupling of Dialkylcyanamides at a Pt(IV) Center Giving a New Family of Diimino Ligands

“…Being interested in the amplification of these works to other (more complicated) nitrile systems, we focused our attention on so-called push−pull nitriles , such as cyanamides (i.e., cyanamide, H 2 NC⋮N, and dialkylcyanamides, R 2 NC⋮N), and we observed some unusual reactivity patterns 26,40 unknown for RCN species. Moreover, literature data also give nice examples of exciting chemistry for cyanamides at various metal centers.…”

Dinitrogen Coordination Chemistry: On the Biomimetic Borderlands

“…As in iron N 2 chemistry, early work was based on octahedral complexes of the general formulation [(P) 4 M(N 2 )(L)] or [(P−P) 2 M(N 2 )(L)], where P is a phosphine donor, P−P is a bisphosphine, and L (in cis or trans geometry 101 ) is one of many other ligands including dinitrogen. The preparations and properties of these complexes have been widely reviewed, and new variants are still being developed. , …”

Direct synthesis of (imine)platinum(ii) complexes by iminoacylation of ketoximes with activated organonitrile ligands

“…The metal oxidation state exhibits a key role and, in contrast to the above reactions with oximes or other types of nucleophiles, 11-13 at electron-rich Re I or Mo 0 centres 14, 15 the nitrile group is activated towards electrophilic attack. In the case of an oxime, the coupling reaction with NCR proceeds at Pt IV , 7,16 but not at Pt II , and in order to obtain Pt II products one has to reduce the previously synthesized corresponding Pt IV complexes.…”