TRANSITION-METAL CHEMISTRY OF MAIN-GROUP HYDRAZIDES .10. PHOSPHORUS HYDRAZIDES AS BUILDING-BLOCKS FOR POTENTIAL PHOTOAFFINITY LABELS - SYNTHESIS AND COORDINATION CHEMISTRY OF PERFLUOROARYL AZIDE CONJUGATES OF PHENYLPHOSPHONOTHIOIC DIHYDRAZIDE

The phosphorus hydrazide PhP(S)(NMeNH2)2 1 reacted with the azido func tionalized aldehyde 4-N3C6F4CHO to give a mixture of Schiff-base adduc ts with one or two perfluoroaryl azido substituents on 1. However, the reaction with R'CHO (R = 4-O2NC6H4, 3-O2NC6H4 or 2,4-Me2C6H3) resulte d in a considerable selectivity of incorporating one aromatic substitu ent in the terminal hydrazide unit of 1 via Schiff-base coupling to pr oduce PhP(S) (NMeNH2) (NMeN=CHR') (R' = 4-O2NC6H4 3, 3-O2NC6H4 4 or 2, 4-Me2C6H3 5). These mono-Schiff-base adducts 3-5 undergo further Schif f-base coupling with azidotetrafluorobenzaldehyde to produce the azido -functionalized phosphorus hydrazides PhP(S)-(NMeN=CHC6F4N3) (NMeN=CHR ') (R' = 4-O2NC6H4 7, 3-O2NC6H4 8 or 2,4-Me2C6H3 9). The ligating prop erties of the representative phosphorus hydrazides 2 and 9 with pallad ium(II) were investigated. The crystal structure of the complex [PdCl2 {PhP(S)(NMeNH2) (NMeN=CHC6F4N3-4)}] reveals that the palladium(II) is bound in a chelating cis arrangement to the phosphorus chalcogenide an d the hydrazine nitrogen via a five-membered metallacyclic framework: monoclinic, space group P2(1)/n, a = 7.826(10), b = 18.051(20), c = 18 .330(3) angstrom, beta = 98.196(7)-degrees, Z = 4, R = 0.038 and R' = 0.053.