In the series of organometallic complexes N3P2(X)5P-SPACER-MLn X= Cl and OR, MLn= organometallic fragment , the delta31 P-NMR coordination chemical shift parameter correlates with the length of the spacer, decaying exponentially with the length of it. The bridging spacers behave like a "molecular wire" showing dependence of the charge transfer with the distance, similar to electron transfer in donor-acceptor systems. Extended Hückel molecular orbital calculations on the model series N3P2(X)2 P-SPACER-MLn X=Cl- and OH- molecules shows that the changes of the Mulliken charges on the phosphorus and metal atoms upon coordination exhibits also an exponential dependence with the length of the spacer