Error: expected template-name before '<' token, C++?

Question

going to go ahead and say this is homework. I'm trying to compile a program that uses virtual functions, and templates. However I'm getting the error:

Error: Expected template-name before '<' token struct compareItem : binary_function{

error: expected '{' before '<' token error: expected unqualified-id before '<' token

This is the main.C

#include "Item.h"
int main(){
    priority_queue<Item*, vector<Item*>, compareItem> pq;
    W* w = new W(0, &pq);
    T* t = new T(10, &pq);
    pq.push(w);
    pq.push(t);
    while(!pq.empty()){
       Item* i = pq.top();
       pq.pop();
       i->Run();
    }
    return 0;
}

this is the Item.h

#ifndef ITEM_H
#define ITEM_H
#include <functional>
#include <queue>
#include <vector>
#include <iostream>

class Item{
   int key;
public:
   Item(int k) : key (k){}
   friend class compareItem;
   int getKey() {return key;}
   void setkey(int x) {key = x;}
   virtual void Run(){}
   virtual ~Item(){}
};

struct compareItem : binary_function<Item*, Item*, bool>{
    bool operator()(const Item* t1, const Item* t2) const{
        return (t1->key > t2->key);
    }
};

class W : public Item{
    priority_queue<Item*, vector<Item*>, compareItem>* q;
    public:
    W(int k, priority_queue<Item*, vector<Item*>, compareItem >* q1) : Item (k), q(q1){}
    void Run() {cout << "W at " << getKey() << endl;
                setKey(getKey()+10);
                q->push(this);
    ~W(){}
};

class T : public Item{
    priority_queue<Item*, vector<Item*>, compareItem >* 1;
    public:
    T(int k, priority_queue<Item*, vector<Item*>, compareItem >* q1) : Item (k), q(q1){}
    void Run() {cout << "T at " << getKey() << endl;
                setKey(getKey()+25);
                q->push(this);
    ~T(){}
};

#endif