Disclosed herein are the compounds shown below and methods of their synthesis. The value m is a positive integer. R comprises an alkyl chain or an alkoxy chain. Each X comprises a metal binding group. Each E is a methoxy group or comprises a biomolecule reactive group or a residue thereof. E optionally comprises a protecting group. The value n is a positive integer. The value p is zero or one. Y is OCH3, OH, NH2, or COOH.